Tow eng fail of four eng a/c
Guest
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Tow eng fail of four eng a/c
Good afternoon gentlemen!
I have a question about eng failure during T/O. What will you do if you have two engine failure of four engine a/c during t/o roll after V1?
Any information will be appreciated.
Thank you.
Edited for clarity
[This message has been edited by Checkboard (edited 04 April 2001).]
I have a question about eng failure during T/O. What will you do if you have two engine failure of four engine a/c during t/o roll after V1?
Any information will be appreciated.
Thank you.
Edited for clarity
[This message has been edited by Checkboard (edited 04 April 2001).]
Guest
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Failure of two engines on one side presents several big problems.
1. Performance - T/O data is based upon loss of only 1 engine (4 eng airplane). Unless very light weight, the airplane's speed and/or altitude will decay.
2. Controllability - If the loss of two engines is on the same wing, then the inflight minimum control speed is likely to be much higher than takeoff safety speed. Result? If working engines are kept at high thrust, the airplane will yaw, then roll due to the lack of rudder authority to counteract the severe assymetric thrust.
3. If it happens below decision speed, then abort. If above V1, an abort is almost inevitable also. Just hope that you can stop in the clearway. Better to have a controlled runway excursion than an uncontrolled crash.
1. Performance - T/O data is based upon loss of only 1 engine (4 eng airplane). Unless very light weight, the airplane's speed and/or altitude will decay.
2. Controllability - If the loss of two engines is on the same wing, then the inflight minimum control speed is likely to be much higher than takeoff safety speed. Result? If working engines are kept at high thrust, the airplane will yaw, then roll due to the lack of rudder authority to counteract the severe assymetric thrust.
3. If it happens below decision speed, then abort. If above V1, an abort is almost inevitable also. Just hope that you can stop in the clearway. Better to have a controlled runway excursion than an uncontrolled crash.
Guest
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For what it's worth, I remember during my '400 sims the instructor showing us a double eng failure just after rotate ( at a reasonably heavy weight, using 13 HKG, so no immediate obstructions if you keep it straight). The trick was to immediately retract the flaps to either 15 or 10 or 5 0r whatever the next up flap setting was ( I can't remember, it's been a while!) This gets rid of the drag, puts you perilously close to the stall (in the shaker, I recall) but lets you float serenely out to sea, level - ish and sloowwly accelerating to 2-eng climb speed. Then - voila!
Not a practical procedure, but the only one I ever saw, so I stored it away somewhere in the cobwebs. ( Not on the 744 any more, so don't care....)
Not a practical procedure, but the only one I ever saw, so I stored it away somewhere in the cobwebs. ( Not on the 744 any more, so don't care....)
Guest
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SV had one of these on an 'SP in the mid-eighties out of JED. Knew the Captain rather well. They were very lucky. Number two engine had an uncontained failure and the F/E (without saying anything) pulled the number one fire handle. The F/E was gone rather....ah, quickly.
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It is not a Cert' requirement,except on the three-engine ferry case(four engine aircraft)
with the DC8/B707/B747/corronado,whereas the 'perf' weights and flap settings were reduced to try and save a 'second'failure during the Takeoff.eg; the DC8 2engine out VMC was about 155k,with up to 10* of bank to the 'dead'side,and on the ground the assymetric engine was not at 'TakeOff' thrust
setting until VR-to avoid compounding the Dead engine drag.With reduced flaps(max 25*)-the higher speeds covered the VMC case.This was a regular occurrence in the 60/70's ,but was gradually phased out when only 'Check pilots' were to perform them(Big Bucks)
with the DC8/B707/B747/corronado,whereas the 'perf' weights and flap settings were reduced to try and save a 'second'failure during the Takeoff.eg; the DC8 2engine out VMC was about 155k,with up to 10* of bank to the 'dead'side,and on the ground the assymetric engine was not at 'TakeOff' thrust
setting until VR-to avoid compounding the Dead engine drag.With reduced flaps(max 25*)-the higher speeds covered the VMC case.This was a regular occurrence in the 60/70's ,but was gradually phased out when only 'Check pilots' were to perform them(Big Bucks)
Guest
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That should of course read" ten degrees of bank to the'LIVE' side.. Cheers
The 727 second egineout case ,on final was just as interesting: Lose it by the marker and one wouldn't reach the field unless one went to Flaps5,mct on the remaining engine,'Bug' up 30knots,and standby rudder on(one doesn't forget)
The 727 second egineout case ,on final was just as interesting: Lose it by the marker and one wouldn't reach the field unless one went to Flaps5,mct on the remaining engine,'Bug' up 30knots,and standby rudder on(one doesn't forget)
Guest
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Good points made by Roadtrip.I dont agree with GBJ's assessment that V1 is a hard and fast rule.Not always.You can abort after rotation if the a/c doesnt want to go flying.The normal rules about V1 may not necessarily apply when both engines go on the same side.Depends on the stopway environment but assuming a heavy 744,better to abort right up to Vr -5.
Guest
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On a runway of infinite length, close all
throttles, keep it straight, get it stopped
and exit to bar.
If you are at V1 or above you are of course
supposed to get airborne. One problem however
is that you are way below VMCA2 so in all
probability you will have to ease back on the
throttle of the outboard live engine against
all instincts as this will reduce of aircrafts determination to roll and yaw
towards the failed engines. So.... get the
gear up to reduce drag, keep it straight -
probably level is the best you can hope for
unless very light. Slowly but surely your
airspeed will increase allowing you to reduce
your flap setting to a point where it is more
of a help than a hinderance. As airspeed builds your ability to use the outboard live
engine will improve - more power = more
performance = more speed = climb !
If the aircraft in question has a fuel dump
system then do so asap.
Try and avoid carelessly positioned hills,
buildings, trees, HGV'S and the like.
All in all its a bit of a problem. If of
course you have taken off from an airfield
at the top of a hill you could always use
the downslope to best advantage !
When its all sorted - land the beast off a
long steady approach with a nice high DH -
two engine go-round performance not very good !
Revert to original plan - go to bar, accept
grateful thanks of Chief Pilot and sue the
company for stress - everybody else seems to
do it these days !
throttles, keep it straight, get it stopped
and exit to bar.
If you are at V1 or above you are of course
supposed to get airborne. One problem however
is that you are way below VMCA2 so in all
probability you will have to ease back on the
throttle of the outboard live engine against
all instincts as this will reduce of aircrafts determination to roll and yaw
towards the failed engines. So.... get the
gear up to reduce drag, keep it straight -
probably level is the best you can hope for
unless very light. Slowly but surely your
airspeed will increase allowing you to reduce
your flap setting to a point where it is more
of a help than a hinderance. As airspeed builds your ability to use the outboard live
engine will improve - more power = more
performance = more speed = climb !
If the aircraft in question has a fuel dump
system then do so asap.
Try and avoid carelessly positioned hills,
buildings, trees, HGV'S and the like.
All in all its a bit of a problem. If of
course you have taken off from an airfield
at the top of a hill you could always use
the downslope to best advantage !
When its all sorted - land the beast off a
long steady approach with a nice high DH -
two engine go-round performance not very good !
Revert to original plan - go to bar, accept
grateful thanks of Chief Pilot and sue the
company for stress - everybody else seems to
do it these days !
