Comment by positron26

Comment by positron26 11 hours ago

6 replies

There is a dead zone between rejection and successful take-off speeds. We see it hit too often.

I think pilot training is playing a factor. A normal rotation kills too much energy. One engine can climb when you have some airspeed and get clean, but if you lose too much energy on rotation, the inefficiency of the AoA for the rest of the short flight means that engine can no longer buy you any up. I've seen too many single-engine planes going down while trying to pitch up the whole way down.

So, less aggressive single-engine rotations and energy absorbers at the ends of runways that can't get longer. This seems like the kind of thing where we do it because it removes a significant cause of people dying.

Just watched this angle a few more times: https://x.com/BNONews/status/1985845907191889930

Another crash video shows the aircraft clearly descending before colliding with anything. It manages to go up a bit, so it's fast enough to get airborne. The normal looking rotation kills too much energy. The plane is then too inefficient to maintain speed. AoA goes up while energy goes down. Power available goes negative and then it's over.

mannykannot 10 hours ago

Rotation does increase drag, but you need to rotate in order to achieve the necessary angle of attack. The only way to reduce the rotation angle is by going faster than the normal rotation speed for the given weight and airfield density altitude, but doing so is out of the question in this scenario.

bigbadfeline 10 hours ago

> It manages to go up a bit, so it's fast enough to get airborne. The normal looking rotation kills too much energy.

Yes, it did get airborne for a few seconds but from the video below, it looks like the left wing was damaged by the fire and could not provide enough lift, then the right wing rolled the plane to the left causing the crash.

https://bsky.app/profile/shipwreck75.bsky.social/post/3m4tvh...

  • positron26 9 hours ago

    > looks like the left wing was damaged by the fire

    The wings and aerodynamics don't really care if air or air with combustion are flowing around them.

    Roll is a consequence of the loss of control due to low speed and the yaw of the good engines. Speed up, rudder works, plane might maintain positive climb.

    • loeg 8 hours ago

      > The wings and aerodynamics don't really care if air or air with combustion are flowing around them.

      Not saying it's what happened here, but if the heat is intense enough to deform the wing / control surfaces, it matters.

      • positron26 7 hours ago

        For skin, a few seconds might be significant. For the spars, not nearly enough time to matter. It's also not at cruise speed slamming into a downdraft or anything. This is about a 1G loading. Negligible for a while. While the fire looks cool, there's a lot of free stream mixing in and the temps won't really get that high beyond the cowling.

brazzy 4 hours ago

There might be other kinds of damage where the quicker altitude gain of a normal rotation is crucial for survival.

I'm skeptical whether pilots can realistically make this kind of decision, given that they have no more than a few seconds to make it, and in cases such as this based on very incomplete information about the state of their aircraft.