Speedbrakes upon RTO

[Spin737 102]

Here's what Boeing has to say in Jet Transport Performance Methods:

 

http://www.theairlinepilots.com/forumarchive/quickref/jettransportperformancemethods.pdf

 

V1 – the RTO Action Speed

For every single takeoff, there are three critically important speeds that the pilot must observe carefully. Two of those you already understand: VR and V2, the rotation and engine-inoperative initial climb speeds. But the third one needs very careful and detailed discussion because it’s widely misunderstood. That’s the speed we call V1.

 

V1 has historically been referred to as the decision speed, but that isn’t really a good name for it. If a pilot making a takeoff experiences some critical situation such as engine failure and he decides at V1 to reject the takeoff rather than continue it, he would initiate the rejected takeoff (RTO) procedure some short time after V1 since no pilot can react instantaneously to a decision to reject. Even the best pilots have some delay time between making the decision to reject and then initiating the rejected takeoff procedure by first applying the wheel brakes.

 

 

In FAR Part 1, the FAA defines V1 as “the maximum speed in the takeoff at which the pilot must take the first action (e.g. apply brakes, reduce thrust, deploy speed brakes), to stop the airplane within the accelerate-stop distance. V1 also means the minimum speed in the takeoff, following a failure of the critical engine at VEF

at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance.”

 

etc.

 

Worth a read, especially if you've followed this thread. The book goes into the certification of the 737CL and NG and how the timing of an abort happens.

[JoeDiamond 67]

This one doesn't need over-complication, guys. There's times we want you to think... and times we don't. Bad problem below V1, abort. Bad problem above V1, fly. The end.

 

If you only read one sentence from Stearmandriver's post, make it that one.

 

When you have a problem during takeoff the fact that you have a problem is often obvious.  What is not obvious is what exactly is causing the problem.  Believing that a pilot can accurately asses the condition of the aircraft in a matter of critical seconds, with the limited information available, all while maintaining control of the aircraft is not realistic.

 

Statistically, I believe the hazard of the pilot making the situation worse by a bad decision far outweigh the hazard involved if the correct abort/go procedures are followed.  The system is designed to make the decision making process for the pilots easier, don't make it harder than it needs to be.

 

Additionally, should the day not go quite as you had planned and you one day find yourself sitting at a long table at the hearing with a bunch of guys from the company and the FAA looking across at you, would you rather be able to justify your actions with the SOP, or having to explain why you thought your way was better?  That's assuming you are still around to tell your side of the story.

[Driver170 42]

It all depends on the type of failure and the speed

All airlines use a speed to differentiate between a high speed and low speed. In low speed, you would abort the take off for any failure, all the time Master Caution light comes up, ABORT take off

In the high sopeed regime, it is normally for aircraft unable or unsafe to fly, engine fail, any fire or windshear. If master caution comes up, continue, find out in the air. In the air there is lot of time to solve the problem. High speed RTO's are prone to runway excursions