> they tried to take off instead of accelerate past the runway at ground level
Do runways have some sort of barrier between them and the next "important" thing. It seems like that would be prudent both for cases like this, and breaking failures following landings.
> Do runways have some sort of barrier between them and the next "important" thing. It seems like that would be prudent both for cases like this
Ha, Jeju Air Flight 2216 smashed into a barrier on the second landing attempt in Muan last year [0], and people commented "How could there be a barrier at the end of the runway, so obviously stupid, irresponsible", etc.
Now a plane does not smash into a barrier at the end of the runway and people suggest putting barriers at the end of the runway.
Don't mean to attack parent post, but may I suggest that
a) hordes of experts have thought long and hard about these issues, and it is unlikely that you can encounter this for the first time as a lay person and come up with a solution that has eluded the best engineers for decades ("why don't they attach a parachute to the plane?"), and
b) we are very close to an optimum in commercial aviation, and there are few if any unambiguous ("Pareto") improvements, but rather just tradeoffs. For example: You leave cockpit doors open, terrorists come in and commandeer the plane to turn it into a weapon. You lock the cockpit doors closed, and suicidal pilots lock out the rest of the crew and commandeer the plane to turn it into a weapon of mass-murder-suicide.
One improvement is a bed of concrete at the end of the runway that will catch the wheels and slow an airplane down to a stop. Pretty much everyone agrees it’s a good idea but it’s not always possible due to space needs or cost. https://en.wikipedia.org/wiki/Engineered_materials_arrestor_...
If you're designing a new airport, sure, you can have runways with ample safety margins and generous overrun areas at the end of the runways. If you want to make an existing airport safer, and you can't buy up and demolish buildings around it, using EMAS is actually a cost-effective safety improvement.
After 9/11, unlock the pilot doors. The passengers will revolt against any attempted aircraft hijackings.
We need members of the public ready to help in a situation where a pilot goes crazy, and they can’t help with a locked door making it impossible for them to enter.
The belief is that MH370 was depressurized which would have killed the passengers. A better example is Germanwings 9525 where the locked door allowed the first officer to crash the plane.
The solution is to "free" the perimeter of takeoff/landing. Bonus: People don't have to chose to work/live in these noisy areas. I understand some areas have challenges to come up with space but the US has tons of space and maybe the sea should be used to host these airports.
This is how almost all airports built in the last 50 years have worked. They were built way outside the cities. The cities grew to the airports.
More so, because of strong property rights it's very difficult to stop any development near the airports at all. The airport would have to buy up hundreds of square miles of land to prevent it at a staggering cost.
Lastly, one of the buildings that was hit was the UPS warehouse that stored goods to load on the plane. You want that as close as possible to the airport. Though right at the end of the runway is not the greatest place.
The ramp will need to be very long and very high in order to absorb the momentum of a fully loaded widebody jet. Not something that you'd want near a runway where planes can land in either direction.
Consider the possibility that gigantic flying aluminum tubes filled with tons of flammable fuel hurtling around at hundreds of kilometers per hour comprise a dilemma that has no trivial answers. Even defining what "important thing" means at any given instant is not straightforward.
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...
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.
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.
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.
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.
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.
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.
> 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.
> 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.
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.
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.
Some runways have been extended with ‘engineered materials’ surfaces, often a form of porous concrete into which an airliner’s wheels will sink, absorbing a lot of energy and arresting the airplane without causing it to break up. It is very effective for landing overruns, but I don’t know about last-seconds aborted takeoffs.
Security/debris fencing yes, but that's like, orders of magnitude short of what would stop the amount of energy we're talking about here.
You also don't particularly want it to be catastrophically effective as there are real world cases where planes have clipped the fence and then NOT gone on to crash, or at least to crash in a fairly controlled manner with the majority onboard surviving. Hitting a brick wall at 180mph is going to have a 0% survival rate.
Yet a reinforced concrete wall of e.g. triangular section and anchored with "long enough" piles would be about the only not-that-expensive way to turn a short strip of "airport land" past the EMAS into a V1 stopping supermarket.
Do runways have some sort of barrier between them and the next "important" thing. It seems like that would be prudent both for cases like this, and breaking failures following landings.