From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,fb1663c3ca80b502 X-Google-Attributes: gid103376,public X-Google-Thread: fac41,e01bd86884246855 X-Google-Attributes: gidfac41,public From: "Robert I. Eachus" Subject: Re: Interresting thread in comp.lang.eiffel Date: 2000/07/12 Message-ID: <396CA5AD.EE955F7A@earthlink.net>#1/1 X-Deja-AN: 645545506 Content-Transfer-Encoding: 7bit References: <8ipvnj$inc$1@wanadoo.fr> <8j67p8$afd$1@nnrp1.deja.com> <395886DA.CCE008D2@deepthought.com.au> <3958B07B.18A5BB8C@acm.com> <395A0ECA.940560D1@acm.com> <8jd4bb$na7$1@toralf.uib.no> <8jfabb$1d8$1@nnrp1.deja.com> <8jt4i0$18ec7$1@ID-9852.news.cis.dfn.de> <8k5a31$1p61t$1@ID-9852.news.cis.dfn.de> <3966D7B0.5D6475E4@earthlink.net> X-Accept-Language: en,pdf Content-Type: text/plain; charset=us-ascii X-Complaints-To: abuse@earthlink.net X-Trace: newsread1.prod.itd.earthlink.net 963421444 63.24.56.181 (Wed, 12 Jul 2000 10:04:04 PDT) Organization: The MITRE Corporation MIME-Version: 1.0 NNTP-Posting-Date: Wed, 12 Jul 2000 10:04:04 PDT Newsgroups: comp.lang.ada,comp.lang.eiffel Date: 2000-07-12T00:00:00+00:00 List-Id: Ken Garlington wrote: > Are we sure that there was no contractual arrangement between Arianespace > and Sextant with respect to the use of the SRI on Ariane 5? The inquiry > doesn't explicitly say either way, but having nothing at all would certainly > be an unusual practice in my experience. My vague recollection of the > Aviation Week & Space Technology articles from July-August 1996 was that > there was some relationship, but I'll have to go by the library today to see > for sure. As I remember it, there was planned to be a relationship as part of the full-up simulation of the flight control system. When the decision was made not to use the SRIs in the simulation, that part of the contract was cut back or cancelled. I think they still had the SRI hardware supplier on contract, but not the software developers. I argee however, that the real lesson that should be drawn from this is that there has to be a project library--possibly on-line--that is accessable to all subcontractors, and that has at least all the interface specifications and the operational concept. As near as I can figure out, the management disconnect occured because there was an original test plan which covered all the bases, but changes to that plan were not communicated to everyone who needed to know about them. As a result the lower level test plans still allocated test objectives to tests that were not conducted. (The high level objectives were redistributed, but there were lower-level and derived requirements that were never reallocated.) Incidently, I was just looking at your YF-22 crash data. The cause may be called Pilot Induced Oscillation, but the real culprit was lack of feedback to the pilot. There was no direct relationship between the position of the stick and the position of the stabilators in the later part of the event due to the rate-limited nature of the stabilator controls. I hope that this is fixed in the production F-22. (The nasty effect of the change in flight control mode when the gear went up seems to have been key. The pilot was trying to cancel out the change, but had no direct feedback.)