In the Brazilian accident the one plane was scheduled to change altitude an an enroute intersection but was unable to contact Air Traffic Control (fairly common in Brazil) and so remained at the same altitude, there was no radar coverage. By accident the Aircraft Transponder in one aircraft was turned off. This led to aircraft at the same altitude going in opposite directions on the same airway, the collision avoidance system only works when both Transponders are working. Hence the accident. Hence the recommendation to offset by 1 or 2 Nautical miles right of course.
Mike Payne ----- Original Message ----- From: John M. Steele To: U.S. Metric Association Cc: U.S. Metric Association Sent: Wednesday, 21 April 2010 18:13 Subject: [USMA:47217] Re: Air flight altitudes in meters I was under the impression that odd and even altitudes (1000' increments) were assigned by course heading. I would expect a pilot to question an assignment to an altitude not "owned" for the duirection he is going. ------------------------------------------------------------------------------ From: Harry Wyeth <hbwy...@earthlink.net> To: U.S. Metric Association <usma@colostate.edu> Cc: U.S. Metric Association <usma@colostate.edu> Sent: Wed, April 21, 2010 1:37:54 PM Subject: [USMA:47216] Re: Air flight altitudes in meters When we were in New Zealand in 2004 I read an article in the NZ Herald that a head on collision was narrowly avoided between two aircraft traveling to and from the US in the middle of the night somewhere around Tahiti. The Tahiti controller had mistakenly told one plane to change altitude to match that of the oncoming plane, and only because the automatic crash avoidance radar told one to dive and one to climb did they miss by some hundreds of meters. HARRY WYETH
