Re: 777-style cabin windows on 767-400(ER)

Date:         30 Nov 98 03:07:54 
From:         Marc Schaeffer <marcmsc*@cmdnet.lu>
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"Brett L. Anderson" wrote:
> Close Marc, but no cigar... Now you are just continuing an urban myth.
> The Fatal Flaw for the poor comet was a lot of poor fatigue details
> combined with a poor material choice.  IIR the  1954 fatigue test of a
> Comet only made 3600 pressurization cycles before it failed at the
> corner of a passenger detail.  BUT..  the one recovered from the ocean
> was determined to have initated a crack at the top corner of the ADF
> cutout on the airplanes centerline.  This crack then grew to the forward
> butt splice and down into the window belt area leading to a catastrophic
> failure.

Bratt at the risk of self-promoting :o) I know this all too well as I
maintain the DH Comet website at http://surf.to/comet. The full YP
report is on my site and the pics with the cracks you are referring to
are shown as well, consider this as the starting point of modern civil
aviation. It's part of the history.

> Anyway nothing inherently wrong with square windows but the material
> selection and gage had better be sufficient to cover the relative stress
> concentration in the corner over the acceptable design life.

This is right, afterwards they changed the thickness of the skin and the
type of the alloy. But again those guys were pioneers ...

--
Marc Schaeffer --- Luxembourg --- mailto:marcmsc@cmdnet.lu
The DE HAVILLAND COMET website:       http://surf.to/comet
The AIRCRAFT ORDERS    website:      http://surf.to/orders
The ORDERS MAIL-LIST:   http://www.eGroups.com/list/orders