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octaane a day ago

Unless you have a berm several dozen meters high with a 100 meter base, you ain't stopping something like this from a physics standpoint unfortunately.

Many airports have this problem. The recent korean air disaster which echos this is another example. BTW, this is why most airports, if possible, point out to sea...

wickberg a day ago | parent | next [-]

Newer airports usually try to have space, that's the only thing helping with the physics involved here.

Older airports might have EMAS [1] retrofitted at the ends to help stop planes, but that's designed more for a landing plane not stopping quickly enough (like [2]) - not a plane trying to get airborne as in this case.

[1] https://en.wikipedia.org/wiki/Engineered_materials_arrestor_... [2] https://en.wikipedia.org/wiki/Southwest_Airlines_Flight_1248

positron26 a day ago | parent | prev [-]

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 a day ago | parent | next [-]

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.

LgWoodenBadger 20 hours ago | parent | prev | next [-]

Increased thrust requirements for airliners that force planes to hit an increased v1 (or whatever it's called) sooner on the runway to allow for more time to reject takeoff.

bigbadfeline a day ago | parent | prev | next [-]

> 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 a day ago | parent [-]

> 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 a day ago | parent [-]

> 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 a day ago | parent [-]

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.

SAI_Peregrinus 13 hours ago | parent [-]

More likely is the hydraulics on that side burst, leading to a loss of pressure keeping the control surfaces deployed. If that lead to the leading-edge slats retracting (like they did in AA 191) you'd get a massive loss of lift on that side. The structural parts of the wing didn't have time to melt, but the fire certainly could damage all the internal control materials.

brazzy a day ago | parent | prev [-]

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.