Human Factors Issues In Aircraft Maintenance And Inspection: Fill & Download for Free

There are several good answers to your question already posted. Let me come at it from a different direction.Up front, let’s be clear on what we’re talking about. This Skybrary article — Uncontained Engine Failure — provides a common starting point. In particular, here are the first two paragraphs from it:“Most gas turbine engine failures are “contained” which means that although the components might separate inside the engine, they either remain within the engine case or exit it via the tail pipe. This is a standard design feature of all turbine engines and generally means that the failure of a single engine on a multi engine aircraft will not present an immediate risk to the safety of the flight. Sizeable pieces of ejected debris may, though, present a hazard to persons on the ground.“However, an “uncontained” engine failure is likely to be a violent one, and can be much more serious because engine debris exits it at high speeds in other directions, posing potential danger to the pressurised aircraft structure, adjacent engines, the integrity of the flight control system and, possibly, directly to the aircraft occupants.”I offer this as context for the rest of my response.Following the release of the 1997 White House Commission on Aviation Safety and Security (WHCASS) and follow-on National Civil Aviation Review Commission (NCARC) reports, the Commercial Aviation Safety Team was created as a government-industry partnership to address the most frequently identified safety issues leading to fatal aircraft accidents — the “tall bars” on a Pareto chart developed by the Boeing Company in cooperation with other prime manufacturers of airliners and the regulators and investigative bodies overseeing them.This is what the Pareto chart looked like after the first few years CAST was underway:As it happens, engine failures were not a particularly big contributor to the body count even before CAST was created, but they had cost a lot of airlines a lot of money over time. The FAA and engine manufacturers already had been actively working on reducing them as much as possible pre-1997, so engine safety was rolled into CAST’s agenda to help the group score what amounted to an early, easy win, even though engines didn’t loom particularly large in the greater scheme of things.A CAST “safety enhancement” (SE084: Uncontained Engine Failures) was duly identified and subjected to CAST’s “joint safety enhancement team” (JSAT) and “joint safety implementation team” (JSIT) processes, partly as a means of validating the effectiveness of those processes in zeroing in on contributory aspects of a given safety concern under investigation. These bodies felt the best way to get at the problem was through “mandatory inspections of turbine engines disks during shop visits.”I give you this history for two reasons:Some of the smartest aeronautical engineers in both the public and private sector felt like they could keep all smaller component failures “contained” as defined above — to them, the real worry was big, heavy chunks of engines breaking apart, not individual components from the low or high-pressure sections of those engines.They were, to be blunt, arrogant in asserting that their approach would eliminate (their word) uncontained engine failures. They were smart enough never to straight-up commit this to paper, but it was their mantra in CAST circles.I personally waved a huge B.S. flag when this assertion was made at a CAST meeting. I was basically mocked as not knowing what I was talking about by an FAA engineer involved in the effort. My response — which I continue to stand by — is that the kinds of temperatures and pressures developed by the latest generation of jet engines cannot be completely protected against by engine housings, period.Things will break, and there’s nothing that can completely prevent that; when what breaks is made of something like titanium, moving at incredibly high speed, you don’t always know where it’s going and the part won’t care what’s in its way or what collateral damage it might cause. The best that can be hoped for is to continue efforts to minimize post-failure consequences. (Truthfully, my real-time rebuttal was a lot less eloquent and might have contained a few observations regarding what said speaker was full of. That material was in fact fully contained.)In fairness, the pre-CAST engine improvement efforts were chasing the cause of a tragic 1996 accident (Delta Air Lines Flight 1288 - Wikipedia) and a previous high-profile accident involving The Crash of United Flight 232 in 1989. Unfortunately, in my opinion, they got tunnel vision. Engineers sometimes do that. I think that’s because they’re problem-solvers and occasionally have trouble with the notion that new problems they haven’t anticipated can crop up to replace old ones. I’m an air safety investigator. I don’t like assumptions, and I’ll accept previous prevention attempts at face value while never, ever assuming they’re absolute.So, to your question: anything mechanical is capable of breaking. Anything humans make can, under the right (wrong) conditions unmake itself. My kind establishes what led up to an observed failure; engineers and others then try to get at means of preventing such failures by improving manufacturing, maintenance and inspection processes and failure prediction capabilities. They also act to protect against previously unrecognized sources of risk, e.g., places where multiple critical components or back-up systems can be affected by a single golden bullet hitting exactly the right (wrong) spot.Two factors that stand in the way of absolute prevention have to be taken into consideration as well, both money-related:A practical, designed-in defense against a highly improbable failure sometimes may be deemed too costly to implement; andThe cost of making a highly improbable failure totally impossible usually can be sidestepped by building in redundancies, getting better at spotting impending failures, etc.Could the engine failure aboard Southwest 1380 have been prevented? We don’t know yet. It could be that something new and unexpected happened that existing repair, inspection and replacement cycles aren’t designed to spot or head off; it could be that one of those activities wasn’t performed as prescribed; it could be that the failure happened at just the right time to avoid detection before it turned deadly.Could something have been done to prevent the consequences of the failure once it happened? Again, we don’t don’t know yet. It’s possible that armor inside the skin of the fuselage, bulletproof glass and the like might have prevented debris from puncturing the aircraft, but there would have to be extensive testing done to see if even those measures could have made a difference. And, even if they could, such modifications would be incredibly costly and add weight that would have to be carried around by every single aircraft against a one in 100 million chance of a similar failure in the future.Would that cost be worth incurring? Not my department.

Legally? In the US, in most cases the heirs are entitled to nothing; except a refund of the original ticket price, value of luggage, etc... small stuffIt's kinda like medicine; to be entitled to some kind of big monetary award the heirs/estates would have to prove negligence, that the company was actively ignoring/subverting regulations, that they were deceiving regulators, etc. Just the fact that people died isn't enough to create liability.Why is this a good thing? Two reasons.Airlines and aircraft manufacturers get legal immunity from civil lawsuits by self reporting. If they inform the FAA of any issues they discover that could impact the safety of flight within ~24 hours (I forget the exact time it's definitely under 72 hours though) of discovering it they are protected from any civil lawsuits that may result if there is an incident. The companies get immunity for federal oversight of the issue from the very beginning. Believe me, the FAA guys are not some government chumps. I've been in the meetings where they're involved and they will ride you hard. They will demand high levels of action and progress that are appropriate to the potential risks. If they are not happy, they have the power to shut down every flight/aircraft impacted by the issue costing your company Billions and the industry Trillions. They can essentially put you out of business overnight.This gives the aerospace industry a completely different attitude about safety compared to most industries (ahem *cars* *cough* *GM* *cough* *VW* ahem). If anything we over report! Sometimes we basically tell the government hey "uhh we see this discrepancy, we're not sure if it's an issue because we're still investigating the impact, but theoretically, worst case, it could be; so we're reporting it." We report tiny stuff like "we found mislabeled raw materials while auditing a supplier's inventory at their facility" (not even in our own facility!). Because once you see it the clock has started, the whole department starts investigating, and unless you can prove, 100% for sure, that no one has accidentally used any of that mislabeled material when you start getting close to the ~24 hour mark you report that sh*t. No serious aerospace company would dream of covering up or hiding a potential safety issue from the FAA today. It would be suicidal because eventually something will happen and even if this was just a minor contributing factor it will come out in the investigation and then they'd lose everything. They'd be open to corporate and individual lawsuits that would wipe them out, destroy their reputation, etcWho would work on planes if they could be sued in the event something happened? Aircraft are incredibly safe, and when something does happen it's usually the result of several small normally insignificant events combining in an unforeseen way with some human error on top that results in incidents that have fatalities (most incidents don't involve any fatalities). I mean I wouldn't touch an airplane if I thought it meant a couple hundred people might sue the crap out of me. I'd need 2 witnesses, a couple engineers, and an army of lawyers just to perform basic maintenance. Whose going to pay for all that? Basically, no one would be able to afford to fly with that kind of sysetem.Aerospace is different because we have to be. We take safety very very seriously. Just ask someone in the industry how important is "safety of flight?" Everyone from the mechanic who assembled that part in the factory, to the guy who installed it, services it, all the way to the pilot and flight crew will all tell you it's the single most important thing. It's a big complicated supply chain and it's hard to know what part will end up on what planes; our friends and families all fly too.Aerospace mechanics have to sign, stamp, and certify their work. They take that responsibility very seriously, and they're personally liable if they sign off on something that isn't 100% true and correct to the engineering manual. I've had guys refuse to sign off on assemblies because of a typo in the assembly manual; not a technical error a typo! I know a major US airline (one of the biggest) that will send parts back if the finished wiring hasn't been routed in a way that looks neat/clean enough; nothing wrong with the part it's just not pretty so it's harder to inspect on the aircraft so they won't accept it. No sign off means no shipment, no installation, no payment, no flight to *insert vacation destination here*...