Did Composite Parts Bring Down Air France 447? (And Will the New FAA Do Its Job?)

 In the two weeks since the Air France 447 crash, I’ve written several times about the possibility that composite parts may have played a role in the disaster. This prospect has dire implications for the future, since these lightweight, fiber and resin materials are increasingly replacing aluminum in aircraft construction. AF 447 was an Airbus A330-200, a plane a body fuselage built of metal, but significant levels of  composite in its other parts–most importantly, the wings and the tail. 

Now, wreckage recoved from the crash shows that 447 may have broken up in midair–which raises new questions and offering new clues on this subject of composites, according to a piece today in the Christian Science Monitor.

“There is a very compelling need to find the wreckage,” says Richard Healing, a former member of the National Transportation Safety Board and an aviation safety consultant. “We need to know, if some of the composite parts failed [on Flight 447, whether they failed at a point that any other material would have failed.”

Some of the biggest pieces of debris found so far appear to be the plane’s tail fin and vertical stabilizer. These parts are made partially of composite materials, and their failure has contributed to several crashes in the past. In the 2001 crash of American Airlines Flight 587, an Airbus 300 with a similar design to the A330, the vertical stabilizer snapped off in severe turbulence. One of the first questions investigators addressed was whether the composite materials used in the component contributed to the crash, according to Mr. Healing.

“The tail that broke off was a composite structure and was attached to the aircraft in six places. The bolts [some made of composite materials] holding it into place failed,” he says.

In fact, I’ve quoted other sources who say the turbulence encountered by American Airlines 587 before it crashed was mild compared with what Air France 447 might have met over the equatorial Atlantic. And while the bolts in question had passed safety tests, as have various composite parts, numerous questions have been raised about the methods used in testing new composite parts during the design process, as well as during routine ground testing prior to flights.

Boeing has hung a good part of its future on its new 787 Dreamliner, a midsized passenger jet built from over 50 percent composite materials, by weight. The Dreamliner is about to begin flight testing, and is supposed to be released next year. The lightweight construction of the 787 and other high-composite aircraft promises big savings to airlines in fuel costs. But with even a possibility that composites contributed to the 587 and 447 disasters, more testing and strict federal oversight, at the least, are needed before this new generation of aircraft begins flying.

Is this due diligence likely to happen? Remember that the fortunes of America’s largest aerospace manufacturer are in the mix, and that Boeing has given the 787 a huge buildup: The Dreamliner was supposed to be the highlight of the Paris Air Show, which opens up next week under the twin clouds of global recession and the 447 crash, but Boeing now says its first flight will be delayed. In fact, the plane is well behind schedule, placing Boeing is in competition with Airbus, which is working on its own high-composite jet.

It will be up to the Federal Aviation Administration to ensure that public safety comes before private profits–not something the FAA has been known for. The last FAA administrator, Marion Blakely, was a fervent freemarketeer who opposed increasing government regulation. She went on to become chief lobbyist for the aerospace industry group. Obama’s appointee, Randy Babbitt, is the former head of the airline pilot’s union, and ought to have some interest in ensuring that planes don’t fall apart in midair.

14 responses to “Did Composite Parts Bring Down Air France 447? (And Will the New FAA Do Its Job?)

  1. I find the title and subtitle of your article to be inflammatory. You have no basis to claim that composite parts are the reason for the Air France 447 crash. It is pure speculation on your part. The A-330 has an impeccable safety record. No airplane is guaranteed to survive flying directly into a multi-cell storm system with tops estimated at up to 50,000 ft! You might as well have started off with “Did aliens shoot down AF447 and will the USAF do its job?”

    Moving on:
    Severe turbulence was not the reason the American Airlines A-300 tail “snapped off as you infer.
    The National Transportation Safety Board (NTSB) concluded that the enormous stress on the rudder that broke the vertical stabilizer off, was due to the first officer’s “unnecessary and excessive” rudder inputs, and not the wake turbulence caused by the [preceeding] 747.
    “The vertical stabilizer fractured from the fuselage in overstress, starting with the right rear lug while the vertical stabilizer was exposed to
    aerodynamic loads that were about twice the certified limit load design envelope and
    were more than the certified ultimate load design envelope.”
    see: http://www.ntsb.gov/publictn/2004/AAR0404.pdf

    In regards to composite construction of the B-787: Interstingly enough, the composite structure is not really lighter (or significantly so) than the aluminum structure it replaces (the efficiencies are largely gained with aircraft-wide advanced systems design. But, the composite structure is not subject to corrosion like metallic structures, and is stronger than aluminum as well. Composite construction is not really new. Has been used in military fighter and helicopter aircraft for sometime.

    Your inflammatory writing is more suited for Nancy Grace than serious aviation safety inquiries.
    (The commenter is an A-330 Captain and instructor)

  2. IH8ASSUMPTIONS

    I also am appalled by the title and comments made on this blog. What WF palmer says is 100 % correct. These assumptions you are making are without any basis. First of all NOBODY knows what happenend to AF 447. Even the experts are scratching their heads! So coming up with ridiculous theories is not helping anyone! Composite construction has been used for an extensive amount of time. and the principle is thousands of years old! It like any material has advantages and disadvantages. As well as limitations which are well known. It is used in numerous light aircraft, boats, gliders, military aircraft! The A330 is a very robust aircraft, it has been around since 1994 and has a excellent safety record. If the tail has sheared off in this case (it is not confirmed yet) it would most likely be due to a very aggressive input by the pilot or extreme winds. and not due to it being composite rather than traditional aluminium. The vertical stabiliser is designed on all aircraft (especially twinjets) to withstand extreme loads, including crosswinds, engine failure and a combination of both. They are very robust regardless of what type of material.

    Please check your sources before commenting on this subject matter again!

    (The commenter is an aircraft engineer)

  3. I’m a layperson who lost a relative in the 2001 AA Flight 586 crash in Queens, NY where the composite vertical stabilizer also detached, in-flight, from the fuselage. I have one question:

    Are there instances where a metal vertical stabilizer has broken off the fuselage, in-flight, on large conventional passenger jets?

  4. Are you on crack? Why do you continue to spread misinformation about AF447? You may as well work for Fox News or CNN.

    First of all, to say that the Airbus A300 that crashed in Queen’s and the A330-200 that disappeared over the Atlantic are “similar in design” is about as accurate as saying that my Mazda3 is similar in design to the AMG S-63 I passed on the turnpike today. Sure, they both have 4 wheels, an engine, and 4 doors, but that’s about where the similarities end.

    Likewise, implying that composite parts caused the vertical stabilizer to detach from AF447, and thus doomed the flight, is premature at best, and irresponsible as a whole. Nobody knows WHEN the vertical stabilizer detached from AF447, and so you’re attempting to make a chicken-and-egg arguement without ANY concrete evidence. Furthermore, I have a real aversion to media misinformation related to AA586 and the “failure” of the composite parts that resulted in vertical stabilizer separation. If you read the NTSB final report on AA586, you’ll note that during the last few moments of “flight”, as the aircraft pitched down toward the earth, both engines separated from the wings due to the extreme loads they were subjected to in a near 90 degree downward pitch. Would you be so bold as to say that the hardware holding the engines on the aircraft “failed” because they allowed separation of the engines when they were subjected to loads far beyond their design limitations? I doubt it. Now apply the same logic to the vertical stabilizer–the co-pilot on AA586 had a history of overcorrecting for wake turbulence, and recreations of the final moments of flight revealed that the FO’s aggressive rudder inputs (and aileron overcorrection) in fact upset AA586, NOT the wake turbulence. FACT: Knucklehead FO fully deflected the rudder 3 times in rapid sequence subjecting the vertical stabilizer to forces that it (and it’s mounting hardware) were NOT DESIGNED to withstand. Now, whether or not AA’s upset training and evaluation procedures, and Airbus’s envelope disclaimers played a role as well is up for debate, but the bottom line is that the vertical stabilizer performed as designed–so don’t blame the composite parts.

    Let’s all use our heads and wait for the FDRs and aircraft debris to drive our judegement. Until then, ALL we can say about AF447 is that it disappeared while flying over the atlantic, possibly through a storm cell, and that automated messages sent from the aircraft SUGGEST that conflicting airspeeds were being recorded during the final moments of flight. That’s it.

  5. In addition to the 2001 crash of American Airlines Flight 587 (which lost its tailpiece); blamed on pilot error, there was another incident…In March 2005 a 300-series Airbus (Air Transat Airbus A310) lost most of its rudder on a flight from Varadero, Cuba, to Quebec City. The weather conditions during this flight were not unusual, so external forces didn’t appear to have been a factor. In trying to figure out what had happened, CTSB investigators focused on structural problems that might have cause the rudder to break apart–and how they could have been missed during pre-takeoff inspections of the aircraft.They took already damaged composite specimens–some from other A310 rudders–and placed them in a vacuum chamber. The samples experienced pressure changes simulating changing altitude during many simulated flights.

    “The areas of the damage almost doubled instantly,” the report says. “The rapid propagation event was explosively loud and violent.” The explosion even damaged their test chamber. The TSB say this explains the loud bang heard by the crew.

  6. Pingback: Am I “On Crack” When It Comes to Flight 447? « Unsilent Generation

  7. As a retired aircraft System Safety specialist with a major aerospace company, I am in full agreement with you. The use of composite construction for anything as vital as the vertical stabilizer on a commercial airliner is unthinkable. Determining a composite structure’s precise strength at time of manufacture, and predicting its subsequent degradation due to stress, temperature extremes, age and other factors, is an inexact science. Also, Airbus’s decision to cantilever this massive fin on top of the fuselage, rather than integrating it into the aft fuselage structure, is an unforgiveable design practice. It virtually guarantees it will snap off under even anticipated aerodynamic loads. Loss of the vertical stabilizer on flight 447, apparently due to turbulence, was the initial failure (it was recovered, nearly intact, upstream of the debris field), and all 24 telemetered failure messages merely reported the rapid disintegration of the A330.

  8. Ground the Airbus?

    Used in law, science and philosophy, a rule known as Occam’s Razor requires that the simplest of competing theories be preferred to the more complex, and/or that explanations of unknown phenomena be sought first in terms of known quantities.

    We do not know if Air France Flight 447 was brought down by a lightning storm, a failure of speed sensors, rudder problems or pilot error. What we do know is that its plastic tail fin fell off and the plane fell almost seven miles into the ocean killing everyone aboard.

    Article at Consortium News: http://consortiumnews.com/2009/062009a.html

    Article at Global Research: http://globalresearch.ca/index.php?context=va&aid=14025

  9. I worked in engineering flight test for a major airframe manufacturer and I have to point out that the critics of Mr. Ridgeway are reacting as if composite airframe structures are a mature and proven technology. They are not.

    Only after millions of flight hours and several decades of daily service are in the books will we be able to say that. Even with aluminum it took decades before metal fatigue was understood — and that question is still being studied today.

    As of right now, the composites record is spotty. There have already been two in-flight failures of the composite vertical tail on the Airbus — the first being AA Flight 587 in 2001, an Airbus A300-600, and the second being Canadian Air Transat Fight 961 in 2005, An A310-308, which lost its composite rudder after taking off from Cuba.

    The NTSB accident report on flight 587 noted that a vertical stabilizer (tail fin) separating from an airliner in flight was “unprecedented.” The report also found that the composite lugs, which are the attachment points to the fuselage, failed, while the aluminum lugs and the titanium bolts did not.

    The report did not fault the composite construction however, but found that the loads imposed by the pilot’s rudder inputs exceeded the ultimate loads to which the airplane was designed. In other words, the pilot cycling — alternating left and right — rudder pedal inputs put more load on the fin than it was designed to take.

    This despite the fact that the pilot was flying the plane at design maneuvering speed, Va, which is a slower speed than cruise and is the speed at which the airplane is designed — according to FAA certification requirements — to withstand maximum control inputs without structural damage.

    The tail is supposed to be designed to take full rudder deflection at maneuvering speed, but not necessarily cycling the rudder back and forth, which could exceed the allowable load.

    I can tell you that in flight testing a new airplane, the complete flight envelope is fully explored, including the maximum flight loads that the wings and tail are designed to take. If an airplane is going to break, it will break in flight testing.

    In every airframe design there is a built-in margin of safety, which means that the tail or wings are not supposed to break right at the limit, there is a cushion there. I am also sure that many airline pilots have in the past cycled the rudder pedals from full stop to full stop — this used to be part of the training. But not one tail ever broke, except for a composite tail.

    That is as far as I am going to go. Every pilot, engineer or airline passenger can draw their own conclusions. But saying that we should not ask questions about plastic airplanes does not make sense. They will soon be everywhere and there will be many more lessons learned — just as we did with metal planes and wood planes before that.

    I will also make a technical comment about composite structures. They are indeed very strong and rigid and can be lighter than aluminum, but they are also difficult to attach to other pieces. The attachment points are the achilles heel because composites do not take point loads, or bearing loads, well.

    If you take an airplane part made of carbon fiber and attach it with a bolt or a rivet, that joint will fail well before the strength limit of the fastener is reached. This is very well known in the aircraft industry and is due to the material property of plastics. Plastic by definition means it is malleable. Over time, the material tends to act like an extremely viscous (thick) fluid and will “creep” under point loads, such as when tightened with a screw. The composite material will slowly flow out from under the head of the fastener.

    That is why the attachment points of composite airplane parts need special attention. Usually a metal bearing surface is embedded in the composite in order to spread the load out over a wide area, so as to minimize point loads. In looking at the drawing of the fin attachments in the NTSB report, it is easy to see that designing this critical area could be tricky.

    The Airbus fin attachment lugs are made of composites and they failed. The mating lugs on the fuselage are made of metal and they did not fail. Again I do not want to speculate further because I have only very sketchy information about the actual design and have done absolutely no analysis on these parts. I am simply pointing out the obvious.

    I also noted with interest one of the other posts here from a person familiar with disassembling Airbus parts who noted that most of the fittings, or attach points, are made of composites, not metal. Again, not being familiar with the specifics of the design, but this does not sound like a good idea. That’s as far as I will go with that.

    And now we have an almost intact vertical tail (fin and rudder) from AF 447. This almost certainly means that the tail broke off first. I fully expect that the investigators know exactly what happened right now — even without the flight data recorders. And I expect they will anounce that it was the tail coming off (again) that led to this crash.

    Raising questions about composite airplanes is a good idea. I certainly hope that the new plastic planes will prove to be great and free of defects. But we will have to wait and see…

  10. Found a link to lightning caused composite failure. perhaps you’ll post this one.
    http://www.pdfxp.com/pdf/www9-9flightsafety9-9org/hs/hs_jan_feb98.pdf

  11. As a member of the flying public I go to extremes to avoid two things in flying – commuter airlines and Air Bust aircraft. Air Bust aircraft specifically, because of their composite construction – Flight 587 and composite race cars. When the race cars lose control and crash they shatter completely. Why would not an aircraft act the same way under similar circumstances? The implications for aircraft manufacturers and the airline industry are far too disastrous to contemplate if Air Bust planes are grounded as being unsafe to fly. IMO, this is why Boeing continues to delay the 787 – composite aircraft can’t fly!

  12. Michael Cook

    Right now Boeing and Mitsuibishi Industries are holding a hot potato due to the fact that the composite skin of the new 787 is visibly seen to delaminate under stress tests right at the juncture where the wing joins the fuselage. A few years back Boeing fired a senior engineer because the man would not roll over and shut up about the fact that as attractive as carbon composites are no one really knows their fatigue profiles. Unfortunately, I forget the guy’s name but he became a crusader on the subject and has his own website somewhere. He basically claims that Boeing rushed headlong into the composite revolution and wiser heads (like his) were steamrolled by corporate politics.

    At present Boeing is claiming that only eleven small areas one each side of the aircraft have to be replaced and the fix will be easy and fast. Mitsuibishi (which manufactures the affected areas) says that the problem is that the Boeing design of these small pieces is wrong and Mitsuibishi is not to blame for building them incorrectly.

    The problem with Boeing’s quick and easy fix of the long-delayed dreamliner is this–if Boeing engineers used a wrong formula to design these small composite components, did they use the same formula and assumptions in designing bigger parts?

    That is likely to be the case, actually. I hope not, because the Airbus 300 series probably deserves to be grounded and Boeing would prosper greatly in that event but for having similar with the 787.

  13. IMO the Air Bust aircraft should be grounded. We just had another 300 series plane crash “mysteriously off the Comoro Islands yesterday. Are thes planes coming apart in mid air because of age, use, stress/fatigue, design engineering errors and flimsy construction? This certainly appears to be the case. The flying public must insist on not flying in Air Bust aircraft until Air Bust comes clean.

  14. Regardless of the cause of Air France downing, an obvious conclusion is that the carbon fibre vertical fin departed the alloy fuselage in tact. Not the first time!…Remember Americas Cup, the first Carbon Fibre Sloop snapped in two and sank within seconds?…Notice the lack of progress with the “Dreamliner”? with all its delam issues…If it walks like a duck…quacks like a duck…You know the rest. Much rides on the potential failure of this fin and this trend, both for Airbus and Boeings new 787. Does anyone think at this juncture they would admit design flaws or limits to its use based on mass?

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s