Re: Boeing 777 - Totally Irresponsible?

Date:         28 Dec 96 14:20:08 
From:         Stuffle@pcii.net (Stuffle)
Organization: MidWest Communications, Inc.
References:   1 2 3
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In message <airliners.1996.3058@ohare.Chicago.COM> - 27 Dec 96 13:32:19
jfmezei <jfmezei@videotron.ca> writes:
>
>Bernie Gracy, Jr. wrote:
>> He went on to say that because of the millions of lines of code written
>> for the 777 that it would be impossible to test all of the failure
>> conditions, and therefore was irresponsible to design and deploy such an
>> aircraft.  He vowed never to fly on one...
>
>1-	How much of the 777's code is actually *NEW* ????? I.E. how much
>	of the code in a 777 actually brand spanking new and instead of
>	pieces adopted from previous aircrafts or code which resides in
>	components that have existed for a long time already ?
>
>	For instance, did they rewrite the actual autopilot code to
>	determine where the plane is and where it should go (waypoints
>	etc) ? Or did they just adapt code from the 747-400 (Boeing's last
>	new plane prior to the 777).

As I understand it (I was one of the engineers to do structural verifcation
(white box testing) on the software for the AFDC of the 777, and worked with
several of the folks who did the same on the 747-400), the AFDC software for
the 777 was largely adopted from the 747-400 as mentioned.  The major
modifications
were as folows:

	1.)  Programming language change from AED to Ada.
	2.)  Modifications for different hardware.
	3.)  Modifications for different physical characteristics
	     of the actual aircraft.

IOW, the software was largely a modification of existing design (as already
assumed).

The company that I work for also performed the functional (black box) testing
on the 777's AFDC.  From what I know of the testing done, I can at least be
sure that the autopilot system is _quite_ well tested.

If the rest of the aircraft was tested as well as the AFDC software, I
really doubt if there is a reason to worry about the safty of the 777.

--
Ken Sodemann  (Stuffle)
Stuffle@PCII.NET
http://users.mwci.net/~stuffle/