Originally posted by ATC Watcher
Now it is its technical ( in abroad sense ) shortcomings that are being discussed.
Thanks for your reply. I fully agree that there are probably technical shortcomings and PBL is quite possibly aware of them. Have never said different.
Originally posted by ATC Watcher
TCAS was introduced in the USA without a proper safety case , for political reasons.
It has been over 21 years now since the midair collision over L.A. of a DC-9 and a mode-C equipped Piper. For most of the past 21 years in the U.S. all airliners have had TCAS and there have been no airliner midairs. In the 21 years before the L.A. collision there was:
1) 25 September 1978; Pacific Southwest 727-200 vs Cessna172; San Diego, CA-143 dead.
2) 6 June 1971; Hughes Airwest DC9-31 vs. F-4; Near Duarte, CA-50 dead.
3) 9 September 1969; Allegheny DC9-31 vs. Piper Cherokee; Near Fairland, IN-84 dead
4) 19 July 1967; Piedmont 727 vs.Cessna 310; Hendersonville, NC-82 dead.
5) 9 March 1967; TWA DC9-14 vs. Beech Baron; Near Urbana, OH-26 dead.
Keep in mind that there have been way more airline flights in the 21 since the L.A. collision than the 21 previous years. This reality is what makes me smile behind my PC.
Originally posted by ATC Watcher
based on the regulations in force in July 2002 , it was not irrational for the Tu154 crew to follow the ATC instruction.
From the final report in part:
The TU-154 AOM contains general recommendations regarding the use of TCAS. The AOM reference draws attention to the fact that manouvering opposite to TCAS can lead to a collision.
The TU-154 AOM stated that manouvering opposite to the RA is PROHIBITED.
One final thought about the rationality of manouvering visually to avoid that 757(against the RA) based on
"engineering facts". Exactly what facts were used to determine that one can successfully visually manouver around this fast moving jet. Is it just assumed that it can be successfuly accomplished or is there actual data on how easily it is done(in daytime, at night, over brightly lit areas, in marginal visibility or with different cloud formations in the background and the illusions they can create with false horizons which I have also seen with northern lights, etc.). If so please publish this engineering data.
Like I said I have no engineering data. But I do have real world knowledge of a midair between two airliners caused by improper evasive action by one of them when none was required due to illusion.
http://www.prop-liners.com/midair.htm
And I know that according to a Flight Safety Foundation(perhaps the best known safety study group) publication, a JAL 747 captain figured the could go against the RA and visually avoid a DC-10. He was right. He missed by 135 meters and only injured 99 people on his plane and lodged a galley cart in the ceiling(following an RA is a one-quarter G manouver by the way).
http://www.flightsafety.org/fsd/fsd_mar04.pdf
And finally our much talked about TU-154 captain who attempted to visually manouver by a 757. Results catastophic.
I eagerly await these
"engineering facts".