Comments on: Airbus 320 Gone Wild

By: Wayne Farmer

Wayne Farmer — Fri, 07 Mar 2008 00:28:04 +0000

Greg said:”What occurred to me was that a human may make far fewer adjustments for any one of a number of reasons than a computer on the same landing. Does that make sense?”Yes, if the computer program is not as experienced and savvy as the pilot. I’ve programmed control systems (although not for avionics) and it sounds to me as if the automated landing program was either getting faulty sensor readings, or it was underreacting or overreacting to valid sensor readings, so that it was constantly making adjustments to its flight control surfaces (and probably engine throttle as well) to get the aircraft back into position for landing.

By: Greg Laden

Greg Laden — Tue, 04 Mar 2008 13:19:11 +0000

HerkDriver: I was told this by a former military pilot then working commercial, and I think what you are saying agrees with this. His point was that typical commercial passengers think a hard hit on the runway is a bad landing, and a nice soft landing that you can’t even feel is a good landing, and that he felt commercial pilots were being inappropriately encouraged to land a plane in a way that made the passengers feel good about the landing even when he, as an experienced pilot, knew better.We can argue about the words “hard” and “slam” but I think you get my point. Thanks very much for the additional information.I’ve often wondered about this, maybe you can address it: One time I was in a commercial plane, I think an airbus, landing from overseas in NY or Boston. I noticed that on approach, for a very log time, there was a LOT of adjustment going on. I could hear the little motors or hydraulics or whatever constantly adjusting the flight control services, and the plane was making many little tilts and adjustments in its three dimensional orientation. There was virtually not noticeable turbulence.When we landed, the pilot came on and explained that this was an entirely computer controlled landing.What occurred to me was that a human may make far fewer adjustments for any one of a number of reasons than a computer on the same landing. Does that make sense?

By: HerkDriver

HerkDriver — Tue, 04 Mar 2008 11:46:35 +0000

Quote KP: “I can only imagine what was going on inside the passenger area during this.”That might not be as scary as what was going on in the head of the pilot during this!Spoilsport: certain large aircraft are specifically designed to land in a “crab,” i.e. the wheels can handle not being aligned perfectly with the direction of movement. In fact, in many large aircraft with under-wing nacelles/pods, this is the required way to land in crosswinds.Greg: It is not correct to say military pilots like to slam the plane onto the ground. If you are landing on an aircraft carrier, I suppose that’s mandatory (I dont land on aircraft carriers). But we don’t like compressing our spines, either. Note also, that a huge number of civilian pilots are also military pilots in the reserves.During a high-crosswind landing, flare should typically be minimized or not performed at all, and a “firm” touchdown (not a “slam”, though it may feel like that depending on where you sit) is appropriate. The slower you go, the more nose-up you are (both happen in the flare), the more susceptible you are to wind. And in this configuration, it is often the strong, unpredictable gusts that will get ya.During normal wind conditions there is absolutely nothing particularly dangerous about a gentle, greased-on landing.

By: laurisa

laurisa — Tue, 04 Mar 2008 03:14:12 +0000

I took flying lessons this summer and that’s one of the charts you need to know how to read, the crosswind factor.That one right there is scary. But planes are common mode of transportation in Alaska. Aborted landings get your attention but when the oxygen masks pop out, that’s when Houston we have a problem.

By: ekzept

ekzept — Tue, 04 Mar 2008 01:50:33 +0000

Yeah, it happens. Alas, certain systems once proposed for the FAA, like the ASDE-X system (built by Sensis) once had rules which prevented it from properly assigning approach runway if the nose of the plane was more than 5 degrees antiparallel with it. Thus, if a plane were landing in a crosswind, and if there were traffic on the runway, ASDE-X would have never alerted on it.

By: Coturnix

Coturnix — Mon, 03 Mar 2008 20:33:56 +0000

Actually, the pilot of my flight into Raleigh slammed it hard onto the runway. It was a small plane, and that was probably the best thing to do at the time as we were just a toy for the wind and landing fast and firm felt like a good idea.

By: tincture

tincture — Mon, 03 Mar 2008 15:54:06 +0000

WTF, this runway is all over the place!

By: kezdro

kezdro — Mon, 03 Mar 2008 14:42:38 +0000

As for the military part: Yes, and imagine not only all of that, but doing it on a short carrier runway at high speed so if you miss the wire you have enough lift to do it again..(not an aviator myself, but the air force was for a while plotted on my career path)

By: Spoilsport

Spoilsport — Mon, 03 Mar 2008 13:49:03 +0000

The pilot should never have tried that. The wheels roll forward only, they don’t turn to compensate for wide angular aspects. What if he’d blown all the tires on one side? The plane would slam into the runway and break up.

By: Greg Laden

Greg Laden — Mon, 03 Mar 2008 13:45:53 +0000

This is why (I am told) military pilots like to slam the plane hard on the runway, reducing the amount of time one can be floating around like a leaf. A moving plane with negative lift is a heavy object not likely to get blown away.A nice soft landing where you barely notice the wheels touching the ground is very dangerous. You want to SLAM into the ground, nice and firm.But not too hard. Too hard is bad too.