4 ms·
Yes, but when the engine came off, it also disrupted the third engine in the tail. Can't take off in this model with 2 out of 3 engines gone.
by baggy_trough 11mo ago
Yes, but when the engine came off, it also disrupted the third engine in the tail. Can't take off in this model with 2 out of 3 engines gone.
- jeffbee 11mo agoEven if they had the thrust (doubtful) there wouldn't be enough lift with a gaping hole in the leading edge of one wing.
- sq_ 11mo agoYeah, if they had had more altitude, I would guess that this would have looked even more like the AA 191 crash from 1979, with the left wing stalling and causing a roll and pitch down. 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_shootdown_incident https://en.wikipedia.org/wiki/2003_Baghdad_DHL_attempted_sho...
- crote 11mo agoAn important factor in AA 191 is that the engine leaving did significant damage to the hydraulic lines in that wing - including those for the leading-edge slats. At the time the plane was not equipped with any mechanism to keep the slats extended, so after hydraulic pressure was lost airflow over the wings caused them to retract, which significantly lowered that wing's stall speed. 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.
- AceyMan 11mo ago> significantly raised the stall speed (yeah, it's one of those weird metrics where "bigger is worse", so you're absolved)
- sokoloff 11mo agoThe video of the aircraft crossing the road wings level (well after #1 separated) and maintaining relatively controlled flight until too much energy bled off suggests to me the aircraft was likely to be controllable to a landing if sufficient thrust was available.
- PunchyHamster 11mo ago..for a moment. If there was sufficient hydraulics damage it might've stopped being controllable. And even if they worked the fire might've damaged the plane enough. For example https://www.faa.gov/lessons_learned/transport_airplane/accidents/N1819U https://www.faa.gov/lessons_learned/transport_airplane/accid... when they lost tail engine, all of the hydraulics went down
- loeg 11mo agoTo be clear, we don't yet know if the UPS flight lost hydraulics or not. There are several somewhat redundant hydraulic systems. (Also, as a result of the Sioux City crash you linked, there were several ADs issued requiring changes to hydraulics in these airframes.)
- loeg 11mo agoI thought the leading edge of the wing was intact in this case? I may be misremembering.
- bunderbunder 11mo agoYeah, pilots I know saw puffs of flame coming out of the engine, and said that that's a tell-tale sign of a compressor stall. Which could have been caused by debris from the separating left engine striking the turbine.
- loeg 11mo agoDebris, or even just smoke from the wing fire.
- bunderbunder 11mo agoIt was specifically the distinct, rhythmic puffing. I'm not sure you could expect the same pattern from debris or a wing fire.
- mlyle 11mo agoI think they were saying that smoke/particulates could be sufficient to upset the rear engine-- things short of what we ordinarily call "debris".
- loeg 11mo agoI'm just saying that smoke alone can cause a compressor stall -- it doesn't necessarily require larger debris.
- bunderbunder 11mo agoAh, gotcha. My bad.