Air Transat loses A310 rudder inflight (part 2)

[alph2z]

(Since the original thread is closed)

full report
http://www.tsb.gc.ca/en/reports/air/2005/a05f0047/a05f0047_index.asp

see also

Inspection programs not adequate when Air Transat plane lost rudder over Cuba 13 hours ago

GATINEAU, Que. - Investigators say inspection programs were inadequate at the time an Air Transat Airbus lost its rudder and started to go out of control more than two years ago.

But the Transportation Safety Board of Canada report, released Thursday, says "corrective actions" will be taken by both Transport Canada and the European Aviation Safety Agency, the certification authority for Airbus products.

Air Transat (TSX:TRZ.B) Flight 961 left Varadero, Cuba, for Quebec City on March 6, 2005, with 262 passengers and nine crew on board.

Those aboard the Airbus A310 heard a loud bang and felt some vibration before the aircraft started to roll 17 minutes after takeoff.

The flight was cleared to a lower altitude and the pilot managed to bring the plane under control before returning to the company's maintenance facilities in Varadero.

The pilot had no pedal control over the plane's yaw during landing and it was later discovered that almost the entire rudder was gone - most likely because of damage that existed before takeoff.

One flight attendant suffered a minor back injury during the incident.
Investigators found that inspection programs for the particular model of composite rudder were not adequate for "the timely detection of defects."

The board said a rudder separation reduces directional control and could cause the vertical tail plane to fall off.

The board is an independent agency that investigates marine, pipeline, railway, and aviation transportation incidents.

http://canadianpress.google.com/article/ALeqM5iVE79NR4WLFnjgQJvIYemsX-YJpQ
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[Two's in]

Another excellent example for all those automation fans out there that when things go bump in the night, if the answer's not on the ECAM, it better be in your head!

[DozyWannabe]

Two's in:

While the A300/A310 does have advanced automation, it is of a much more traditional type than that fitted to the A32/3/4/80 series.

[alph2z]

Cool, they have pics before the incident, possibly from a plane spotter. The future is here

1.11.7 Examination of Pre-Occurrence Photos

Photographs of the aircraft taken before the occurrence showed curious visual features on the rudder. Photo 4 shows an example of one of these features. It was taken 11 days before the occurrence and shows light-coloured vertical lines on the left side of the rudder below the hydraulic actuators. There were also earlier photographs that showed arc-shaped lines on the left side panel just aft of the hydraulic actuators, and white spots on the trailing edge. These features were not present on the most recent photographs.

Photo 4 - Pre-occurrence photograph of aircraft

There was insufficient resolution in the photographs to conduct a photogrammetric analysis that would determine whether these vertical lines represented an out-of-plane deformation such as a disbond bubble. Since the vertical line features were observed on photographs taken on different days under different lighting conditions by different photographers, they were actual physical features on the rudder, and not simply reflections or dirt on the camera lens.

The vertical line features first appeared in photographs starting in early 2003, and the aircraft was subject to all its regular inspections in the intervening time. Examination of other aircraft found that staining of the rudder near the hydraulic actuators was not unusual. Subsequent testing found that hydraulic fluid could dissolve the Air Transat tail decal material and analysis of a vertical streak on sister aircraft MSN 600 found the streak to be composed of a mixture of hydraulic fluid and dissolved decal material.

http://www.tsb.gc.ca/en/reports/air/2005/a05f0047/images/a05f0047_photo_4.jpg


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[alph2z]

>> 26 liters of water found in a rudder !!???? I wouldn't like to see that repeatedly freeze at 40000 ft.

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http://www.tsb.gc.ca/en/reports/air/2005/a05f0047/images/a05f0047_photo_6.jpg

Trapped fluid was found in the lower nose area of the rudder of aircraft MSN 701 during the AOT-2 inspection (see Photo 6). The fluid was not formally identified, but was reported to be mostly water with some dirt, possibly

containing hydraulic fluid and sealant chips. The fluid level was reported to be up to the lower inspection hole.

The rudder box aft of the spar was dry. The two drain openings in the nose section were found to be clogged. The tap test did not show any

sign of disbond. An X-ray and thermography inspection of side panels adjacent to the fluid did not reveal any fluidity entrapped inside the sandwich.

Photo 6 - Fluid accumulation in the nose of the rudder of aircraft MSN 701

Back to top
1.12.5 Fluid Contamination Program

As a result of the findings on aircraft MSN 361, a separate investigation was launched by the National

Transportation Safety Board (NTSB) with support from Airbus to address the issue of hydraulic fluid contamination and its effect on structural strength. This program is ongoing, but preliminary conclusions include the following:

* Hydraulic fluid contamination does not have an immediate effect on mechanical strength; the effect takes time to develop.

* The effect of a hydraulic fluid/water mixture is more severe than that of hydraulic fluid alone.

* The effect of hydraulic fluid/water or hydraulic fluid is not reversible whereas the effect of water.

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[SIUYA]

For those interested in this thread, see also:

http://www.iasa.com.au/folders/Safety_Issues/others/ramificationsforAA587.html

[Slats One]

I have posted on this before and AGAIN - it all reminds me of a letter that I wrote to Flight International on ageing composites- and which was printed as letter of the week..

As a piece of conjecture based on subsequent evidence- and not dangerous speculation, can we now give any credence to a train of thought that says that in the American Airlines AA557 Airbus crash at JFK, that the rudder failed- leading to the control issues that led the PIC to react on the rudders, which may or may not have contributed to a fin failure that was going to happen anyway as a result of the rudder departing the airframe - with or without the subsequent rudder pedal technique controversy?

You may react in the negative at such comment- but it is very clear that the Transat rudder failure, nearly led to a subsequent fin /attachment failure. We know that the departure of the rudder weakened the fin- which stayed attached -on this occasion.........

And I am sure many will recall the litres of fluid drained from AA composite rudders over the years on the ramp..

Having studied composites for years, I know that fluid ingression and freezing of such in a cyclical pattern as achieved in flight cycles and high altitude flight, is guaranteed to cause internal fibre fissure fatigue and delamination.

Surely its time to retrospectively apply the FACTS of the TransSat events to the AA557 investigation? Maybe the co-pilot was not the casue- just a reactive contributory not of his making.

Makes you think- does it not?

[bubbers44]

Yes it makes you think, but Airbus and investigators would rather blame the dead pilot again because it doesn't cost as much. I think the captain of AA587 would not have allowed his copilot to misuse the rudders even if the copilot, for some reason, forgot how to gracefully get out of a typical wake turbulence encounter without throwing the flight attendants in the back violently back and forth, severing both engines from the wings and ripping off the perfectly airworthy vertical stabilizer with a patch job at the factory right where it separated from the fwd bracket. Makes me think.

[lomapaseo]

but Airbus and investigators would rather blame the dead pilot again because it doesn't cost as much. ...
but that belief misses the real point.... you can't fix something that you don't know why it broke.
...there is really no incentive for Airbus to off load a blame culture onto anybody. They would be willing to fix what they knew had broken on its own and be done with the onward risk of it happening again. But since there is no other fixable explanation they can just stand by and read the final reports like the rest of us.
Anybody who can provide a defensible and credible argument to the contrary of the final report is welcome. And if it can be shown that the material or the design is defective against the acceptable standards under the regulations, then I believe it should and will be addressed. But simply saying "fix it", without such an analysis is more likely to provoke a shot-in-the-dark mentality of addressing causal factors following an accident investigation.

[DozyWannabe]

I can see how the two incidents are related in terms of potential disbonding issues, but firstly I'd presume that if inspection regimes have been criticised in the Air Transat incident, whereas they were not in the case of AA587, then AA had a better inspection regime and found no problems with the rudder on that aircraft.

Secondly, with AA587 you had colleagues on record as saying that Sten Molin had a tendency to hit the rudder pedals quite hard when dealing with wake encounters, and you have the AA advanced maneouvering training being criticised for teaching aggressive rudder use during loss of control situations.

Thirdly, you have the data from the number crunchers that proved that the lateral loads on the tail during the accident sequence exceeded the design limit of the vertical stabiliser, even if the rudder was new and not fatigued or repaired - in fact the stabiliser remained attached past that limit for a few seconds, so the 'patch' in fact did not degrade the strength of the structure.

As composites are used more and more in aviation, I think we are going to learn a lot more about their behaviour in flight-cycle conditions and I expect that the water-retention issue will become more clearly understood. However I doubt this will reverse the findings of the AA587 report, but I'm always ready to be wrong.

[airsupport]

Glad to see more people are at least considering this was the cause of the AA Crash, as I have thought was at least possible all along, and stated so on the original thread, but was ridiculed for my views.

I was working with an almost identical A300-600 to the AA one at the time, also operating out of JFK, and also operating down through the Caribbean.

When it was in the hangar overnight for A checks, we would spend all night draining water from the tail, yet there were no internal inspections of the tail required, only a visual external inspection.

It was only after the sad AA incident that thought was given to this trapped water freezing and thawing every flight between checks, around 4 weeks.

[DozyWannabe]

I don't think you'll ever get it down as the cause, but you might get acknowledgment that it may have been a contributing factor. Again though, the tail held past the point of ultimate load, and that was definitely caused by PIO.