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Boeing Jets Part Scare

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Old 21st Aug 2006, 07:02
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Boeing Jets Part Scare

Doesn't sound too good - if true

Families are flying off on their summer holidays on potentially dangerous aircraft, Sky News has learned.

In an exclusive report our US correspondent Andrew Wilson examines claims by two former auditors of Boeing that the aircraft manufacturer built some of its aircraft in the knowledge that certain parts were defective.

Wilson's six-month investigation has unearthed allegations that parts were wrongly made, had holes drilled in the wrong positions or did not fit properly on the aircraft.

The parts were used in assembling the Boeing 737NG between 1994 and 2002.

EasyJet is among the British airlines who have bought the 737, without knowing of the claims.

Boeing said the allegations were "without merit" and stressed a multi-tiered control process in place for decades has been effective in maintaining quality and safety.

Former auditors Taylor Smith and Jeannine Prewitt told Sky that Boeing accepted defective parts for 737s and other jets from Ducommun, a Californian supplier, and installed them even though they knew them to be faulty and potentially dangerous.

The components - which are crucial to the safety of an aircraft's fuselages - are alleged to have had incorrectly drilled holes and other physical defects that make them more likely to fail.

Ms Prewitt said safety was compromised by "so many manufacturing and quality discrepancies", building the planes should have stopped immediately but did not.

Ducommun did not return any calls to Sky.
-Sky News
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Old 21st Aug 2006, 07:26
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glad to that Sky are on the ball as usual - this story broke last October
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Old 21st Aug 2006, 07:37
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Old News - Misleading charge

The bits in question where inspected and signed off by the build guys.

Holes and spacing were within tolerance thanks to the over-engineered original specs.
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Old 21st Aug 2006, 11:29
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Originally Posted by vapilot2004
The bits in question where inspected and signed off by the build guys.
The whistle blowers were threatened with legal action by Boeing 'security' so the build guys maybe didn't want to rock the boat and just conformed.

Originally Posted by vapilot2004
Holes and spacing were within tolerance thanks to the over-engineered original specs.
Maybe that is why they have not been falling out of the sky but it's still a worry.

... and that doesn't include the infamous rudder actuator problems ...
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Old 21st Aug 2006, 13:13
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A piece of classy SKY reporting!!!! One shot showed one of the doomed Airbus 737's on approach!!! I particularly liked the comment that a passenger could be sucked out of a gap an inch wide!!!

I'm not surprised Boeing or the FAA wouldn't talk to them. Whatever you say will be reported inaccurately and sensationalised.

A lack of confidence in Boeing? More like a lack of confidence in SKY news reporting. If there is a story here lets have it told dispassionately and with some attention to detail and the facts.

Well done to Capt Moody though. I thought he was very tactful and the consumate professional
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Old 21st Aug 2006, 13:49
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The quotes from the 'whistle blowers' and 'auditors' tend to discredit the story in my view. They talk of 'bear straps'. The items in question are actually called 'tear straps'.
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Old 21st Aug 2006, 15:13
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Originally Posted by morroccomole
The quotes from the 'whistle blowers' and 'auditors' tend to discredit the story in my view. They talk of 'bear straps'. The items in question are actually called 'tear straps'.

Actually the items in question are 'Bear Straps' - not to be confused with 'Tear Straps' which serve a different purpose altogether.
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Old 21st Aug 2006, 15:41
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In which case I stand corrected. What purpose do the 'bear straps' serve then?
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Old 21st Aug 2006, 16:43
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Bear straps are extra layers of skin, generally around openings (cargo door cut-outs etc.) to transmit loads away from the weakened opening into the rest of the fuselage.

Tear straps are a reinforced doubler on the inside of the fuselage skin, that give a fail-safe area that contains any fatigue cracking.
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Old 22nd Aug 2006, 10:15
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I think I may have found the offending components(s) being peddled through ebay! Won't be long before Sky gets hold of this information so just for the record, I got there first!

http://www.ebay.com.my/viItem?ItemId=300015872322
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Old 22nd Aug 2006, 11:46
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mis-manufactured parts?

I don't think it's uncommon for parts that have been mis-manufactured to have their condition re-assessed for suitability of use.
When drilling or machining so many holes, in anything to do with an aircraft, some mistakes are made; some are recoverable, and some are not.

I would assume it would be uncommon for an airplane to be delivered from manufacture without some form of manufacturing concession, or variation from an intended state (my phrase - not a manufacturers).

Holes in the wrong places are not uncommon. It's the ones without legal concessions that are the problem!
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Old 22nd Aug 2006, 13:04
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Hi Morrocomole,
I thought everyone knows what "bear straps" are
Although a humble avionics man, I even know what freeze plugs are (bet a few are used to cover production mistakes!).
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Old 22nd Aug 2006, 13:53
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Originally Posted by Jet II
Bear straps are extra layers of skin, generally around openings (cargo door cut-outs etc.) to transmit loads away from the weakened opening into the rest of the fuselage.

Tear straps are a reinforced doubler on the inside of the fuselage skin, that give a fail-safe area that contains any fatigue cracking.
Worked in aircarft structures for over 40 years and I have never heard of "External Doublers" being called "Bear Straps". I learn something new everyday?
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Old 22nd Aug 2006, 16:18
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Originally Posted by glhcarl
Worked in aircarft structures for over 40 years and I have never heard of "External Doublers" being called "Bear Straps". I learn something new everyday?

who said they were external? - most 737 bear straps are internal - don't know about every other make of aircraft.
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Old 22nd Aug 2006, 19:46
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Hello.
All Boeing programs have "bear straps". No, they are not external neither on 37 nor on other programs (47,57,67).

Bear straps were more used on older programs when sheet metal was the preferred forming (ever heard of quintupler?!?!?!)..
Today, with NC machining you can generally avoid layers.

Tears straps were mostly, as explained by JET II, used as a fail-safe parts, therefore used on 37 and 47 programs.

However, since FAA will probably bring the fail-safe criteria back in FARs (in addition to damage tolerance) we can see more of that stuff.

Boeing (or any other) QC report what they see as imperfection (sort of speak). In general it is up to Stress to evaluate and get the final call if the part should be replaced.

I seriously doubt that Stress would accept a problematic part (at least I wouldn't).


Cheers,
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