Airbus rudder FALLS OFF in midair

[Joe]

link

At 35 000 feet above the Caribbean, Air Transat flight 961 was heading home to Quebec with 270 passengers and crew. At 3.45pm last Sunday, the pilot noticed something very unusual. His Airbus A310's rudder -- a structure over 8m high -- had fallen off and tumbled into the sea. In the world of aviation, the shock waves have yet to subside.

Mercifully, the crew was able to turn the plane around, and by steering it with their wing and tail flaps managed to land at their point of departure in Varadero, Cuba, without loss of life. But as Canadian investigators try to discover what caused this near catastrophe, the specialist internet bulletin boards used by pilots, accident investigators and engineers are buzzing.

One former Airbus pilot, who now flies Boeings for a major United States airline, told The Observer: "This just isn't supposed to happen. No one I know has ever seen an airliner's rudder disintegrate like that. It raises worrying questions about the materials and build of the aircraft, and about its maintenance and inspection regime. We have to ask as things stand, would evidence of this type of deterioration ever be noticed before an incident like this in the air?"

He and his colleagues also believe that what happened may shed new light on a previous disaster. In November 2001, 265 people died when American Airlines flight 587, an Airbus A300 model which is almost identical to the A310, crashed shortly after take-off from JFK airport in New York. According to the official report into the crash, the immediate cause was the loss of the plane's rudder and tailfin, though this was blamed on an error by the pilots.

There have been other non-fatal incidents. One came in 2002 when a FedEx A300 freight pilot complained about strange "uncommanded inputs" -- rudder movements which the plane was making without his moving his control pedals. In FedEx's own test on the rudder on the ground, engineers claimed its "acuators" -- the hydraulic system which causes the rudder to move -- tore a large hole around its hinges, in exactly the spot where the rudders of both flight 961 and flight 587 parted company from the rest of the aircraft.

On Sunday night Ted Lopatkiewicz, spokesperson for the US National Transportation Safety Board (NTSB), which conducted the flight 587 investigation, said that the board was "closely monitoring" the Canadian inquiry for its possible bearing on the New York crash. "We need to know why the rudder separated from the aircraft before knowing whether maintenance is an issue," he added.

Airbus -- Europe's biggest manufacturing company, to which British factories contribute major components, including aircraft wings -- has now overtaken Boeing to command the biggest share of the global airliner market. In sales literature to operators, it described the A300 series as a "regional profit machine".

The firm recently launched its superjumbo, the two-storey A380, which is due in service next year. Like earlier Airbus models, this relies heavily on "composite" synthetic materials which are both lighter -- and, in theory, stronger -- than aluminium or steel. Fins, flaps and rudders are made of a similar composite on the A300 and A310, of which there are about 800 in service all over the world.

Composites are made of hundreds of layers of carbon fibre sheeting stuck together with epoxy resin. Each layer is only strong along the grain of the fibre. Aircraft engineers need to work out from which directions loads will come, then lay the sheets in a complex, criss-cross pattern. If they get this wrong, a big or unexpected load might cause a plane part to fail.

It is vital there are no kinks or folds as the layers are laid, and no gaps in their resin coating. Holes between the layers can rapidly cause extensive "delamination" and a loss of stiffness and strength.

Airbus, together with aviation authorities on both sides of the Atlantic, insists that any deterioration of a composite part can be detected by external, visual inspection, a regular feature of Airbus maintenance programmes, but other experts disagree.

In an article published after the flight 587 crash, Professor James Williams of the Massachusetts Institute of Technology, one of the world's leading authorities in this field, said that to rely on visual inspection was "a lamentably naive policy. It is analogous to assessing whether a woman has breast cancer by simply looking at her family portrait."

Williams and other scientists have stated that composite parts in any aircraft should be tested frequently by methods such as ultrasound, allowing engineers to "see" beneath their surface. His research suggests that repeated journeys to and from the sub-zero temperatures found at cruising altitude causes a build-up of condensation inside composites, and separation of the carbon fibre layers as this moisture freezes and thaws. According to Williams, "like a pothole in a roadway in winter, over time these gaps may grow".

Commenting on the vanishing rudder on flight 961, he pointed out that nothing was said about composite inspection in the NTSB's report on flight 587. This was an "unfortunate calamity", he said. Although the flight 961 rupture had yet be analysed, he continued to believe Airbus's maintenance rules were "inadequate", despite their official endorsement.

Barbara Crufts, an Airbus spokesperson, said visual inspections were "the normal procedure" and insisted Williams's case was unproven. "You quote him as an expert. But there are more experts within the manufacturers and the certification authorities who agree with these procedures." She disclosed that the aircraft used in flight 961 -- which entered service in 1991 -- had been inspected five days before the incident. She said did not know if the rudder had been examined.

Despite these and earlier assurances, some pilots remain sceptical. The Observer has learnt that after the 587 disaster, more than 20 American Airlines A300 pilots asked to be transferred to Boeings, although this meant months of retraining and loss of earnings. Some of those who contributed to pilots' bulletin boards last week expressed anger at the European manufacturer in vehement terms. One wrote that having attended an Airbus briefing about 587, he had refused to let any of his family take an A300 or A310 and had paid extra to take a circuitous route on holiday purely to avoid them: "That is how convinced I am that there are significant problems associated with these aircraft."

Another seasoned pilot with both military and civilian experience said: "Composite experts across the country advocate state-of-the-art, non-destructive testing to prevent this type of incident from happening, yet civil aviation authorities still only require 'naked eye' or other rudimentary inspections. How many more incidents have to occur for decision-makers to do the right thing by passengers and crews?"

He said that while flight 961 had come down safely, to land a plane without a rudder in a crosswind or turbulence could be impossible. The rudder was all the more important on a plane such as an A310, because its wing design meant that it was "aerodynamically unstable" and needed the rudder for stability.

Air Transat, a charter operator which flies from Canada to Europe and the Caribbean, said that after the incident it "immediately carried out a thorough visual examination of all its Airbus A310s... and no anomaly was detected."

The separation of the rudder may have further implications for the cause of the 587 crash. In its report, the NTSB said the tail and rudder failed because they were subjected to stresses "beyond ultimate load", imposed because the co-pilot, Sten Molin, overreacted to minor turbulence and made five violent side-to-side "rudder reversals". The report said the design of the A300 controls was flawed because it allowed this to happen.

However, the NTSB investigation has been criticised by many insiders. Ellen Connors, the NTSB chair, told reporters last January that the report was delayed because of "inappropriate" and "intense" lobbying by Airbus over its contents, adding: "The potential for contaminating the investigation exists." In America, the NTSB staff is small and manufacturers provide many of the staff employed on air-crash investigations into their own products.

Dozens of former accident investigators, engineers and pilots, including some who were involved in the official inquiry but were disappointed by its conduct, poured their expertise into a parallel investigation run by Victor Trombettas, who lives near the crash site and runs a website, usread.com. Drawing on the huge mass of technical data released after the crash, they question the conclusion that "aggressive" rudder inputs were the crash's main cause.

"I don't think the NTSB did a quality job," said Vernon Grose, a Washington safety consultant who is a former board member. He supported the conclusion of Trombettas's group -- that more than ten seconds before any rudder movements, the 587 pilots were fighting to regain control of the aircraft for reasons that remain unknown: a still-to-be investigated technical failure, or possibly a terrorist bomb. The crash, he recalled, took place two months after 9/11. Ninety per cent of the witnesses who saw the plane from the ground said they saw smoke or fire billowing from it before the tail and rudder fell off, Grose said.

Against this background, a spokesperson for the Canadian Transport Safety Bureau, which is performing the investigation, disclosed that there is "no evidence" of any movements by the rudder before its rupture, while Air Transat confirmed that it had separated when the plane was at cruising altitude and speed. "You barely use the rudder at all in those conditions," the former A300 pilot said. "If this plane lost a rudder with no one doing anything, it has to raise new questions about the fate of flight 587."

And the pressure is now on the aviation authorities to review whether testing by the naked eye is really enough to keep air passengers safe. - Guardian Unlimited © Guardian Newspapers Limited 2005

[Montcalm]

What i find funny about this is the pilot claimed he was denied to land the plane in Florida,and now like for the other Air Transat plane which pilot Robert Piché glided to the nearest airport,all passengers are sueing Air Transat for the stress and other reasons.

[Jalinth]

What i find funny about this is the pilot claimed he was denied to land the plane in Florida,and now like for the other Air Transat plane which pilot Robert Piché glided to the nearest airport,all passengers are sueing Air Transat for the stress and other reasons.

Yet another reason to avoid Air Transat. They seem to have some maintenance problems at that place. So in Canada we have airlines that go bankrupt and those that lose bits of themselves in mid-air - lovely.

I'd be more worried if the rudder dropped off a major airline where maintenance standards are theoretically higher - more likely to indicate a problem with the airplane rather than the maintenance.

[Darth Wong]

So the rudder is known to have a problem with becoming weak and brittle with age, and the solution is naked-eye inspection? That's pretty goddamned disturbing; I've seen parts in which a surface crack is not visible to the naked eye; how the fuck are you supposed to visually detect internal delamination of composite layers with the naked eye?

[Aaron]

Yet another reason to avoid Air Transat. They seem to have some maintenance problems at that place. So in Canada we have airlines that go bankrupt and those that lose bits of themselves in mid-air - lovely.

I'd be more worried if the rudder dropped off a major airline where maintenance standards are theoretically higher - more likely to indicate a problem with the airplane rather than the maintenance.

I've never heard of Air Transat. Don't we just have:

Westjet
Jets Go
Air Canada

[Col. Crackpot]

Jalnith, i think this has less to do with shoddy maintanence and more to do with a design flaw. This isn't the first time this happened.

*note to self: avaoud 300-series Airbus jets like the plauge.

[Darth Wong]

Yet another reason to avoid Air Transat. They seem to have some maintenance problems at that place. So in Canada we have airlines that go bankrupt and those that lose bits of themselves in mid-air - lovely.

I'd be more worried if the rudder dropped off a major airline where maintenance standards are theoretically higher - more likely to indicate a problem with the airplane rather than the maintenance.

I've never heard of Air Transat. Don't we just have:

Westjet
Jets Go
Air Canada

They're not a regular airline. They're an air charter company.

[Montcalm]

Yet another reason to avoid Air Transat. They seem to have some maintenance problems at that place. So in Canada we have airlines that go bankrupt and those that lose bits of themselves in mid-air - lovely.

I'd be more worried if the rudder dropped off a major airline where maintenance standards are theoretically higher - more likely to indicate a problem with the airplane rather than the maintenance.

I've never heard of Air Transat. Don't we just have:

Westjet
Jets Go
Air Canada

Air Transat is a Quebec airline company,i think it was Air Quebec or something like that.

[Darth Wong]

By the way, for those who need the article's technical discussion of the problem described in the simplest possible terms, the Airbus 300 series' rudder is literally held together with glue. Technicians are expected to inspect the rudder periodically with the naked eye to ensure that it's not coming apart, ie- the stuck-together layers aren't becoming unstuck.

[Aaron]

By the way, for those who need the article's technical discussion of the problem described in the simplest possible terms, the Airbus 300 series' rudder is literally held together with glue. Technicians are expected to inspect the rudder periodically with the naked eye to ensure that it's not coming apart, ie- the stuck-together layers aren't becoming unstuck.

Glue? Aren't aircraft parts typically riveted together?

[Col. Crackpot]

By the way, for those who need the article's technical discussion of the problem described in the simplest possible terms, the Airbus 300 series' rudder is literally held together with glue. Technicians are expected to inspect the rudder periodically with the naked eye to ensure that it's not coming apart, ie- the stuck-together layers aren't becoming unstuck.

which is fucking insane. How the hell are you supposed to see delamination of internal layers of a composite when the goddamn epoxy is opaque!

[Col. Crackpot]

By the way, for those who need the article's technical discussion of the problem described in the simplest possible terms, the Airbus 300 series' rudder is literally held together with glue. Technicians are expected to inspect the rudder periodically with the naked eye to ensure that it's not coming apart, ie- the stuck-together layers aren't becoming unstuck.

Glue? Aren't aircraft parts typically riveted together?

no composite aircraft parts consist of strands of carbon fiber "soaked" in a thermoset epoxy and "woven" into a sheet of material. The layers are then joined by more epoxy.

[Mayabird]

Umm, Joe, your link goes to a BBC page about the protests in Beirut. I wouldn't be picky about this except I'd like to send the article to someone.

[GrandMasterTerwynn]

Umm, Joe, your link goes to a BBC page about the protests in Beirut. I wouldn't be picky about this except I'd like to send the article to someone.

The correct link is Here.

[Joe]

Argh. Mea culpa.

[Admiral Valdemar]

Typically they use ultrasonic imaging to detect any flaws, but even that has limits. There have been sand grain sized flaws in engine components or rivets in the past that have led to disastrous results.

[aerius]

How the hell are you supposed to see delamination of internal layers of a composite when the goddamn epoxy is opaque!

Superman X-ray vision of course, doesn't everyone have x-ray vision?

[Wicked Pilot]

What concerns me is that it came off at cruise altitude, where you never touch the rudder. I hope the FAA issues some kind of airworthiness directive to have every A310 and equivilant throughly inspected for any sign of rudder failure. Nothing bad happened this time, but if in the future some A310 loses and engine on takeoff, and the rudder snaps off when the pilot steps on the good engine, people will die.

[Rogue 9]

SHIT! I flew on an Airbus A330 (I think) coming back from England! Was Boeings the rest of the way, but I'm glad we didn't lose the rudder mid-Atlantic...

[Darth Fanboy]

Superman X-ray vision of course, doesn't everyone have x-ray vision?

I fear for swim teams everywhere if you do.

[Jon]

OMFG all Airbus planes must sux0rz!

Ahem, worrying issue with the A310's- iirc this is one of the older models in the Airbus line? I'm not trying to excuse something like that happening though, not good.

[MKSheppard]

OMFG all Airbus planes must sux0rz!

Considering the computer can override the pilot's input on an Airbus, yeah.

[Col. Crackpot]

OMFG all Airbus planes must sux0rz!

Ahem, worrying issue with the A310's- iirc this is one of the older models in the Airbus line? I'm not trying to excuse something like that happening though, not good.

the greatest problem here is Airbus' proscribed method of inspection for wear on composite components is to visually inspect the affected area for FUCKING DAMAGE INVISIBLE TO THE NAKED EYE! So, yes, Airbus' engineering department is 't3h sux0rz!' as you so eloquently put it.

[Darth Wong]

OMFG all Airbus planes must sux0rz!

Ahem, worrying issue with the A310's- iirc this is one of the older models in the Airbus line? I'm not trying to excuse something like that happening though, not good.

Apart from the problem of their ridiculous preventive maintenance recommendations, there is also the problem that they are continuing to design this type of rudder into newer planes. Composites sound really cool in ad-copy and save fuel costs, but metal is more reliable and has more gradual failure modes; a matter of no small importance from an engineering perspective.

[Mayabird]

Argh. Mea culpa.

Hey, don't worry about it. We all mess up. The important thing is that I have a link now so I can mock Airbus with my friends, and my friend who works for an airline can shudder some more.