Hacker News Reader

Hacker News

Comment by contrarian1234 | Hacker News Reader

Parent Full thread

contrarian1234

why don't they land on the tail instead of the nose?

Seems a lot less risky to drag the back than scrape the front - which can flip the plane

Is it simply the center of gravity? (engines look like they're behind)

View on HN

Imagine how tipped the plane would be to land on the tail.

They do align the plane as much as they can to keep the nose off the ground for as long as they can.

But yes, it's the total center of gravity, it can't land on the tail.

You could bring up ALL the gear but then you have no control and it will almost certainly veer off the runway and then it may break apart.

If the center of gravity wasn’t between the front and rear gear, the planes would tip on the ground normally.

In a gear abnormal, land on what you have and the outcome is almost always great for the occupants.

Any injuries are likely to be from the evacuation after everything is stopped.

What makes you say they didn't land on the rear landing gear first? Part of the normal landing is -- AIUI, IANAPilot -- to flare, that is to increase the angle of attack of the aircraft (pull up the nose, increase drag) in order to reduce forward speed; this also puts the rear gear closest to the runway, the rear gear being bilateral means this spreads the load.

In fact, I've just looked at a video on YouTube "AIRLIVE" [0] and you can see the shadow of the nose off the ground when the plane shakes (at 0:07s) indicating the rear gear has made contact. I think the nose contacts at 0:13, so gently it's amazing.

[0] https://youtube.com/watch/I1dthJSuZLk

> I think the nose contacts at 0:13, so gently it's amazing.

If you like that, check out JetBlue 292; landing's about half way through the video. https://www.youtube.com/watch?v=epKrA8KjYvg

I would guess you can’t land well with the wings pointed in the “going up” direction

You'd be in a deep stall, which, as I understand it, is very much not how you want to land.

It would be less likely than throwing a Leaning Jowler in Pig Mania!

https://en.wikipedia.org/wiki/Pig_Mania#Relative_frequencies

I don't know what model of plane this is, but I was watching a Real Engineering video on the Boeing 787. He said that some planes have a third engine for generating electricity (the APU) and the exhaust for that is at the tip of the tail.

Maybe there are concerns about potentially damaging the APU?

Most commercial planes have APUs (That's the loud sound you hear/exhaust you smell from the jet bridge) but a tail strike would hit closer to underneath the back seats of the plane than the middle of the tail like that. The only concern in emergency situations like this is getting every passenger safely on land. Not their bags, not every component of the airplane. Both of those are more easily resolvable via insurance than lost passenger lives.

Speculating: the nose is gonna come down anyway (as sokoloff said, CoG is ahead of the main landing gear), so it's safer for the front to impact from as little height as possible. If you hit tail-first and keep the nose up you're setting yourself up for a hefty impact when the front crashes down. Better to scrape from the start.

Once the mains touch down you keep the nose off as long as possible for minimal energy at impact. It will float down naturally and you don't really have any control over the manner in which it makes contact as long as you have full back pressure on the yoke. There's not really any way to affecting the height at which it starts coming down.

Reply on news.ycombinator.com