Re: Boeing and Dreamliner

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

Alexander Kopilovitch wrote:

> No, simple "stupid management" is not enough here. Something more technical
> was rotten. There was not single decision (or couple of decisions) taken by
> top level manager at the last moment - there was nothing like ordering a
> launch despite inappropiate weather. It was a long project with many presumably
> competent people involved; and it is important to investigate more deeply:
> why consequences of initial wrong decision (which was made by incompetent
> people) were not recognized by scientific and technical staff before the
> actual failure happened.

I can give you some of the answers from memory, but the best thing to do 
is to actually read the technical report on what happened. (I found a 
copy at http://www.dcs.ed.ac.uk/home/pxs/Book/ariane5rep.html)  There 
are a number of places where the international politics are not included 
in the technical report.  But some political details are important.  The 
French didn't want Germans getting access to the Ariane 5 performance 
data, even though the SRI software was written by the English subsidiary 
of a German company, if I remember right.

But the real cap on the whole thing was that there was supposed to be a 
full up test rig which would allow system test for the gyros, the 
computers and the engine controls.  This test platform was behind 
schedule so the French decided to go ahead and launch without doing the 
test!  I don't know about the formal test methods in Russia, but in the 
US the common practice is to come up with a set of test objectives, then 
  assign them to one of four major categories.  In effect what happened 
was that ALL the guidance and engine control subsystems test objectives 
that were supposed to be Demoed (i.e. demonstrate that the subsystem 
does what it is supposed to do in operation) were signed off without 
ever being run.

But to me the crowning idiocy of the whole thing is in one sentence of 
the report: "The main explanation for the absence of this test has 
already been mentioned above, i.e. the SRI specification (which is 
supposed to be a requirements document for the SRI) does not contain the 
Ariane 5 trajectory data as a functional requirement."

The SRI requirements document was never updated for the Ariane 5, and as 
I pointed out, the software had built in parameters that reflected 
physical constants relating to the Ariane4.  Also, it doesn't take a 
genius to tell you what that ten second period of "pressure surges" in 
the flight control hydraulics was.  But of course the politics of the 
situation kept the fact that oscillations were building up in the stack 
from being an obvious part of the official report--and from being left 
out of it:

"One anomaly which was brought to the particular attention of the Board 
was the gradual development, starting at Ho + 22 seconds, of variations 
in the hydraulic pressure of the actuators of the main engine nozzle. 
These variations had a frequency of approximately 10 Hz.

"There are some preliminary explanations as to the cause of these 
variations, which are now under investigation.

"After consideration, the Board has formed the opinion that this 
anomaly, while significant, has no bearing on the failure of Ariane 501."

Don't you just love that attempted slight of hand?  The stack was 
swinging back and forth ten times a second.  (Of course it was, the 
control systems model didn't match the actual system.)  Before the 
oscillations got too bad, this other thing destroyed Ariane 501.  Of 
course, if you just fix that other bug, Ariane 502 will go boom! a 
little higher up.  But we aren't going to say that in public.