Abort or continue ?
 

Question about pilots' decision:

Upon you approaching V1,the take-off configuration warning comes out, would you like to abort take-off or not?

What does the brief say?

You stop.

The poor souls on Spanair Flight 5022 did not get a warning. They paid a heavy price.

I doubt "just prior to V1" you'd ever get a config warning. The system is designed in most (if not all) aircraft to trigger this warning as soon as the throttles/power levers/thrust levers are advanced past a predetermined angle. A master warning however, well that's a different story.

It certainly is possible. I got one at about 90 - 100 kts a few months ago.

All of the items that would trigger the warning are essential for flight (save the parking brake), so the answer is fairly straightforward. You stop. It may be later determined that the warning was caused by a faulty sensor/indication problem, but at or near V1 is not the time to consider such things, nor is it the time to be reconfiguring.

That same horn at altitude, on the other hand, is an entirely different kettle of fish on the 737.

less serious items are not good reasons to discontinue the takeoff , especially as you approach V1

Engine failure, or engine fire are good reasons to stop.

THERE IS ONE OVER ARCHING reason to stop and that is a perceived inability to fly, serious control problems included.

A pilot must understand the systems and their limitations to make a good judgement at this critical speed.

BUT if you have checked the flaps and trim (and parking brake on some planes) and you have the warning it is a tough call.

the span air flight is interesting as the detroit northwest airline flight many years ago.


both of those were DC9s. our DC9 operations manual indicated if you stall a DC9 to put the flaps down to their max takeoff...firewall power flaps 15/17

You would immediately be flying if you did this and both the detroit and span air crash could be prevented or recovered with this mindset.

IT was drilled into us: FIREWALL POWER FLAPS !15 (md 80 slightly different number but same sort of idea).

ONE reason for configuration warning might have been movement of the trim (stab trim) without command...a trim runaway.

Good luck at this moment. Double checking things on the runway (killer items) seems to make this situation less likely.

Don't worry about it, it's just the speed brake lever jiggling out of it's detent on this bumpy runway

You could speculate forever on all the possible combinations of perceived systems failures that would cause the pilot to reject at high speed nearing V1.

In the end you play the statistics. One of those is the likelihood of an over-run if choosing to abort at high speed on a runway limiting take off including a wet runway.

I have read countless accident reports where over-runs on a limited runway length have occurred due to stuff ups by the pilot initiating the abort sequence. Examples: Indecision before taking action, slow reaction to ensure speed brakes are up, less than maximum braking used, aborting a few seconds after V1 but before VR. And gut feeling aborts which proved wrong or unnecessary.

Boeing in its 737 FCTM lay down good advice based upon study of numerous accidents caused by unnecessary high energy (high speed) aborts. Studies many years ago revealed that if a tyre burst occurs on a limited runway and after reaching 20 knots below V1 then it is safer to continue due to chances of degraded braking capability.

You can get quite spooked playing the "what if" game. The dangers of a high speed rejected take off are well known which is why a prudent pilot will be go-minded from the time the aircraft reaches 15 knots below V1 and accelerating fast. Play the statistics. Very few pilots have clipped the branches of a 35 foot tree because they decided to go shortly before V1 is attained in the take off run on a limited runway... its called good airmanship.