Some AA Pilots Want A300 Grounded

[whatshouldiuse]

Wino;

. .Regarding why the 737's weren't grounded after the Colorado Springs and Pittsburgh disasters, you state an immediate fix was implemented, namely to fly 5 to 10 miles faster during crossover.

You are confusing cause and remedy. Boeing never could find a cause, but they could find a work-around. Two totally different things. If it happens again (and let's pray it doesn't), will Boeing increase it to 15-20mph faster?

You analogy is like to going to a mechanic with your car. Your tell him, every time you reach 40mph it shakes, but when you get above 45mph it's fine. The mechanic tells you not to go 40mph and everything will be fine... or NOT !!

Whatshouldiuse

[ORAC]

SaturnV, you mean this link?:

<a href="http://pull.xmr3.com/p/25356-E59F/30254611/rudder.html" target="_blank">http://pull.xmr3.com/p/25356-E59F/30254611/rudder.html</a>. . <img src="smile.gif" border="0">

[Raas767]

Fish.. .I don't think the problem is in the flight control system itself but in the manner that the FDR measures the degree and rate of movement for the individual control surfaces. As far as I know the-600 has a standard hydraulic system similar to the 767/757.

[dallas dude]

raas 767,

The A300 has a multi channel DFDR. However, the signals sent to the DFDR are not the actual "raw data" (real time) signals but are a repeat of the "averaged" signal as indicated on the pilot displays PFD's, ND's etc.

Hypothetically, if the rudder was slamming from stop to stop (NOT saying it was) the indication would be damped and shown to be far less severe on both the turn coordinator and the DFDR rudder channel(s) than it may ACTUALLY have been. Repeat, hypothetically.

I believe the FAA requested Airbus remove the DFDR averaging several years ago but Airbus never "got round to it", at least on this airplane.

Cheers,

[Al Weaver]

&gt;I believe the FAA requested Airbus remove the DFDR averaging several years ago but Airbus never "got round to it", at least on this airplane.&lt;

Why is this an Airbus responsibility. They don't own or maintain the airplane. Why wasn't this an AAL responsibility?

I suppose all this will be revealed at the NTSB public hearing someday.

[Wino]

The aircraft are still supported by Airbus. That is who does the engineering, issues revisions to the software (The yawdampener is revision 7 fyi) and generally makes changes as requested by the customer or atleast creates the procedure that is then used by the customer to carry out the change.

As to the 737 fix being a work around, yep it is, but tell me, what sort of work around would you have for a structural failure where the tail falls off? As an A300 pilot for AA tell me, I would love to know! Find me a work around and I will shout down anyone who says to ground the aircraft.

While I haven't advocated grounding the aircraft myself, I certainly see my fellow pilot;s point of view.

Even on the Colorado springs or the Pittsburg 737 I can say to myself, I would have reduced angle of attack firewalled the engines and flown it out instead of snap rolling it. Whether I really would have or not is not the issue, atleast there was a chance to fly those aircraft out. When the tail came off of 587 2 good friends of mine were dead, even though their hearts kept beating for another minute or so till they hit the ground, no chance at all. That is hard to accept.

Tails should not fall off of aircraft, can anyone really argue with that? Oddly enough it is airbus's own statements that flooring the rudder in response to an upset would snap the fin off makes me now think that it is a yaw damper problem, not a composit problem. There have been numerous cases of yawdamper failures on the A300 where the airplane swings violently from side to side. Airbus's own statements say that the fin could snap if opposit rudder is applied into a slip, which is what happens in the failure mode of the airbus yawdamper.

So now I am thinking its a computer problem and not a structures problem...

Cheers. .Wino

[PaperTiger]

IIRC, the initial post-crash reports mentioned the yaw-damper software had to be 'fixed' (rebooted, reloaded or what ?). Everybody seems to have been very quiet about that since.

Coincidentally, Airwise is reporting the findings of the Kenya A310 crash (but not the full text).. .A faulty stall warning ? I can't tell from the sparse details if it went off when it shouldn't or didn't when it should have. . .<a href="http://news.airwise.com/stories/2002/02/1012570108.html" target="_blank">http://news.airwise.com/stories/2002/02/1012570108.html</a>

[ 02 February 2002: Message edited by: PaperTiger ]</p>

[whatshouldiuse]

Wino;

. .My deepest sympathies regarding the untimely deaths of your fellow pilots. And yes, the tail did fall off the plane. The question becomes whether this was the 1st failure or as a result of another failure. I don't know. Hopefully, the NTSB final report will shed some light on this. Having said that, and living in New York, this was the last thing the city needed after September 11th....it was the last thing anybody needed !!!

. .Rumor has it however, a New Jersey transit camera caught most of the unfolding events on film. Hopefully this will at least come close to pin-pointing the sequence of events.

. .Whatshouldiuse

[Hand Solo]

PaperTiger - my hazy memory of the Kenyan crash was that one of the angle of attack vanes was bent by a ground handling vehicle, which caused a false stall warning once airborne. Unfortunately in responding to the stall warning at night the crew flew the aircraft into the sea.

[boss man]

Quote

Tails should not fall off of aircraft, can anyone really argue with that?

Says it all really if the guy’s up front don’t feel 100% about the AC then they shouldn’t fly them.

[GeofJ]

All of this talk regarding Airbus "plastic tails" - if you care to check the details modern Boeing planes have composite tail sections as well - it is the modern weight saving method of construction.

[SaturnV]

ORAC, yes that is the link to the Aviation Week engineering analysis, complete with diagrams and all.

Thank you.

[PaperTiger]

HS. .That makes the 'pi**t er**r' finding even more outrageous. WTF were they supposed to do - keep the nose up believing they'd fall out of the sky, or push it down ? Fate is the hunter indeed.

[arcniz]

An alternative to grounding:

At the moment, some things are clear regarding A300 tails and some are not:

Clear: . .a. A lot of A300 flight hours have been logged with tails remaining attached. . .b. AA587 . .c. some plausible reports cite anomalies in rudder ops on other A300's.

Not clear: . .a. cause and mechanism of AA587 failure. .b. potential for similar failure elsewhere in the fleet

If money, careers, and company futures were not at stake, it might be a no-brainer to ground the fleet. Under real-world rules, that is hard to do without a clear and specific reason. Nobody really has the authority to make that decision - absent more facts.

A certain list of people in govt. and industry have a very great responsibility of care and diligence right now - to ascertain the facts. If another accident were to occur, and if it were shown that responsible parties in the chain of accountability had not made the absolute maximum effort to find the cause ASAP, then the folks on that short list might well have civil and possibly criminal responsibility for their failure to act.

Short of grounding aircraft, what can be done to move the failure diagnosis forward faster?

Obtaining better information about the actual performance of flying aircraft could do this. One constraint now is the limitations of the onboard integrated flight data capture systems - which evidently are not generalized enough to provide fully meaningful data in this instance.

I suggest that the airlines, agencies, and/or airframe manufacturer immediately commence a 'Supplemental Data Aquisition' program, whereby a significant number of aircraft are quickly fitted with add-on flight-recording equipment that is optimized to monitor and record all movement at the wiggly end of selected A3xx aircraft in the course of their scheduled operations. This can be done, at least in the first cut, without any modification to aircraft systems - using a self-contained electronics package stowed in the back in the same form factor as a beverage cart or food pod.

The data from deployment of these units would vastly increase our knowledge about:

a) actual tail movements & stresses in normal real-world operations

b) performance variations among individual aircraft, and operators

c) the possibility of occasional 'anomalous events' (hiccups) in the operation of the aircraft controls & systems. . .

Increased flight data collection is something practical, constructive, and quickly do-able in the direction of resolving the A300 tail quandry.

From my own experience - over decades of creating and finding really obscure problems in very complex systems - there are always some telltale precursor signs of systems instability or component flaws that can be detected from measurement and analysis of the operating signature - easy, once you know what to look for.

The cost of this measurement initiative would be very small in relation to the economics of day-to day airline ops, and it would not materially impact ongoing operations. Time to implement a first-cut deployment of the first half-dozen flying packages accumulating real data could be about 30 days from 'go', with more units and improving analytical strategies following in short order after that.

The only way the uncertainty surrounding AA587 can be put to rest is by obtaining better data.. .I will gladly assist, if needed, and welcome any opportunity to help make this happen.

[Captain104]

In my opinion interesting posts yesterday, right back on track. <img src="smile.gif" border="0"> . .ORAC and SaturnV. .Thank you very much for this vital information from Aviation Week. Hopefully a lot of people take their time to read it thoroughly. For me quite new and surprising: yes, it's possible to shake your tail off, at least a yaw damper bug might do it or one in the rudder limiter?. .Can't remember any piece of information in my hands like this before during or after flying A 312/313 or 306(300-600).. .Wino. .Loosing 2 close friends like this is hard to accept, my feelings are with you. . .Mind, me asking where this information is coming from, that there is a known history of yaw damper failures with A 300-600 exeeding normal? Tech.Dep. of my company (one of Europs big 5 and operating Airbus's in Hundreds) tell me, nothing alike, just routine problems as on other AC.. .I am shure, if that's not true or airlines and manufacturer are trying to cover up something we will know some day. . .Hope very much someone with more influence than me little old pilot reads SYSTEMGUY's post. Sounds reasonable, cool and professional. Nice appraoch to the problem and not to expensive. Might this creep into the minds of NTSB or Airbus poeple?

Abidjan crash, like most of other crashes A-310 or A-300-600 under the headline "how to mishandle a modern airplane by not understanding the AFS" has nothing to do with our thread. Left AOA vane damaged, poor guys up front had now idea what was going on. A look for basic settings, i.e. attitude, powersetting, climbrate and speed should have helped. But...at night, tired, I felt sorry for them.

[Belgique]

The Relevance of the SIA A300 Incident

This snippet below, (from the recent NTSB 7th update) would seem to revisit my theory of a pressure-wave reverberation induced within the Central Air Data Computer by aberrant pitot-static measured pressure inputs. Whether by water in the system or otherwise-induced pressure fluctuations, in my opinion it remains a mechanism by which a chaotic flutter mode could be introduced into the rudder circuit via the rudder limiter or yaw damper.

This SIA incident (below) could just as likely have been caused by water in the static system. The tricky woo aspect of water in the static system is that normal post-incident trouble-shooting can eliminate it, without its presence (and therefore significance) ever being noted (or suspected). It is then perhaps wishful thinking to cinch up some pneumatic connections a little tighter and then put it all down to having been an air-leak.

I see this incident as a significant development in the sleuthing of AA587's initiating events.

Other Airbus Event

The Safety Board is interested in another upset event last year involving an Airbus aircraft. On November 25, 2001, a Singapore Airlines A340-300 departed Singapore for a scheduled flight to Dhaka, with 96 persons aboard. Shortly after takeoff, the pilots noticed a problem with airspeed indicators. Among other things, there were overspeed warnings and large rudder movements without pilot input. The aircraft returned to Singapore and made a safe landing; there were no injuries.

Inspection subsequently found problems with the pitot and static connections to the air data computers, which may have been introduced during recent maintenance. The Civil Aviation Authority of Singapore is investigating the incident. Due to computed loads that might have been experienced by the vertical stabilizer, it and the attached rudder were removed from the aircraft shortly after the incident and were recently examined in Germany. Although no damage was found in either the stabilizer or the rudder, the Board is interested in the rudder system's role in this event.



http://www.pprune.org/forums/showthr...7&pagenumber=2

[vikingwill]

Materials science and statistics

How a material behaves is typically modeled in mathematical simulations as it is almost impossible to run real time studies under real in-use conditions for a number of reasons:

* can't predict all the variables
* can't run them to exclude all failure modes

Real in-use experience from real flying hours over the years with planes fabricated from lightweight metals such as aluminium, magnesium alloys allows manufacturers to predict part life. However, adding significant structural components made from composites means that ALL we have is mathematical models of stability and performance projected for the lifetime of the part (aircraft). Real time experience is now being gathered. The fact that an A300 rudder or other composite component failed may be the first piece of real time experience that we have a problem.

I suspect that Airbus Industries have masses of data to support the airworthiness of the composites. However, I'll wager that the majority of this is "technical justification" based on so called validated modeling techniques, supplemented by real time flying hours.

This may not be deja vue with the Comet, but its right to be concerned and at minimum inspection frequencies should be reduced.

Vikingwill

[RatherBeFlying]

NTSB asking for Wake Vortex Model

NTSB update #7 also contains:

The Safety Board has asked NASA to produce a model of the wake vortices that flight 587 encountered to further study their possible role in the sequence of events.

Belgique is suspicious of pitot-static system faults and the SIA event certainly adds support for this possibility.

My stronger suspicion still leans on possibly misleading signals from the sideslip sensor as the a/c transected various flow regions of the vortex. I suspect significant periods where the sideslip sensor was in different flow regions within the vortices than the fin and look forward to what the model will show.

[Ignition Override]

How many airlines now operating the 737 or A-300 require pilots to fly through simulated uncommanded rudder "hardovers", even if above crossover speed?

Not all US major airlines require unusual attitude training, although United began this training years ago due to the very controversial B-737 accident at Colorado Springs. This would do much more to improve safety in any plane than doing a [parallel..] PRM approach (yes: early last December), knowing already that the primary airport does not even do PRMs anymore.

But gosh Mr. VP Cost Accounting 501, think of the cost to operate those sims just an extra 10 minutes! That would blow our 4-hour sim session blocks and those precious budgets...those management bonuses are such sacred cows.

[TheShadow]

The American Airlines A300 Pilots Group have again written to the Powers that Be

see their paper via this thread:

AA587 Revisited