B1C17L1011
Topic Author
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DC-10 Engine Out Procedures

Wed Dec 04, 2002 1:33 am

I was reading a report about the AA DC-10 crash in 79, and it stated that the pilot followed the engine out procedures of pitching up and slowing the aircraft down to V2+6 or 159 knots. The cause of the crash aside, this surprised me as I thought it would be prudent to flatten out the angle of attack and gain as much speed as possible to avoid a stall. Can anyone elaborate on this for me.


B1C17L1011
 
Rick767
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RE: DC-10 Engine Out Procedures

Wed Dec 04, 2002 2:01 am

The procedure is to reduce to V2 plus a safety margin as this speed will result in the best climb angle. There is no risk of a stall at such speeds, the problem with the DC-10 incident was that physical separation of the engine took the leading edge slats with it I recall.
I used to love the smell of Jet-A in the morning...
 
XFSUgimpLB41X
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RE: DC-10 Engine Out Procedures

Wed Dec 04, 2002 6:43 am

Rick767 is correct... if lost in the first 1000 feet you maintain to V2+10, or whatver you have above V2 (not to exceed above +10) to give the best climb angle. At 1000 AGL you select vertical speed to zero to accelerate the airplane and clean it up.

The reason the DC-10 in 79 crashed is because the engine took the slats with it. The crew had no idea what happened. The engine separated b/c the mechanics mounted the engine wrong.
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BlatantEcho
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RE: DC-10 Engine Out Procedures

Wed Dec 04, 2002 11:18 am

to further what XFSU said, the #1 engine didn't literally take the slats with it.

From http://www.airdisaster.com/cgi_bin/view_details.cgi?date=05251979&airline=American+Airlines

"The aircraft crashed on takeoff from Chicago O'Hare. During rotation, the no.1 engine separated from the wing, tearing out vital hydraulic lines. The loss of the no.1 electrical generator disabled the slat disagreement system, and the aircraft rolled over as the left-side slats retracted causing that wing to stall."

Nothing the crew could do  Sad

George

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POSITIVE RATE
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RE: DC-10 Engine Out Procedures

Wed Dec 04, 2002 2:29 pm

Actually the crew could have saved the aircraft if only they had recognised the onset of the left roll to be a stall. Because of left wing slat retraction the stalling speed increased and the left wing stalled and dropped thus initiating the left roll. If the flightcrew had recognised this left roll to be a stall they could have applied forward elevator and possibly accelerated out of the stalled condition(was demonstrated in the simulator after the crash). If the crew had maintained excess airspeed, even as little as V2+10 kts the accident might not have occured. But the engine seperation took away electric also so the stick shaker stall warning device was inoperative.
 
XFSUgimpLB41X
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RE: DC-10 Engine Out Procedures

Wed Dec 04, 2002 4:28 pm

The airplane was too heavy for the V2+10 to keep it from stalling... e.g. on a heavy DC-10 at 580,000 pounds or so minimum clean speed is around 267 knots... it will stall around 230 knots. That airplane probably would have needed to have nosed over and accelerated to around 215 knots or more- an instinct very contrary to engine out training just after liftoff and in the first phase of climb.

Hindsight 20/20 in this case could save them... but would you really have thought that your engine had separated and slats had retracted when it happens that fast?


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XFSUgimpLB41X
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RE: DC-10 Engine Out Procedures

Wed Dec 04, 2002 4:29 pm

On a sidenote.... does anyone know if they got a disagree light because of the slats? That is really the only indication that could have saved them that I can think of.
Chicks dig winglets.
 
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RE: DC-10 Engine Out Procedures

Wed Dec 04, 2002 8:54 pm

In Air Disaster Volume 2 it says that the crew would probably have got some stall buffet through the control columns also at the time the left wing stalled but this would have been masked due to the high winds in the area producing moderate turbulence.

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