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Comment by t0mas88

14 hours ago

There is some margin in the calculations. But the training is very very clear, before V1 you must abort and after V1 you must continue. No discussion, no decision to make. You call V1, hands go off the throttles and no matter what you're going to fly.

The margin is for example that the plane must not just be able to fly, but also reach a minimum climb gradient to clear obstacles with a bit of safety margin. There is also an allowance for the time it takes from calling abort to actually hitting the brakes. And for example headwind is part of the calculation (it makes the takeoff distance shorter) but only 50% of the headwind is used in the calculations.

But all of those margins are not for the crew to use, the crew must just execute the procedure exactly as trained which means at V1 you're committed to continue the takeoff. And before V1 in case of an engine failure you have to hit the brakes to make sure you can stop before the end of the runway.

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t0mas88

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panxyh  12 hours ago

[flagged]

  • crazygringo  11 hours ago

    Nothing about it reads as AI to me. I'm not even the commenter and I take offense when people suggest that knowledgeable, helpful HN comments are AI.

    • panxyh  10 hours ago

      I see now that it probably wasn't, but "nothing" is an overstatement.

      And knowledgeable and helpful responses can be AI, so there might be a fallacy somewhere in your offence-taking. Are you offended when people do that in general, or only when they are wrong?

      I do appreciate the effort put into writing a good comment.

      2 replies →

  • t0mas88  9 hours ago

    Nope, AI would probably have written it nicer, I just typed it on my phone :)

    • panxyh  9 hours ago

      Oh, cheers then :)

      But regarding flight ability, wouldn't that be V2? I thought there exist conditions where V1 is well below rotation speed.

      Anyways,

      > to make sure you can stop before the end of the runway

      answers my main question, and makes sense from a procedural standpoint.

      But still, hard to believe that there is no room for in-situ evaluation if runway overrun is worse than likely crash. Of course then again, those have to be split second decisions.