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Are Thrust Reversers Useable If Takeoff Is Aborted  
User currently offlineBOACVC10 From United States of America, joined Jul 2006, 587 posts, RR: 0
Posted (4 years 9 months 1 week 4 days 13 hours ago) and read 3659 times:

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!
14 replies: All unread, jump to last
 
User currently offlineSW733 From United States of America, joined Feb 2004, 6265 posts, RR: 9
Reply 1, posted (4 years 9 months 1 week 4 days 13 hours ago) and read 3653 times:

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...

User currently offlinePGNCS From United States of America, joined Apr 2007, 2756 posts, RR: 45
Reply 2, posted (4 years 9 months 1 week 4 days 12 hours ago) and read 3645 times:

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.


User currently offlineTb727 From United States of America, joined Jun 2005, 1548 posts, RR: 8
Reply 3, posted (4 years 9 months 1 week 4 days 11 hours ago) and read 3600 times:

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.



Too lazy to work, too scared to steal!
User currently offlineFlyASAGuy2005 From United States of America, joined Sep 2007, 7004 posts, RR: 11
Reply 4, posted (4 years 9 months 1 week 4 days 10 hours ago) and read 3563 times:



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.
User currently offlineWILCO737 From Greenland, joined Jun 2004, 8903 posts, RR: 76
Reply 5, posted (4 years 9 months 1 week 4 days 7 hours ago) and read 3530 times:
AIRLINERS.NET CREW
HEAD MODERATOR

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



It it's not Boeing, I am not going.
User currently offlineHAWK21M From India, joined Jan 2001, 31573 posts, RR: 57
Reply 6, posted (4 years 9 months 1 week 4 days 6 hours ago) and read 3514 times:



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

Especially the Carbon ones.
regds
MEL.



Think of the brighter side!
User currently offlineDispatchguy From United States of America, joined Jan 2006, 1248 posts, RR: 2
Reply 7, posted (4 years 9 months 1 week 3 days 19 hours ago) and read 3379 times:

They are usable, but for performance calculations, their effects are not calculated, nor are considered.


Nobody screws you better than an airline job!
User currently offlineWILCO737 From Greenland, joined Jun 2004, 8903 posts, RR: 76
Reply 8, posted (4 years 9 months 1 week 3 days 19 hours ago) and read 3370 times:
AIRLINERS.NET CREW
HEAD MODERATOR



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



It it's not Boeing, I am not going.
User currently offlineEcuadorianMD11 From , joined Dec 1969, posts, RR:
Reply 9, posted (4 years 9 months 1 week 3 days 15 hours ago) and read 3298 times:



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


User currently offlineWILCO737 From Greenland, joined Jun 2004, 8903 posts, RR: 76
Reply 10, posted (4 years 9 months 1 week 3 days 15 hours ago) and read 3296 times:
AIRLINERS.NET CREW
HEAD MODERATOR



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



It it's not Boeing, I am not going.
User currently offlineEcuadorianMD11 From , joined Dec 1969, posts, RR:
Reply 11, posted (4 years 9 months 1 week 3 days 14 hours ago) and read 3274 times:



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


User currently offlinePilotpip From United States of America, joined Sep 2003, 3139 posts, RR: 11
Reply 12, posted (4 years 9 months 1 week 3 days 9 hours ago) and read 3224 times:

That's what antiskid is for. Each wheel is monitored. You also keep steering with the nose wheel/rudder and differential braking.


DMI
User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 13, posted (4 years 9 months 1 week 3 days 8 hours ago) and read 3223 times:



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.


User currently offlineWILCO737 From Greenland, joined Jun 2004, 8903 posts, RR: 76
Reply 14, posted (4 years 9 months 1 week 3 days 8 hours ago) and read 3219 times:
AIRLINERS.NET CREW
HEAD MODERATOR



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



It it's not Boeing, I am not going.
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