----- Original Message ----- From: "Jon Wright" <jwright@halcyon.com> To: <AIRLINE@LISTSERV.CUNY.EDU> Sent: Monday, July 08, 2002 8:41 PM Subject: Re: Pilot's instructions before crash contradicted <snip> > Is this how TCAS is supposed to work--issuing coordinated instructions > to the different planes in conflict to maximize evasive manuevers? TCAS is supposed to do exactly what it did in this case. If one plane is ordered to descend the other is ordered to climb. > What > are pilots trained to do when given instructions from ATC that are > counter to a TCAS TA? There appears to be confusion over this question. Apparently some national authorities give priority to the TCAS and others to the ATC, and some don't take up the question at all. Since the TCAS is there and the controller isn't, it would seem better to recommend to the pilot that TCAS has priority. It is very interesting that for some time after the collision it was apparently assumed that the Tu154 TCAS was not working, when in fact it proves to have been doing fine. Further questions about this collision include asking why the two aircraft were cleared into the same airspace at the same altitude at the same time, apparently by ATC's of two different nationalities, Italian and some other. As has been said, TCAS is not supposed to be the first line of defense against collision. > Would the DHL 757's TCAS started doing anything > different when it figured out the Tu-154 was descending too--like, > go from "Descend" to "Dive"? > I don't think TCAS can respond in time to this situation. With heavy heart Gerry http://home.columbus.rr.com http://www.fortunecity.com/victorian/pollock/263/egypt/egypt.html