Boeing faces fresh safety questions after engine fire on flight from Scotland
Boeing faces fresh safety questions after engine fire on flight from Scotland
Passengers saw flames soon after flight left Edinburgh for New York in 2023, leading to emergency landing in Glasgow
Boeing faces fresh questions about the safety of its aircraft after an engine fire on a transatlantic flight from Edinburgh caused an emergency landing soon after takeoff.
Flames were seen by passengers briefly shooting from the engine of a Delta Air Lines 767 soon after it took off for New York in February last year, after a turbine blade broke off during takeoff.
The flames subsided while the plane was airborne but it made an emergency landing at Prestwick airport south of Glasgow, where ground crew noticed fuel leaking from the plane’s right wing.
The Air Accidents Investigation Branch, the UK government agency that investigates aviation safety, has written to the Federal Aviation Administration in the US asking it to take action with Boeing, which has its headquarters in Virginia.
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Boeing doesn't make engines.
Nobody is accusing Boeing for the turbine failure. They are questioning Boeing's drain tube track design failure. Source
According to the (Air Accidents Investigation Branch) AAIB, a high-pressure turbine blade had "fractured" in the 767's right engine, damaging a further five blades.
Vibrations from the "out of balance" turbine led a section of the wing to rupture, causing fuel to leak out, which was then ignited by the engine's exhaust.
The AAIB's report questioned why the vibrations from a broken engine were sufficient to fracture the Boeing 767's "slat track housing drain tube."
At the end of its report, the AAIB said: "It is recommended that the Federal Aviation Administration requires the Boeing Airplane Company to demonstrate that following this serious incident, the design of the slat track housing drain tube on the Boeing 767 family of aircraft continues to comply with the certification requirements for large transport aircraft."
The new design was vibration tested for five hours both laterally and vertically without failure and the system had a first mode resonant frequency response at 170 Hz and a second mode at 260 Hz. Analysis of the drain tube at 165 Hz demonstrated that with a 5g or 10g input load, the drain tube would fracture after either 200,000 or 21,000 fatigue cycles respectively, at the bend adjacent to the slat track housing. This equates to approximately either 20 minutes or 2 minutes of operation.
Doesn't seem to be major issue there either. Above is a quote from the AAIB report. They're talking about an already redesigned and upgraded drain this plan had installed in 2012. It was found the redesigned part performed better than required. Even when damaged on purpose before testing. The recommendation here is more like hey FAA maybe you should update the test requirements. 20 minutes or 2 minutes of holding up while shit is going wrong might not be enough.
https://asn.flightsafety.org/wikibase/308139
But even with all this going on the engine was making thrust. Pilot was just worried about flying across the Atlantic with a vibration they noticed was getting worse after 20 minutes in the air. They suspected but didn't even know the engine was blown until back on the ground. The fire was happening in the exhaust stream and not within any part of the plane itself.
Yup, most engine manufacture is undertaken by specialists. As a good example, Rolls-Royce is an airplane engine company that sometimes makes cars as publicity stunts.
HOWEVER.
It's not just about who makes engines. Aircraft are meant to last a good 30 years in service and you can't just ask some schmuck to clean it for $7.50 an hour and call that maintenance. Maintenance is extremely skilled work that tends to be operating under horrible time crunches, especially if a part is suspect and needs to have a plane partially taken apart so it can be changed for a fresh one- a plane that might be due to fly again tomorrow. Maintenance that needs that sort of knowledge tends to have some involvement with the parent company who built the planes, or is even contract work for them.
Boeing is rather notorious for being willing to put the schedule before safety- we've seen that in a lot of other accidents. I would absolutely believe that a Boeing manager skimped on engine maintenance because someone in the chain of command said "Get that plane out of the maintenance hangar today or you're fired, and damn the safety regulations."
But, that's just my industry knowledge. The actual circumstances could be way different, so let's go read the article.
OK, checking out the article, actually it seems totally innocent on the maintenance side of things- there was a turbine blade fracture during flight. Turbines are generally very reliable but it's a gargantuan pain in the ass to test those blades because they're crystalline structures, so a fracture goes from nanoscopic to taking out the whole blade all at once. I wouldn't expect maintainers to catch that.
The criminal part is actually way more interesting and concerning.
Civilian aircraft are built to be safe. I mean REALLY safe. Every system has a redundant (backup) system you can switch to if that system goes down and a way to isolate a damaged system. Planes can fly on only one working engine, or even safely glide down to the ground if they have no engines. We literally blow some engines up in their final stages of testing to make sure they can't blow up hard enough to take the wing out. Regulations demand it.
So that's why this is a criminal case. Because after that engine blade came loose and hit the wing, it ruptured a fuel line...
In an aircraft that was designed in compliance with regulations, while this would still be be cause to turn around and land the plane, it shouldn't actually be a safety problem at all. Just isolate the damaged system and switch to the redundant one. And they didn't have the ability to do that. Meaning that their aircraft design itself is likely out of compliance with regulations and doesn't meet the minimum safety requirements to have civilians on it. Which is... honesty way weirder, because who the hell signed off on this thing if it had a design issue like this?
Boeing.
The FAA has been allowing them to self-certify some safety analyses. I don't know if it was this model, or this kind of certification, but the FAA has definitely not been doing a thorough job.
Every system has a redundant (backup) system you can switch to if that system goes down
Well, except for the wings. And the cockpit. And the fuselage. And its accompanying door plugs
Are you daft? Why do you think it has TWO wings and TWO doors? And clearly you've never been invited to the under cock pit, where they keep plugs fit for any hole.
(is joke don't bite)
Not sure about the commercial planes, but some planes have a redundant wing.
https://theaviationgeekclub.com/time-israeli-air-force-f-15-baz-landed-one-wing-missing/
Turbines are […] crystalline structures
Are you implying they are not metal? Or that their heat treatment makes them brittle? If it’s the latter, that’s clearly a defect. Metals can achieve high rigidity and still retain great resistance through heat treatment.
Of the top of my head, IIRC the blades in a turbine are grown into a single crystal of titanium so there's no weak points between the crystalline structure.
Not titanium, nickel alloy.
Christ on a cracker!
Metals are crystalline, and high stress loads associated with being rotated like crazy make things brittle. IDK how brittle though, steel normally is super stretchy if I remember my studies right.
That’s why I asked for clarification. The line about them being crystalline makes no sense. Copper is crystalline, and can be super malleable or quite brittle depending on the grain structure. And you just don’t use brittle materials for high speed rotating equipment. And there are non destructive tests to check for embrittlement/fatigue.
Metals are made of crystals, they usually defourm along the grain boundaries and fatigue cracks also grow along them. By eliminating those boundaries you reduce the chance for fatigue cracks and make the overall blade stronger.
What page did you see those details on in the report? I skimmed it between meetings and will look again later.
They technical don't make airframes or doors either (and still don't until their buyout of their supplier goes through).
It's funnier than that. Spirit was Boeing. Before dipshit Jack Welch copycats spun it off. Now they're buying it back.