Comment by k1w1 | Hacker News Reader

Comment by k1w1 | Hacker News Reader

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I think the original author is drawing the wrong conclusion here. Sully may have had the stick all the way back, but that doesn't mean it was wrong. The lowest energy way to land is to try to prevent the aircraft from landing. So when you are in the flare, the technique is to pull back on the stick to keep the aircraft in the air a few feet above the runway, until you have no more elevator authority, and the aircraft will settle onto the runway with the least amount of energy. Exactly what you want in a off-field landing too.

As my glider instructor put it: those last few seconds before touchdown are the prime rib of flying. Keep pulling back on the stick and make it last.

In fact if you look at the Wikipedia article that the OP linked to it suggests that Sully was unhappy that the aircraft was not responding to his full back stick:

> However, Sullenberger said that these computer-imposed limits also prevented him from achieving the optimal landing flare for the ditching, which would have softened the impact.

My understanding is that transport-class aircraft (i.e. large passenger jets) are typically landed differently than smaller planes like a Cessna Skyhawk or a glider. In my brief flight training experience in a small plane, I was taught to stall the A/C just above the runway as you describe. However, I believe ATPs are taught to land at about 1.3x stall speed, then use the spoilers to dump the lift entirely and get full weight on the wheels in a very controlled way.

I'm of course discussing typical on-field operations, not emergency dead stick ditchings. I don't know how those are supposed to go, but one might imagine that going to full stall just before impact would indeed result in the minimum energy state. The trick is to not accidentally do that too high!

From what I read "the stick all the way back" is correct, because it's telling the computer your intent, "raise the nose of the plane". Airbus aircraft use flight laws to control the actual control surfaces, so there's no reason to make your intent less strong than it actually is.

Airbus airplanes have several different flight law modes (including direct law, which has no protections). So the biggest risk is probably that it switches laws and actually tries to carry out what you're doing.

I know, for all of Boeing's problems not doing that is a big plus. At least on the 777. I hope they haven't changed that since.

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