I finally got around to watching the recent episode of HDNet's Dan Rather Reports titled "Plastic Planes," about alleged safety problems with Boeing's new 787 "Dreamliner" passenger jet. I was interested in the story for two reasons.before, I want to someday-- and secondly, I've long been fascinated with composite materials.
Vince Weldon, a former Boeing engineer, alleges that the composites used in the 787-- principally forms of carbon-fiber reinforced plastic (CFRP)-- are brittle, insufficiently tested, dangerous in a fire, and vulnerable to lightning strikes.
Boeing, for its part, says the Dreamliner development process has included many physical tests and simulations covering all of these issues, and that the 787 meets all relevant FAA standards.
Although Weldon worked for Boeing for 46 years, his engineering duties apparently never involved designing with composite materials. He offered no facts in support of his allegations, but Rather was happy to let Weldon present his accusations without supporting evidence (literally: Rather was all smiles during the Weldon interviews).
Boeing, in response, referred Rather to vast amounts of engineering test data, although it did not release much (if any) of the actual test data to the show for competitive reasons. (I see nothing wrong with that; if any random crank can force a company to disclose confidential engineering data by making unsupported public accusations, there'd be no such thing as confidentiality for any engineering project.)
The FAA, however, does have the test results, and says that if the tests don't show the 787 is safe within the limits of today's engineering knowledge, and indeed that it's at least as safe as existing jetliners, the 787 simply won't be certified.
I have some experience with designing and building composite structures myself (as an enthusiast, not professionally-- sometimes using materials purchased from Boeing's retail surplus store, in fact).
In my opinion, Weldon seemed to be trying to mislead Rather and his viewers. He was using terms (such as "brittle") that have meanings in an engineering context that are different from, and sometimes contrary to, their ordinary conversational meanings, which would inevitably lead Rather and his viewers to false conclusions.
For example, Weldon's claims would give most people the impression that the 787's composite materials are "brittle" the way a ceramic tile is-- in particular, I think Rather reached this conclusion during the interview-- but in fact, modern composites aren't like that; they break down in a progressive way that absorbs energy, exactly contrary to Weldon's claim.
In fact, the ability of CFRP to absorb energy is one of the biggest advantages of a carbon-fiber structure over a traditional aluminum structure. Both CFRP and aluminum structures will crumple in an impacts, but because CFRP is so much stronger, it can absorb more energy. Look at this YouTube video of the testing of a CFRP nose section from a Formula One car:
Starting two minutes into the video, there's a closeup of the nose as it collapses against a solid barrier. Although the individual carbon fibers shatter quite sharply, the structure as a whole breaks down gradually, just as the designer intended, dissipating the energy of the crash as the car slows to a stop-- very quickly, but smoothly. The chassis of the race car further back from the nose suffers no apparent damage, and the driver's compartment is totally undeformed. Obviously an airplane crash would produce different effects, but the video contradicts Weldon's first claim.
Similarly, Weldon's other specific claims about carbon-fiber composites are either wrong or just don't justify his conclusions.
I was particularly surprised to see Mary Schiavo, famous for writing a grossly sensationalized book about aviation safety following a brief stint at the US Department of Transportation, brought in by Dan Rather Reports to say that CFRP structures can't conduct the energy of a lightning strike away from the site of the strike because... "They're plastic! And so there is nothing to direct the lightning around [a fuel tank] rather than into it."
But Schiavo is clearly in over her head on this one; she has no business posing as an expert in materials science. CFRP is mostly carbon, not "plastic," and carbon is conductive. While CFRP isn't as conductive as aluminum, it isn't an insulator as the word "plastic" would suggest to most viewers.
Ultimately, if Weldon was correct about the behavior of carbon-fiber composites, these materials simply wouldn't be as widely used as they are in racing cars, military and civilian aircraft, and other systems that operate in high-stress, high-risk environments.
Weldon also seemed to be deliberately taking Boeing's statements out of context. For example, Boeing was quoted as saying that it would be performing regular visual inspections of the 787. In a long section of the program, Weldon and Rather interpreted this statement to mean that Boeing was ruling out non-visual inspections-- but I simply don't believe that's true, and they apparently never asked Boeing to confirm if it is true.
Rather brought in independent experts to describe other inspection techniques, implying that Boeing was not aware of, or was not going to use, these other techniques. But I know from my own reading (I have read several books on this subject, and I subscribe to some of the trade magazines in the composites industry) that these other techniques are already widely used in the aviation industry and would inevitably be part of Boeing's periodic inspection processes. The fact that Boeing did not happen to mention these processes doesn't mean it's decided not to use them.
I think the overwhelming weight of the engineering evidence on Boeing's side in this matter is enough to justify dismissing Weldon's claims out of hand, but there are some troubling personality issues involved in this case as well.
According to OSHA, as reported by the Seattle Times, Weldon was fired for threatening the life of a supervisor. Dan Rather never mentioned this fact, which greatly undermines Weldon's credibility.
The omission, and the uncritical use of claims from people like Weldon and Schiavo who lack the professional credentials to justify them, undermines Rather's own credibility, which was fragile enough in the wake of his bizarre report on 60 Minutes Wednesday about the Killian memos allegedly describing George W. Bush's service in the Texas Air National Guard. Like thousands if not millions of others, I was flabbergasted by Rather's personal insistence that the obviously computer-typeset memos were actually produced on a typewriter in 1972.
It was apparent to me at the time that Rather had lost the ability to evaluate the credibility of his sources, which is an essential skill for any reporter-- certainly for one operating at the national level.
And now, of course, Rather is suing CBS and Viacom for... well, I can hardly tell what for; the complaint is not very clear. But if I was running HDNet, I'd be very concerned about Rather making such strong accusations with such weak support. If he continues, the network may be forced to dismiss him, which could well lead to yet another lawsuit...