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Crash Test
2

Crash Test

Crash Test

(OP)
Dear All,

So Boeing has carried out their composite fuselage 787 crash test...
Is it a new requirement only for composite fuselage or also for monolithic Aluminium ?

Regards

RE: Crash Test

What?

RE: Crash Test

What do you mean by "monolithic aluminum"?

The crash test was required to show equivalent safety to existing, aluminum fuselage aircraft.

RE: Crash Test

(OP)
Monolithic Alu, just the usual Aluminum sheet or plate, not laminates, ARALL, or Glare.

If I understand correctly, FAA required a full scale composite fuselage test article for the crash test. Cannot it be a smaller scale or only a few frame bays of fuselage structure only? Is there any background evidence to require such a test?

RE: Crash Test

if think FAA were worried about the new materials introducing new effects, responding to the loads differently, being upset by different things compared with what we "know" (ie monolithic Al skins ... 2024, 7075).  I think scaling only works when you're comfortable with the material and the test to know that you're scaling the right parameters correctly.

RE: Crash Test

I want to see them break the 787 wings.  I watched the 777 tests.

= = = = = = = = = = = = = = = = = = = =
Still trying to help you stop corrosion.
formerly Trent Tube, now Plymouth Tube
eblessman@plymouth.com
or edstainless@earthlink.net

RE: Crash Test

How did the 777 test go, did they achieve ultimate load??

RE: Crash Test

Yep, a little bit past ultimate load for the 777 wing test, right at the predicted failure load and location.

RE: Crash Test

A380 didn't.  They had to do a minor re-design to pass, but no re-test.  I think that they made 148%.  150% is required.  As I recall 777 went to 153%.  They sure go with a bang.

= = = = = = = = = = = = = = = = = = = =
Still trying to help you stop corrosion.
formerly Trent Tube, now Plymouth Tube
eblessman@plymouth.com
or edstainless@earthlink.net

RE: Crash Test

What did Boeing actually have to do for the 'fuselage crash test'?

RE: Crash Test

Oh, I got excited for a minute.  I was imagining re-creating that crash they did in the early 80s with that old convair.

Now that looked fun!

KENAT, probably the least qualified checker you'll ever meet...

RE: Crash Test

Why did Boeing drop the 787 fuselage only 15 feet, when they dropped the 737 fuselage 30 feet?  Will they drop a 787 fuselage 30 feet at some later date?

How would this aircraft survive the type of crash experienced at Pearson airport in 2005?
http://en.wikipedia.org/wiki/Air_France_Flight_358

Would all the passengers get out after the type of fire that ensued?  Building the entire fuselage from CF must be challenging from a FAR 25.853 point of view...

Steven Fahey, CET

RE: Crash Test

Speaking of crashes....

thread1088-197935: Composites are deadly.

Wes C.
------------------------------
No trees were killed in the sending of this message, but a large number of electrons were terribly inconvenienced.

RE: Crash Test

...And why would Boeing drop a 737 fuselage section 30 feet anyway?  FAR 25 doesn't seem to have that requirement.  A drop of 19 feet will give a descent velocity of 35 ft/sec, like the criteria of 25.562 (35 ft/sec).  But the landing conditions in 25.473 and .723 don't require this...

Steven Fahey, CET

RE: Crash Test

The 737 test was to evaluate the structual effects of an aux fuel tank on the structure in a crash.

http://citeseer.ist.psu.edu/626400.html

in the right hand side of the page is a pdf which will open up a report.

RE: Crash Test

Re deadly, deadly composites (see wes616's post), see the following from COMPOSITES PROCESSING 2006 27th April 2006, "Composites in Aircraft Crashes" by John Andrews - Post Crash Management Systems.

"...when test pieces were subjected to high kinetic energy impact at the same time as high temperature (1000ºC) flame, substantial quantities of respirable fibres were released."

The author says that to get really dangerous you need both impact and high temperature simultaneously. With regard to the A340 crash at Toronto he says:

"...because any high energy impact was not coincident with the high temperature fire, there was little or no release of respirable fibres. Additionally the weather was kind and a short rainstorm each day minimised the risk from respirable dust. The overall site hazards from this crash, which were expected to be severe, were easily managed with disposable coveralls and respiratory protection."

So, not exactly nothing to worry about, but not quite as bad as it could be.

PS: ally fuses can to burn through quite rapidly when flames from the outside impinge on them (Burn-through contributed to a few of the deaths at Manchester UK in 1985 - though most were toxic gas inhalation). A carbon laminate is a lot more resistant to burn through. On the other hand, you don't want it to increase FST dangers inside the fuse. Even external materials are increasingly subject to FST regs these days.

PPS: Swearingen and Fatstress, thanks for the Boeing fuse test links.

RE: Crash Test

I am amazed how many people defend Boeing"s expertise in COMPOSITES when I look at the schedule slippage.

JIM

RE: Crash Test

come on ! ... Everybody has schedule slippage on a new program ... look at all the slippages Airbus had on 380 ... i thin Boeing has decided to have one slip and take their lumps.  

RE: Crash Test

We understand this won't be the only slippage. They have a lot of work to accomplish and if they don't have the sub-contractor COMPLIANCE/CONFORMITY DATA the components they have received can't be used in any testing.

jim

RE: Crash Test

Hands up whose ever worked anything approaching a major program without program slippage?

Sure it happens but my guess is that there's more often a slip than not.  Or, my personal favorit, something gets dropped/pushed out till later.

From my experience management never want to use anything approaching 'worst case' estimates for setting schedules.  Compounded by the fact that often our guesses at 'worst case' are in fact optimistic, then programs like this tend to slip and/or go over budget.

KENAT, probably the least qualified checker you'll ever meet...

RE: Crash Test

I'm with KENAT on this.  I don't think that I have ever worked on an aerospace project that actually met the initial schedule.

RE: Crash Test

Boeing has, since 1958, certified the first 707, 720, 727, 737, 747, 757, 767 and 777. THE AVERAGE DAYS BETWEEN ROLL OUT AND FIRST FLIGHT HAS BEEN 61 DAYS — TO CERTIFICATION — 349 DAYS. The July 8 2007 (aka 7-8-7). was a dog & pony show that detracts from the skills of the many talented and dedicated people in the Boeing family. . . . the 777 required 370 days and someone thinks they can accomplish 787 flight & Certification testing in less than six months?

jim



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