Re: Ariane5 FAQ

["Robert I. Eachus" <rieachus@attbi.com>]

Alexander Kopilovitch wrote:

> Ok, I agree, I recognize that kind of logic (I think I have seen it several
> times, when I contacted with high-position managers). And I think that too
> high concentration of this kind of logic within a project is a smoking gun
> by itself. Well, I downgrade the seriouseness of the allegation (in some
> non-technical sense -;), but I'm still not sure enough that not giving the
> part of the source code to the simulator's developers is true fact and not
> just good guess.
> 
> Anyway, assuming that that is a true fact,  I'm going to include into the next
> draft of FAQ the following Q-A pair:
> 
> ----------------------------------------------------------------------------
> Q. So, if the limitations were clearly reflected in comments within the source
> code then most probably they would be seen by the simulator's developers and
> the disaster would be averted?
> 
> A. Probably NO. Because that part of the source code (aligment function),
> where the limitations were violated in the flight, was not given to the
> simulator's developers. That happened because simulation of that function
> of real device was excluded from the contract for the simulator development.
> 
> The reason for that omission was that for Ariane 5 that function is not needed
> after takeoff, and that before takeoff that function was really identical for
> the Ariane 4 and Ariane 5. What was overlooked is that for the Ariane 4 that
> function WAS executed after takeoff (about 40 seconds), so the unchanged real
> device will execute that function for the Ariane 5 despite the absence of any
> need for it there.
> ----------------------------------------------------------------------------

As far as I know the simulation developers did have ACCESS to all of the 
source code.  It was the documentation that they didn't have.  So some 
programmer might have noticed that the alignment code ran for 40 seconds 
after ignition, but without the documentation the hypothetical 
simulation programmer had no reason to doubt that it was done for valid 
reasons.

-- 
"As far as I'm concerned, war always means failure." -- Jacques Chirac, 
President of France
"As far as France is concerned, you're right." -- Rush Limbaugh