boacvc10
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Are Thrust Reversers Useable If Takeoff Is Aborted

Mon Jul 13, 2009 12:06 am

With the recent discussion of the EK a/c incident in Australia, where the aircraft had a very very long takeoff run, would it have been possible for the pilot to deploy thrust reversers in addition to brakes to try to stop the plane from going past the runway edge if needed ? Would brakes be effective at all ? If thrust reversers are not allowed in that (take-off) configuration, what options would he have had if he had to stop due to some significant issue such as loss of an engine, or some problem, apart from the one issue of mis-configured weight of the aircraft.

I realise that any abrupt stop would be catastrophic for the aircraft itself, but would this be better or worse than the alternative: lift off the runway and struggle to climb and then ... crash down ?
Up, up and Away!
 
sw733
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RE: Are Thrust Reversers Useable If Takeoff Is Aborted

Mon Jul 13, 2009 12:19 am

Reverse thrust can be used in aborted takeoffs, I believe. I think the big question is airline procedure...some may like it, and some may not. In the end, one would imagine they will take a rule-breaker if it means saving the passengers and a/c...
 
PGNCS
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RE: Are Thrust Reversers Useable If Takeoff Is Aborted

Mon Jul 13, 2009 12:33 am

On all airliners I have flown, reversers are useable on an RTO; the limiting factor may be directional control depending on aircraft type and variable conditions.

Brakes are extremely effective at stopping an aircraft whether on landing or on an RTO.
 
tb727
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RE: Are Thrust Reversers Useable If Takeoff Is Aborted

Mon Jul 13, 2009 2:04 am

It depends on the airline. If you read the recent final report of the Kalitta 747 over run in Brussels, they probably could have stopped it by the end if they had deployed the T/R's. Per Kalitta Air RTO procedures, they are to be used. Why they weren't used isn't known but there are a lot of variables so it's hard to say. If they had 3-4 more seconds to assess the situation and think of pulling 1+4, it may have worked but of course, hindsight is 20/20.

On the other hand at my company we were taught not to use them on an RTO in the Lear 20 series. We did not "Arm" them for takeoff since they apparently had a mind of their own sometimes, they are hydraulic and had to be armed in order for them to move when the sub-throttles were pulled back. The thought was that if you switched them and 1 didn't arm and you got in a hurry and pulled back on both, you would have an asymmetric deployment and really had a directional problem in addition to the RTO. They have since been pinned due to an AD so it's a non-issue. Fortunately I have not been involved in any high-speed aborts in my type aside from the sim. We just do max-braking until stoppage is assured as well as deploy the air brakes and at the Captains discretion, pull the drag chute. We do not have T/R's installed.
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FlyASAGuy2005
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RE: Are Thrust Reversers Useable If Takeoff Is Aborted

Mon Jul 13, 2009 3:28 am



Quoting PGNCS (Reply 2):
Brakes are extremely effective at stopping an aircraft whether on landing or on an RTO

Love the videos that shows the brakes heating to fire red and melting the tires! Big grin
What gets measured gets done.
 
wilco737
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RE: Are Thrust Reversers Useable If Takeoff Is Aborted

Mon Jul 13, 2009 5:33 am

We use thrust reverser as well for RTO's. The thrust reverser are most effective at higher speeds. The slower you get the less effective they are. But the brakes are the main thing you use to slow the airplane down.
It is impressive how good the brakes are.

wilco737
 
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HAWK21M
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RE: Are Thrust Reversers Useable If Takeoff Is Aborted

Mon Jul 13, 2009 6:49 am



Quoting WILCO737 (Reply 5):
It is impressive how good the brakes are.

Especially the Carbon ones.
regds
MEL.
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dispatchguy
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RE: Are Thrust Reversers Useable If Takeoff Is Aborted

Mon Jul 13, 2009 6:09 pm

They are usable, but for performance calculations, their effects are not calculated, nor are considered.
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wilco737
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RE: Are Thrust Reversers Useable If Takeoff Is Aborted

Mon Jul 13, 2009 6:31 pm



Quoting Dispatchguy (Reply 7):
but for performance calculations, their effects are not calculated, nor are considered.

We make a difference here. If on wet or dry runway.

wilco737
 
EcuadorianMD11
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RE: Are Thrust Reversers Useable If Takeoff Is Aborted

Mon Jul 13, 2009 9:40 pm



Quoting WILCO737 (Reply 5):
It is impressive how good the brakes are.

Is this in combination with the Air Brakes?
Those spoilers put all the weight on the wheels, correct?

Ecuadorian MD11
A lot of people need to be offended on a regular basis I always felt, and I�´m the very boy to do it! - Billy Connolly
 
wilco737
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RE: Are Thrust Reversers Useable If Takeoff Is Aborted

Mon Jul 13, 2009 9:47 pm



Quoting EcuadorianMD11 (Reply 9):
Is this in combination with the Air Brakes?

The brakes itself produce the most deceleration.

Quoting EcuadorianMD11 (Reply 9):
Those spoilers put all the weight on the wheels, correct?

The spoiler kill all the lift so that all the weight of the airplane is on the ground and the brakes can work just perfectly.

wilco737
 
EcuadorianMD11
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RE: Are Thrust Reversers Useable If Takeoff Is Aborted

Mon Jul 13, 2009 10:41 pm



Quoting WILCO737 (Reply 10):
The spoiler kill all the lift so that all the weight of the airplane is on the ground and the brakes can work just perfectly.

Vielen Dank!
Now in a car, if I hit maximum brake at a speed of (for argument´s sake) 140 km/h, my car goes haywire..........it will either spin around (perhaps unlikely in a plane) or veer off to the right or left. Not necessarily, but you know what I´m getting it, right? Behavior is hard to predict in circumstances like these.

What can you say on the stability of planes in case of emergency braking!?
Have you done some involuntarily off roading yourself perhaps?

Cheers mein Freund,

Ecuadorian MD11
A lot of people need to be offended on a regular basis I always felt, and I�´m the very boy to do it! - Billy Connolly
 
pilotpip
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RE: Are Thrust Reversers Useable If Takeoff Is Aborted

Tue Jul 14, 2009 4:22 am

That's what antiskid is for. Each wheel is monitored. You also keep steering with the nose wheel/rudder and differential braking.
DMI
 
tdscanuck
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RE: Are Thrust Reversers Useable If Takeoff Is Aborted

Tue Jul 14, 2009 4:35 am



Quoting Dispatchguy (Reply 7):
They are usable, but for performance calculations, their effects are not calculated, nor are considered.

They are for wet runway values on some aircraft (definitely on 737NG). Dry runway is done without.

Tom.
 
wilco737
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RE: Are Thrust Reversers Useable If Takeoff Is Aborted

Tue Jul 14, 2009 4:45 am



Quoting EcuadorianMD11 (Reply 11):
What can you say on the stability of planes in case of emergency braking!?

I never had a real RTO - Thank god. but the stability is pretty good (in the simulator). Even with an engine failure you can keep the airplane on the runway with the rudders or the nose wheel steering at lower speeds.

wilco737

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