On Thu, 11 Oct 2007 07:19:04 -0700, Ron Wanttaja
wrote in
:

On Thu, 11 Oct 2007 09:36:02 GMT, Larry Dighera wrote:

On Wed, 10 Oct 2007 23:00:18 -0700, Ron Wanttaja
wrote in
:

With the first airplane so close to completion, why would Boeing delay its
completion over this?

If design changes need to be implemented to meet FAA certification
standards, it would be foolish to test an aircraft that doesn't
employee them, IMO.

Prototypes rarely match the production models;

That's understandable given the reasons for testing in the first
place, and serves little disincentive for aiming for a prototype as
close as possible to the final design goal as it is envisioned at the
time of testing.

that's one reason why companies
like Boeing retain them for company "hacks." The allegations have nothing to do
with how the airplane's going to fly; any changes will be internal.

The response to the FAA Rules Docket cites concerns with the
structural integrity of composite materials Boeing has specified for
the Dreamliner, as I recall. Because of that, Boeing may choose to
refine its engineering in that area.

Yet the
test period does typically reveal the need for mechanical/aerodynamic changes.
*If* there are delays triggered by the allegations, flight testing the prototype
would allow *other* changes to be incorporated in parallel.

It's my understanding that flight testing isn't the only thing being
delayed.


I suppose the final rule will reveal just how
much the former Boeing engineer's revelations changed the standards
the design will be held to.

I suspect you mean, "Final ruling," rather than "final rule." AFAIK, there's no
change in FAA policy pending over the allegations.

Until the final ruling is published, how would you know the effect on
the FAA of 46-year former Boeing employee Weldon's seventeen page
comment?

The controversy is over a
difference in engineering opinion, rather than a revelation of hidden flaws.


There are a number of points raised in Weldon's comment:

1. The large number of failure modes for the relatively brittle
composite structure used in the 787.

2. The difficulty in testing the composite structure used in the
787.

4. The FAA's apparent intent to not thoroughly test Boeing's
prototype that represents a re-definition of jetliner design.

5. Boeing's corporate policy of intimidation of employees who
raise ethical questions about design and testing issues.

6. The sensitivity to hot/wet and freeze/thaw conditions an
through-thickness crack growth that represent fatigue-like failure
modes thought to be nonexistent in composites.

7. Visually undetectable impact caused micro-cracking as might
occur with hail damage.

8. The combustibility of composite materials reduces the
evacuation time window.

9. The design decision not to continuously electrically bond the
Faraday cage along the length of the joints of adjacent major
structural segments which may result in composite damage due to
arcing.

10. Lack of adequate testing of the system for nitrogen inerting
the fuel vapor above the liquid level in fuel tanks.

11. The FAA's issuance of crash worthiness special conditions and
inadequate testing requirements.

12. The smoke from burning carbon-epoxy composite structure of
the type used in the 787 is so toxic that it has been banned from use
in the interior of aluminum jetliners.

13. ...



Ron Wanttaja