It normally is to power up and get more. The speed is reduced so you get a good angle of climb but it is reduced by raising the nose not by reducing engine power. Can you cite the reference to the engine power being reduced? (Not doubting you as such just need some context to comment further.)
My first thought, not being multi-engine rated, is to reduce asymmetrical thrust that could result in excessive yaw and a roll/spin into the non-functioning engine side.
*The first officer raised the nose up to 14 degrees, to reduce the airspeed from 165 knots (306 km/h), to the V2 speed of 153 knots (283 km/h), specified in the emergency procedure for engine failure during takeoff. However, the engine separation severed hydraulic fluid lines which controlled the leading edge slats on the left wing, causing those slats to retract under air load. That raised the stall speed of the left wing to at least 6 knots higher than the prescribed V2 speed, at which the plane was then flying, and thus the left wing stalled.
*
From Wikipedia. I was wrong about reducing engine power. But the procedure still called for a reduction in airspeed. Why?
So I guess he raised the nose and that reduced the speed, not cut engine power. But it also says “That raised the stall speed of the left wing to at least 6 knots higher than the prescribed V2 speed”. Isn’t a 6 knot margin of error between stall and no stall rather narrow?
I’m sure there are rational reasons for all these procedures, it just doesn’t make sense to a non pilot.
V2 is the take-off safety speed. It is the minimum safe speed that gives the required performance with a failed engine to clear any obstacles in the take-off path. When the airline performance guys put together the charts that tell you what weight at which you can take-off from each airport it is based on having an engine failure at the most critical point of the take-off roll, then climbing away at V2 to a safe altitude then accelerating to a higher speed and retracting flaps and slats.
It used to be that if you suffered an engine failure and you were faster than V2 you would reduce speed to V2 by adjusting the aircraft pitch angle. This gave you a known speed that guaranteed obstacle clearance in the initial climb. I believe the current thinking is that, for some jets at least, you can maintain the speed at which the failure occurred because to a limited extent slightly faster speeds can give better performance.
In the case of flight 191, climbing at V2 would have been just fine if all of the flaps and slats had been in the expected positions and what the First Officer did was the correct thing to do. Unfortunately they had additional problems and it didn’t work out for them. Something to remember is that emergency procedures are designed around single failures, where you have multiple failures you just have to do the best you can.
Edit: If the flaps and slats had still been extended the stall speed for both wings would have been well below V2 and the margin quite safe.
Once the plane began rolling due to the left wing stalling, if the pilot had guessed correctly what was happening, could he have increased power to increase airspeed and had a chance to recover? Would the plane have sped up quickly enough for the left wing to get lift? I realise this is all second guessing and the whole scenario played out very quickly. I’m just curious what was possible.
If he had lowered the nose the airspeed would have increased and the angle of attack of the stalled wing would have been reduced and he may have got it flying again. That is pure speculation and I have no idea if they would have had the time and altitude available to make it work*. They would still have been left with the problem that one wing had flaps and slats while the other didn’t, that’s going to make the aeroplane want to roll regardless of the wing being stalled, to counter the roll you need to input aileron in the opposite direction, this creates more drag which would further decrease the performance of the aircraft.
- The quote from the accident report in post #7 flatly states that the situation was technically recoverable but that it was not reasonable to expect a pilot in the heat of the moment to correctly identify and recover from the situation they had. I think that’s about as good an answer as you’ll get.
If you make the working wing match the configuration of the busted wing you’ll have to put in a lot less input to make corrections. You can land a big airplane without the use of flaps, slats, slots, etc. by using a “slip” - it just takes a bunch more runway as you’ll be coming in at a higher airspeed. Probably much more likely to be survivable than an out of control crash, even if you’re not at a complete stop by the time the pavement runs out. At least whatever you hit you’ll hit at a much slower speed.
However, they probably didn’t have the time to make such adjustments simply due to lack of altitude.
With the thread having sprung back to life, I just want to reiterate that the accident report noted AA191 never got higher than 325 feet and lasted only 31 seconds after the engine came off.
Contrast that with US Airways 1549, “the miracle on the Hudson.” When the bird strike disabled both engines on that flight, the plane was at 3,200 feet and the airspeed was 215 knots (247 mph). Even with that, the plane only stayed in the air another 2 1/2 minutes. The crew had to ditch rather than trying to land at Teterboro airport, which was only about 4 miles away.