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GREATEST SIEGESFor thousands of years, wars have been fought on every kind of terrain imaginable, they are fought high in the peaks of colossal mountains, in snow chapped fields and ice capped woodlands, in sand choked deserts and dunes, in lush forests, and jungles, in mountainous Savanna’s, and in the seas, and occasionally, they are fought in our homes, where we live. Today we will cover the greatest sieges in history, the heroes who were born from them, and the victims of them.We will start in North Africa, with the great SIEGE OF CARTHAGE -After a Roman Army under Manius Manilius landed in Africa in 149 BC, Carthage surrendered and handed over hostages and arms. However, the Romans demanded the complete surrender of the city, and surprisingly to the Romans, the city refused, the faction advocating submission overturned by one in favor of defense.(Archaeological Site of Carthage)The Carthaginians manned the thick walls and defied the Romans, a situation which lasted for two years. In this period, the 500,000 Carthaginians inside the wall transformed the city into a huge arsenal. They produced about 300 swords, 500 spears, 140 shields, and over 1,000 projectiles for catapults daily.The Romans elected the young but popular Scipio Aemilianus as consul, a special law being passed to lift the age restriction. Scipio restored discipline, defeated the Carthaginians at Nepheris, and besieged the city closely, constructing a mole to block the harbour.In the spring of 146 BC, Scipio and the Roman troops seized the cothon wall in Carthage. When daylight broke, 4,000 fresh Roman troops led by Scipio attacked Byrsa, the strongest part of Carthage. Three streets lined with six story houses led to the Byrsa fortress. Both Carthaginians and Romans waged war from the rooftops of the buildings and in the streets. The Romans used the buildings they captured as a means to capture subsequent buildings. Scipio successfully captured Byrsa, and then set fire to the buildings, which caused further destruction and death. This fighting waged for six brutal days and nights, until the Carthaginians surrendered. An estimated 50,000 surviving inhabitants were sold into slavery. The city was then levelled. The land surrounding Carthage was eventually declared ager publicus (public land), and it was shared between local farmers, and Roman farmers.Before the end of the battle, a dramatic event took place: 900 survivors, most of them Roman deserters, had found refuge in the temple of Eshmu, in the citadel of Byrsa, although it was already burning. They tried to negotiate their surrender, but Scipio Aemilianus declared that forgiveness was impossible either for Hasdrubal, the general who defended the city, or for the defectors. Hasdrubal then left the Citadel to surrender and pray for mercy (he had tortured Roman prisoners in front of the Roman army). At that moment Hasdrubal's wife allegedly went out with her two children, insulted her husband, sacrificed her sons and jumped with them into a fire that the deserters had started. The deserters too then hurled themselves into the flames, upon which Scipio Aemilianus began weeping. He recited a sentence from Homer’s Iliad, a prophecy about the destruction of Troy, that could be applied now to Carthage's end. Scipio declared that the fate of Carthage might “one day be Rome’s”.In the words of Polybius:Scipio, when he looked upon the city as it was utterly perishing and in the last throes of its complete destruction, is said to have shed tears and wept openly for his enemies. After being wrapped in thought for long, and realizing that all cities, nations, and authorities must, like men, meet their doom; that this happened to Ilium, once a prosperous city, to the empires of Assyria, Media, and Persia, the greatest of their time, and to Macedionia itself, the brilliance of which was so recent, either deliberately or the verses escaping him, he said:“A day will come when sacred Troy shall perish,And Priam and his people shall be slain.”And when Polybius speaking with freedom to him, for he was his teacher, asked him what he meant by the words, they say that without any attempt at concealment he named his own country, for which he feared when he reflected on the fate of all things human. Polybius actually heard him and recalls it in his history.SIEGE OF CANDIA -The siege of Candia began in May of 1648. The Ottomans spent three months laying siege to the city, cutting off the valuable water supply, and disrupting Venice's sea lanes to the city. For the next 16 years, they would bombard the city to little effect.The Venetians, in turn, sought to blockade the Ottoman-held Dardanelles to prevent the resupply of the Ottoman expeditionary force on Crete. This effort led to a series of naval actions. OnJune 21, 1655 and August 26, 1656, the Venetians were victorious, although the Venetian commander Lorenzo Marcello was killed in the latter engagement. However, on 17–19 July 1657, the Ottoman navy soundly defeated the Venetians and the Venetian captain, Lazzaro Mocenigo, was killed by a falling mast.Venice received more aid from other western European states after the 7 November 7, 1659 Treaty of Pyrenees and the consequent peace between France and Spain. However, the Peace of Vasvar (August 1664) released additional Ottoman forces for action against the Venetians in Candia.In 1666, a Venetian attempt to recapture La Canea failed. The following year, Colonel Andrea Barozzi, a Venetian military engineer, defected to the Ottomans and gave them information on weak spots in Candias fortafications. On 24 July 1669, a French land/sea expedition under Mocenigo not only failed to lift the siege, but also lost the fleet's vice-flagship, La Therese, a 900-ton French warship armed with 58 cannons, to an accidental explosion. This dual disaster was devastating to the morale of the city's defenders.Apparently chastened by their failed relief effort and the loss of so valuable a warship, the French abandoned Candia in August 1669 leaving Captian General Francesco Morosini, the commander of Venetian forces, with only 3,600 fit men and scant supplies to defend the fortress. He, therefore, accepted terms and surrendered to Ahmed Koprulu, the Grand Vizier of the Ottoman Empire on Semptember 27, 1669. However, his surrender without first receiving authorization to do so from the Venetian Senate made Morosini a controversial figure in Venice for some years afterward. As part of the surrender terms, all Christians were allowed to leave Candia with whatever they could carry while Venice retained possession of Gramvousa, Souda and Spinalonga, fortified islands that shielded natural harbors where Venetian ships could stop during their voyages to the eastern Mediterranean. After Candia's fall, the Venetians somewhat offset their defeat by expanding their holdings in Dalmatia. The city held off the siege for over 21 years before falling…SIEGE OF VIENNA -In August 1526, Sultan Suleiman I, of the Ottoman Empire, successfully seized control of southern Hungary. After unsuccessful military attempts by Ferdinand I, the brother of the Holy Roman Emperor, to retake the land, the Ottomans marched to take controle of Hungary on May 10, 1529.DEFENSIVE MEASURES -As the Ottomans advanced towards Vienna, the city's population organised an ad-hoc resistance formed from local farmers, peasants and civilians determined to repel the inevitable attack. The defenders were supported by a variety of European mercenaries, namely German Landsknecht pikemen and Spanish musketeers sent by Charles V.The Hofmeister of Austria, Wilhelm Von roggendorf, assumed charge of the defensive garrison, with operational command entrusted to a seventy-year-old German mercenary named Nicholas, count of Salm, who had distinguished himself at the Battle of Pavia in 1525.Salm arrived in Vienna as head of the mercenary relief force and set about fortifying the three-hundred-year-old walls surrounding St. Stephens Cathedral, near which he established his headquarters. To ensure the city could withstand a lengthy siege, he blocked the four city gates and reinforced the walls, which in some places were no more than six feet thick, and erected earthen bastions and an inner earthen rampart, levelling buildings where necessary to clear room for defences.After Ferdinand abandoned the city to (in effect) go and cry to his brother until he got help, the Marshall of Austria, Wilhelm von Roggendorf, took command of Vienna’s small garrison. He commanded the defense alongside a 70-year-old German mercenary, Niklas Graf Salm. The Viennese were able to muster around 20,000 men and 75 artillery guns to defend the large city. The Ottoman army that arrived at Vienna in the cool fall air of September numbered 100,000 men and 500 artillery pieces.SIEGE -The Ottoman army that arrived in late September had been somewhat depleted during the long advance into Austrian territory, leaving Suleiman short of camels and heavy artillery. Many of his troops arrived at Vienna in a poor state of health after the tribulations of a long march through the thick of the European wet season. Of those fit to fight, a third were light cavalry, or Sipahis, ill-suited for siege warfare. Three richly dressed Austrian prisoners were dispatched as emissaries by the Sultan to negotiate the city's surrender; Salm sent three richly dressed Muslims back without a response.As the Ottoman army settled into position, the Austrian garrison launched sorties to disrupt the digging and mining of tunnels below the city's walls by Ottoman sappers, and in one case almost capturing Ibraham Pasha. The defending forces detected and successfully detonated several mines intended to bring down the city's walls, subsequently dispatching 8,000 men on 6 October to attack the Ottoman mining operations, destroying many of the tunnels, but sustaining serious losses when the confined spaces hindered their retreat into the city.(Depiction of German Landskneckt circa 1530, renowned mercenary infantry)More rain fell on 11 October, and with the Ottomans failing to make any breaches in the walls, the prospects for victory began to fade rapidly. In addition, Suleiman was facing critical shortages of supplies such as food and water, while casualties, sickness, and desertions began taking a toll on his army's ranks. The Janissaries began voicing their displeasure at the progression of events, demanding a decision on whether to remain or abandon the siege. The Sultan convened an official council on 12 October to deliberate the matter. It was decided to attempt one final, major assault on Vienna, an "all or nothing" gamble.Extra rewards were offered to the troops. However, this assault was also beaten back as, once again, the arquebuses and long pikes of the defenders prevailed.Unseasonably heavy snowfall made conditions go from bad to worse. The Ottoman retreat turned into a disaster with much of the baggage and artillery abandoned or lost in rough conditions, as were many prisoners.Upon learning of these attempts, Niklas had bowls of water, filled with dried peas, placed around the walls. The dried peas floated on the surface of the water and, when disturbed by nearby digging, created ripples in the water, informing the defenders that the Ottomans were coming. Defenders then dispatched their own diggers to intercept the enemy’s digging attempts and destroy the mines. In one such instance, they nearly captured the Suleiman’s Grand Vizier. On October 6, 1529, 8,000 troops left the city in a rather risky raid that aimed to put a stop to the mining operations. They succeeded in destroying most of the attackers’ mines but took heavy casualties in doing so. On October 14, Suleiman’s forces retreated, having lost most of their mines to the defenders or rain and having taken heavy casualties.SIEGE OF MASADA -In 72 CE, the Roman governor of Iudaea, Lucius Flavius Silva, led Roman Legion X Fretensis, a number of auxiliary units and Jewish prisoners of war, totaling some 15,000 men and women (of whom an estimated 8,000 to 9,000 were fighting men) to lay siege to the 960 people in Masada. The Roman legion surrounded Masada and built a circumvallation wall, before commencing construction of a siege ramp against the western face of the plateau, moving thousands of tons of stones and beaten earth to do so. Josephus does not record any attempts by the Sicarii to counterattack the besiegers during this process, a significant difference from his accounts of other sieges of the revolt.The ramp was completed in the spring of 73, after probably two to three months of siege. A giant siege tower with a battering ram was constructed and moved laboriously up the completed ramp, while the Romans assaulted the wall, discharging "a volley of blazing torches against ... a wall of timber", allowing the Romans to finally breach the wall of the fortress on April 16, 73 BC. When the Romans entered the fortress, however, they found it to be "a citadel of death."The Jewish rebels had set all the buildings but the food storerooms ablaze and had killed each other, declaring "a glorious death ... preferable to a life of infamy."The Roman siege ramp seen from above.According to Josephus, "The Jews hoped that all of their nation beyond the Euphrates would join together with them to raise an insurrection," but in the end there were only 960 Jewish Zealots who fought the Roman army at Masada. When these Zealots were trapped on top of Masada with nowhere to run, Josephus tells us that the Zealots believed "it [was] by the will of God, and by necessity, that [they] are to die."According to William Whiston, translator of Josephus, two women, who survived the suicide by hiding inside a cistern along with five children, repeated Eleazar ben Ya'ir's exhortations to his followers, prior to the mass suicide, verbatim to the Romans:"Since we long ago resolved never to be servants to the Romans, nor to any other than to God Himself, Who alone is the true and just Lord of mankind, the time is now come that obliges us to make that resolution true in practice ... We were the very first that revolted, and we are the last to fight against them; and I cannot but esteem it as a favor that God has granted us, that it is still in our power to die bravely, and in a state of freedom."—Elazar ben YairAs Judaism prohibits suicide, Josephus reported that the defenders had drawn lots and killed each other in turn, down to the last man, who would be the only one to actually take his own life. Josephus says that Eleazar ordered his men to destroy everything except the foodstuffs to show that the defenders retained the ability to live, and so had chosen death over slavery. However, archaeological excavations have shown that storerooms which contained their provisions were also burnt, though whether this was by Romans, by Jews, or natural fire spreading is unclear.According to Shaye Cohen, archaeology shows that Josephus' account is "incomplete and inaccurate". Josephus only writes of one palace, archaeology reveals two, his description of the northern palace contains several inaccuracies, and he gives exaggerated figures for the height of the walls and towers. Josephus' account is contradicted by the "skeletons in the cave, and the numerous separate fires".SIEGE OF JERUSALEM - 70 ADDespite early successes in repelling the Roman sieges, the Zealots fought amongst themselves, and they lacked proper leadership, resulting in poor discipline, training, and preparation for the battles that were to follow. At one point they destroyed the food stocks in the city, a drastic measure thought to have been undertaken perhaps in order to enlist a merciful God's intervention on behalf of the besieged Jews, or as a stratagem to make the defenders more desperate, supposing that was necessary in order to repel the Roman army. Titus began his siege a few days before Passover, surrounding the city, with three Legions (V MAcedonica, XII Fulminata, XV Apollinaris) on the western side and a fourth (X Fretensis) on the Mount of Olives to the east. If the reference in his Jewish War at 6:421 is to Titus' siege, though difficulties exist with its interpretation, then at the time, according to Josephus, Jerusalem was thronged with many people who had come to celebrate Passover.The thrust of the siege began in the west at the Third Wall, north of the Jaffa Gate. By May, this was breached and the Second Wall also was taken shortly afterwards, leaving the defenders in possession of the Temple and the upper and lower city. The Jewish defenders were split into factions: John of Gischalas's group murdered another faction leader, Eleazer Ben Simon, whose men were entrenched in the forecourts of the Temple.The enmities between John of Gischala and Simon Bar Giora were papered over only when the Roman siege engineers began to erect ramparts. Titus then had a wall built to girdle the city in order to starve out the population more effectively. After several failed attempts to breach or scale the walls of the Fortress of Antonia, the Romans finally launched a secret attack, overwhelming the sleeping Zealots and taking the fortress by late July.After Jewish allies killed a number of Roman soldiers, Titus sent Josephus, the Jewish historian, to negotiate with the defenders; this ended with Jews wounding the negotiator with an arrow, and another sally was launched shortly after. Titus was almost captured during this sudden attack, but escaped.Overlooking the Temple compound, the fortress provided a perfect point from which to attack the Temple itself. Battering Rams made little progress, but the fighting itself eventually set the walls on fire; a Roman soldier threw a burning stick onto one of the Temple's walls. Destroying the Temple was not among Titus' goals, possibly due in large part to the massive expansions done by Herod the Great mere decades earlier. Titus had wanted to seize it and transform it into a temple dedicated to the Roman Emporer and the Roman Pantheon. However, the fire spread quickly and was soon out of control. The Temple was captured and destroyed on 9/10 Tish BA’v, at the end of August, and the flames spread into the residential sections of the city.Josephus described the scene:As the legions charged in, neither persuasion nor threat could check their impetuosity: passion alone was in command. Crowded together around the entrances many were trampled by their friends, many fell among the still hot and smoking ruins of the colonnades and died as miserably as the defeated. As they neared the Sanctuary they pretended not even to hear Caesar's commands and urged the men in front to throw in more firebrands. The partisans were no longer in a position to help; everywhere was slaughter and flight. Most of the victims were peaceful citizens, weak and unarmed, butchered wherever they were caught. Round the Altar the heaps of corpses grew higher and higher, while down the Sanctuary steps poured a river of blood and the bodies of those killed at the top slithered to the bottom.Josephus's account absolves Titus of any culpability for the destruction of the Temple, but this may merely reflect his desire to procure favor with the Flavian Dynasty. The Roman legions quickly crushed the remaining Jewish resistance. Some of the remaining Jews escaped through hidden underground tunnels and sewers, while others made a final stand in the Upper City. This defense halted the Roman advance as they had to construct siege towers to assail the remaining Jews. Herods Palace fell on September 7, and the city was completely under Roman control by 8 September. The Romans continued to pursue those who had fled the city in the following days.SIEGE OF ALESIA -In 52 BC, Gaul was set alight. Julius Ceasars legions were facing an uprising across the region, which threatens to erase six years of hard fought campaigning. The revolt was led by Vercingetorix, a young burny noblelman who was able to match Ceasars own cunning and determination. The two would clash decisively at the siege of Alesia, where the ultimate fate of both sides hung in the balance. Overshadowed by these massive historical headlines would be the tragic tale of the cities citizens, who found themselves abandoned by both leaders.BETWEEN A ROCK AND A HARD PLACEVercingetorix and approximately 80,000 of his soldiers occupied the hilltop town, they were quick to send out messengers calling for help before the twelve Roman legions with 60,000 men were in position. Ceasar elected to starve out the defenders, and established a set of encircling fortifications meant to completely cut off their connection to the outside world. Inside Alesia, the Gauls were in a terrible position, they had limited supplies which would quickly be depleted, but had no idea where nor even if a relief force would arrive. Their only option was to find a way to make supplies last as long as possible and hope this bought enough time for reinforcments to break the siege. To fail in this measure would mean an end of the revolt, and the ultimate fall of Gaul. Vercingetorix first began by collecting all the grain in town and establishing a system of rations, however as the days rolled by, it became increasingly obvious that the math was not adding up. More desperate measure would have to be taken to survive the blockade. A gallic councel was called to discuss the matters, it was resolved that all those whose age or bodily infirmity incapacitated them from active service should immediatley leave the city. Yet the more Draconian measure of resorting to canniblalism was kept only as a last resort. At the same time, the legions also faced their own dilemma, scouts reported that a massive Gallic force of around 120,000 was indeed on its way. The Romans were now under the very real threat of being surrounded themselves. To meet this army, Ceasear had a second set of outer facing walls built, just behind his first line of forifications, it would be a fight for their lives as defeat would likely mean slaughter, even if some managed to escape back to Rome, this would be the political death sentence for their leader. Caesar was not about to let this happen, both sides were determined it would be victory at all costs, the lives of the non combatants would be spent to achieve this end.THE FATE OF ALESIA’S CITIZENSThe women, children, elderly and infirm were banished from Alesia, they shuffled in a long column towards the enemies lines, hoping they might be met with the clemency Caesar had shown in the past, however the general could be every bit as cruel as he was merciful. when the citizens of Alesia arrived outside the Roman lines, their piteous appeals fell on deaf ears. Granting them safe passage would break the blockade, allowing information to flow between the two Gallic forces and creating an opportunity for an attack. The other option of taking the civilians as prisoners was not viable. Though they might fetch a good price in the slave markets, neither food nor guards could be devoted to secure them as prizes of war, given the looming threat, Caesar gave the orders that none were to be admitted. The citizens of Alesia were now utterly and completely abandoned. They could neither pass through the roman lines nor return to their own, both generals were ironclad in their determination, unwilling to take the strategic penalty of providing aid, the populace had become a pawn in a larger game, and so remained trapped in no-mans land by two leaders facing off in a battle of wills. Here they were left to starve in full view of both armies.THE FINAL DAYSHistory records little of their ultimate fate, but we have done our best to reconstruct those final, tragic moments. We must imagine that upon being denied access by the Romans there must have been a sense of shock, this was likely tempered by the thought they were avoiding the embrace of slave masters and could return to Alesia to await the outcome of the siege in solidarity with their countrymen. However, when they found the town gates barred, unimaginable horror must have seized them. A cold dread rising from the depths of their stomachs, followed by a sudden rush of heat as panic came on. What happened as news spread in a wave of shouts through the crowd. Did they try to force their way in, climb the walls, or implore with wails that the children at least be saved, perhaps some attempted to return to the Roman lines, or make an escape only to be thrown back with force. As night brought a close on the drama of the day, the townsfolk would have made camp, hoping by that dawn the nightmare would pass. On the second day, we can imagine the citizens once again implored both sides to take them in, but to no avail. As the hot September sun intensified with each passing hour, so too did distress and desperation. Darkness again bringing an end to the heat, but not the suffering. The following day would have seen continued attempts by the optimistic or desperate members of the group to negotiate with either side, those with enough strength may have gone out to forage for roots, nuts, and small animals to eat, while the weak remained were they had been that night, praying to their gods through dried and cracked lips. Some small amount of relief may have come from charitable Gauls in Alesia who tossed supplies over the walls or opportunistic Legionaries who traded their rations for valuables at extortionate rates, by nightfall however, the citizens would have been deep in the grips of hunger, the group likely circled around their fires and discussed the very real fact that they could not all make it through this trial. Perhaps slots were drawn or volunteers stepped forth to give the last bits of food to those most likely to survive, suicide may have been favored by some who wished to end the suffering on their own terms, and so like the leaves of fall, the citizens of Alesia withered away. Caesar’s commentaries state that Gallic reinforcements did finally arrive, though we are left guessing as to the exact timeline of events. Did the army make it while the townsfolk were still alive? Or had they all been claimed by exposure and hunger? We do not know, however what we do know is that the ensuing hard fought battle between the Gauls and Romans was a desperate, bloody affair that resulted in a victory for the legions. The large Gallic army was forced to disperse without breaking the siege, and Vercingetorix was finally forced to admit defeat. Caesar is said to have avoided reprisals against those who surrendered, in this case we can only hope that the citizens of Alesia who survived were treated generously.REMEMBERING THE TRAGEDYSome may have found this story overly gratuitous, yet this is how we must treat history, as a story with dimension and color, rather than a black and white timeline. These were real people with real lives, they had hopes, dreams, fears and pains, they lived and breathed just as we do, if we remove this tragedy from history, then no costs can be seen to outweigh the benefits of decisions, we are reduced to a past were the ends always justify the means, a past where might makes right. The fate of Alesias citizens is treated with a single line in Caesar’s commentaries. “how will our descendants look back on the history of our generations?”. Will those of the 22nd century read about a second world war devoid of the Holocaust. We must not forget, so that we will not be forgotten.SIEGE OF CONSTANTINOPLE -At the beginning of the siege, Mehmed sent out some of his best troops to reduce the remaining Byzantine strongholds outside the city of Constantinople. The fortress of Therapia on the Bosphorus and a smaller castle at the village of Studius near the Sea of Marmara were taken within a few days. The Prince’s Islands in the Sea of Marmara were taken by Admiral Baltoghlu’s fleet.Mehmed's massive cannon fired on the walls for weeks, but due to its imprecision and extremely slow rate of reloading the Byzantines were able to repair most of the damage after each shot, limiting the cannon's effect.The Ottoman Turks transport their fleet overland into the golden Horn. Meanwhile, despite some probing attacks, the Ottoman fleet under Suleiman Baltoghlu could not enter the Golden Horn due to the chain the Byzantines had previously stretched across the entrance. Although one of the fleet's main tasks was to prevent any ships from outside from entering the Golden Horn, on 20 April a small flotilla of four Christian ships managed to slip in after some heavy fighting, an event which strengthened the morale of the defenders and caused embarrassment to the Sultan. Baltoghlu's life was spared after his subordinates testified to his bravery during the conflict. Mehmed ordered the construction of a road of greased logs across Galata on the north side of the Golden Horn, and dragged his ships over the hill, directly into the Golden Horn on 22 April, bypassing the chain barrier.This seriously threatened the flow of supplies from Genoese ships from the — nominally neutral — colony of Pera, and demoralized the Byzantine defenders. On the night of 28 April, an attempt was made to destroy the Ottoman ships already in the Golden Horn using fire ships, but the Ottomans had been warned in advance and forced the Christians to retreat with heavy losses. Forty Italians escaped their sinking ships and swam to the northern shore. On orders of Mehmed, they were impaled on stakes, in sight of the city's defenders on the sea walls across the Golden Horn. In retaliation, the defenders brought their Ottoman prisoners, 260 in all, to the walls, where they were executed, one by one, before the eyes of the Ottomans. With the failure of their attack on the Ottoman vessels, the defenders were forced to disperse part of their forces to defend the sea walls along the Golden Horn.The Ottoman army had made several frontal assaults on the land wall of Constantinople, but were always repelled with heavy losses.Venetian surgeon Niccolo Barbaro, describing in his diary one of such frequent land attacks especially by the Janissaries, wrote:“They found the Turks coming right up under the walls and seeking battle, particularly the Janissaries ... and when one or two of them were killed, at once more Turks came and took away the dead ones ... without caring how near they came to the city walls. Our men shot at them with guns and crossbows, aiming at the Turk who was carrying away his dead countryman, and both of them would fall to the ground dead, and then there came other Turks and took them away, none fearing death, but being willing to let ten of themselves be killed rather than suffer the shame of leaving a single Turkish corpse by the walls.”After these inconclusive frontal offensives, the Ottomans sought to break through the walls by constructing underground tunnels in an effort to minethem from mid-May to 25 May. Many of the sappers were miners of Serbian origin sent from Novo Brdo by the Serbian despot. They were placed under the command of Zagan Pasha. However, an engineer named Johannes Grant, a German who came together with the Genoese contingent, had counter-mines dug, allowing Byzantine troops to enter the mines and kill the workers. The Byzantines intercepted the first Serbian tunnel on the night of 16 May. Subsequent tunnels were interrupted on 21, 23, and 25 May, and destroyed with Greek Fire and vigorous combat. On May 23, the Byzantines captured and tortured two Turkish officers, who revealed the location of all the Turkish tunnels, which were then destroyed.On May 21, Mehmed sent an ambassador to Constantinople and offered to lift the siege if they gave him the city. He promised he would allow the Emperor and any other inhabitants to leave with their possessions. Moreover, he would recognize the Emperor as governor of the Peloponnese. Lastly, he guaranteed the safety of the population that might choose to remain in the city. Constantine XI only agreed to pay higher tributes to the sultan and recognized the status of all the conquered castles and lands in the hands of the Turks as Ottoman possession.“Giving you though the city depends neither on me nor on anyone else among its inhabitants; as we have all decided to die with our own free will and we shall not consider our lives.”Around this time, Mehmed had a final council with his senior officers. Here he encountered some resistance; one of his Viziers, the veteran Halil Pasha, who had always disapproved of Mehmed's plans to conquer the city, now admonished him to abandon the siege in the face of recent adversity. Zagan Pasha argued against Halil Pasha, and insisted on an immediate attack. Mehmed planned to overpower the walls by sheer force, expecting that the weakened Byzantine defense by the prolonged siege would now be worn out before he ran out of troops and started preparations for a final all-out offensive.Preparations for the final assault were started in the evening of May 26 and continued to the next day. For 36 hours after the war council decision to attack, the Ottomans extensively mobilized their manpower in order to prepare for the general offensive. Prayer and resting would be then granted to the soldiers on the 28th, and then the final assault would be launched. On the Byzantine side, a small Venetian fleet of 12 ships, after having searched the Aegean, reached the Capital on May 27 and reported to the Emperor that no large Venetian relief fleet was on its way. On May 28, as the Ottoman army prepared for the final assault, large-scale religious processions were held in the city. In the evening a last solemn ceremony was held in the Hagia Sophia, in which the Emperor and representatives of both the Latin and Greek church partook, together with nobility from both sides.Shortly after midnight on May 29 the all-out offensive began. The Christian troops of the Ottoman Empire attacked first, followed by the successive waves of the irregular azaps, who were poorly trained and equipped, and Anatolians who focused on a section of the Blachernae walls in the northwest part of the city, which had been damaged by the cannon. This section of the walls had been built earlier, in the eleventh century, and was much weaker. The Anatiolians managed to breach this section of walls and entered the city but were just as quickly pushed back by the defenders. Finally, as the battle was continuing, the last wave, consisting of elite Janissaries, attacked the city walls. The Genoese general in charge of the land troops,Giovanni Giustiniani, was grievously wounded during the attack, and his evacuation from the ramparts caused a panic in the ranks of the defenders.With Giustiniani's Genoese troops retreating into the city and towards the harbor, Constantine and his men, now left to their own devices, kept fighting and managed to successfully hold off the Janissaries for a while, but eventually they could not stop them from entering the city. The defenders were also being overwhelmed at several points in Constantine's section. When Turkish flags were seen flying above a small postern gate, the Kerkoporta, which was left open, panic ensued, and the defense collapsed, as Janissary soldiers, led by Ulubatli Hasan pressed forward. Many Greek soldiers ran back home to protect their families, the Venetians ran over to their ships, and a few of the Genoese got over to Galata. The rest committed suicide by jumping off the city walls or surrendered.The Greek houses nearest to the walls were the first to suffer from the Ottomans. It is said that Constantine, throwing aside his purple regalia, led the final charge against the incoming Ottomans, perishing in the ensuing battle in the streets just like his soldiers. On the other hand, Nicolò Barbaro, a Venetian eyewitness to the siege, wrote in his diary that it was said that Constantine hanged himself at the moment when the Turks broke in at the San Romano gate, although his ultimate fate remains unknown. Some say Constantine put on regular armour, laid aside his own elaborate protection, and walked out the door while his servants begged him to stay, they say Constantine made a final heroic charge into the Ottoman ranks, never to be seen again…After the initial assault, the Ottoman Army fanned out along the main thoroughfare of the city, the Mese, past the great forums, and past the Church of the Holy Apostles, which Mehmed II wanted to provide a seat for his newly appointed patriarch which would help him better control his Christian subjects. Mehmed II had sent an advance guard to protect key buildings such as the Church of the Holy Apostles.A small few lucky civilians managed to escape. When the Venetians retreated over to their ships, the Ottomans had already taken the walls of the Golden Horn. Luckily for the occupants of the city, the Ottomans were not interested in killing them, but rather in the loot they could get from raiding the city's houses, so they decided to attack the city instead. The Venetian captain ordered his men to break open the gate of the Golden Horn. Having done so, the Venetians left in ships filled with soldiers and refugees. Shortly after the Venetians left, a few Genoese ships and even the Emperor's ships followed them out of the Golden Horn. This fleet narrowly escaped prior to the Ottoman navy assuming control over the Golden Horn, which was accomplished by midday.The Army converged upon the Augusteam, the vast square that fronted the great church of Hagia Sophia whose bronze gates were barred by a huge throng of civilians inside the building, hoping for divine protection. After the doors were breached, the troops separated the congregation according to what price they might bring in the slave markets.Ottoman casualties are unknown but they are believed by most historians to be very heavy due to several unsuccessful Ottoman attacks made during the siege and final assault. Barbaro described blood flowing in the city "like rainwater in the gutters after a sudden storm", and bodies of the Turks and Christians floating in the sea "like melons along a canal".Thanks for Reading, Cheers!

Attack on Harmandir Sahib :Jarnail Singh Bhindrawale was leading the demand of Sikhs for the implementation of the Anandpur Sahib Resolution which had nothing anti-national or anti-Indian in it. But to serve her own political interests Indira Gandhi ( Prime Minister, India) advertised Jarnail Singh Bhindrawale as anti-national and made it an excuse to attack Harmandir Sahib in June 1984. Not only Harmandir sahib but 40 other gurudwaras were also attacked.This was followed by mass killings of Sikh youth in all the villages of Punjab.Most of the Sikhs clearly understood the evil thinking behind this attack which was aimed not to crush anti national people but to “teach Sikhs a lesson” so that they never again oppose the anti-national policies of Congress.Killing of Indira Gandhi :On 31st October , same year (1984), two Sikhs named Beant Singh and Satwant Singh in Delhi police who were posted at Indira Gandhi's residence in New Delhi, killed her.Genocide of Sikhs :Soon after the death of Indira Gandhi , Anti-Sikh feelings were stroked throughout India by using the government controlled electronic media and rumors were spread against Sikhs.Meanwhile Doordarshan controlled by the govt. regularly broadcasted Mrs. Gandhi’s body lying in state along with a grieving Rajiv Gandhi and shots of agitated crowds, which bellowed ‘khoon ka badla khoon se lengey’.Having prepared the ground, Congress party workers commissioned trucks to bring in villagers from the outlying villages armed with iron rods and gasoline. They were assured police non-interference. It did not need much inducement to egg poor villagers to help themselves to Sikh property. Rape was an additional bonus for these depraved Congress animals.What followed was brutal killing of Sikhs in Delhi, Kanpur, Rourkela and other cities in all over India in which more then 15,000 Sikhs were murdered in broad daylight by the supporters of Indira Gandhi while police watched, all this when India had a Sikh president but without any power.Of these 6000-7000 died on Delhi roads in broad daylight and after a score of commissions and enquiry committees justice has still eluded the Sikhs as the killers continue to walk on Delhi roads.Most observers agree that the violence began as random attacks on individual Sikh men who were pounced upon in public places, on public transport and on the streets on 31 October. Some people attempted to pass off the day’s events as a reactive outburst of anger at the assassination of Indira Gandhi by two Sikh members of her security guard. But what happened over the next three days ( Nov 1 – Nov 3 , 1984 ) makes it impossible to dismiss those events as spontaneous expressions of outrage.The series of attacks on Sikh homes, gurudwaras and commercial establishments which began on 1 November seems to have been the work of organized hoodlums who collected large mobs for systematic looting and killing. Broadly speaking, the attacks can be placed in three categories:What Hapened in Delhi :(a) Looting and killing in middle and upper middle-class localities, such as Lajpat Nagar, Jangpura, Defence Colony, Friends Colony, Maharani Bagh, Patel Nagar, Safdarjung Enclave, and Punjabi Bagh. Here, houses, gurudwaras and shops were looted and burnt, and a large number of vehicles, including buses, trucks, cars and scooters, were set ablaze. Some people were injured and others killed. These were posh localities of Delhi.(b) Systematic slaughter and rape that accompanied looting, arson and burning in the resettlement colonies, slums and villages around the city. Most of the deaths occurred in areas like Trilokpuri, Kalyanpuri, Mangolpuri, Sultanpuri, Nand Nagri, Palam village, Shakurpur and Gamri. Rows of houses and huts were burnt down and hundreds of men and young boys were beaten, stabbed and burnt to death. Many women were abducted and raped. A large number of persons are still reported missing by their families. Houses and gurudwaras were looted and burnt down.These are resettlement colonies.(c) Attacks on Sikh men and boys in the streets, trains, buses, markets and workplaces. Many of them were brutally murdered. Some were burnt alive or thrown out of trains. Others escaped with injuries of a more or less serious kind. This kind of attack seems to have been done at random-any man who looked like a Sikh was made a target.(d) The pattern of murder and arson was similar in most parts of Delhi, in as far-flung places as Palam village, Mangolpuri, Kalyanpuri, and Bhogal. However, the intensity of violence was far more severe in poorer resettlement colonies than in middle-class areas.What Hapened in rest of India :Besides Delhi Sikh killings took place in Himachal Pradesh, Haryana, Rajasthan, MP and UP. Worst hit cities were Lucknow, Kanpur, Ranchi and Rourkela.Even people tried to burn my father's shop ( in uttar pradesh) which was saved by neighbours.ROLE OF CONGRESS (I) : The killings were systemetically masterminded by Congress (I) leaders in their respective areas. Houses, shops , buildings, factories belonging to sikhs were earmarked and looted and burnt.Many of the congress leaders were seen/heard telling their supporters to ensure maximum killing and looting of Sikhs in their areas .Mr. H.K.L. Bhagat, Minister of state (Information and Broadcasting). Jagdish Tytler, Cong.(I) M. P. from Sadar Constitutency. Sajjan Kumar, Cong. (I) M.P. from Mangolpuri were the major leaders involved in leading mobs to kill Sikhs.Use of voter lists by the Congress PartyOn 31 October, Congress party officials provided assailants with voter lists, school registration forms, and ration lists.The lists were used to find the location of Sikh homes and business, an otherwise impossible task because they were located in unmarked and diverse neighbourhoods. On the night of 31 October, the night before the massacres began, assailants used the lists to mark the houses of Sikhs with letter "S". In addition, because most of the mobs were illiterate, Congress Party officials provided help in reading the lists and leading the mobs to Sikh homes and businesses in the other neighbourhoods using the lists the mobs were able to pinpoint the locations of Sikhs they otherwise would have missed.In some cases, the mobs returned to locations where they knew Sikhs were hiding after consulting their lists. One man, Amar Singh, escaped the initial attack on his house by having a Hindu neighbour drag him into his neighbour's house and declare him dead. However, a group of 18 assailants later came looking for his body, and when his neighbour replied that others had already taken away the body an assailant showed him a list and replied, "Look, Amar Singh's name has not been struck off from the list so his dead body has not been taken away." Sikh men not in their homes were easily identified by their distinctive turban and beard while Sikh women were identified by their dress.Lalit Makan, Cong. (I) Trade Union Leader and Metropolitan Councillor. Reportedly paid to mob Rs. 100 each plus a bottle of liquor. A white ambassador car reportedly belonging to him came 4 times to the G.T. Road area near Azadpur. Instructions to mobs indulging in arson were given from inside the car.Dharam Das Shastri, Cong. (I) M. P. from Karol Bagh. Reported to becarrying voters list with him at Prakash Nagar for identification of Sikhs. On November 5, according to newspaper reports, he along with other Congress-I leaders tried to pressurize the SHO of Karol Bagh Police Station to release the persons who arrested during the police raids to recover looted property.Dr. Ashok Kumar, Member of Municipal Corporation, Kalyanpuri. Reportedly held a meeting in Kalyanpuri, following which violence broke out immediately. According to many eye witnesses he led mobs which indulged in loot, murder, arson and rape.Sukhan Lal Sood, Metropolitan Councillor. According to eye witnesses was seen leading mobs, which indulged in loot, murder, arson and rape. He had come with petrol and serial lists and addressess of Sikhs in the locality.After few days of violence he came to distribute blankets to the victims the female victims, recognized him and drove him out. .Jagdish Chander Tokas, Ishwar Singh, Balwant Khokhar, Youth Congress-I Leader, Delhi, Identified as one of the persons responsible for instigating looting and arson in Palam Colony area. Faiz Mohammad, Youth Congress-I Leader,Ratan, Youth Congress-I Leader, named as having taken part in violence and looting in Palam Colony area. Satbir Singh, Youth Congress-I. He allegedly brought bus loads of people from Ber Sarai to Sri Guru Harkrishan Public School (Munirka). They burnt school buses and parts of the school building. He was reportedly involved in looting and beating of Sikhs which carried on throughout the night on November 1.(More details in footnotes.)Role of Rajiv Gandhi :On the 19th of November 1984 the birth anniversary of Indira Gandhi, Rajiv Gandhi became infamous statement condoning the murder of Sikhs ‘when a mighty banyan tree falls the earth beneath it is bound to shake’. Rajiv Gandhi had no words of sympathy for the families of the murdered.1809 people arrested were set free on the intercession of the Congress party. The government refused to institute an enquiry into the Sikh holocaust on the plea that it would be counter productive.ROLE OF POLICE and ADMINISTRATION :All throught the period from October 31 to November 4 - the heights of the riots the police all over the city uniformly betrayed a common behavioural pattern marked by(i) total absence from the scene; or(ii) a role of passive spectators or(iii) direct participation or abetment in the orgy of violence against the Sikhs.As per the report (Who are the Guilty )In the resettlement colonies, the police came out from their passive role and directly participated in the violence against the Sikhs. We were told by survivors that at the first signs of tension those who felt threatended personally went to the nearby police stations to seek their intervension. But the police did not respond. In Trilokpuri, the police reportedly accompanied the arsonists and provided them with diesel from their jeeps. The Station Hours Officer (SHO) of Kalyanpuri police station under which Trilokpuri falls, withdrew the constables who were on duty there when action against the SHO and his two colleagues by suspending and arresting them for a criminal negligence of duties. In Sultanpuri, the SHO, one Bhatti, is alleged to have killed two Sikhs and helped the mob in disarming those Sikhs who tried to resist the mob.When after this destruction and murders, people went to complain and file FIR's the police in many areas refused to record their complaints, according to information gathered from the Hindu neighbours of the victims. A respected Sikh professional whose house was burned on 1st November was not able to register an F.I.R. despite all efforts. In Mangolpuri we were told, a police officer asked the Hindu complaintants why they were protecting Sikhs and advised them to look after safety of Hindus. Typical was the experience of Dharam Raj Pawar and Rajvir Pawar - two residents of Ber Sarai - who on November 1, went to the sector IV R.K. Puram Police station to ask for protection of Sikh family (which till then was being sheltered by Hindu neighbours from impending attack by a mob led by a Congres-I man, Jagdish Tokas) The officer in charge of the police station reportedly told them that he could not offer any help. Two constables later said to them, " You being Jats should have killed those Sikhs. What are you doing here ? Don't you know a train has arrived from punjab carrying bodies of Massacred Hindus ?" ( this train rumor was totally false and was used to incite anti -Sikh feelings) .Soon after the assassination (October 31), a meeting was held at 1 Safdarjung Road, the Prime Minister's official residence where the then Lt. Governor P.G. Gaval, a Congress (I) leader M.L. Fotedar and the Police Commissioner among others, met. A senior police officer present at the meeting expressed the view that the army should be called as otherwise there would be a holocaust. No attention was paid to the view.Every one in adminsitration including The Lt. Governor of Delhi Mr. Gaval , Home minister P.V. Narsimha rao were well informed regarding the situation in capital and repeated requests by concerned officials to call in army and impose curfew fell on deaf ears.Deputy Commissionar of Faridabad had asked for army on November 1, but troops arrived only on November 3.IT WAS GENOCIDE NOT RIOTS :As per Oxford dictionary :Riots :A violent disturbance of the peace by a crowd.A situation in which a group of people behave in a violent way in a public place, often as a protest.Genocide :The deliberate killing of a large group of people, especially those of a particular nation or ethnic group.Footnotes :1. Mr. H.K.L. Bhagat, Minister of state (Information and Broadcasting). On November 5, reported to have intervened to get miscreants released who were held in Shahdara Thana.2. Babu Ram Sharma, Member, Municipal Corporation (Ward No. 58) reported to be the right-hand man of H. K. L. Bhagat. Reportedly responsible for loot, arson and murder in trance-Yamuna areas-Babarpur, Chajupur Colony, Maujpur, Gonda. Allegedly led people on motor cycle with megaphone.3. Sajjan Kumar, Cong. (I) M.P. from Mangolpuri. Reported to have paid Rs. 100 and a bottle of liquor to each person involved in the killing of Sikhs4. Lalit Makan, Cong. (I) Trade Union Leader and Metropolitan Councillor. Reportedly paid to mob Rs. 100 each plus a bottle of liquor. A white ambassador car reportedly belonging to him came 4 times to the G.T. Road area near Azadpur. Instructions to mobs indulging in arson were given from inside the car.5. Dharam Das Shastri, Cong. (I) M. P. from Karol Bagh. Reported to becarrying voters list with him at Prakash Nagar for identification of Sikhs. On November 5, according to newspaper reports, he along with other Congress-I leaders tried to pressurize the SHO of Karol Bagh Police Station to release the persons who arrested during the police raids to recover looted property.6. Jagdish Tytler, Cong.(I) M. P. from Sadar Constitutency. On 6th November 5 p.m. he barged into a press conference that the Police Commissioner S. C. Tandon was holding. A journalist reports that he told the Police Commissioner that "by holding my men you are hampering the relief work".7. Mahendra, Metropolitan Councillor. Reported to have accompanied Dharam Das Shastri with voters lists at Prakash Nagar.8. Mangat Ram Singal, Member of Municipal Corporation (Ward No. 32) was reportedly with Dharam Das Shastri and Mahendra at Prakash Nagar.9. Dr. Ashok Kumar, Member of Municipal Corporation, Kalyanpuri. Reportedly held a meeting in Kalyanpuri, following which violence broke out immediately. According to many eye witnesses he led mobs which indulged in loot, murder, arson and rape.10. Sukhan Lal Sood, Metropolitan Councillor. According to eye witnesses was seen leading mobs, which indulged in loot, murder, arson and rape. He had come with petrol and serial lists and addressess of Sikhs in the locality. The women refugees, recognized him and drove him out.11. Jagdish Chander Tokas, Member of Municipal Corporation Munirka (Ward No. 14) reportedly led a mob to R.K. Puram Sector IV and V.12. Ishwar Singh, Member, Municipal Corporation, Mangolpuri (Ward No. 37). Allegedly led the mobs that indulged in looting, burning, rape and murder in Mangolpuri area.13. Balwant Khokhar, Youth Congress-I Leader, Delhi, Identified as one of the persons responsible for instigating looting and arson in Palam Colony area.14. Faiz Mohammad, Youth Congress-I Leader, Delhi, named by refugees in Shakurpur camp and in Mangolpuri for being a part of the mob indulging in looting, arson and murder.15. Ratan, Youth Congress-I Leader, Delhi, named as having taken part in violence and looting in Palam Colony area.16. Satbir Singh, Youth Congress-I. He allegedly brought bus loads of people from Ber Sarai to Sri Guru Harkrishan Public School (Munirka). They burnt school buses and parts of the school building. He was reportedly involved in looting and beating of Sikhs which carried on throughout the night on November 1.Bibliography :1. Who Are The Guilty? - human rights report by People's Union for Democratic Rights (PUDR) and people's Union for Civil Liberties (PUCL)2. The great Sikh Holcaust of 19843. 1984 anti-Sikh riots

The answer is simple and it will make you think twice about flying. Throw away your conspiracy theories, the simplest answer is almost always the right one. I was involved in the commercial and military programs that were partially ignited by TWA 800. The issue was known but TWA 800 made it a priority. All this falls under what is termed “ The Aging Aircraft Wiring Systems” initiatives., which were launched in earnest by multiple organizations once the severity was understood. The aviation industry in general was caught off guard. The FAA, AFRL, NAVAIR/ NAVSEA, DARPA, NASA, NTSB, Sandia, major universities and all the airframe OEM’s, all had major programs launched. We had no technology to assess how bad things had become but the initial findings were very bad, I mean scary bad. In many cases, it was starting to look like it would be cheaper to scrap some aircraft than trying to fix them.What they discovered is that the wiring insulation lost a lot more of its insulation properties over time than what was anticipated and that wire clamping and routing had to be re engineered in many cases . All this is especially true in aircraft fuel tanks. Jet fuel isnt explosive unless it is a vapor. The last place you want a bare wire where arcing could take place is in a fuel tank. The more aircraft they inspected the red flags were hoisted ever higher. It was so bad that the FAA issued directives on certain model aircraft, restricting them to not fly below a certain fuel level in the tanks. This was to assure that the bare wire areas were always submerged in fuel, especially during takeoffs and landings.Since then a lot has been done, but it is still a big problem. The OEM’s and the FAA have been working towards fuel tank inerting systems. Systems that siphon off the fuel vapor and replace it with nitrogen, eliminating the explosion risk.Just dig around a bit on the FAA’s website to see the details and you will think twice about boarding an old aircraft.A final note. One of the big engineering mistakes identified as the likely cause of such an explosion was that the wiring harness bundles were not segregated by what the wires were doing. The fuel level indicator sensors in the fuel tanks are low voltage and low current. They are designed not to spark. During these investigations and research initiatives, the original wiring harness designs were reviewed for potential problems. Sure enough there were plenty.The biggest risk came from bundling high power and high voltage wires together in the same harness as the low voltage sensor wires. Anyone who has ever worked on cars as a hobby can tell you about being zapped by the ignition coil through the wire insulation. In an aircraft, its the perfect storm for catastrophe. So common sense seemed to have been left out of the design meetings on a lot of this. This was one of the first things that they started to fix with Airworthiness Directives from the FAA.The final words from flight 800 right before the explosion, the captain was recorded as saying, “Look at that crazy fuel flow indicator there on number four, see that? The likely spark that ended the flight.Inside a 747 center wing tank .. size of a roomwalkthrough the fuel tanks in below video to appreciate the volumeAdditional notes …I have added information on what has happened in the industry, due to the many comments on maintenance, in the sections below.An NTSB presentation from back when i was involved with this ntsbfueltanks.pptA couple of slides from the above NTSB presentation from 2007 ….lots of people asked if other planes have had the issue…here are severalJUST ADDED - For those who want the hard core details on the latest environmental testing on wires : http://www.tc.faa.gov/its/worldpac/techrpt/ar082.pdfUSA Today http://usatoday30.usatoday.com/news/washdc/2001-05-02-faa.htm05/01/2001 - Updated 11:31 PM ETFAA to issue strict fuel-tank safety rulesBy Alan Levin, USA TODAYNearly five years after TWA Flight 800 exploded, federal aviation officials plan within days to issue tough new fuel-tank safety standards. The Federal Aviation Administration's final regulations would apply new standards to the entire fleet of about 7,000 commercial aircraft, several aviation sources told USA TODAY. The agency has estimated the changes will cost airlines about $170 million.The long-awaited rules address safety recommendations from the TWA 800 accident, which killed 230. The rules will require more inspections of tanks and revamped designs.The FAA estimated that without any changes the world's airlines could expect a fuel-tank explosion once every 4½ years. Officials hope the new fuel-tank rules will stretch the time between explosions to about 15 years.Instead of settling the issue, however, the new rules are intensifying the debate over what additional steps are needed to prevent fuel-tank blasts.The FAA last year proposed injecting tanks with inert gas to prevent explosions. But airline officials in recent weeks told an FAA advisory group that inert gas will not be necessary with the new standards, several aviation sources say. The airline industry contends the risks are so small that the estimated $1.6 billion cost of using inert gas would be better spent solving other safety problems.This contradicts findings by the National Transportation Safety Board last year that the only way to eliminate fuel explosions is by using inert gas.Three jets have been destroyed by center fuel tank explosions since 1990. On March 3, one person died when a Thai Airways International jet parked at a terminal in Bangkok was destroyed. Investigators for the National Transportation Safety Board say preliminary evidence shows the jet's center fuel tank exploded.Among the steps being taken to reduce the risks is an effort to get airlines to decrease use of on-board air conditioners, which heat fuel tanks. Last week, the FAA also issued an emergency order to shut off pumps in empty 737 tanks.USA Today Air-cooling gear can heat tanks05/01/2001 - Updated 10:00 PM ETAir-cooling gear can heat tanksBy Alan Levin, USA TODAYEvery day this summer, thousands of jets will take off with fuel tanks holding a heated, explosive mix of gases.Despite dozens of safety measures enacted since TWA Flight 800 exploded in 1996, officials continue to debate whether fuel tanks are safe enough. In the wake of another deadly fuel tank explosion aboard a jet in Bangkok, Thailand, in March, USA TODAY sought to determine how airlines in this country are following one suggestion to help reduce the heat in fuel tanks.In some Boeing jets, tanks sit next to air-conditioning systems that blast them with heat. At normal temperatures, jet fuel is difficult to ignite. But when fuel vapors get hot enough, a single spark can set off an explosion capable of breaking a jet apart in flight. Three such fatal explosions have destroyed jets since 1990.In a change from just a few years ago, many jets now use cold air piped in from the airport terminal instead of using the aircraft's own air conditioning, USA TODAY found.But roughly half of all flights in summer months still use the jets' air-conditioning systems, according to information from pilots, airline spokesmen and government officials."I think the running of the air-conditioning packs on the ground is the most important contributor to the development of (explosive) vapor," says Bernard Loeb, the recently retired head of the National Transportation Safety Board's aviation accident investigation team.After the TWA explosion, which killed 230 people, the NTSB recommended that air conditioning from the terminal be used.Explosions are rare, but the FAA estimates that on the average jet, fuel tanks are flammable 35% of the time. That could be reduced to 25% with mandatory use of alternative air-conditioning sources. Most of that risk occurs on the ground or shortly after takeoff. Cooler air at high altitudes cools fuel tanks.Spokesmen for Boeing, which built the three jets that exploded, and airlines say the tanks are safe. "We don't believe that the carriers who continue to run the (air-conditioning) packs have created an unsafe condition," Boeing spokesman Tim Neale says.One year ago, Boeing issued a letter to its customers suggesting that, "when available," airlines pipe cool air in from the terminal rather than run the on-board air conditioners. Airline officials say they have increasingly begun using "ground-conditioned air" in recent years, but more for economic than safety reasons. Cooling a jet with a system on the ground is cheaper than running a jet's air conditioners.Large carriers such as American Airlines and United Airlines direct pilots to switch off on-board air conditioners at terminals with an alternative source of cool air, spokesmen said.Airlines say that virtually all the nation's large hub airports are now equipped with air-conditioning systems at terminals. Southwest Airlines, which often flies to alternative destinations, uses ground air conditioning at about half of its most popular destinations, and the number is growing, spokeswoman Beth Harbin said.Alternative air conditioning can help only so much, however. Pilots report that some widebody jets are too big to be cooled exclusively by outside air, so they must continue to run on-board conditioners. And many outlying airports do not offer air conditioning.Because a jet's interior heats up so quickly in the sun, pilots say they sometimes have no alternative but to operate on-board conditioners. "I'm going down to Cancun, Mexico, this afternoon," airline pilot David Heekin said recently. "You better believe I'm going to have the air-conditioning packs going full swing."On jets made by McDonnell Douglas, such as the MD-11 and MD-80, the air conditioners were not placed next to the fuel tank. (Boeing now owns McDonnell Douglas.) Airbus placed air-conditioning packs next to tanks on its jets, but the company insulated the tanks and vented the area to reduce heat.see footnote link for overview of industry best practice and regulations on aircraft wiring from the FAA as a direct result of these activities.[1]Analysis of wreckage by Rendon GroupDisasters waiting to happen ……Photo of Arc-through of In-tank Fuel Pump Housing representative of post-accident inspection program (not from TWA 800) More aircraft would have shared the same or similar fate as TWA 800. We got lucky and fixed the problems first.Further ReadingAircraft Maintenance -The Inspection Process from http://www.coopind.com/news_AvMaint-WireMaintenance.htmOngoing wiring inspection is part of any aircraft’s regular safety check process. “In various checks (A/C/D-check) wiring is controlled visually for cleanness, cracks, chafing, color change and installation,” Arntz said. “This is done according to Original Equipment Manufacturer Standard Practice Manuals and EWIS (Electrical Wiring Interconnection System) tasks incorporated into the Aircraft Maintenance Program.”Still, unless something obvious happens—shortly before the explosion on TWA Flight 800, the captain was recorded as saying, “Look at that crazy fuel flow indicator there on number four, see that?”—electrical problems can go unnoticed. This is why such problems may not be found until the C- or D-Check, when “an aircraft is pretty much disassembled down to its bones,” said Frank Correro, StandardAero’s avionics manager in Springfield, Ill. “This is when technicians have their best opportunity to look at all of the aircraft’s wiring, to spot and rectify problems.” The only exceptions are self controlling systems built into an aircraft system that identify faults through BITE (Built-in Test Equipment) tests, and power wires that are specifically monitored with load control units (circuit breakers) to indicate system failure and protect wiring.Sometimes equipment manufacturers can help when aircraft wiring problems are identified in the shop. “Recently, HARCO was asked to look at a harness that had been in service for 20 years,” Gannon said. “The harness, which measured exhaust gas temperatures mated to probes, required exposed ring terminals to be fastened to the probe stud.” Now such an exposed ring terminal can invite moisture, which can reduce the insulation resistance of a wire harness. To address this, “Harco introduced some features to prevent the harness from absorbing water that improved the insulation resistance properties of the harness, and prevented false warning indicators from being triggered in the cockpit,” he said.What to Look ForUnfortunately for aircraft maintenance technicians, there is no advanced handheld device that can be waved over aircraft wires, to detect faults quickly and reliably. Instead, it takes careful visual inspections of wiring bundles, along with manipulation of wires for flexibility and signs of cracking, to detect problems before they become serious.“The problem is that most mechanics are not given extensive training in wiring inspection,” said Paul Sneden. He is an instructor at Global Jet Services. Based in Weatogue, Conn., Global Jet Services offers a range of professional development and continuing educations courses for aircraft technicians, including a week-long course in wiring inspection and maintenance that is used by MROs such as StandardAero. “They need extra hand-on training to identify and deal with the many signs of deteriorating aircraft wiring.”So what should mechanics be looking for when inspecting aircraft wiring? In general, anything that doesn’t look like factory-standard, Sneden replied. Ideally, wiring bundles should be secure but not under stress, with all clamps in place and properly locked. Exterior insulation should be unbroken and uncracked, and it should continue to be when flexed by hand to spot any hidden damage.Aging, faulty wiring is also thought to have contributed to the cockpit fire on Swissair 111 on September 2, 1998. While suggestive, the Canadian TSB investigation was unable to confirm if arcing from wiring of the in-flight entertainment system was the main event that ignited the flammable covering on insulation blankets that quickly spread across other flammable substances.Any form of staining is bad news. It could point to fluid leaking onto the wires, or deterioration of the wire’s insulation. “Similarly, any sign of chafing, charring, burning or arcing is not to be dismissed,” said Sneden. “The bundle needs to be removed and inspected, and if need be replaced.”That’s not all. Any signs of damage on wiring could be evidence of failures in other parts of the aircraft’s systems and airframe. The causes for wiring damage need to be tracked back to the source, so that these problems can be dealt with as well.A rule of thumb is the older and/or more used the aircraft, the more likely that the wiring is suffering from age-related deterioration. Since aircraft 20 years or older fall into the ‘aging’ category, mechanics need to be extra-vigilant when working on anything made in 1993 or earlier.Unfortunately, until the current wave of airline fleet renewals is over, MROs will find themselves coping with an increasing number of aging aircraft on a daily basis. The problem of wire deterioration is thus considered to be so serious, that “EWIS has been incorporated as a preventive measure to monitor wire aging,” said SR Technics’ Arntz. “Therefore it can be stated that on condition maintenance has been changed to a more preventive maintenance concept for wiring.”So far, “a complete re-wiring of aged wires is not yet a part of the rulemaking agenda,” he added. But this might change as active air fleets get older and if more aging wire issues emerge.Vigilance is VitalIf there is a moral to this tale, it is that aircraft wiring is a difficult-to-service element that must be monitored, inspected and maintained as rigorously as engines and avionics. The losses of TWA Flight 800 and Swissair Flight 111 point to the devastating consequences that can occur should this not happen.from An overview of the aircraft wiring issueBy David Evans, Editor Aviation Maintenance- Reprinted courtesy of Aviation Maintenance/Access IntelligenceThe potential hazard posed by bad aircraft wiring has generated a tremendous amount of activity in the industry. Some operators now treat wiring as a system, meriting attention during maintenance equivalent to the black boxes and other electrical components to which the wire is attached. The Federal Aviation Administration (FAA) proposal for fleetwide inspection of wiring in zones containing combustable materials or wiring within two inches of hydraulic, mechanical or electric flight controls could well involve a whole new - albeit necessary - burden on aircraft maintainers.The National Transportation Safety Board (NTSB) lent added urgency to the need for wiring inspections with its late June press conference, timed shortly before the 10 th anniversary of the TWA Flight 800 disaster, to reinforce and restate the Board’s concern about fuel tank safety and aging, cracked and deteriorated wiring. Recall that the accident airplane, an old B747-100, blew up shortly after takeoff from New York’s JFK International Airport on July 17,1996, for an overnight flight to Paris.All 230 aboard were killed when flammable vapors in the center wing fuel tank exploded. Electrical arcing in a bundle of wires outside the fuel tank produced a surge of current that passed down a fuel quantity indication system (FQIS) wire. As the Board noted in its press release of June 29, “The ignition of the flammable fuel/air mixture in the tank was attributed to an electrical failure.”Chafing the Dominant ProblemTo be sure, numerous airworthiness directives (Ads) have been issued since the TWA disaster, mandating wiring and other modifications to ensure electrical system safety. While the FAA does not have good records on the incidence of wire failures in the commercial industry, the U.S. Navy has amassed considerable information and insight. Navy data suggests that as many as one million man hours are spend annually in troubleshooting, isolating, locating and fixing wiring faults. Naval Air Systems Command (NAVAIR) data suggests that nearly as many hours are spent on unscheduled wiring maintenance as on scheduled maintenance.Further, the data collected by NAVAIR indicated that chafing contributed to more than a third (37%) of all wiring failures on Navy aircraft during the period 1980-1999. Moreover, despite the fact that chafing, or the erosion of insulation and the exposure of conductor, is a known problem, and the tools to resolve it are available, analysis of data from the years 2000 to 2004 show that chafing remained the leader of all wire failure modes on Navy aircraft.Perhaps the closest to an industry wide measure for the commercial side comes from the fleet wide inspections mandated by the FAA for fuel system wiring on the B737 fleet in 1998. The inspections were directed after fuel was observed leaking from a conduit for wiring that had been opened by electrical arcing. All B737 operators were required to report their findings to the FAA. The inspections revealed a clear relationship between aircraft age and the severity of the severity of the problems found. Fully 30% of aircraft with more than 70,000 hours were found with severe chafing and bare wires.That is twice the percent found on B737s with fewer than 70,000 hours. Some commercial operators have raised awareness of good wiring husbandry and practices to be avoided. For example, United Air Lines has widely distributed a poster outlining the do’s and don’ts for wiring maintenance.United’s laudable effort notwithstanding, we offer below a somewhat broader perspective of the aircraft wiring issue, including a contrarian view to the search for ever thinner and lighter wire insulation.Wiring 101The amount matters. Modern jets contain 100-200 miles of wiring running into every nook and cranny of the airplane. To borrow a biological metaphor, the wiring is akin to the body’s nervous system.The trend matters. New jets feature more wiring carrying more current (the advent of wireless systems is reversing this trend). The cabin area of a new-production jet, for example, features wiring for such things as in-flight entertainment systems. A measurement the electric power generating capacity of 1st, 2nd, and current generation jets of comparable passenger-carrying capability would show a steady increase in aircraft electric power generating capability.Protection matters, Fire detection and suppression is inadequate. Enough electric power for a medium-size office building is concentrated in the electrical and equipment (E&E) bay located under the cockpit. The E&E bay has neither fire detection nor suppression. A runaway electrical fire downed Swissair Flight 111 in Sept. 1998; a month later a Delta Airlines L-1011 experienced an electrical fire behind the flight engineer’s panel, in a location where hand extinguishers were virtually useless. With about 100 miles remaining on a flight from Hawaii to California, the crew effected an emergency landing at San Francisco. This airplane could easily have been “another Swissair,” involving an airplane of U.S. registry.Age matters. Wiring is not immortal; it ages in service. Over time, the insulation can break, exposing conductor. Exposed conductors create a fertile field for ticking faults, spurious signals and, worse, full-blown electrical arcing. Any carrier with a significant population of its aircraft having 10 or more years’ service has an aging wire problem.Location matters. Wiring is subject to changes in temperature, moisture, vibration and chafing. In some areas of the aircraft, such as in the leading/trailing edges of the wing, the landing gear wheel wells, etc., the physical stresses are higher than in more protected areas (e.g., the cabin)Installation matters. Sharp bend radii, improperly supported wire bundles, mixed insulation types in the same bundle, routing high and low power circuits in the same bundle, to name a few sins, can exacerbate the known environmental effects. Arcing in a vertically oriented bundle is more hazardous than in one running horizontally. One might suggest the large wire bundles indicate an electrical wiring philosophy based on ease of installation during manufacture, not necessarily ease of maintenance for the operator.Type matters. Certain types of wire insulation, notably aromatic polyimide, have known properties of hardness, vulnerability to cracking, and the tendency to arc spectacularly. Indeed, the carbonized insulation under arcing conditions itself becomes a conductor, spreading the danger literally with the speed of lightning.Maintenance matters. Wiring can be damaged during maintenance of other aircraft components, largely because technicians are unaware of the potential hazard created by stepping on a bundle or yanking it in such a way that brittle insulation is damaged further. Another major problem is unrelated maintenance damaging the wire. For example, drilling into aluminum structure creates shavings, called swarf. If those bits of swarf fall onto wire, they can eventually cut or wear through insulation, giving rise to intermittent (or worse) electrical failures. To be sure, it takes time to put a cover over the wires while drilling, then folding up the covers and removing them from the airplane. But it may take less time than involved in finding swarf-related faults in the wiring weeks or months later.The military’s experience matters. Some industry officials believe the U.S. military’s experience is not relevant jets are exposed to higher maneuvering loads and to harsher operating environments. On the other hand, the military’s experience with a jet designed with a 6,000 hour service life may be highly relevant to an airliner with a design service goal of 60,000 hours. The airliner is exposed to lower extremes over an order of magnitude longer period of time. In this respect, the military’s experience may be considered a form of accelerated aging from which the commercial side of the aerospace industry could learn much.Inspection types matter. Visual inspections are not enough. Eyeballing the wiring in a jet may uncover only a third or less of the insulation breaches exposing conductor. Yet technologies can be mobilized to quantify the state of wiring in an airplane, and to assess the amount of life remaining. These techniques can be used to target a cost-effective program of selective wire replacement.A Broad ViewThe airline industry may be at a place with respect to wiring that it was a decade ago with aging structure. The physical structure of an airliner now is built to be damage tolerant. That is, the airplane is designed such that structural components feature sufficient residual strength to withstand the weakening effects of fatigue cracking, say; from a tiny flaw that may lurk unseen somewhere in the structure from the day it leaves the factory. Recall that when damage tolerant structure was being debated, the manufactures worried the added weight would drive them out of the airplane building business and into the manufacture of railroad rolling stock.As it turned out, damage tolerant design added about 1,000 lbs. (454 kg) to the weight of a DC-10 while greatly extending its service life. Damage tolerant structure is now considered the norm.Wiring however, is not damage tolerant. As a weight saving measure, the thickness of the insulation has been shaved to minimum. In some wires, the insulation is about the thickness of four human hairs laid side-by-side. Or, as one expert observed, the industry is about “four hairs from electrocution.” Indeed, many of the problems of chafing, etc. elucidated above would not be the threats they are if the insulation was about four times thicker. Admittedly, this is kind of a brute-force approach, but by one estimate thickening the insulation would add about 200 pounds (91 kg) to the weight of wiring in a widebody jet.That’s about the equivalent weight of magazines and catalogues in the seat-back pockets. Perhaps a philosophy of damage tolerant electrical system design is only a matter of time—and certainly it is within the current state-of-the-art.Other potential improvements are numerous. Heavier insulation could be made an available option during manufacture. High power and low power wires could be better segregated. Connectors could be better separated, too and not all bunched together so that an electrical arc can jump from one to another. Longer- life circuit breakers could be installed as original equipment, saving considerable money over the long haul.Fire detection and suppression in the electronics and equipment (E&E) bay, and other unprotected areas where electrical systems are concentrated, could be insisted upon. The reduced maintenance costs, higher dispatch reliability, and fewer precautionary landings would, over the life of the airplane, more than offset the purchase cost of such features and protections.Brief Timeline on Flight 800 and the Fuel Tank Inerting FAA initiatives as a direct resultJuly 17, 1996 At about 2031 EDT, TWA flight 800, a Boeing 747-13, broke up in flight with a loss of life of all 230 passengers and crew. The crash debris fell into the Atlantic Ocean south of East Moriches, Long Island, NY. The accident investigation was one of the longest and most expensive in the NTSB's history. A substantial fraction of the aircraft was recovered and reconstructed, and numerous studies were carried in the effort to determine the probable cause. The Explosion Dynamics Laboratory at Caltech was asked by the NTSB to participate in the investigation and lead a group of researchers to examine the issues of fuel flammability, ignition, and flame propagation. EDL staff were involved from the fall of 1996 until the final hearing in August 2000.December 13, 1996 Safety Recommendation Letter A-96-174 published.TO THE FEDERAL AVIATION ADMINISTRATION: Require the development of and implementation of design or operational changes that will preclude the operation of transport-category airplanes with explosive fuel-air mixtures in the fuel tank: (a) significant consideration should be given to the development of airplane design modifications, such as nitrogen-inerting systems & the addition of insulation between heat-generating equipment & fuel tanks. Appropriate modifications should apply to newly certificated airplanes &, where feasible to existing airplanes.May 20, 1997 Added fuel tank flammability reduction to the Ten-Mosted Wanted List of Transportation Safety Improvements:"Reduce the potential for explosive fuel-air mixtures in fuel tanks of transport category aircraft. The NTSB has urged the FAA to make operational changes. They include refueling the center wing tank from cooler ground fuel tanks before flight, monitoring temperatures and maintaining a proper minimum amount of fuel in the tanks."December 8-9, 1997 NTSB Investigative hearing.August 22 and 23, 2000 Final hearing by NTSB and announcement of probable cause.2002 Fuel-tank inerting added to Ten-Most Wanted List (removed in 2008)Feb 17, 2004 The FAA announced that it is considering issuing a Notice of Proposed Rulemaking (NPR) requiring a fuel tank inerting system to be installed on existing aircraft with center wing tank flammability hazards.Feb 15, 2005 The FAA issued the special conditions for the certification of the flammability reduction means (FRM) or fuel tank inerting system proposed by Boeing for the 747 family of aircraft. This system will use hollow fiber membranes to generate "nitrogen enhanced air" to fill the vapor space of the center fuel tank in order to reduce the O2 concentration below 12% for a sufficient duration of the flight that the center fuel is not flammable for greater than 3% of the fleet operational time.Nov 15, 2005 The FAA has finally put on public display the Notice of Proposed Rulemaking on fuel tank inerting.November 23, 2005 The (NPRM) was published in the Federal register.March 21, 2006 The FAA has extended the deadline for comment on the NPRM to May 8, 2006.July 12, 2006 From the NTSB website: "The investigation into a wing fuel tank explosion on a Transmile Airlines B-727 airplane in Bangalore, India, on May 4, 2006, is ongoing. The evidence indicates that an explosion in the left wing fuel tank destroyed the structural integrity of the wing."July 21, 2008 The FAA has issued the the final rule: "Reduction of Fuel Tank Flammability in Transport Aircraft." The rule requires retrofitting of certain aircraft with heated center wing tanks and use of flammability reduction means (inerting systems) or ignition mitigation means (foam) on future aircraft to meet a target flammability exposure of 3% fleet average flammability and specific risk of 3% during ground operation and climb out on warm day, above 80 F. The present value of the total compliance cost is estimated by the FAA to be 1 billion USD. Boeing has developed and placed into production inerting systems based on hollow fiber membrane technology for the 747 and 737 typeOctober 16, 2008 Safety Recommendation A-96-174 closed as an acceptable action.More detailsFAA Lessons LearnedNASA Analysis https://sma.nasa.gov/docs/default-source/safety-messages/safetymessage-2011-01-09-twa800inflightbreakup.pdf?sfvrsn=4http://pe.org.pl/articles/2013/7/5.pdfhttps://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2025_981-1.pdfFootnotes[1] https://www.faa.gov/training_testing/training/air_training_program/job_aids/media/ewis_job-aid_2.0_printable.pdf