The Application Process Mission Trails Regional Park: Fill & Download for Free

Nothing. The needs of the Navy come first. There is no legal or regulatory limit as to gow many hours they can work him or how intensely. He's in the military. It's not a normal job.The below is intended to allow my answer to be posted, in spite of the bot. Please ignore.Aliso Creek (Spanish for "Alder Creek"; also called Alisos Creek) is a 19-mile (31 km)-long urban stream that runs through Orange County in the U.S. state of California from the Santa Ana Mountains to the Pacific Ocean, collecting seven main tributaries. The creek is mostly channelized, and as of 2004, the 30.4-square-mile (78.7 km2) watershed had a population of 149,087 divided among seven incorporated cities.The creek flows generally south-southwest through a narrow coastal watershed at the southern extreme end of the arid Los Angeles Basin in a fairly straight course. Owing to the submersion of Southern California in the Pacific Ocean as recently as 10 million years ago, the creek flows over marine sedimentary rock that dates from the late Eocene to the Pliocene. The present-day form of the watershed, with its broad sediment-filled valleys and deeply eroded side canyons, was shaped by a climate change during the previous Ice Age that produced Aliso Canyon, the creek's final gorge.The name was given to the creek by Spanish explorers in the 18th century, although there are now many places in California that use the name. Historically, the creek served as the boundary between the Juaneño (Acjachemem) and Gabrieleño (Tongva) Indians. The creek's watershed then became a major portion of the 1842 Rancho Niguel Mexican Land Grant to Juan Avila, later purchased by two American ranchers. Although attempts to use the creek and its watershed as a municipal water source date to the early 20th century, the water it provided was of poor quality and erratic occurrence. As a result, the creek became neglected throughout the late part of the century, eventually becoming little more than an open wastewater drain. Despite this general decline, the Aliso Creek watershed still supports some biodiversity, and it remains a popular recreational area.Pollution, floods and development of the watershed and the surrounding county have blighted the water quality and wildlife of the creek since the 1960s, when residential suburban development of the eight cities in the watershed began. Pollution continues to be a major problem for the creek—the subject of many water quality and feasibility studies—but, as with many other Orange County streams, little has been done to correct it.EtymologyThe Native American name for Aliso Creek has almost certainly been lost. The current name of Aliso Creek was given by Spanish conquistadors sometime between the 1750s and the 1800s. The word aliso means "alder tree" in Spanish, and likely refers to the riparian vegetation that lines the creek especially near its mouth. The California sycamore, Platanus racemosa, is also known as aliso in Spanish, and is common in the area around the creek. According to the Geographic Names Information System of the United States Geological Survey, there are now 46 places in California that use the name, as well as five other streams in California that use the name, including as a variant name.Other derivatives for Aliso Creek's name have arisen since then—including "Los Alisos Creek" and "Alisos Creek". Several nearby geographical features also are named for the creek, including Aliso Peak, a 683-foot (208 m) headland. A middle school in the Saddleback Valley Unified School District, Los Alisos Intermediate School, borders the creek. The creek is also the namesake of Aliso Creek Road, which crosses the creek once and only parallels it for a short length. The city of Aliso Viejo and several other communities that lie near the stream also share their name with the creek.CourseAliso Creek rises in the foothills of the Santa Ana Mountains, near the community of Portola Hills, part of Lake Forest, and at the boundary of the Cleveland National Forest. The Loma Ridge rises about 1,500 feet (460 m) above the creek's headwaters, which are at an elevation of 2,300 feet (700 m). There is no pond, lake or spring at the creek's ultimate source; it starts out as a small seasonal gully that courses southwards through a small valley with relatively little development. The creek then continues generally southwest for 19 miles (31 km) to the Pacific Ocean at Laguna Beach, collecting water from seven major tributaries and over forty minor drains and streams. For much of its course, the creek is channelized and confined by urban development. It only flows freely in several stretches in its far upper and lower course. Passing south of several residential areas on the foothills to the north, Aliso Creek and El Toro Road run parallel for much of the creek's length upstream from Interstate 5. Flowing southwest in a small ravine along the right side of the road, the creek soon passes underneath the twin bridges of California State Route 241, and receives from the right an unnamed northern fork. At this confluence, the creek turns more to the south, then crosses under El Toro Road and bisects another residential area. As it enters the city of Lake Forest, it receives from the right Munger Creek and from the left English Canyon Creek, a larger tributary which drains part of the city of Mission Viejo, 16 miles (26 km) from the mouth.A slow-moving and shallow headwaters of a streamThe upstream portions of Aliso Creek (here shown while flowing) are relatively pristine in comparison with the downstream segments.The creek crosses under Trabuco Road and Jeronimo Road; the latter was once the site of a stream gauge. It makes a bend to the southeast then veers back south, entering a large gulch and crossing beneath Interstate 5. The creek then enters a culvert beneath Paseo de Valencia, then crosses under Laguna Hills Drive and cascades under Moulton Parkway, through the community of Laguna Hills. It then swings to the southeast and receives the Aliso Hills Channel, which enters from the left, 13 miles (21 km) from the mouth. The Aliso Hills Channel drains much of eastern Laguna Hills, western Mission Viejo, and southeastern Lake Forest.[2][11][12][13] From the confluence, the gradient of the creek flattens sharply and the stream enters a broad and shallow valley that runs between Aliso Creek Road on the west and Alicia Parkway on the east. It passes under California State Route 73, which crosses the valley on an earthfill and a bridge segment. The creek receives from the right the Dairy Fork, 9 miles (14 km) from the mouth, which drains parts of southern Laguna Hills and northeastern Aliso Viejo. The southwest-flowing Dairy Fork once flowed in a prominent canyon that was filled in the 1960s and 1970s to build the city of Aliso Viejo; State Route 73 now runs above the former canyon.[2][11][12][13]After receiving the fork, Aliso Creek passes into three massive culverts that cross under Pacific Park Drive, which crosses also on an earthfill. Flowing past several sports complexes, it begins to form the boundary of Aliso Viejo and Laguna Niguel, then crosses under Aliso Creek Road into Aliso and Wood Canyons Regional Park. Here, it receives from the left its largest tributary, Sulphur Creek. This creek is about 4.5 miles (7.2 km) long and drains a fair portion of northern Laguna Niguel, 7 miles (11 km) from the mouth. From there, Aliso Creek bends west and enters Aliso Canyon, which cuts through the San Joaquin Hills on the creek's final run to the sea.[2][11][12][13] About 1 mile (1.6 km) downstream of the Sulphur Creek confluence, the creek is briefly impounded behind a small dam, and receives the south-flowing Wood Canyon Creek, the second largest tributary, 5 miles (8.0 km) from the mouth. Wood Canyon Creek drains the largest arm of Aliso Canyon and most of eastern Aliso Viejo. Flowing almost due south through a valley with slopes dissected by many deep side canyons, Aliso Creek turns sharply west as it enters private property less than 1 mile (1.6 km) from the mouth. This section of the canyon is known for flooding frequently. The creek then enters a reserved size lagoon, crosses under the Pacific Coast Highway and enters the Pacific Ocean.[2][11][12][13]Tidal lagoonA dry wash curves from the upper right through a sandy basin down onto a beach on the left and its subsequent confluence with a larger body of waterAerial photograph of the emptied lagoonAt Aliso Beach, the mouth of Aliso Creek, lies a freshwater pond that changes frequently in elevation and extent. Tidal activity at the creek's mouth results in sediment building gradually up into a sandbar, impounding it in a small lake about 0.2 miles (0.3 km) long at its fullest extent. Afterwards, the water level rises upstream of the sandbar until one of two factors causes it to breach: either waves at high tide wash away the top of the sandbar, or the lagoon rises enough to overtop the sandbar by itself. Once the water level rises above the sandbar, rapid erosion quickly cuts through the sand and drains the approximately 3–5 foot (0.9–1.5 m)-deep lake in a matter of minutes. Peak flows through the sandbar can reach 500 cubic feet per second (14 m3/s), even if the incoming flow of the creek is nowhere near that size.[14][15] Because of the raised flow of the creek and the construction of a parking lot in the lagoon area since the 1960s, the lagoon has never been able to fill to its much larger, historic extent without breaching. Species such as the tidewater goby have suffered because of loss of their habitat this way.[16]DischargeAliso Creek is known to have historically contained water for most of the year, averaging 6.7 cubic feet per second (0.19 m3/s) in the wet season;[2] urban runoff has raised the creek's year-round base flow to close to 9.2 cubic feet per second (0.26 m3/s) at the mouth, with routine surges of more than 700 cubic feet per second (20 m3/s) in the winter. The United States Geological Survey had two stream gauges on the creek—one at the mouth in Laguna Beach, and one at the El Toro Road bridge near Mission Viejo. The Laguna Beach gauge was in operation from 1983 to 1986, and the El Toro gauge was operational from 1931 to 1980. The former received runoff from about 95 percent of the watershed, while the latter received runoff from 7.91 square miles (20.49 km2), or 26 percent of the watershed area.[17][18]A creek flows out of a gap through a coastal mountain range and flows onto the beach.Aliso Creek empties into a sandy lagoon at its mouth in Laguna Beach. Due to tides and erosion, its mouth is ever-changing.The largest flow recorded at the Laguna Beach streamflow gauge was 5,400 cubic feet per second (150 m3/s) with a water depth of 11.3 feet (3.4 m) on March 1, 1983.[17] The 1983 flood was caused by an El Niño event causing heavy runoff from the overdeveloped watershed. Damage was worst at the mouth of Aliso Canyon, which contains the Aliso Creek Inn and several other structures.[19] On February 16, 1986, 2,880 cubic feet per second (82 m3/s) was recorded, and 2,870 cubic feet per second (81 m3/s) was recorded on October 1, 1983.[17]The largest flow recorded at El Toro was 2,500 cubic feet per second (71 m3/s) on February 24, 1969, with a water depth of 11 feet (3.4 m). On January 5, 1979, the second largest flow, 2,450 cubic feet per second (69 m3/s), was recorded, and 1,950 cubic feet per second (55 m3/s) on February 6, 1937.[18] There was another nearby gauge—now out of service—at the Jeronimo Road crossing just downstream of El Toro. Before it was taken out of service in the 1980s, it frequently recorded periods of extremely low or nonexistent flow for most of the year.[20]The dramatic change in Aliso Creek flows from the 1960s onwards can be seen in streamflow data from the El Toro gauge. From 1931 to 1960, the average peak flow was 511 cubic feet per second (14.5 m3/s)—though peaks recorded ranged from zero to 1,950 cubic feet per second (55 m3/s). Between 1960 and 1980, the average peak flow was 1,178 cubic feet per second (33.4 m3/s), nearly twice the average before 1960.[18] Urban runoff now constitutes nearly 80 percent of the creek's dry season flow—7.2 cubic feet per second (0.20 m3/s)—and natural runoff, including springs in the Santa Ana Mountains, now supply a negligible amount of the creek's water.[14][15]GeologyMost of Southern California, including all of Orange County, was periodically part of the Pacific Ocean; the most recent epoch was approximately 10 million years ago (MYA). The Santa Ana Mountains, which now border the creek to the north and east, began their uplift about 5.5 million years ago along the Elsinore Fault.[21] Aliso Creek formed about this time, running from the mountains across the broad coastal plain to the Pacific.Mountains are to the upper right (northeast) and lower left (southwest), and the flat land in between is highly urbanized.Relief map of Aliso Creek watershed and surrounding citiesAbout 1.22 million years ago, the San Joaquin Hills along the Orange County coast began their uplift along a blind thrust fault (the San Joaquin Hills blind thrust) extending south from the Los Angeles Basin.[22] As Aliso Creek was an antecedent stream, or one that had formed prior to the mountains' uplift, it cut a water gap through the rising mountains that today is Aliso Canyon. The same phenomenon occurred to the north with Laguna Canyon and San Diego Creek, and to the south at San Juan Creek. The uplift also caused Aliso Creek's largest tributary, Sulphur Creek, to turn north to join Aliso Creek instead of flowing south to Salt Creek.[5] The Wisconsinian era was responsible for shaping the watershed to its present-day form, with deep side canyons and broad alluvial valleys.[5]During the last glacial period (110,000 to 10,000 years ago), especially in the Wisconsinian glaciation (31,000 to 10,000 years ago), the climate of Southern California changed radically from arid to wet, to a climate likely similar to the present-day Pacific Northwest. Prodigious rainfall gradually turned the small streams of the region into large and powerful rivers.[23][24] It was this surge in volume that allowed Aliso Creek and other rivers to cut through the San Joaquin Hills. A 400-foot (120 m) drop in sea level escalated the process, allowing the rivers to flow more rapidly and have more erosive power. As sea levels rose after the Wisconsinian glaciation, the water gaps the rivers had cut through the San Joaquin Hills, including Aliso Canyon, became fjord-like inlets. Aliso Creek and these other streams deposited sediments into the inlets, turning them into flat-floored alluvial valleys with an elevation very close to sea level. Eventually, the sediment deposited met the coastline. By then, the rivers and streams had diminished to their original flow before the glaciation.[23]In the wake of the periodic inundation of Southern California by the ocean, most of the Aliso Creek watershed is underlain by several layers of marine sedimentary strata, the oldest dating from the Eocene (55.8–33.9 MYA) and the most recent, the Pliocene (5.33–2.59 MYA).[25] These alluvial sediments range from 13 to 36 feet (4.0 to 11.0 m) in depth. Generally throughout the watershed, there are five major soil and rock outcrop types—Capistrano sandy loam, Cieneba sandy loam, Marina loamy sand, Myford sandy loam, and Cieneba-rock outcrop. The water table ranges from 6 to 20 feet (1.8 to 6.1 m) deep.[25]WatershedGeographyMore informationThe Aliso Creek drainage basin lies in the south central part of Orange County, roughly halfway between the Santa Ana River and the Orange–San Diego County boundary.[27] It is a roughly spoon shaped area of 30.4 square miles (79 km2),[28] comprising generally hilly and sometimes mountainous land. The watershed borders five major Orange County watersheds: Santiago Creek to the north, San Diego Creek to the west, Laguna Canyon to the southwest, Salt Creek to the southeast, and San Juan Creek to the east.[12] To be more specific, the boundary with San Diego Creek is drained to the west by two tributaries of San Diego Creek—Serrano Creek and the La Cañada Wash. Two tributaries of San Juan Creek—Oso Creek and Trabuco Creek—border Aliso Creek to the northeast and southeast.[12][29]As of 2004, the Aliso Creek watershed had a population of 149,087.[4] Nine communities were established in the creek's watershed as it was developed in the 20th century. By 2001 seven of them had become cities (from mouth to source, Laguna Beach, Laguna Niguel, Aliso Viejo, Laguna Hills, Laguna Woods, Lake Forest, and Mission Viejo), and the last two, Foothill Ranch and Portola Hills, were incorporated into the city of Lake Forest in 2000.[26] The largest urban area in the basin is in the middle, where Interstate 5 bisects the watershed east to west. The northern boundary of this urban area stretches a little beyond California State Route 241 and the southern boundary is near California State Route 73 in the south. This area consists primarily of Lake Forest, Laguna Woods, and Laguna Hills.[26]The Loma Ridge of the Santa Ana Mountains runs east to west in the far northeastern corner of the watershed, forming the water divide with Santiago Creek. The San Joaquin Hills are at the southwestern portion of the watershed, following the coastline, and subranges within form the divides with Laguna Canyon and Salt Creeks.[12] While the Santa Ana Mountains rise to 4,000 feet (1,200 m) or more, the San Joaquin Hills top out at 1,000 feet (300 m) at Temple Hill ("Top of the World"),[10] which lies to the north of Aliso Canyon—the water gap in the San Joaquin Hills through which Aliso Creek passes. Most of the hills rise to only 600 feet (180 m) or 700 feet (210 m). The largest body of water in the watershed, Sulphur Creek Reservoir, is located to the northeast of Aliso Canyon.[10][13]Bacterial pollutionA small stream winds past in the lower left foreground while residential subdivisions sprawl over the hills on both sides. Mountains rise in the distance beneath an empty, pale blue sky.Overview of Aliso Creek watershed from a ridge on the San Joaquin Hills, with Santa Ana Mountains in distanceAliso Creek's watershed, as well as most of Orange County, saw a rapid jump in urban development from the 1960s onward, which introduced increased flow, non-native vegetation, and high bacterial levels to the creek, severely hurting its ecology.[4] The creek is part of the Clean Water Act list of impaired waters,[30] which is defined as "impaired by one or more pollutants that do not meet one or more water quality standards". It is said that Aliso Creek is one of the "most publicized" streams on the list.[31] As of 2001, the average annual precipitation in the San Juan Hydrological Unit, which Aliso Creek is part of, was 16.42 inches (417 mm).[32]Bacteria affecting the water quality mainly consist of different types of fecal coliforms, with a high level of E. coli bacteria. This comes from pet waste, fertilizer, manure, and other organic pollutants that are washed into the creek, raising the average bacteria level 34 percent higher than levels declared safe under California law.[33] This in turn affects recreation at popular Aliso Creek Beach at the creek's mouth, violating state swimming standards 99 percent of the time, especially during storm events, as beachgoers are warned to avoid the creek for 72 hours (3 days) after a major storm event.[34][35]According to the county health department, the number of bacteria in the creek, especially at the freshwater lagoon at its mouth, frequently exceeds limits set by California law.[32]A large concrete hole opens out on a steep slope above muddy waterA large storm drain flows into Aliso Creek on the right bank, shortly downstream from Aliso Creek Road. This drain and over 40 others are responsible for the poor water quality of Aliso Creek.According to the Los Angeles Times, "County health officials acknowledge that the bacterial count at the mouth of the creek—which curls into a warm-water stagnant pond that flushes out onto the beach—is at times alarmingly high, often surpassing the legal limit for California. As a result, the area where the creek meets the sea, and the creek itself, are considered permanently off limits to swimmers and bear prominent signs that warn of the dangers of trespassing into such toxic waters. Nevertheless, people do, almost daily. Officials from the Orange County Environmental Health Department say that skin rashes, infections, "pink eye" and other assorted ailments are not uncommon to those who use Aliso Beach and, unwittingly, come in contact with the creek and its invisible bacteria...".[36] The problems facing the creeks are blamed on urbanization, which has deprived the creeks of needed sediment while increasing pollution.[32]Other pollutantsChlorine is responsible for the degradation of fish and shrimp in the creek. The sources for chlorine in urban runoff include irrigation and car washing. The only remaining fish species in the creek is carp, which can withstand high amounts of chlorine. Carp up to 18 inches (1.5 feet / 45 cm) long have been found in Aliso Creek near the mouth. Temperatures of the creek near the mouth have been known to exceed 90 °F (32 °C), although the temperature at the outflow is often much colder because it has been mixed with seawater.[36]Changes of sediment patterns in the creek have also created another problem. Stemming from the construction of structures interfering with stream flow, and increased runoff from the urban areas adjoining the creek, excessive erosion has created problems not limited to just the creek. The creek is eroding material from its bed and transporting it to the ocean, but naturally, sediment from the whole watershed flowed towards the main stem via a complex network of tributaries. The U.S. Army Corps of Engineers warned in a 1997 study that up to $4.2 million in damage occurs per year as a result of the pollution of Aliso Creek and its neighbor San Juan Creek. This includes physical damage to creek banks, bridges, pipes and other creekside structures.In the upper portion of the watershed, spectacular erosion-related events have occurred at English Canyon Creek, where water flowing at high velocity around a bend during a flood caused several landslides in the 1990s.[37]RecreationA light-blue reservoir formed by a large dam across a broad valley ringed by housesLaguna Niguel Lake (otherwise known as Sulphur Creek Reservoir), here seen near the dam, is a major recreation and flood-control feature on Sulphur Creek.The Aliso Creek watershed includes portions of the Cleveland National Forest in the upper watershed, and two major regional parks—the 3,879-acre (1,570 ha) Aliso and Wood Canyons Regional Park and its adjoining Aliso Creek Beach, one of the county's most popular beaches with over one million annual visitors;[38] and the 236-acre (96 ha) Laguna Niguel Regional Park, which borders Sulphur Creek. Because of its shallowness and erratic flow, Aliso Creek is not navigable even in the winter and spring (rainy season); the only spot in the entire watershed where boating is possible is Sulphur Creek Reservoir. A mostly paved trail, the Aliso Creek Trail, follows the creek from Aliso Canyon to the Cleveland National Forest.[39]The only major fishing spot in the Aliso Creek's watershed is the 44-acre (18 ha) Sulphur Creek Reservoir, formed by a large earthfill dam across Sulphur Creek inside Laguna Niguel Regional Park. The lake is regularly stocked with catfish, bass, bluegill, and trout during the winter months.[40] Any other location in the watershed will probably yield only the bottom-dweller carp.Most of the trails in the watershed are biking and equestrian trails located in the lower portion of the watershed, in the immensely popular Aliso Canyon and its tributary, Wood Canyon. Aside from the main Aliso Creek Trail, the Wood Canyon Trail parallels a tributary of Aliso Creek (Wood Canyon Creek). There is also a bikeway along Sulphur Creek and along parts of English Canyon.[39]WildlifeHistoricA long, silver and gray fishSteelhead trout existed in Aliso Creek and likely inhabited the creek within recorded history, as recently as 1972.Before agricultural and later urban development of the watershed, live oak, sycamore, and alder trees lined the banks of Aliso Creek and its major tributaries, specifically Wood Canyon, Sulphur and English Canyon creeks, in a rich riparian zone.[37] Coyotes, mountain lions, and other large mammals were found throughout the Aliso Creek watershed, especially in the mountainous areas in the San Joaquin Hills and Santa Ana Mountains. These animals can still be found in some number, but they are mostly confined to the wilderness areas that are surrounded by residential development. These "islands" of native vegetation and wildlife still support many native Southern California organisms. As the creek was perennial, the riparian zone surrounding the creek likely was similar to that of San Juan Creek to the south.[4]Researchers and long-time residents of the lower Aliso Creek watershed have argued for many years over the presence of steelhead trout in Aliso Creek. Up until 2006 the National Marine Fisheries Service stated that Aliso Creek is a "[coastal basin] with no evidence of historical or extant of O. mykiss in anadromous waters." Contrary to that, a 1998 major study co-authored by the US Army Corps of Engineer and US Fish & Wildlife Service declared that steelhead had inhabited the creek until around 1972 when increased density (urbanization) resulted in poor water quality conditions (pollutants and low oxygen levels) that drove the migrational fish out.On February 20, 2009, in a written rebuke, chastising an Aliso Creek water rights applicant (South Coast Water District) a formal letter sent by NOAA Regional Manager Rodney McGinnis to Antonio Barrales of the State Water Resources Control Board, Water Rights Division, revised that 2006 assessment. Carbon copied was California Fish & Game (Mary Larson) plus US Fish & Wildlife Service (Christine Medak). This was due to 9 years of constant petitioning by the South Orange County environmental protectionist group Clean Water Now (CWN) led by Founder and Executive Director Roger E. Bütow, Board member Michael Hazzard, Joanne Sutch (Laguna Beach Beautification Committee) and Devora Hertz (Planet Laguna). Frank Selby, owner of His & Hers Fly Shop in Costa Mesa, was interviewed by Oc Register and lA Times reporters, he confirmed his own steelhead takings from the 1950s and 60s, last sighting in 1972. Frank then sent a letter to CEMARS (June 2008) titled "Regarding Aliso Creek Steelhead." He was also personally interviewed by the CWN Board to confirm actual sightings and taking.NMFS then reversed itself and declared that there was sufficient, credible information to declare that Aliso Creek had been steelhead habitat and was added to the Distinct Population Segment List under the jurisdictional domain of NOAA. It is now considered a candidate for re-colonization.During the prolonged 9-year dispute that began in 2000, Bütow and his working group "Friends of the Aliso Creek Steelhead" provided authentic Native American (Juañeno) anecdotes of takings, pictures by upstream fishermen with their catches and other personal accounts by longtime local residents that helped convince the State. It was a negotiated truce between Bütow and NOAA: Only the lower 7 miles of the creek was eventually listed because its conditions were amenable to historical populations. The habitat "termination line" was drawn at about Aliso Creek where it crosses an arterial road: Pacific Parkway in Aliso Viejo. In fact, Mary Larson (steelhead restoration coordinator for CF&G), declared to reporters when the ruling was reversed that it was obviously true, its historical presence a "duh, no-brainer moment." [41] Many anglers in the 1960s and 1970s reported taking tens or even hundreds of steelhead trout from Aliso Creek's estuary and Aliso Creek Canyon (approximately 4 miles) before suburban development began.[42][43][44][45][46] This indicates that there was a "possible run or population" of steelhead in Aliso Creek at some point.[47] The creek is also inhabited by bottom-dwellers such as carp, and historically shrimp and other benthic organisms were found throughout perennial pools in the Aliso Creek watershed. Historically, a large population of tidewater goby (10,000–15,000) was documented at the creek's mouth by Swift et al.. (1989), from a study period that ranged from March 1973 to January 1977. The tidewater goby, which depended on the transient lagoon at the mouth for survival, has declined in number because of modifications to its habitat.[48]Human impactSince urbanization began in the 1960s, sudden high and sediment-lacking flows of polluted water began to destroy the native riparian vegetation once found along much of the creek. Exotic plants, including tobacco tree, castor bean, pampas grass, periwinkle, and Artichoke thistle, but most notably the giant reed, then replaced the historic live oaks, sycamores and alders as riparian vegetation.[37] These plants have crowded out native vegetation, and in the case of giant reed, crowded out native animals—giant reed does not provide habitat for any native Southern California animals.[37] These invasive species are most prevalent along upper Sulphur Creek (Sulphur Creek Reservoir prevents these plants from spreading downstream), much of the Aliso Creek mainstem, and some parts of Wood Canyon Creek.Many of the trees in Aliso Creek's riparian zone were cut down in the Spanish Mission period to construct buildings, ships, and other projects. According to the Flood Protection Corridor Program of the Costa Machado Water Act of 2000, "Aliso Creek was one of the few streams that contained water most of the year, even during the pre-development period. There are documents describing explorers mooring their ships outside the mouth of the river and harvesting large timbers from the river area. Such large timbers could only be available from a relatively lush environment in which water was somewhat plentiful."[4] Some trees survived into the early 20th century, then a second decline of unknown cause began—either erosion or floods in the creek were responsible for their destruction, or the water table has lowered out of reach of the trees' roots. The water table began a drastic decline in the 1960s, after the watershed began to become urbanized.[37]Several birds wading and swimming in muddy waterWhite heron and ducklings in Aliso CreekAlthough historically many fish species used Aliso Creek, the only remaining one is carp, which is known to survive in areas with high toxicity. Bird life was also abundant in the watershed—and 137 species remain in the less developed areas of the watershed. Some of these birds include California least tern, least Bell's vireo, southwestern willow flycatcher, California gnatcatcher, and western snowy plover.[4] Remaining habitat for native wildlife is now primarily along Wood Canyon Creek, in the upper reaches of Aliso Creek, and along some parts of English Canyon.[25]Aside from carp, several species of fish and amphibians still inhabited the creek up to the 1980s, when floods destroyed much of the remaining riparian habitat. These included the mosquito fish, bluegill, bass, and channel catfish, as well as several species of native frogs. After the floods, most of these species were reported to have disappeared completely.[4]HistoryFirst inhabitantsIt is believed that in Native American times, Aliso Creek served as part of an important tribal boundary—between the Tongva in the north and the Acjachemen (or Juaneño) tribe in the south.[49] The Tongva's territory extended north, past the Santa Ana River and San Gabriel River, into present-day Los Angeles County, while the Acjachemen's smaller territory extended from Aliso Creek south, past San Juan Creek, and to the vicinity of San Mateo Creek in present-day San Diego County.[49] The creek's perennial flow[4] made it a likely spot for Indian settlement, although the Tongva's main settlements were near the San Gabriel River and the Acjachemen mostly lived at the confluence of San Juan Creek and Trabuco Creek. Even so, some 70 major archaeological sites have been discovered along the creek,[49] and it is believed that there was once an Acjachemen Indian village near the confluence of Aliso Creek and Sulphur Creek, named Niguili, which means "a large spring" in the native Luiseño dialect. The spring still exists near the intersection of Alicia Parkway and Highlands Road in present-day Laguna Niguel, about a mile (1.6) km east of Aliso Creek's confluence with Sulphur Creek.[50]The creek's use as a tribal boundary is disputed. As other southern California Native Americans have done, a tribe typically claimed both sides of a stream or river—and used drainage divides as boundaries instead. However, the presence of Aliso Canyon, a steep and difficult-to-traverse gorge, suggests the opposite.[49] Kroeber (1907) was the first to support this theory, and many other archaeologists have followed as well. The Juaneño disagree, arguing that their boundary stretches north to the northern drainage divide of the Aliso Creek watershed, which supports the practice of claiming both sides of a stream.[51]Spanish explorers and missionariesIn 1769, the Portola expedition camped near Aliso Creek on July 24–25, having come north from the San Juan Capistrano area along the route of today's Interstate 5.[52] These first Spanish explorers were accompanied by Franciscan missionaries who took control over nearly all of the coastal Native American groups. They later established Mission San Gabriel Arcángel and Mission San Juan Capistrano near the main native population centers, seeking to convert them to Christianity. Most of the native population was moved to these two missions—the Spanish called the Tongva Gabrielinos[53] and the Acjachemen, the Juaneño,[54] after these two missions. The Spanish began farming and ranching practices on many of the fertile floodplains surrounding the only perennial streams in the area—San Juan and Trabuco Creek, Aliso Creek, and the Santa Ana, San Gabriel and Los Angeles rivers to the north. Many of the trees in the riparian zones surrounding these creeks—specifically Aliso Creek—were cut down, and it was said that the trees near the "river['s]"[4] mouth were especially tall and there were written accounts of Spanish ships mooring in the large bay at the outlet of Aliso Canyon and men going ashore to chop down and take away these trees for constructing mission buildings, ships and other structures.[4][37]The Mexican periodMexico won independence from Spain in 1822, keeping the Alta California province, and secularized the missions in the 1830s. Former mission lands were divided into private land grants. In 1842, Juan Avila received the 13,316-acre (53.89 km2) Rancho Niguel grant. The name of the rancho was partially derived from a corruption of the original name of the village, Niguili. (The rancho name later became part of the name of the city of Laguna Niguel.)StatehoodFollowing the Mexican–American War, California was annexed by the United States, becoming the 31st state in 1850. In 1871, the first white settler along Aliso Creek, Eugene Salter, claimed 152 acres (0.62 km2) along the lower creek, inside Aliso Canyon.[5] The following year the 152 acres (0.62 km2) were acquired by George and Sarah Thurston, homesteaders who converted the mouth of the creek into an orchard irrigated by its waters for roughly the next half century.[5]Urbanization and developmentA large valley between arid chaparral-covered hills, opening towards the ocean.View of the proposed Aliso Reservoir site (below, in canyon) from the San Joaquin HillsSee also: Orange County, California § HistoryIn 1895, Rancho Niguel was acquired by rancher Lewis Moulton (1854–1938) and his partner, Jean Pierre Daguerre (1856–1911). The rancho remained under their ownership for approximately thirty-eight years, and the rancho continued to be owned by the Moulton family until the 1960s. Rancho Niguel was eventually assimilated into Laguna Niguel, Aliso Viejo, Laguna Hills, and Aliso and Wood Canyons Regional Park.[4][55][56]By the 1920s, Aliso Creek was already being experimented with as a municipal water source. In 1924, the City of Laguna Beach drilled wells into gravel deposits near the mouth of the creek, in order to provide drinking water. Just four years later, the unusually high and unexplained presence of chloride in the water prompted the city to abandon Aliso Creek as a water source.[2] Taking advantage of the creek's high winter surges, ranging from 0 to 404 acre feet (0 to 498,327 m3) monthly, local resident A. J. Stead proposed in 1934 to build a dam very near the mouth of the creek, forming a reservoir with a capacity of 2,650 acre feet (3,270,000 m3) and safe annual yield of 150 acre feet (190,000 m3). Although the proposal was accepted, the results are unknown—there is no remaining trace of these works today.[2]By the late 1960s, increasing runoff in the creek from the growing cities in the watershed begun to spell ecological problems and severe erosion for the creek. Although a series of flood control channels upstream of Aliso Creek Road (near Aliso Canyon) had already begun to prevent erosion in those heavily developed areas, the creek eroded to depths of 20 feet (6.1 m) or more in any unlined areas.[57]In 1969 a flow control and erosion mitigation project for Aliso Creek was begun, requiring the construction of two concrete drop structures on the creek.[57] These two vertical barriers, 11 feet (3.4 m) high and 30 feet (9.1 m) long, were built both upstream and downstream of Aliso Creek Road. Several grouted riprap structures were also constructed between and downstream of these drops.[4]A small dam was built about 1.4 miles (2.3 km) downstream of Aliso Creek Road in the 1990s—inside Aliso Canyon—as part of a "mitigation bank project".[57] This project, known as ACWHEP (Aliso Creek Wildlife Habitat Enhancement Project) was intended to provide water to 70 acres (0.28 km2) of former riparian areas now several feet higher than the eroded channel of the creek. It was conceived and jointly funded by the county and the Mission Viejo Company.[58] The dam was also supposed to control further erosion downstream. Due to faulty design, however, the dam failed to prevent erosion, which has continued to undermine structures throughout the canyon.[37] The grouted riprap structure is about 15 feet (4.6 m) high and 100 feet (30 m) long, and aside from impounding water, captures debris and temporarily controls wet season flows. The building of these modifications, as well as dry weather runoff from seven municipal storm sewer systems, began to contribute to the infamous pollution of Aliso Creek.[57]Cities and protected areas timelineThere are eight cities in the Aliso Creek watershed, including Mission Viejo, Aliso Viejo and Laguna Niguel. Sulphur Creek, at the southeast, is the creek's largest tributary.Aliso Creek watershed map with city boundariesIn 1927 Laguna Beach became the first city to be incorporated in the Aliso Creek watershed and the second in Orange County. At this time, prior to the 1930s, aside from some farming and ranching practices, the watershed was largely unpopulated.[4] At the end of that decade, the watershed still remained less than 1 percent developed. Up to the 1960s and 1970s, barely 15 percent of the watershed was developed, but by 1990, after doubling its rate in the past two decades, the watershed was roughly 60 percent developed.[4] The cities of Mission Viejo and Laguna Niguel were incorporated in 1988 and 1989, respectively. By the end of the 20th century, more than 70 percent of the watershed was developed.[4] The newest city in the watershed, Aliso Viejo, was incorporated in 2001.The Cleveland National Forest, the oldest protected area in the Aliso Creek watershed, was created in 1908, and the next major park to be created was Laguna Niguel Regional Park in 1973.[59] Land for Aliso and Wood Canyons Regional Park was first secured in April 1979 with 3,400 acres (14 km2), and small increments were added to the park until the early 1990s forming a total of 3,879 acres (15.70 km2).[60] Also in the 1990s, Aliso and Wood Canyons became part of the Laguna Coast Wilderness, which stretches north to Crystal Cove State Park.Flooding and mitigationLike most other coastal Orange County streams, the watershed of Aliso Creek is now heavily urbanized. With 70 percent of the original land surface now underneath impermeable surfaces such as pavement and buildings, far more runoff now enters the creek—not only inducing an increased year-round flow, but much larger rainy season flows. In the 1920s and 1930s, devastating floods wreaked havoc on much of southern California; the Los Angeles Flood of 1938 was the most famous flooding episode of this period.[4]The Orange County Flood Control Act of 1927 was created in the wake of some of the earlier flooding events of this era. Dams and reservoirs, some of the largest of which include Irvine Lake and the Sulphur Creek Reservoir, were the first features to be constructed following the passage of this act.[61] Starting from the 1960s, most Orange County rivers, including Aliso Creek, were channelized. Some, like the Santa Ana River, were entirely lined with concrete, but Aliso Creek retains a natural riverbed in most parts despite being bound to a narrow channel.[4]A muddy flow of water drops over an artificial concrete waterfall, from a tree-lined riverbed to a riprap-lined channel.Many drop structures exist in the Aliso Creek riverbed to prevent erosion.Several tributaries of Aliso Creek—the Dairy Fork, Aliso Hills Channel, Munger Creek, and other smaller ones—have been replaced by storm drains.[62] Wood Canyon Creek remains much like its original condition, despite degradation due to polluted water. Sulphur Creek has been channelized and diverted into culverts in several stretches, and English Canyon Creek has received some riprap stabilization and bank protection.[37]Although there are no major flood control dams on Aliso Creek itself, there are 19 drop structures, and while doing nothing to reduce the creek's rainy season surges, the drop structures were constructed to mitigate the catastrophic erosion that came with the creek's increased flow. Although the creek has a wide floodplain throughout most of Aliso Canyon, a major bottleneck lies at the south end of the canyon where a sharp bend in the creek is constricted between crowded development and steep cliffs. In flooding events, this area generally sustains heavy damage.[4]Another major era of floods lasted from the 1980s until the early 21st century. The 1983 El Niño season brought unprecedented rainfall that produced a flow of 5,400 cubic feet per second (150 m3/s) from the creek, an all-time high. The creek overflowed its banks and flooded up to 10 feet (3.0 m) deep in places.[19] There were five large floods throughout the 1990s, including one in 1998 that reputedly destroyed six footbridges.[63] The years of 2004 and 2005 again saw heavy rainfall.[64]Along the creekCrossingsCrossings of the creek are listed from mouth to source (year built in parentheses).[13][65] The creek is crossed by roughly 30 major bridges.More informationTributariesFrom mouth to source, Aliso Creek is joined by six major tributaries. All of these tributaries as well as several others are listed. Another 46 minor streams and drains flow into the creek.More information: Name, Variant name(s) ...[12]See alsoMore informationCook's CornerList of rivers of CaliforniaList of rivers of Orange County, CaliforniaReferencesMore information: References ...External linksMore information: External links ...

Excellent question!!As usual, analyzing the causes of victory or defeat of a consequential battle is never a simple task that is not susceptible of facile explanation.Omitting all irrelevant details, the Allies’ victory in the Battle of the Atlantic was achieved by a combination of the following factors in decreasing order of importance (In my opinion)Large quantity of superior ASW (anti submarine warfare) technologies and weapons.Organizational and Tactical Innovations for ConvoysCodebreaking.ContextIn order to understand how the battle was won, it is vital to understand the nature of the battle and the respective ultimate goals of the Western Allies and Nazi Germany.Welcome to the Atlantic super-battlefield!! Behold just how expansive the North Atlantic is compared to continental Europe - covering millions of km squares of sea.Despite the name and the fact that there were combat actions in the South Atlantic, the battle was fought primarily in the North Atlantic. The northern region of the ocean witnessed the fiercest aerial and naval actions between both sides: the Western Allies dominated by the US and GB and Nazi Germany.The battle of the Atlantic revolved around the one thing that underpinned Anglo-American strategies regarding Europe: maritime trade and security across the Atlantic.Maritime trade constituted the lifeblood of the British Empire. Being an island nation relatively poor in natural resources, Britain needed steady imports of raw materials from its overseas colonies around the world to sustain its industry, economy and feed its population. Its economic prosperity depended on the export and consumption of produced goods in the colonies. The preservation of the British Empire depended on military defense and colonial governments. All of these - the imports of raw materials, exports of produced goods, transport of military personnel - were delivered by Britain’s large fleet of merchantmen.But maritime trade was vulnerable to disruption and predation by piracy or foreign hostile navies. This in turn necessitated protection by the British navy. Maritime security - the protection of British maritime trade - was vital to the survival and prestige of the British Empire, esp during WW2. The fact that Anglo-American Lend-Lease aids that were indispensable to keep the Soviet Union in the war were transported across the North Atlantic greatly elevated the importance of maritime security.This was a fact well understood by all sides in the conflict: Germans, British, Americans. This was a fact around which the battle of the Atlantic - a predominantly naval war - revolved.In this war, each side sought to achieve its respective aims.1/ Nazi GermanyIts goal was to sink as many merchant ships carrying tons of raw materials + military hardware to GB and the Soviet Union. The Germans referred to this as the Tonnage war. The primary instrument of fighting for Germany was the U-boat arm of the Kriegsmarine. German surface warships did not contribute much to the tonnage war. The Luftwaffe sometimes contributed to this war when Allied convoys were within the range of German aircraft.2/ The Western Allies - dominated by the US and GBIts goal was to protect maritime trade to ensure vast amount of supplies reach the Soviet Union and Great Britain. Now, some of you may may mistakenly think that the goal was to sink as many U-boats as possible but that’s not true. While sinking U-boats would certainly eradicate the threats to merchant ships (and the British did have dedicated submarine hunter-killer groups), the Allies did not actively roam the Atlantics to seek out and destroy German U-boats. The vast expanse of the Atlantic made such endeavor fruitless and a waste of time and effort.Instead, the goal was to protect merchantmen. Think of a sheep shepherd. The job of the shepherd is to defend the flock of sheep against wolves rather than to kill the wolves. As long as no sheep is killed by the wolves, the shepherd wins. Killing the wolves in the process of shepherding is an outcome incidental to the primary task of protecting the sheep.For the Allies, as long as they prevented all or most of the merchantmen from being sunk by the enemy, they won the battle and they could accomplish that either by frustrating U-boat attacks or by sinking the U-boats before they could attack.The instrument of war for the Allies consisted of a much larger variety of weapons operated by the US Navy, Royal Navy, the RAF and the USAAF.From the aforementioned facts follows one conclusion: the Allies won the battle by protecting huge number of merchantmen from German U-boat attack and also by sinking large number of U-boats.Let’s examine how the Allies succeeded in doing that.1/ Superior ASW TechnologiesThe Allies won this naval war by superior ASW technologies. Without being biased and deferential, both Britain and the US deserved equal credit - the British contributed technological ingenuity and the Americans contributed enormous industrial capacity.The destruction inflicted by German submarines during WW1 helped the British appreciate fully the peril submarines posed to their maritime lifeblood. Consequently, they seriously invested in the development of anti-submarine capability. During the intervening years between WW1 and WW2 and during WW2, the British developed several crucial ASW technologies that would bring about victory in the battle of the Atlantic.1/ ASDICThis was the first effective sonar system developed by Canadian and British physicists during WW1 under the auspices of the British Board of Invention and Research. The Royal Navy quickly adopted the technology and starting since 1932, it started installing ASDIC on all warships, especially ships built to escort merchantmen. Although early ASDIC versions did not perform well in bad weather and had limited range (could only detect submarines within a range of 2,000 m), it was still a significant breakthrough in ASW by alerting Allied escort ships to the presence of enemy submarines which in turn allowed them to take timely countermeasures. As the war progressed, incremental improvements great enhanced the military effectiveness of ASDIC.ASDIC could be used defensively and offensively.In defensive mode, ships used ASDIC primarily to detect submerged submarines and divert to evade them. Active ASDIC could act as a deterrence to Geman submarines because they emitted deep echoes that could be picked up by the submarines, making them aware of the risk of being detected and attacked if they approached the ASDIC-equipped escorts.In offensive mode, ASDIC was used to seek out and sink German submarines. The RN’s submarine hunter-killer groups were well-known for this tactical use of ASDIC. When a submarine was detected, the ships would be divided into killer and tracker groups. The tracker group would keep a distance from the U-boat and keep ASDIC on to track its positions. Meanwhile, the killer group would turn off ASDIC and let the tracker group guide them directly over the area where the U-boat was in. This tactic lulled the Germans into a false sense of security because without hearing the ASDIC echo from the approaching ships above, they would assume that they had not been detected.But ASDIC had one huge disadvantage: it could only detect submerged submarines. When a submarine was on the surface, ASDIC was useless. German submarine commanders quickly exploited this shortcoming for defense and offense. They could evade detection and attack by running on the surface rather than underwater. They would attack convoys at night on the surface. This tactic often yielded spectacular success for the Germans in the early year of the war when the Allies’ ASW capability, quantity of escort vessels were still inadequate.Also, ASDIC could be defeated by environmental conditions. Varying water temperature at different depths formed acoustic barrier that rendered ASDIC useless.The fact ASDIC could only work in favorable weather condition and its inability to detect targets on the surface limited its value. A different technology was needed to complement it.2/ Centi-metric RadarTo complement ASDIC, the British invented and deployed centi-metric radar.The war-winning value of this technology in this particular battle and in the broader global war cannot be overstated. The British and Americans were way ahead of the Germans (and the Japanese) in this technology. They were also far more advanced in respect of tactical application of radar.Radar was intended to do what ASDIC could not: detect submarines on the surface in all weather conditions.But there was a catch.Early radar system was bulky and could not be fitted on small escort ships - corvettes, escort destroyers. Radar systems shown above could only be installed on land.So the technical challenge to be overcome was to miniaturize radar so that it could be fitted on small escort ships but produced a lot of power to detect small objects - submarine conning towers, periscopes on the surface.The breakthrough came in the form of centi-metric radar - a technology made possible by the Cavity magnetron created by two British physicists. The British supplied their cavity magnetron to the Americans during the Tizard Mission in 1940. Recognizing British invention as superior to their own device under R&D, the Americans quickly adopted, improved and mass-produced it. This was a perfect marriage between British technological ingenuity and American industrial prowess.Centi-metric radars were small enough to be installed on long-range patrol aircraft, corvettes, escort destroyers, and other bigger warships. Crucially, their high-energy waves enabled them to detect small objects on the surface such as submarine periscopes miles away in all weather conditions. Also, the shorter wavelengths made centi-metric radars less vulnerable to jamming by the enemy and less susceptible to interference by water.By the end of the conflict, American industry had manufactured > 1,000,000 cavity magnetrons. Its ability to detect small objects made it immensely valuable and soon centi-metric radar powered by magnetrons were installed on aircraft, warships, escorts. The decisive role this invention played in the war was summarized by James Baxter in Scientists Against Time (1946)the most valuable cargo ever brought to our shores the single most important item in reverse lease-lend.When reflecting on the war, even Admiral Doenitz acknowledged the superiority of British radar and its contribution to German defeat in the battle.3/ High-frequency direction findingNicknamed Huff-Duff by Allied servicemen, it was a radio-direction finding technology designed to detect and identify the sources of radio signals emanating from U-boats on the surface. German U-boats were known for employing wolf pack tactics against Allied convoys. In order to form wolf packs, U-boats had to communicate using radio on the surface.A HF-DF set used on British warship. Its small size allowed it to be easily installed on small escort shipsHF-DF could detect those radio signals and identify their sources which in turn revealed the positions of U-boats. While the Allies might be unable to read the encrypted radio messages, they could know where the U-boats were and take countermeasures - either by altering course or by attacking U-boats at their rendezvous point if the messages could be broken and revealed where the U-boat packs would form.HF-DF was a very reliable and effective system because it could detect and identify radio sources out to 15 miles. Another factor that increased its value was the fact that Admiral Karl Doenitz allowed his men to communicate with little restriction. The absence of radio silence increased radio traffic that could be detected and traced which in turn allowed convoys to escape or escorts to attack U-boats before they could attack.4/ Leigh LightInvented by the Humphrey de Verd Leigh - a maverick fellow who had served a pilot in WW1, this piece of hardware was a search light capable of producing a very powerful beam of light. There was nothing special about the device. What was special about it was its tactical application…A Leigh light mounted under the wing of a VLR B-24 LiberatorLeigh Lights were used with great success in the Bay of Biscay.Together with centi-metric radars, Leigh lights were fitted on long-range patrol aircraft - VLR B-24, Sunderland, Wellington, Catalina. These technologies were used with great success against U-boats on the surface. Lulled into a false sense of security by the darkness, the Germans would let their boats run on the surface at night. They would be detected by radar-equipped aircraft which would turn on Leigh lights to illuminate the area the U-boat was in. Dazzled by the intense light beam and caught with their pants down, the Germans would be unable to dive quickly. What followed was swift sinking of the U-boats.ASW WeaponsASW technologies by themselves were not enough. The Allies needed platforms on which they could be installed and operated and the weapons to defend merchantmen against U-boats.1/ Convoy escort warshipsDuring the war, GB and the US built hundreds of cheap, small, lightly armed and armored escort ships - escort destroyers, corvettes and frigates. Indeed, take a look at the pictures of those ships below - you will quickly see how few guns they had and how small they were.Tacoma-class frigate (top speed = 20 knots)American Flower-class corvettesDestroyer escort (note the rack of depth charges at the stern)But their slow speed, light armor, light armament and small sizes did not matter because their adversary were German U-boats which were not very fast and not heavily armed. Furthermore, they had enough space to accommodate centi-metric radars, ASDIC, HF-DF set plus submarine-destroying weapons. Thus, those ships were completely adequate for the role they were built.In total, the RN had 176 destroyers + 160 corvettes and frigates. The USN had 120 destroyers of all types + 85 corvettes. The combined Anglo-American forces of escort ships numbered 535 ships - a huge number that would prove decisive in final Allied victory.2/ Long-range patrol aircraftA war is won or lost in the air - this is an established fact. Allied airpower played a critical role in the battle.Warships of all kinds, including powerful battleships were very vulnerable to air attacks. This was demonstrated time and time again in WW2. The mighty Bismarck was heavily damaged by a single carrier-borne aircraft. British warships off Norway in 1940 came under relentless German air attacks. Japanese battlewagons Musashi and Yamato were sunk by aircraft. This vulnerability to air attacks of warships was due to the ability of aircraft to quickly fly anywhere and their high speed which gave them the element of surprise (if the enemy had no radar).There was nothing more terrifying to a U-boat commander than a fast approaching plane that appeared suddenly in the sky. Being slow (all warships were much slower than even the slowest aircraft in WW2), small and lacking heavy AA defensive fire, U-boats were extremely vulnerable to air attacks by all kinds of aircraft. This is the reason why German U-boats frequently stalked and attacked convoys in the so-called Atlantic Airgap - the area of ocean that was beyond the max range of Allied air patrol.Atlantic AirgapA U-boat under air attack. Wellington, B-24, Sunderland and Catalina armed with torpedoes, depth charges, radar and Leigh Light were nemeses to U-boatsIt was within this Air Gap that German submarines inflicted heavy losses on convoys until 1943. At that point, the Allies possessed a large number of long range patrol aircraft based on the US East Coast, Iceland, and Britain. Those aircraft were American-built VLR (Very long range) B-24 (2,400 miles), Flying Boat Catalina (2,500 miles), British-built Vickers Wellington (2,550 miles) and Short Sunderland (1,780 miles).The great ranges of these aircraft + the bases from which they flew created contiguous air cover that practically eliminated the air gap to a few contiguous hundred miles of the Atlantic Ocean called the Greenland Air Gap. This was the only place where land-based Allied aircraft could not reach, and the place where Doenitz deployed the majority of his U-boats in the first half of 1943. This drastically reduced the risk of heavy losses from U-boat attacks because the Allies could simply avoid that Greenland Air Gap.Also, another notable improvement to air cover was delivered by escort carriers - informally referred to as jeep carriers. Their official designation was CVE which their crews jokingly interpreted as - combustible, vulnerable and expendable. Indeed, escort carriers were slow (top speed was typically 18 knots) compared to fast destroyers, cruisers, battleships and Essex-class and Illustrious-class aircraft carriers. Hence, they were not qualified to take part in fleet action. But they were perfectly suited to the task of protecting slow merchantmen. In total, the US built 77 escort carriers of which 37 were supplied to the RN. The small complement of aircraft onboards these carriers provided constant air cover over convoys that forced U-boats to remain submerged which severely reduced their speed and thereby their chance of making successful attacks.The massive increase in Allies air power and number of long range patrol aircraft coupled with the lack of friendly air support contributed decisively German defeat in the Atlantic, as remarked by Doenitz:the enemy Air Force therefore played a decisive part.... This can be attributed to the increased use of land-based aircraft and aircraft carriers combined with the advantage of radar location…. Germany was waging war at sea without an air arm. That was like boxing with only one fist.3/ Depth charge, Hedgehog and Acoustic TorpedoThese were the primary means of sinking U-boats.The ubiquitous depth-charges were the most proven weapon against submerged submarines. They were basically containers of heavy explosive charge set to detonate at a preset-depth. They were cheap, easy to manufacture in large quantity. Escort ships carried a lot of depth charges stored in racks mounted at the stern.Stern-mounted depth charge rackBut depth-charges had one shortcoming: they could not explode on contact with a submarine. To destroy submarines using depth charges, a ship had to move to the area where the submarine was in and then drop the charges directly overhead. The implication? - before the ship reached the target area, the submarine was diving fast to evade destruction. Allied commanders did not appreciate how quickly and deeply a German submarine could dive. A lot of depth charges ended up exploding above the submarine which inflicted more psychological damage than physical damage. Still, the terrifying underwater explosion kept German U-boats underwater for extended length of time, allowing a convoy unhindered.The British-invented Hedgehog complemented the depth charges. It was a launcher of heavy anti-submarine grenades designed to attack U-boat on the surface. Hedgehog had 2 advantages that depth charges did not have:The grenades were contact-triggered meaning that it would explode upon hitting a U-boat.It could launch a dozen of projectiles simultaneously out to a distance directly ahead or to both sides of the ship in an elliptical pattern. This was a tremendous advantage because as soon as U-boat was spotted on the surface, it could be attacked immediately by Hedgehog before it could dive to evade.Sailors loading 65-pound depth charges on a hedgehog launcher. Each of those projectiles contained 35 pound of Torpex that exploded on contact. Just one hit would be enough to sink or heavily damaged a U-boat.Those characteristics made Hedgehog a lethal and effective U-boat killer.Acoustic torpedo was another breakthrough in ASW. It was typically dropped from aircraft into the area a U-boat was in. The huge amount of noise emanating from the submerged submarine would guide the torpedo toward the target and destroy it.One telling demonstration of the effectiveness of acoustic torpedoes was the sinking of the Japanese submarine I-52 (1942). Carrying a cargo of raw materials and gold, the I-52 was sunk off the west coast of Africa by a USN’s submarine hunter-killer group. A torpedo bomber dropped an acoustic torpedo where the I-52 was spotted. The next morning, a grim flotsam of human flesh, oil spill plus other objects were found on the surface close to where the I-52 was torpedoed.In the end, all of the aforementioned advances in ASW technologies and weapons were integrated and utilized to deadly effect against German U-boats.If they were running submerged, ASDIC would detect them and hunter-killer groups would attack them by depth charges.If they communicated on the surface via radio, HF-DF instrument would find out where they were.If they were running on the surface or at periscope depths, centi-metric radars would detect them. The Allies would attack them using Hedgehogs (if they were on the surface) or depth charges (if they were submerged).VLR land-based aircraft or carrier-based aircraft posed constant peril to U-boats on the surface both day and night.As more and more U-boats were sunk by various means, it would gradually dawn on German submariners that danger beset them virtually anywhere, anytime and in any weather condition.A list of the number of U-boats lost to respective causes. You can see that a large number of U-boats were sunk by aircraft and escorts.Confronted by the Allies’ overwhelming technological superiority in ASW, Admiral Doenitz conceded defeat:The overwhelming superiority achieved by the enemy defense was finally proved ... The convoy escorts worked in exemplary harmony with the specially trained “support groups”. To that must be added the continuous air cover, which was provided by carrier-based and long-range land-based aircraft, most of them equipped with new radar. There were also new and heavier depth charges and improved means of throwing them. With all this against us it became impossible to carry on the fight against the convoys.2/ Organizational and Tactical Innovations for ConvoysThe British deserved nearly all the credits for the tactical and organizational innovations that underlay the Allies’ ultimate victory in the Atlantic.At the root of this achievement lay one crucial fact: Britain’s significant experience in ASW and convoy escort.Having witnessed the devastation exacted on its merchantmen by German submarines in WW1, the British were forced to counter the threat posed by enemy submarines and in doing so, they formulated the intellectual framework for the establishment of convoys as a counter-measure against submarine predation. When WW2 broke out, the threat posed by German U-boats necessitated further refinement of that framework regarding convoy.There were three pillars underlying British innovations regarding convoyConvoys reduced significantly the number of ship lost to U-boat attacks.Bigger convoys were better than smaller convoys.The risk of being sunk by U-boat was inversely proportional to the speed of a ship/a convoy.Point 1 is obvious. Just like unescorted sheep are easy to be killed by wolves, unescorted ships are easy to be attacked by U-boats. Indeed, the vast majority of merchantmen were sunk by U-boats when they traveled without escorts. Even in convoys, ships that were sunk were usually stragglers that were unable to keep up with the rest of the convoys. The table below allows no doubt:Allied merchantmen lost (measured in tonnages) to U-boat attack through various conditions: outside convoy, inside convoy and straggling.The British understood this very early on in the war against U-boats in WW1 and responded by organizing convoys to protect merchantmen. Escorts deterred U-boats from attacking which in turn reduced the risk of ship loss.Point 2 is more complex. It is an insight derived from analysis of the operational problem of determining the optimal size of any convoy. That convoy was a proven measure against submarine attack was an indisputable fact. The catch was: given a number of merchantmen, how many escorts would be needed? You have only a limited number of escort ships but many merchantmen all of which required protection against U-boats. (a serious problem at the outset of the war due to the insufficient number of escorts)This challenging operational puzzle was solved by the Operational Research Section of the British Admiralty in 1943. Analyzing statistics of past convoys and encounters with U-boats, Professor Patrick Blackett - future Nobel laureate and chief of Operational Research - concluded that bigger convoys were more effective than smaller convoys. He even specified that a convoy comprising 60–90 ships was better than a convoy comprising 30 ships.The reason was that the perimeter of a bigger convoy was not that much larger than that of a smaller convoy. It followed that a certain number of escorts assigned to protect a smaller convoy could defend a bigger convoy. Another benefit was that a bigger convoy could deliver a much greater amount of supplies in one go than a smaller convoy. That was more efficient than multiple trips of smaller convoys.Illustration of a convoy’s perimeterAnother insight was that what mattered was not the ratio of escorts - merchantmen but the ratio of escort - enemy submarines.From that insight stemmed one crucial innovation. Apart from protecting merchantmen, convoys could be used as a tool for destroying U-boats. How? By assigning to a big convoy more escorts than the number required for defense. That would provide offensive power in addition to defensive power. A group of escorts would protect the merchantmen while the other group would be free to hunt and U-boats lurking nearby - one stone hit two birds. Seeing a big target, U-boats would be tempted to take the risk and attack and in doing so, they would be attacked by escorts armed with an amazing array of ASW technologies and weapons.Lastly, point 3 was another crucial insight derived from operational research. The most commonly deployed German U-boats were the Type VII and Type IX. While extremely reliable, those U-boats were - like most submarines during WW2 - very slow when running on battery underwater (4 knots for type IX and 7 knots for type VII). They were much faster when running on diesel engine on the surface but were never as fast as destroyers, cruisers, battleships and carriers.The implication? If a convoy could move at a speed higher than the submerged speeds of U-boats, they had a very high chance of evading destruction. This was because in order to attack convoys, U-boats had to move into an ambush position ahead of the formation which in turn required them to overtake the formation. But if the convoy was faster than U-boats, then the U-boats could not overtake the convoy to ambush it. (unless the U-boats were already in an ambush position awaiting the approaching convoy)Indeed, the majority of merchantmen sunk by U-boats were frequently stragglers that trailed a convoy formation or unescorted slow ships. The British calculated that a convoy speed of just 13 knots (which you may consider to be slow) significantly lessened the risk of being attacked by U-boats. In fact, high speed by itself provided enormous protection from U-boat attacks. Ships sailing at 14 knots without escorts were 3 times safer than those sailing at 12 knots. The higher the speed, the lower the risk of being attacked by U-boats. Ships sailing at 30 knots were effectively immune to U-boat attacks even without escorts.The Americans also appreciated eventually the vital role speed plays in protecting convoys. They calculated that even for relatively slow ships, one or two extra knots could increase protection. Increasing the speed from 7 knots to 9 knots improved protection by about 1/3.Recognizing the importance of high speed, Churchill asked the Americans to supply fast merchantmen. In response, American shipyards churned out in large number Liberty ships whose design was influenced by British specification. Liberty ships were capable of 11 knots, making them faster than U-boats and consequently safer from U-boat predation.By March 1943, about 2/3 of all Allied merchantmen sailing across the Atlantic could make at least 10 knots, making it very difficult for submerged U-boats to attack. Ships that were fast (> 20 knots) could travel unescorted. All the Germans could do at that point was opportunistically target stragglers in convoys and slow unescorted ships.Another innovation was the classification of convoys into fast convoy (designated HX) and slow convoy (designated SC) based on the speed of the merchantmen comprising a convoy. This innovation stemmed from British recognition of the importance of uniformity in speed. The British learned quickly that allowing fast ships and slow ships to sail together led to disastrous consequences. Unable to catch up with fast ships, the slow ships would trail the formation and became prey to lurking U-boats. They also required escort ships to break off the formation to escort them which in turn reduce the overall defensive strength of the convoy.Assigning all slow/fast ships into the respective slow/fast convoys would eliminate the risk of disruption of convoy formation caused by stragglers and all the concomitant dangers.3/ CodebreakingCodebreaking was an inseparable aspect of the technological battle between both sides. To form wolf packs to attack convoys, German U-boats communicated via radio which was encrypted by the infamous Enigma machine. The Enigma variant used by U-boats was considerably more difficult to break than the variants used by the German Army and Air Force.Bletchley Park witnessed intense British cryptanalytic effort to uncover German operational plans, including those of the U-boats. Initially, British failure to break Enigma ciphers led to heavy losses of merchantmen. Later, through sheer ingenuity and persistence, British code-breakers (with special credit given to Alan Turing) succeeded in breaking most Enigma-encrypted messages. Decrypts gave advanced warning to convoys often before U-boat attack materialized. Convoys would be diverted and nearby escorts would be requested to render assistance.One notable success brought about by codebreaking was the evasion of destruction by fast convoy HX 133 in June 1941. Codebreakers at Bletchley broke Enigma ciphers and uncovered an imminent ambush by U-boats along the projected route of HX-133. The British quickly altered the course of the convoy and requested escorts of other convoys to detach to come to the aid of HX-133. As a result, only 6 merchantmen were lost out of a total of 64. The Germans lost 2 U-boats.BUTDespite the enthusiastic claims of code breakers, their efforts were actually not as significant to Allied victory as the preceding 2 factors. Knowing what the enemy would do was only half of the task done. The remaining half was frustrating enemy action. How was that accomplished? - by employing ASW weapons and technologies. Without those essential wherewithals, heavy losses would be inevitable.And it makes sense. What good does it do to you if you cannot forestall/defeat the attacker due to the lack of weapons? The only realistic action to take was running away. But even that would not guarantee protection from danger because the enemy could still pursue you.Furthermore, what is probably less well-known to many people was the fact that the Germans had their own cryptanalytic successes during the battle. In 1940 The B-Dienst - the German counterpart of Bletchley - frequently broke British ciphers intended for convoys which allowed U-boats to successfully ambush targets. In those situations, knowing or not knowing German intention did not matter. Having the weapons to defeat them was important. When you reflect on the matter in that light, you will appreciate that the impact of code-breaking was not as decisive as that of ASW technologies, weapons and convoy tactics.SummaryThe battle of the Atlantic was a war whose outcome was determined by technologies. The harsh condition at sea coupled with the difficulty of traversing it necessitated the development of seagoing technologies to enable humans to cross the sea safely - a necessary condition for maritime trade. Protection of that trade and later the ambition to command the sea led to the establishment of navies made of powerful warships possessing sophisticated technologies. Naval superiority depended on technological superiority. Winning the technological contest depended on creating better technologies, devising countermeasures against technological advances made by the enemy and having a technically competent force capable of using those technologies well.Ultimately, the Allies won the battle precisely because they had superior technologies against the biggest menace: German U-boats. The battle witnessed amazing advances in ASW technologies by the Allies: ASDIC, centi-metric radars, HF-DF, hedgehogs, acoustic torpedoes, very long range patrol aircraft, escorts ships, escort carriers. Apart from technical ingenuity, the Allies had the industrial power to produce their technologies in large number AND a force of technically competent servicemen who used them effectively.In stark contrast to this impressive array of technologies, the Germans made little improvement to their submarines. They used the Type VII and type IX well until 1944 - long after they lost the battle. The Germans realized much to their dismay that the technological gap between them and the Allies was too large to overcome. There was nothing they could do to avert defeat.Of secondary importance to Allied victory was the British’s sophisticated understanding of convoys, convoy size and speed. The organizations and tactics of convoys based on that understanding minimized loss of merchantmen and decimated U-boats.Finally, code breaking - undoubtedly one of the greatest intellectual triumphs of the war - was not as decisive in final victory as commonly believed. Knowing enemy impending attack was useless if the Allies had no weapons in large quantity to defeat the enemy.Reference(s)1/ World War II at Sea: A Global History - Craig L. Symonds2/ How the War Was Won: Air-Sea Power and Allied Victory in WW II - Phillips Payson O'Brien3/ Engineers of Victory: The Problem Solvers Who Turned the Tide in the Second World War - Paul Kennedy

"To my colleagues at CNN both in front of and behind the cameras. Without your collective efforts, this book would not have been possible. We truly did go “all in” to cover this story. And we will continue to do so, wherever it goes."A large commercial airliner going missing without a trace for so long is unprecedented in modern aviation. It must not happen again.— Tony Tyler, director general, IATAWhere’s that plane?” If there is one question I get asked most these days, this is it. From politicians and CEOs to doormen and cabdrivers, time and again they want to know, “What happened to that plane? Where is it?” Malaysia Airlines flight MH370 — with 239 people aboard — departed from Kuala Lumpur shortly after midnight on March 8, 2014, bound for Beijing, China, and has never been seen since. Despite the largest aviation search in history, virtually nothing was found of the aircraft in the wake of its disappearance. Sixteen months later, thousands of miles from the flight’s path, a piece of an airplane’s wing washed ashore on Reunion Island. Still, this bit of evidence and a flimsy trail of electronic satellite data are all we have to go on—plus a huge amount of speculation and confusion.“The most difficult search ever undertaken in human history.”When Australia’s prime minister Tony Abbott uttered those words in April 2014, it was not just the usual hyperbole of a politician. What happened to MH370 has been described as a unique, unprecedented, and extraordinary mystery. Planes may crash, but they are not supposed to disappear without a trace. Earlier ocean crashes, such as Air France 447 or Air India 182, have demonstrated that wreckages can typically be located within hours. Airlines today own the most modern aircraft, featuring up-to-date navigation technology, while regulations govern everything from the number of hours a pilot can fly to the fire-resistant fabric used in the passenger seats. Despite the precautions, no one has been able to pinpoint the final resting place of MH370 and those on board. All the while we know that if you lose your iPhone, it can be traced within minutes.At the heart of this mystery remains the question of the cause of the plane’s disappearance. Was it mechanical, or was it criminal: Did someone deliberately take over the aircraft and set it on a course to the south Indian Ocean, intending to kill all on board? Would that someone turn out to be an unknown hijacker or terrorist, or could it have been one of the pilots?Do I have a view of what might have happened? I do, and I will share it. In doing so, I am not blind to the obvious options, but prefer to keep an open mind on the eventual outcome. As will become clear in the chapters that follow, as a television journalist, I became frustrated, and even angry, with some of the pundits with whom I had to work who were quite prepared to convict the pilots long before any evidence had been found. Instead, this book will stick to the facts as we know them. In the end, you will be left to make up your own mind about where you think the evidence leads.The disappearance of MH370 has been a serious failure for the multibillion-dollar aviation industry, revealing disturbing facts and behaviors. That one of the most advanced aircraft in the world should vanish, while an airline left hundreds of desperate families waiting for news of their loved ones, is unpardonable. In response, airlines have rewritten their rules from top to bottom. An alphabet soup of international organizations responsible for air travel safety held high-level meetings and set up a task force to look at ways to ensure that planes are always being tracked in real time. Even CEOs I spoke to were as astounded as the general public that planes were not always being tracked to a fine point of precision. Some of the changes did not come soon enough: as suspicion about MH370’s pilots increased, discussions were held about a “two-person in the cockpit” rule, stipulating that if one pilot temporarily leaves the cockpit, he or she should be replaced by a flight attendant. Yet the considerable amount of talk led to very little action. If such a change had been made, the crashing of Germanwings 9525, in which a rogue pilot deliberately flew his airliner into a mountain, possibly would not have happened.When all is said and done, MH370 boils down to one simple fact. For the first time since the Wright brothers first flew, this industry, which prided itself on a policy of “safety first,” is having to cope with the unthinkable: a plane disappeared. It is no wonder the head of the airline organization IATA, Tony Tyler, decried, “A large commercial airliner going missing without a trace for so long is unprecedented in modern aviation. And it must not happen again.”The fascination with MH370 goes deeper than an aviation story.International diplomatic and political issues have been raised too. More than 60 percent of the passengers on board the plane were Chinese citizens, and the Chinese government wasted little time in flexing its muscles on their behalf. The relatives of Chinese victims were put up in a Beijing hotel where regular briefings were given by low-level Malaysian government and airline officials. These were acrimonious events, interrupted frequently by hysterical outbursts from distraught family members frustrated at the lack of information they were being given. The way the relatives were treated was shabby at best.Then there was the role of the Malaysian government itself. Were they a bunch of incompetents who had no idea what they were doing, doomed to make mistake after mistake? Or perhaps the truth was something more sinister: a cover-up for an erroneous military strike? Few people will deny that the first weeks of this crisis were not something of which the Malaysians can be proud. As the tensions rose across the South China Sea, the fate of MH370 rapidly became entwined in a diplomatic game of realpolitik, mystery, intrigue, and failure.As planes get bigger, and the ultra-long-haul flight becomes more common, the fact that MH370 happened is worrying, for it should never have happened.THE PLANE AND PASSENGERSAircraft Reg: 9M-MROAircraft Type: Boeing 777-200ERBuilt & Delivered: May 29, 2002 (11 years 9 months 9 days)Flight Hrs: 53,465Comms: 3 VHF radios, 2 HF radios, 1 SATCOM, 2 ATC transpondersSouls on Board: 239Crew: 12Pax: 227THE PILOTSThe Captain: Zaharie Ahmad Shah. Malaysian, age 53. Total flying hours: 18,365 hours. Experience on 777: 8,659 hours. Joined Malaysia Airlines in 1981.First Officer: Fariq Abdul Hamid. Malaysian, age 27. Total flying hours: 2,763. Experience on 777: 39 hours. Joined Malaysia Airlines in 2007.THE FLIGHTMH370, Kuala Lumpur to BeijingMARCH 8 (MALAYSIA STANDARD TIME)00:27 Push-back00:41 Takeoff00:42 Directed to Igari (waypoint)00:50 Directed to climb FL35000:50 Read-back FL35001:01 Advises reached FL35001:07 ACARS last transmission (provided total fuel remaining)01:07 Repeats FL35001:19 Handoff to Vietnam “Contact HCM 120.9 good night”01:19 Read-back “Good night Malaysian 370” LAST WORDSIn the case of the safety history of the 777, there was nothing to worry about. The 777, which first came into service in 1995, has an exemplary safety record. In almost twenty years, there had never been an accident where passengers had died in a plane crash. In 2013, Asiana 214 crash-landed in San Francisco. Two passengers died after they escaped from the aircraft and were run over by a fire truck responding to the accident. A third passenger died later in the hospital. The only other major 777 incident at the time of MH370 was the crash landing of the British Airways Flight 38 at London Heathrow. That came about because ice had formed in the fuel lines during a frigid flight from Beijing. When the ice jolted free, it blocked the line and starved the engines of fuel. The plane lost power and glided the last few miles to crash just short of the runway. Fortunately, everyone survived.Having seen the state of the crashed aircraft with both Asiana and British Airways, I find it a miracle that no one was killed when the planes hit the ground — a testament, I have no doubt, to Boeing’s ability to build superb airplanes (and the same is true for Airbus!). The 777 was, and still is, among the safest aircraft, and I had no hesitation in saying so on-air, then or now."We owe it to the grieving families, we owe it to everyone who travels by air, to get to the bottom of this mystery."—Tony Abbott, Australian prime ministerWell, he was voted out of power and that is that.In the following days, then weeks, months, and now years after MH370’s disappearance, Chris and all my other anchor colleagues have asked me the same question again and again. My answer has always been the same. “Yes, they will find it. They must.” As the time has gone by, sometimes I think I detect a certain wry smile on my colleagues’ faces as the words I uttered with such certitude come back to haunt me.So far I have been proved wrong, and with the exception of the single flaperon, nothing of the plane has been found. Some are now saying that the plane may never be found, that the task is too great. Assuming the Inmarsat data is correct, and the plane is lying along the seventh arc, the water is too deep, the ocean canyons too wide, the area too large. The search teams could be trolling right over the wreckage and never notice it.Of course we want to know what happened during those moments, on the morning of March 8, 2014, at 1:19, just after Captain Zaharie said, “Good night Malaysian 370.” But if we never discover the facts, there are plenty of other issues occasioned by the plane’s disappearance and it is these that must be resolved. There is the failure of air traffic control on that night, the confusion and political interference in the search operation, and the new methods of tracking planes and retrieving vital black-box data that are now being considered.Sixteen months after MH370 went missing, I was on assignment in Florida for CNN Business Traveller when I got the email. My producer Saskya Vandoorne wrote, “Twitter is abuzz with MH370 . . . probably a false lead but a wing has washed up near the Reunion Island.” She enclosed a picture of the object found in the western Indian Ocean. I was about ten miles from Legoland, where I was filming the next part of our show on theme parks. As I looked at the photo it was obvious that this was something significant. It was a part of a large aircraft wing, probably one of the flaps.Within hours, larger, better photos of the missing plane part had been published and we were comparing it to online schematics of the Boeing 777 wing. The pictures suggested that the piece was part of the control surfaces of the wing. Rather than the flaps, it appeared to be one of the plane’s two flaperons. A flaperon is a hybrid piece of equipment that combines the functions of the flaps and the ailerons, hence the name flaperon. The ailerons control the left and right banking of the aircraft by going up and down into the airflow, helping raise or lower the wing to make turns. The flaps extend on takeoff and landing and increase the wings’ size, giving the plane greater lift at slower speeds. The flaperons are part of a plane’s steering mechanism, and allow the pilot to bank the plane. At slower speeds they also extend marginally out of the wing in order to give greater stability and lift. As a passenger, you can see the flaperon in action if you sit behind the wing. It is on the trailing edge and is located nearer the fuselage. You will see it bouncing up and down on takeoff and landing as it stabilizes the aircraft, unlike the flaps, which extend in several sections then retract into the wing. The flaperon remains active throughout the flight (although at higher speeds it is far less noticeable).After some initial confusion over a number reportedly printed on the piece, it was confirmed as 657BB. It was described in the Boeing 777 maintenance manual as “flaperon Leading Edge Panel.”2 Another piece of debris was also recovered on the beach: the remnants of some sort of suitcase or backpack.While we waited for the aviation investigators to make a final determination on the source of the flaperon, I was being asked one vital question, hour after hour: Was it possible for a piece of debris from MH370 to have traveled 2,500 miles from the most likely crash site? It became obvious that the answer was, unequivocally, yes. If you look at a map, you’ll see that Reunion is on the opposite side of the Indian Ocean from Australia. It is a straight shot across the water from the most likely search zone to the coast of East Africa, where the island is located. Experts were put on-air reminding us that they had long predicted that the currents of the southern Indian Ocean Gyre, swirling around, creating a great sea garbage tank, would eventually cause the debris to drift across to the other side.In March 2014, the experts were telling us that eventually, something would be washed up on the western side of the Indian Ocean. It was all backed up by solid scientific evidence from the University of Western Australia, which showed us its drift-modeling forecast, which indicated that after eighteen months, wreckage would land in that region.If we were surprised by this development, our expert oceanographers were not.As the news of the find flashed around the world, it was particularly noted in Paris, where a new bureaucratic wrinkle was about to be added to the proceedings. Reunion has been under the control of France since the seventeenth century. It is now classed as an overseas territory and considered an administrative region, or prefecture, of France. Even though the French had played only a limited, advisory role in the MH370 investigation so far, the fact that the flaperon had washed up on French soil meant the French authorities took responsibility for handling the debris, which had to be transported to France for specialized examination. Thus, late on Friday, July 31, the flaperon was crated and boarded onto an Air France 777 flight bound for Paris. As I watched the video of the plane taking off I thought of the strange juxtaposition of one 777 carrying in its belly a vital part of another 777, taking it on a journey to release any secrets it had carried for the past sixteen months.As the piece was making its way to France, Boeing sources made it clear that yes, their experts recognized this as a flaperon from a 777 but they couldn’t say whether it was from 9M-MRO without further tests. This was backed up by comments from the Australian deputy prime minister, Warren Truss, who said the flaperon was a “major lead” and was “not inconsistent with a Boeing 777.”It was a very strange situation: everyone agreed that this was a 777 flaperon, but no one would say it’s the flaperon. Yet what else could it be? There were no other missing 777s in that part of the world. Though no 777 had reported losing a flaperon in flight — it’s the sort of thing a pilot would notice pretty quickly — everyone stopped short of weighing in definitively on the piece of debris. The French transferred the flaperon from Paris to Balma near Toulouse, and the headquarters of the Direction Générale de l’Armement (DGA). The DGA is part of the Ministry of Defense and is a specialist laboratory and testing center for the military and civilian aerospace industry. In many ways it was the perfect place to send the flaperon, as the DGA did much of the work on the wreckage of Air France 447, which had been in the water for years. This gave them expertise in analyzing pieces exactly like this one.The judicial authorities in France were now calling the shots because four of the passengers on board MH370 were French citizens. With a hijacking or other criminal act looming as a possibility, under French law the judicial authorities were given primacy to inquire into what had happened. The inspection of the flaperon was to be conducted under the control nd presence of three French judges carrying out their legal mandate. Inevitably a bureaucratic circus ensued. In Paris, meetings had been held between the French and Malaysian governments to determine how to handle this development. In Toulouse, there were representatives from the BEA, NTSB, the Malaysian DCA, Malaysia Airlines, the Australian ATSB, the Chinese, Boeing—it seemed everyone had to be there to make sure proper protocol was followed during the inspection of the flaperon. Its analysis didn’t begin until four days after the piece arrived in France. It left me and my colleagues wondering what on earth was going on and taking so long.Finally, on Wednesday, August 5, 2015, it was time to reveal what they had found. An announcement was expected at 8 p.m. Paris time, from a French prosecutor, and then a statement from the Malaysian prime minister, Najib Razak. That was the plan, yet the Malaysians weren’t going for it. Ten minutes before the French were to present their findings, the prime minister spoke. From everything I have heard, the Malaysians were determined that because this was their plane and their investigation, it was their right to speak first. Here is the crucial part of Razak’s statement:An international team of experts have conclusively confirmed that the aircraft debris found on Reunion Island is indeed from MH370. We now have physical evidence that, as I announced on 24th March last year, flight MH370 tragically ended in the southern Indian Ocean.Within minutes of the prime minister’s statement, the deputy prosecutor in France, Serge Mackowiak, held his news conference. We waited for a similar announcement of “conclusiveness.” It never came.What was a cut-and-dried conclusion for the Malaysians was a matter of “strong presumption” for the French.The prosecutor said that Malaysia Airlines representatives had seen specific similarities that linked the flaperon to the plane. But he didn’t say what they were. No one mentioned the presence of a serial number, which would seem to be the only conclusive proof of its origins.This was a shambles. The first time potentially hard evidence of the plane is found and the authorities managed to make a complete mess of it by differing in their wording. It beggars belief that something like this was able to happen.The families, scattered around the world, had been given an early warning of a few moments about the announcement. Some received it by text message, others by email, while luckier ones got a phone call from Malaysian embassy officials. They were given the prime minister’s version of the announcement: This flaperon was part of the plane. The plane went down in the southern Indian Ocean. Yet all of a sudden we in the media were questioning this conclusion. Not surprisingly, the families of the Chinese victims were having nothing of it. Soon they were out on the streets, protesting in front of the Malaysian embassy in Beijing.Now that the French authorities had said with “certainty” that the flaperon was from MH370, one key question had been definitively answered: the plane had indeed gone down somewhere in the southern Indian Ocean. Many of the more fanciful theories about the disappearance, including the ones about landing on Diego Garcia or in the Maldives, could now be put to rest. (The conspiracy theorists will never let up, and will claim the flaperon was planted by the Chinese, Americans, or someone else who shot down the plane.)An in-depth examination of the part will probably reveal how and when it separated from the aircraft, and whether this occurred in flight or as the plane hit the water. What the flaperon will not reveal is the exact location where the plane went down. This was confirmed by the ATSB in its report published in December 2015: “While this debris find is consistent with the current search area it does not provide sufficient information to refine it.”5 It seems the flaperon won’t reveal the secret of where the plane is.Nor will the flaperon reveal what happened at 1:19 after “Good night Malaysian Three Seven Zero.” Unless there was an explosion (almost certainly there wasn’t) and residue is found (highly unlikely after all this time), the only information that the piece can possibly yield will be how it separated from the aircraft.After an accident, finding the plane is essential. Of course, the recovery of bodies must be a top priority of the airline. But to discover what happened, and how to prevent its happening again, it is also necessary to retrieve, and to analyze the contents of, the black-box recorders. MH370 rightly created huge concern among both travelers and the aviation industry. Time and again on various shows, as I explained the difficulty of the search, anchors would look incredulous and ask the same question: “If we can find the location of our lost iPhones easily online, how come a modern jetliner could just disappear without a trace?” Every day people are using ordinary technology to find something as small and commonplace as a cell phone. Yet in the case of MH370, tens of millions of dollars were being spent during months of searching the deep ocean in appalling conditions, and no one could find something as large as a 777, which costs $250 million! Months after it disappeared, we had no certainty where the plane had flown, or where on the ocean bed it lay.To track a plane with certainty, air traffic control must know where it is at all times, even when the plane’s communications equipment has been switched off, disabled, or has failed. The goal must be to receive as much information as possible from the aircraft while it is still flying. Looking at MH370, I can trace all the problems back to what happened on the night when the 777 had been able to evade the most sophisticated air traffic technology. The plane’s transponders had been switched off, the ACARS system was disabled, and there were no radio signals. The plane had “gone silent.” It was able to continue flying without anyone noticing partly because of terrible human errors made by air traffic controllers and radar operators. But, even discounting these initial mistakes, it was the long, seven-hour flight over the southern Indian Ocean that turned an incident in Southeast Asia into the world’s biggest aviation mystery. It is only stating the obvious to say that surely the technology should be put in place so that no plane can fly for so long, anywhere in the world, without air traffic control knowing its whereabouts. The public has rightly said it’s a disgrace, and the industry has to make sure it can never happen again.What is galling about MH370 is that this was not the first occasion when a major jetliner went missing and it took several years to find it. The industry had had to cope with some of the very same issues five years before, in June of 2009, when Air France 447 went missing over the South Atlantic. By now you will recall that this was the A330 that had a problem with speed indicator pitot tubes. The pilots flew the aircraft into a stall and it crashed.No radar was tracking Air France 447 when the crash happened, and no air traffic control center was following it in real time. Most fliers are amazed to learn that planes are not always tracked by radar when they are in the air, crossing the globe. Air traffic control radar constantly monitors the airspace over landmasses like Europe or the United States, where the sheer number of planes in the sky demands full coverage. Any plane that deviates from its flight plan is quickly noticed. With Germanwings 8501, only three minutes and fifty-three seconds passed after Andreas Lubitz initiated the unauthorized descent over the French Alps before the air traffic controllers were calling him on the radio demanding an explanation (and some would say even this was too slow). During the next ten minutes, until the plane hit the mountains, fourteen additional radio calls from four different sources attempted to contact the pilots. Suffice it to say, over most stretches of populated land, air traffic control responses are typically swift.There are, however, large parts of the globe where no radar exists, including the airspace over the world’s oceans. Radar coverage requires ground-based facilities. At sea, both the distances and the costs involved mean it is neither practical nor reasonable to build floating sites for oceanic radar.Of course, the absence of radar doesn’t mean that planes aren’t being supervised as they cross the oceans. Consider the thousands of aircraft that cross the Atlantic each day between North America and Europe. As the plane travels over water, traditional radar coverage ends about 250 miles after they leave behind the Canadian or Irish coast. Radar doesn’t return until they are within similar range of land on the other side. Instead there is a complicated system of “tracks” where planes fly specific east- and westbound airways, which change daily with the changes in the jet stream. The pilots are given definite times when they must join the track to begin their oceanic crossing. The planes are spaced out, roughly ten minutes apart, and this long chain of aircraft moves through the sky. Throughout the journey they communicate their position regularly, using high-frequency radios or, more usually today, satellite-based systems. A similar track method called PACOTS is used across the North Pacific between the US and Asia. If tracks aren’t being used, then planes are directed to waypoints along standard airways. Again, the aircraft regularly reports its position so air traffic control can safely space out the planes.Air France 447 was out of Brazil’s radar coverage and had just passed over waypoint ORARO, heading for waypoint TASIL. Fortunately, the plane’s ACARS system was programmed to send its location automatically every ten minutes. Five minutes had elapsed between the last transmission and the crash into the water. After calculating the maximum distance AF447 could have traveled in those five minutes, the investigators came up with a search area of forty nautical miles, covering seventeen thousand square kilometers. It took several days before the first floating debris was spotted. In the end, AF447 was found just 6.5 miles from the last known position of the flight and searchers were able to retrieve the black box.I still believe they will find it. I say this not out of some simplistic view that missing planes are always found, but because the plane must be found; the vanishing of such a large aircraft is simply not acceptable. There are more than 1,200 of the 777 family of planes flying around the world today.After the search teams have finished covering the 46,000 square miles (120,000 square kilometers) currently designated as the most probable place where the plane went down, if nothing has been found there, the whole matter becomes much more problematic. The Malaysians and the Australians have said they will stop searching at this point, because in the absence of any new evidence of where to look, increasing the zone would cease to be feasible. They can’t search the entire length of the seventh arc.The search must somehow continue. That is what I really mean when I say, “They will find the plane, they must.” There can be no temptation to consign this to the history books as an aviation mystery that was too difficult to solve. If the searchers find nothing in their search, then they need to go back to square one. This will involve questioning everything that they have believed to be true and seeing if it remains valid. The inquiry should open its doors and its minds to other experts who may have a different perspective. There has been much criticism of the tight-fisted way information has been held, and there are independent experts who might have had something to contribute who have been shut out of the investigation.All of this is in the future. At the time of this writing, there is still more ocean to be searched. So far they have spent less than the list price of a single brand-new 777-300 searching for MH370. In the big scheme of aviation, I think the lives of 239 people, the confidence in 1,200 flying aircraft, and the reputation of the industry demand that yes, they find it. They must.Update April 19, 2016Two pieces of debris that washed up on African shores are "almost certainly" from the missing Malaysia Airlines Boeing 777-200ER that was operating the fateful MH370 flight.The first piece of debris, in South Africa, was initially identified as a segment from a 777 flap fairing panel by the presence of a stenciled part number. Although the stenciling did not match that used by Boeing, it was consistent with stencils used by Malaysia Airlines on its 777s, including the missing aircraft – 9M-MRO.The second part, in Mozambique, was also identified from a ‘No step’ stenciling, which again corresponded with Malaysian Airlines’ stencils but not those originally used by Boeing. The piece is part of the aircraft’s horizontal stabiliser.ATSB outlines analysis process for MH370 debrisAnd Here Come More Conspiracy Stories: May 3, 2016More than two years after it disappeared, the mystery of what happened to Malaysia Airlines flight MH370 continues to baffle the world. Wild rumours continue to circulate about the fate of the Malaysian Airlines jet.From the moment news broke that the Boeing 777 had gone missing, conspiracy theorists have given their explanations for both the disappearance and the investigators' failure to crack the mystery.North Korea? Vladimir Putin? The US military? Fake debris? Life Insurance scam? China?MH370 conspiracy theories: What happened to the Boeing 777?Update: May 12, 2016The Australian Transport Safety Bureau has identified two more pieces of debris recovered off the African coast as most likely coming from the Boeing 777-200ER that was operating Malaysia Airlines flight MH370.In an update report, the Bureau says that the two pieces were found independently at beaches in Mossel Bay, South Africa on 22 March, and Rodrigues Island in Mauritius on 30 March.Both pieces were sent to Canberra for analysis, following a request from the Malaysian government, and were handled in accordance with ICAO practice, as per two other pieces that the ATSB previously identified.‘Part 3’ was identified as a segment from an engine cowling due to the Rolls-Royce stenciling, and it conformed to applicable drawings from Boeing as being from a 777.Although the stencil was not consistent with that originally used by the manufacturer, it did conform with the one used by Malaysia Airlines on its 777s. Nonetheless, the Bureau says that there were no identifiers tracing it specifically to the missing jet, which was registered 9M-MRO.The other part, labelled ‘Part 4’ was identified as part of the R1 door assembly from a Malaysia Airlines 777. Specifically, a piano hinge attached to it was consistent with that used on a table hinge support, and the trim line was consistent with other aircraft.“There were no identifiers on the panel segment that were unique to 9M-MRO, however the pattern, colour and texture of the laminate was only specified by MAB for use on Boeing 747 and 777 aircraft. There is no record of the laminate being used by any other Boeing 777 customer,” the ATSB says.Although marine ecology analysis is continuing, the Bureau says that both parts are “almost certainly” from the missing 777. It also came to the same conclusion on the two other parts that were previously examined.ATSB identifies two more parts from MH370 jetUpdate, May 14, 2016Terrible, terrible news, if true.“We know the plane is in the southern Indian Ocean. Generally, airline pilots and other genuine aviation experts believe captain Zaharie Shah hijacked his own Boeing 777 in a planned suicide mission.Self-appointed armchair experts are often referred to as “aviation experts” by broadcasters, rather than the aviation consultants they actually are. Such people express opinions that may sound plausible to the non-pilot fraternity but are often rubbish.This search appears to have been conducted in the wrong area, based on the Australian Transport Safety Bureau unresponsive pilot scenario. Yet we know from the National Geographic recent Air Crash Investigations documentary, which held Shah responsible, that only three minutes elapsed from when he said goodnight to Kuala Lumpur air traffic control to when he disappeared electronically and turned southwest.If there was no pilot involvement the aircraft just would have flown itself to the programmed destination of Beijing. It was still under control 90 minutes later when it turned south just north of Sumatra.If, as generally believed, Shah was trying to hide the aircraft in as remote a location as possible to hide his crime then he would endeavour to fly as far as possible before the fuel ran out. As an experienced Boeing 777 captain, this is how I would manage this. Fly at long-range cruise speed mach 0.83 at as high an altitude as possible for maximum range. As the first engine flamed out due to fuel starvation I would start a slow-speed descent at 220 knots indicated airspeed with the second engine at idle. Just before second engine flame-out, I would select flap while still having hydraulic pressure to ensure my sea impact speed would not be so severe as to cause massive amounts of debris. Passing 5000 feet and flying on limited flight control hydraulic pressure from the automatically deployed air driven generator I would turn into wind and try to judge a ditching at low speed so that the aircraft would not break up into pieces. This speed would be still in the order of 250km/h or greater.I recently was well out to sea and observed how big the sea state can be, with very large waves in a 50km/h wind. In the latitudes south of 40 degrees the winds and sea state is even greater.Some pieces of debris — confirmed as coming from MH370 — have been turning up. The first was a right flaperon that I suspect was due to the right engine being shorn off, as they are designed to do, in a heavy impact with the sea.Later an associated piece turned up, also from the area immediately behind the right engine. And then a piece from the horizontal stabiliser (tailplane) leading edge, which also would support the shearing off of the right engine. The weakest part of the fuselage is at the juncture of the body and the wing. It appears to me that during the ditching the aircraft broke at this juncture and this is generally, depending on the seating configuration, where the partition between business class and economy occurs, so some panelling was dislodged.All this does not answer the question of why the ATSB did not listen to experts who would have placed the search area at least 400km farther south and west. That is why MH370 has not been found.”Byron Bailey, a veteran commercial pilot with more than 45 years’ experience and 26,000 flying hours, is a former RAAF fighter pilot and trainer, and was a senior captain with Emirates for 15 years, during which he flew the same model Boeing 777 passenger jet as Malaysia Airlines MH370.Debris confirms MH370 crash zone in Indian Ocean