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Comment by viraptor | Hacker News Reader

I've seen people mentioning this could be a big disaster, but I'm curious exactly what the effects could be. Specifically, ignoring the wheels for the moment, would the hull of the landing plane slide off on contact at all, or would the planes just get squashed? I have no intuition about friction / stiffness of materials at that scale. (I'm also assuming the planes were at least a little bit offset to the side)

With the wheels down, they would just tear through the hull of the lower plane, right?

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We're discussing a matter of 10s of feet between the near-collision we saw, clipping the tail of one plane, or hitting the plane behind at landing speed, so I imagine the set of "what could have happened" is rather large.

That said, I suspect the following three crashes give _some_ indication of what might have happened:

USAir 1493 - 737 collides with a turbo-prop on landing; the smaller plane is essentially crushed by the 737

Asiana 214 - Landing gear and tail clip seawall on approach

Tenerife disaster - 747 strikes the side of a second 747 a few seconds after leaving the ground on takeoff; engines, lower fuselage and main landing gear struck the plane. 583 fatalities.

https://en.wikipedia.org/wiki/USAir_Flight_1493 / https://en.wikipedia.org/wiki/Asiana_Airlines_Flight_214 / https://en.wikipedia.org/wiki/Tenerife_airport_disaster

I highly recommend watching the related episode of "Mayday" Air Crash Investigation about Tenerife.

Hulls are so fragile that they've often shred up in flight (De Havaillan, DC-9). Landing is around 200-250kmh only, but planes have caught fire just sliding on runways or terrain. The quantity of jet fuel immediately means catastrophe.

It wouldn’t have been just the wheels.

They’d have flattened onto each other in a big squash that blew fuel everywhere.

It would have probably continued due to momentum as a fireball towards the 3 other fully loaded planes.

Basically it could have been a 5 fully loaded plane bowling alley of flaming metal at 150mph

This. Sure. But pure speculation. The forward momentum of that airplane could have clipped a tail and taken it off while pulling up and max thrust. He was wayyyy below minimum decision height (called out and set before landing, usually a few hundred feet).

OTOH, he could have very well collided with the other Airbus on the taxiway rapidly halting his forward momentum and exploding into a fireball subsequently taking out everything for half a mile ahead.

What's alarming her is the distance of the Air Canada jet to the ground, less the tail of the Airbus = this guy was FEET AWAY from clipping that jet.

Actually the first plane on the ground was staggered with respect to the others and the final two ones had quite a bit of separation so another, not too unlikely outcome, is that it would have hit UAL1 and then veered of the taxiway, wrecking the ACA flight but nothing else (Save for possible some last-row passengers on UAL1).

The hull of a jetliner is about the thickness of sheet metal and disintegrates. The engines are denser and plow through things. Here's NASA footage of a controlled crash:

https://www.youtube.com/watch?v=Y33N0raKZBo

[EDIT: fixed link]

you just linked back in to the ntsb report - clipboard mistake?

Oh, thank you!

Large objects tend not to be stiff against collision. It would look like a high speed road crash - remember that the landing plane is travelling at over 150km/h.

It’s closer to 150 knots, that’s 277km/h.

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