Fired engineer calls 787's plastic fuselage unsafe
 

Make of this what you will. (Mods: Not sure if this is the right place)

A fired Engineer goes public. I've always wondered how Boeing was going to deal with the problem of catastrophic failure (handled in Aluminium hulls by tear strips), since the carbon fibre mast failures I've seen in yacht racing have always been 'spectacular"


http://seattletimes.nwsource.com/htm...boeing180.html

whether the man was fired or not isn't the question...but plastic planes bug me for all the reasons in this article.

Reading the Seattle Times article a sudden chill ran up my spine and the name Roger Boisjolly immediately sprang to mind.

I hope history does not repeat itself.

I second that.

http://en.wikipedia.org/wiki/Roger_Boisjoly

Shades of Dan Applegate re DC 10's cargo doors:eek:

Disaffected ex-employees are about as new and innovative as composite material airframes. If this individual truly has an axe to grind, he might well have reconsidered the timing of his "bombshell", saving it as he did until he himself has been accused of gross professional misconduct.

Not only are these materials being used extensively on aircraft today, but the techniques and methods required for testing and certifying are well understood. To give credence to his theory is to accept that both the FAA and Boeing are colluding in some mass conspiracy to short circuit the certification process for commercial aircraft. The FAA can certainly do incompetence, but they struggle mightily with conspiracy. As for Boeing's motive to expose the travelling masses to such an unquantifiable risk, has anyone noticed the propensity with which Americans sue each other? It's almost a given that composite materials will behave differently to traditional metals, they will produce different toxins under combustion, but does that greatly change the survivability index in a crash over a traditional structure? Only the certification process will establish that, not some shotgun blast of accusations and generic blame throwing.

Incidently, linking it with the Shuttle experience simply demonstrates that e-mail is the preferred media for communicating dissatisfaction within a large anonymous organization, but provides little additional insight.

Hmmm, as I recall, a couple of Boeing engineers also thought that the original B707 was 'unsafe' yet it turned out to be quite a respectable aircraft.

Divergant dutch rolling tendancies and all....:}

Presumably by going public, beyond the designer safety analysis and the regulators approval, the disaffected employee has a chance to see his views and concerns be discussed and analyzed by the myriad of real experts on the various internet discussion boards.

What we really need now is a poll and just skip the discussion:sad:

Both Boeing and the FAA are capable of running their own agendas when they see fit. The cargo door blow out on the United 747 over the Pacific is an example. It took the investigative abilities of the New Zealand parents who had a child killed in the event to find the truth as to the cause, both Boeing and the FAA acknowleged their findings were correct but were not about to alter the incorrect official findings.

His letter to the FAA
 

A person posting on a military aviation newsgroup provided this link:
Weldon letter to FAA
Assuming it is for real, which seems likely to me:
His criticism is so comprehensive, and so over-the-top that is has far less
credibility for me than would a more focused objection to specific design
problems or management actions.
Essentially he demands that no new structural material differ in any way from his beloved aluminum that could ever have any adverse effect under any subset of use conditions. He also takes a commitment to overall safety improvement, and translates it to a requirement for no adverse safety impact in any circumstance, no matter how implausible.
That not only rules out composites, but pretty much anything else. If one considered titanium in a similar mood, I'm pretty sure you could find some killer objections. It is hard to machine, for one thing, so with equal production skill, more likely to have some sorts of flaws.
I'm not saying none of his concerns have any validity. I think maintaining composites appropriately for cases of "hangar rash" and such may take some real field experience and learning before cost and safety get balanced properly, just to pick one.
I am not a pilot. I am a retired engineer, with some experience in arguing unpopular views in a large organization.

I can't help but wonder if Bill Boeing got a similar letter when he decided to build planes out of aluminum instead of sitka spruce.

You are not supposed to crash land an aircraft.
Have also heard Carbon fibre is difficult to join to other materials such as metal or glass, and even in some light aircraft where carbon fibre has been used in conjunction with fibreglass, the carbon fibre has broken away. Im sure Boeing know what they are doing.
I may be a little concerned if:mad: a russian copy comes out though....

787 may be unsafe in a crash
 

Interesting article cites claims by an ex-Boeing engineer that the Dreamliner will shatter on impact, give off toxic fumes in a fire, and will be less able to withstand a lightning strike than an aluminium tube.

Personally, I think it's unsafe to be in any kind of a crash, and would recommend avoiding it.

Can't help wondering, though, if a glass ship like the 787 would simply shatter if it hit a tall building, leaving just the small, solid heavy bits to plough on through.

Thus, the 787 might be a lot less appealing to sociopathic organisations like Al Quaeda than aluminium bodied vessels?

I agree, all aircraft are unsafe in a crash. That's why they are designed not to crash.

An article by an EX-Boeing engineer,no question of an axe to grind.As far as toxic smoke in an accident is concerned the interior fittings give off anough toxic fumes in a fire.

Every single frame on the A380 Main deck (98 of them) is Carbon fibre. and in the interests of accuracy they are manufactured completely differently and with far higher tolerances than boat masts ! (I had to laugh at that one) Furthermore only Titanium fixings are used to secure other structural items to them.

"Fired engineer calls 787's plastic fuselage unsafe"

Well after surviving a crash, you also have to avoid breathing in carbon fibre particles and (if a fire happens) composite material burning in Jet fuel, both not good for the human body. No doubt Boeing are doing their homework:hmm:

As others have pointed out already all aircraft are inherently unsafe in a crash... the very idea of a "crash-safe" aircraft is an oxymoron.

This thread strikes me as completely pointless, and quite possibly a wind-up. Get over it.

I believe the russians make a lot of carbon fibre (raw material) for the world market.
It will be interesting to see how composite aircraft tollerate lightening strikes. I've seen the wing spar of a model plane burn when it acidentally shorted out a small nicad battery. It doesn't conduct as well as Aluminium and the extra resistance causes more heat to be produced - at least that's how I understand it. I'm not a professional composite engineer!

Edit: This report details what can happen to a composite glider (not normally provided with lightening protection). Good job they had parachutes...

http://www.pas.rochester.edu/~cline/...t%20report.htm

I remember doing a post crash management course which bedeviled the properties of Man Made Fibres in the post crash environment especially in fire. But lets be patently honest here, F1 cars crash at ridiculously high speeds and the drivers walk away.

The majority of materials contained within the cabin attribute a vast amount of toxic fumes to the cocktail. Even in an aluminium tube.

The impact survivability of Carbon Fibre structures has been proven to be greater that that of aluminium due to the ability of the composite structure to absorb the impact energy whereas the aluminum deforms.

We all pray that a crash will never occur, however the global pressure from ill informed Governments and environmental groups forces more and more towards lean, light and efficient aircraft. The industry cannot stay in the 60's.

Personally I look forward to flying it :)

hey aero junkie

"Well after surviving a crash, you also have to avoid breathing in carbon fibre particles and (if a fire happens) composite material burning in Jet fuel, both not good for the human body."

plane crashes in and of themselves are not very good for the human body, and all the safety devices in the world aren't going to help anyone.

we all know that the sardines in the back of the airplane cant breath un pressurized oxygen at 36000ft. if there is a depressurization, the pilots' job is to land a plane with a whole bunch of either dead or brain-damaged passengers.

also, the life jackets are only intended to help rescuers find the corpses of the passengers in the "unlikely event of an emergency landing on water"... no one is going to survive that...

the fact that no one died in the China Air fire is probably better classed as "miracle" than "luck".

A some one who's maintenance engineers licence covers a range of composite aircraft I fail to see how this aircraft will be any more of a problem in terms of risk to passengers involved in an accident that aa aircraft of convetional construction, in fact the ability of composites to absorb energy may well be an advantage keeping the structure intact and allowing more people to escape before the (undoubtedly toxic) fire gets going.

For me the main promlems that I forsee are ones of maintenance. Boeing repair manuals are using "dark ages" methodes that would not be used on any light aircraft or glider and are not fit for primery structure due to the glued contact area between the layers of cloth being so small. these practises may well be satisfactory for floor boards and non critical panels but won't do for a pressure hull.

I have no doubt that Boeing have given this much consideration but will an industry that has for so long been wedded to metal put enough effort into re-traininng staff to repair and inspect these "new " structures that are so much better at hiding defects and dammage than metal ever was!

Thabo
 

The China Air fire evacuation was not a miracle or luck it was due to the correct and speedy actions of the crew putting the safety training that they had receved in to practice.

Two small observations responding to comments above;

First; I don't understand the use of the word "spectacular" connected to failures of carbon yacht masts; they just break, exactly like aluminium ones do if a stay breaks or the tensions are set up wrongly.

And second; many years ago (late '70's) the FAA and CAA gave a mandatory mod on TPE 331 engines (up to a certain production number) a 4-year compliance period when it should have been 6 months or less, solely to allow the mod to be done on next overhaul, to avoid grounding the large fleet using those engines. Safety gave way to "commercial reality". Maybe things have changed for the better, maybe not. But no-one should assume that any National Aviation Authority will not give way to commercial pressures, and that applies to FAA and EASA.

A & C
 

you are right... i exagerated.

there are safety standards and proreedures which are there to save lives and they do.

I just hate to think what would have happened if that "missing washer" in the slats had started the fire while the plane was still in the air. (that is what I meant by "miracle")

It is unlikely that the fuel leak from a flap can would be a problem in the air as the airflow over the wing would keep the fuel away from the hot engine.

The fire started on taxi in because the fuel was running inbd along the underside of the wing and falling onto a hot engine.

cwatters

Just a thought, I think you will find as resistence increases, current decreases, Mr Ohm might say E=I x R, and P = V x I.

Cheers

J:ok:

wobble2plankEerrr. As the aluminium deforms - it absorbs the impact energy. :rolleyes:

In order to ascertain whether one material is better than another, you would need to show us the formal tests of two items constructed to identical dimensions and for the same purpose from different material that were then subjected ... etcetera.

As to CF structures been 'proven' to be better in impacts, there is not as much evidence accumulated to compare with Al, due simply to the length of time that Al has been in use for aircraft. That does not mean that Al is better than CF materials but we do not really know. That question can be answered in another 20 years time.

Does anybody know if Boeing has incorporated Aramid type upper layers into the stucture to help alleviate the impact resistance problems of CF, I cant recall a composite structure that has to date, only the polyurethane finish on prop blades and the GE90??
I have heard titanium patch plates and splice pieces will be used within repair schemes, the SRM will make an interesting read!
As for impact testing I think we can rely on a few catering trucks for that first!
:ok:

How would the composite structure cope with lightning strikes - not knowing much about the science behind them would they be an issue? There are still many metallic components on the aircraft.

Thabo,

Really? You've been watching too many movies.

A and C & Captain Bloggs
 

A&C:

youre right, i didnt think of that.


Captain B:

I don't even know what movies are, I have no time to watch them.

at 36000ft with a decent rate of what? 8000ft/min? its going to take you a while to get your passengers back to an altitude where they can breath the oxygen they are being supplied with.

with regard to absorbing impact energy... the vast majority of energy is absorbed during plastic-deformation. cars are designed to have crumple zones which absorb as much energy as possible so that the driver doesn't have to. thats the reason that car accidents look so much worse than they did 20 years ago.

when it comes to designing planes, you take into account maximum flight loads and then add a 5% safety margin or so. you can't design a plane to withstand a crash, the kinetic anergy is just too great and it can not be dissapated.

There is work being done on using composite fittings inside the airplane that produce less toxic fumes when they burn, but you can never produce a plastic for wall panels etc. that is light, sturdy & doesnt burn at all.

Thabo,

You're talking about 3 minutes to get down to an altitude where people could breathe the outside air. People can go from anywhere between 3 - 10 minutes without oxygen without suffering brain damage. Given that as the plane descends there will be _some_ (ok, not much) oxygen around, people would probably be ok. I assume you're talking about a worst-case scenario where oxygen masks have failed to deploy for some reason.

Quite true that aluminium absorbs energy as it deforms. However, to effectively distribute large amounts of impact energy there is normally an energy dissapating structure (crumple zone) behind the aluminium skin which transports the energy around the structure.

Carbon fibre however, due to the complex interwoven nature of its core structure, has the ability to disperse impact energy throughout its own structure in multiple directions therefore dispersing energy and reducing deformation without having to resort to complex energy distribution structures. Whilst this is possibly a good thing in a crash scenario, on the day to day ramp I wonder what will happen when loaders, catering trucks etc get near it. CF is very good at delaminating without it showing on the surface.

:rolleyes:

very true and it relates directly to the area under the stress/strain curve taking into account strain rates, and their effect on the area that can be placed under strain in a very short time before the G-loads kill the passenger.
A car has much less velocity so it has time to bring in large crumple zones before the G-loads are exceeded.
With a composite (non-homogenous- metallic) you are dealing in energy absorption by friction between the fibers as they separate from the glue holding them together. Ideally if you had no glue the whole thing would act like a blanket, Unfortunately it wouldn't stay together long enough to fly.

What concerns me most here is that the FAA position, even if remotely true, seems to be satisfied with safety levels in a new generation aircraft meeting current aircraft saftey levels.

Stop. Rewind. Replay. That's rather like Ford launching a new hybrid vehicle and claiming it matches the safety levels of its 1978 offerings to wit: drum brakes, cross-ply tyres, no ABS, no airbags, no laminated glass, lap-belts.

Let's hope the new Boeing Pinto, sorry 787, doesn't have to be made safer via tombstone technology.:oh:

My concern is the day to day repair of 'hangar rash'. Water ingress into composite laminates, the subsequent freeze/thaw cycles and weave ruptures would not be as quick to fix as a patch of speedtape.

I reckon it'll very quickly become a pain in the ahhhhs.:confused:

Makes me laugh.
All these armchair couchspuds know more than the Boeing designers. 787 will be as popular as 757 and 320. Both of which were ahead of their time.

Not true. There have been numerous updates of the FAR/JARS since 1969 and each "new" aircraft not grandfathered by acceptable service experience has to meet these new standards. Indeed where the technolgy is new and so novel that doubt exist about where it stands relative to historical experience than "special conditions" are proposed that it has to meet. As I recall there were several special conditions that the B777 had to meet beyond the then current certification standards.

The watchdog for such conditions are not only the Regulators but also include other aviation bodies, NASA and the general public through the petition process. So any of you may endorse the disaffected Boeing engineer and put together a technically sound petition to the FAA to issue special conditions against the A380 and the B787