U.S. Orders Rudder Inspections on Some Airbus Planes (A300's and A310's)

Reuters ^ | March 25, 2005 | Reuters

[pitinkie]

I will take all I can to survive!

[norton]

"The problem is they require very different maintenance from the normal aluminum skin of aircraft. If maintenance and inspections are not done properly, then disaster can be the result."

The issue is not 'skin', there are composites all over the place in most aircraft and they are not a threat. The issue here are attachment points and possibly elements in the controls that undergo high stresses throughout the flight. Admittedly, commercial aircraft don't get into dog fights or carrier landings so they are designed way below military stress requirements - but airbust seems to have cut a few too many corners in their design. Real issue is likely to be that the only solution would be a scrap heap because they'd never be able to afford retrofit even if they could design one.

All in all I miss MacDac's more costly, heavy, and somewhat over designed series, too bad we are down to a single maker with a single state-sponsored foreign competitor.

[usafsk]

Airspeed had little to do with it. The forces exerted on the aircraft in the 587 case had to do with sideslip forces more than 2X the design limits on the vertical stabilizer. The first officer had at least two previous incidents of overzealous response to wake turbulence.

In the 587 incident, during the first, minor bump from the 747 wake, he moved the control wheel of the aircraft more than 30 degrees in each direction. This type of action, considering the amount of wake encountered, was dangerous and excessive.

In response to the second encounter, a few seconds later in the flight, he executed 5 cyclic rudder pedal inputs. That's nuts. He snapped the tail off.

If you want aircraft that would not snap the tail off under those circumstances, you'll need to be willing to spend about 100x what you currently pay for a ticket. I was watching A-10 straffing runs at an ANG range in Michigan when a pilot snapped both wings off coming out of a run too aggressively. Physics are physics.

[spanalot]

How can you catagorize failure of this material as a maintenence or pilot issue?

The design is obviously a POS.

And I don't recall aluminum structural failure on any craft as young as these.

[monkeyshine]

Jet Blue and America West are also flying a lot of Airbuses. Not sure if they are this model or not.

[spanalot]

"had to do with sideslip forces more than 2X the design limits on the vertical stabilizer. "

Say what?

Since when do side slip forces come anywhere near the airspeed forces that the rudder always encounters.

And if so, why was it that only the rudder failed?

And re: the "5 cyclic rudder inputs" that were nuts, what about cyclic air forces that occur naturally in normal harmonic buffeting?

[COEXERJ145]

Jet Blue, America West, United, USAirways, and Frontier all operate the A320 family (A318/319/320/321).

The only U.S. airlines flying the A300 are American, FedEx, UPS, DHL, and probably a few more with some small cargo carriers.

[bill1952]

Well, I had a student pilot who was laid off from a major airline at the NY hub after 9/11.

He was an A&P mechanic who worked on the airbus, and he told me that you really can't properly inspect the damn thing without removal, and that removal destroys it.

He was such a poor pilot that we had to wash him out.

But that stuck with me, and I won't fly the airbus.

[bill1952]

Michigan when a pilot snapped both wings off coming out of a run too aggressively. Physics are physics.

He must have been WAY beyond the max manuevering speed.

[monkeyshine]

I had read that the airbus flight control system is designed to prevent exactly this. The pilot is overridden when he moves the control more than 30 degrees in any direction. This could be dangerous, esp if you somehow veer off course and need to go over, say, a mountain. Yes, you could rip the wings off trying to get up over it, but flying into the mountain has a certain inevitable outcome but in trying to avoid it the wings might not rip off.

I think the airbus needs to add a pilot override button that will override the computer pilot override for extreme situations where making a hard manuever is absolutely critical. As far as I know, the Boeing do not have such a pilot override function.

Further, I read that this pilot-override feature is put in place because of the design of the craft itself. It cannot handle stress as well as a Boeing and thus, the restrictions are put in place. Not sure how accurate this info is, but it's what I read on a airplane blog a couple weeks ago.

[monkeyshine]

Thanks for the info.

[usafsk]

The rudder did not fail, the vertical stabilizer failed at the attachment points. The rudder worked fine, right up until the stabilizer snapped off. His actions worked it back and forth like Uri Geller working a spoon on the Tonight Show.

[DuncanWaring]

For certification of the "Business Jet" aircraft, the flight test requires passing a "Double Rudder Kick Test". This involves deflecting the rudder in one direction as hard as the test pilot can, then quickly kicking it as far as possible in the other direction, then back hard in the original direction.

Wearing of parachutes is not unheard-of.

I don't think the large passenger-category aircraft (FAR Part 121? 135?) have to pass such a test, but at only 240 knots the rudder should "stall" before the pilot can kick it hard enough to snap it off.

[Gunrunner2]

777's are just fine.

Logged over 1000,000 miles on them this year alone. No problems. . . .now, the delays out of Chicago, that's a different matter.

[pitinkie]

thanks..wont be going thru there!! Jax to Newark to Madrid.

[Gunrunner2]

You just increased your chances of an on-time departure by 1,000%.

[pitinkie]

LOL

[cpdiii]

Gunrunner, what is your opinion on the American Airlines A300 crash. POS airplane? Pilot Error? Both? or bad output from the onboard computer augmented flight control system? It seemed to me the NTSB pointed the finger at the pilot in haste? Particularly given the propensity of this craft to lose its rudder in straight and level flight.

What would be the indicated airspeed that would allow full rudder deflection and still be within design limits and what kind of margin over the design limits would be built into a craft like this?

[Gunrunner2]

Gosh, asking some pretty detailed stuff.

I am not a heavy driver. I flew fighters. So what does that make me: A fighter pilot and someone that is willing to comment on anything, anything at all, and at any time.

;-)

Anyway, rudder deflections are a problem under certain conditions.

Rudder limits are placed on aircraft all the time and usually are based upon the position of the landing gear and/or flight parameters. While rudders are stressed for certain flight conditions, extreme deflections and/or reversals can and do place the rudder out of design limits.

That said. I did not read in detail the mishap report and am not able to definitively make an assessment as to the "cause." I can guess and my guess is "pilot error." Kills me to say that, but most likely.

Sressed for certain parameters, flight controls abruptly input causing moments and transverse-G beyond what was designed for. . .yeah, I think pilot error. Of course, there may be material factors as well.

How's that for a tap-dance?