The timing and manner of the break make a lot more intuitive sense when you consider that the engine is essentially a massive gyroscope. As the plane starts to rotate, the spinning engine resists changes to the direction of its spin axis, putting load on the cowling. When the cowling and mount fail, that angular momentum helps fling the engine toward the fuselage.
It seems like both are true, but doesn't necessarily prove WHY the mount failed.
* why it failed at rotation (the first/only sudden change of direction under full throttle) rather than as soon as it was mounted onto the plane, while taxiing, as soon as they throttled up, mid-flight, or on landing. This is important because at rotation is the worst possible time for this failure: no ability to abort take-off, no ability to land safety under no or severely limited power, little time to react at all, full fuel. Knowing these failures are likely to manifest then stresses the importance of avoiding them.
* why it failed in such a way that it damaged the rest of the plane.
Not so much what was wrong with the mounting in the first place, if that's what you're asking. Presumably it was designed to withstand the forces of this moment and clearly has done so many times before.
The referenced AA Flight 191 is shockingly similar. It makes me wonder if aviation really is back sliding into a dangerous place.
The murder suicides in the last few decades seem more concerning.
https://www.easa.europa.eu/en/document-library/type-certific...
Dropping an engine entirely is a similar situation to a failure - with the benefit that you now have a substantially lighter if imbalanced aircraft.
Should this plane have been able to fly by design even with an engine fallen off?
https://www.reddit.com/r/aviation/comments/1p276xx/ntsb_issu...
That in turn reminds me of the DHL flight out of Baghdad in 2003 that was hit by a missile [0]. Absolutely amazing that they managed to keep it together and land with damage like that.
[0] https://en.wikipedia.org/wiki/2003_Baghdad_DHL_attempted_sho...
After AA 191 the DC-10 was equipped with a locking system: loss of pressure now results in the slats getting stuck in their current position. The MD-11 will undoubtedly also have this system, so a direct repeat of AA 191 is unlikely.
It doesn't seem aircraft are designed to survive these types of catastrophic failures.
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DCA26 22\C2<But beyond figuring out why the engine mount failed, I am very interested in what caused the actual crash. "Just" losing thrust in a single engine is usually not enough to cause a crash, the remaining engine(s) have enough margin to get the plane airborne. Of course this was a major structural failure and might have caused additional damage.
EDIT: It seems there was damage to the engine in the tail, even though this was not specified in the preliminary report, likely because it has not been sufficiently confirmed yet.
Seems like the risk/reward just isn't really there for the few of them still in service, and if anything happened it would be a PR nightmare on top of a tragedy.
Definitely an end of an era!
And air freight just gets a lot less public attention, I think they are going to keep flying them if they don't get grounded.
(Blancolirio points out that the DC-10 tanker is what they modernized to relatively recently -- before that they were flying even more dangerous WW2 airframes for firefighting.)
I agree on the end of an era. Hearing something else besides just Airbus- or Boeing-something always gives me a bit of joy. Even though MDs and DCs are of course Boeings in a sense now as well.
And the failure of an engine mounted on the left wing can cause debris to cross through the fuselage structure and cause a failure of the engine mounted on the right wing, or to fly thousands of feet in any particular direction, as happened to American Airlines in both a ground run incident, and in their Flight 883 accident.
https://www.dauntless-soft.com/PRODUCTS/Freebies/AAEngine/
https://aerossurance.com/safety-management/uncontained-cf6-a...
Besides the technical aspects that flight is an impressive example of resilience and skill. Bringing that plane down to the ground in nearly one piece was essentially impossible and a one in a million chance in itself.
[1] https://en.wikipedia.org/wiki/United_Airlines_Flight_232
From the photos, it’s clear it went up over the wing and impacted the fuselage with a (at least) minor explosion, which would have thrown foreign objects into the third engine in the tail for sure.
Losing 2/3 of the engines isn’t survivable on takeoff for this class of plane, at the weights they were at.
It's an engine - the thing pushing the entire plane forwards. Provided it is running (and at takeoff that's definitely the case), an engine being liberated from its plane suddenly has a lot less mass holding it back, so the logical thing to do is to shoot forwards. And because the wing is attached to the upper side of the engine, anything short of an immediate failure of all mounting points is probably also going to give it an upwards trajectory.
Add in air resistance, and you get the "swing across the wing and back" seen in the photos.
It’s clear from the photos this wasn’t the engine failing at all, and in fact the engine kept producing a ton of thrust (probably until it ran out of fuel as it pulled it’s fuel line apart while departing the wing), and instead the thing that is supposed to be so incredibly strong that it restrains all this chaos failed.
Which is a pattern in this family of aircraft, but definitely not a common or normal thing in general eh?
Most aircraft, the engine stays with the airframe even if it turns into a giant burning pile of shrapnel and dead hopes and dreams.
Yes, the initial videos were showing the tail engine flaming out. And in the 1979 crash, the engine also severed hydraulic lines that hold the slats extended. So they folded in due to the aerodynamic pressure, essentially stalling the wing.
> A review of the inspection tasks for the left pylon aft mount found both a general visual inspection (GVI) and a detailed visual inspection of the left pylon aft mount, required by UPS's maintenance program at a 72-month interval, was last accomplished on October 28, 2021.
frenchman_in_ny•1h ago
[0] https://avherald.com/h?article=52f5748f&opt=0
tremon•18m ago
If I'm parsing this correctly, they're saying that fatigue cracks should have been visible in the aft pylon mount, and that the forward mount was similarly fatigued but showed no damage on the outside?