- Looks like it's been moved to https://www.ntsb.gov/investigations/Documents/DCA26MA024%20P...
by philip1209
4 subcomments
- Originally explained on the blancolirio channel on YouTube -
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.
- Grounding all MD-11s and DC-10s is a major move. I guess it makes sense as a big factor was the fatigue cracks on the pylon (lugs), despite the pylon not being behind on inspections. I am wondering what the inspections of pylons in other planes will yield, likely that will determine whether the grounding will continue.
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.
by frenchman_in_ny
2 subcomments
- Adding summary analysis from AVHerald [0]
[0] https://avherald.com/h?article=52f5748f&opt=0
by Aman_Kalwar
0 subcomment
- Appreciate the transparency in these reports. The technical breakdowns always highlight how complex aviation safety is.
- Link doesn't seem to be available now:
> Page not found
> The page you're looking for doesn't exist.
- Revised URL -https://www.ntsb.gov/investigations/Documents/DCA26MA024%20P...
by anshumankmr
2 subcomments
- Very fast. Quite sad to see it happen. Also quite puzzling is how the Air India disaster still does not have a root cause analysis done (though supposedly it will be released end of this year)
- A commenter in HN thread covering the initial crash mentioned that the left engine detaching might have been the cause https://news.ycombinator.com/item?id=45821537
The referenced AA Flight 191 is shockingly similar. It makes me wonder if aviation really is back sliding into a dangerous place.
- Link to page that links to the report, as of now: https://www.ntsb.gov/investigations/Pages/DCA26MA024.aspx
by LinuxAmbulance
3 subcomments
- I'm surprised at how many years the plane went without having that part inspected. It looks like the failure was due to fatigue cracks, but the last time the part was inspected was in 2001?
by chimpontherun
3 subcomments
- surprised to see typos in aviation terms and acronyms: ADS-8 (page 3) and 747-BF (page 5)
by londons_explore
8 subcomments
- I was under the impression that a plane could deal with an engine failure at any point in flight - including during takeoff.
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?
by decimalenough
2 subcomments
- TIL about this eerily similar DC-10 crash in 2011:
Shortly after liftoff, 20 feet (6.1 m) above and 7,000 feet (2,100 m) down the runway, the No. 2 engine separated from the wing and struck the No. 1 engine's inlet cowling, causing it to produce drag and reduced thrust. Even with full right aileron and rudder, the plane started to descend and drift to the left. The captain lowered the nose and leveled the wings, which was followed by the plane making multiple contacts with the runway. After touchdown, the plane drifted left and departed the runway, crossing a taxiway before coming to rest in a saltwater marsh. A fire erupted which consumed the top of the cabin and the cockpit. All three crew members survived.
https://en.wikipedia.org/wiki/Omega_Aerial_Refueling_Service...
Obviously the DC-10 is not the MD-11, but the MD-11 is a direct descendant, including the trijet configuration.
- It's just time to kill the MD-11 entirely. These 3-engine aircraft are too risky to continue flying.
by stego-tech
1 subcomments
- As I told my friends, this preliminary report annoys me. It annoys me for the same reason it seemingly annoys the NTSB: American 191 is nearly identical on the surface, right down to the engine detachment and resultant loss of the aircraft, in almost the exact same spot on the airframe, ~45 years later.
Needless to say they’re going to be scrutinizing everything to determine what the cause is and the sequence of events that created the accident, but I also suspect everyone involved is just as annoyed at this as I am, given that this exact situation should have been fixed already.
* Annoyed = seething rage
- The surveillance video mentioned in page 2 -- from which the series of still images are shown -- is that available publicly?
- Not an aviation expert, nor I want to be one, but the images look pretty intense.
by johnnienaked
0 subcomment
- It's so similar to AA191
by Simon_O_Rourke
0 subcomment
- That's terrible. If the NTSB had flagged this flaw before then someone failed with an inspection regime or maintenance.
The NTSB doesn't ever accept the "sometimes bad things happen, shrug" excuse and kudos to the professionals there.
- McDonnell-Douglass right there that's where the problems start.
by BXLE_1-1-BitIs1
0 subcomment
- Gyroscopic precession took the left engine to the right. In AA 191 the right engine departing to the right did not affect the center engine. Sadly the engine failure procedure at the time mandated slowing down to V2 which was below the stall speed with slats retracted. There's now revised procedure and hydraulic fuses.
I expect all remaining aircraft will be getting new rear pylon lugs with shortened inspection intervals - provided the replacement cost is below the value of continued usage.
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