Yesterday, meanwhile we were on approach to Don Mueang Intl. airport in Thailand we have to act in response to a RA – Resolution Advisory – from our TCAS – Traffic Collision Avoidance System. It was a sunny morning with good visibility and that allowed us to make visual contact with the other aircraft well in advance. The ATC controller told us to maintain an altitude of 11000 ft because another aircraft – an Airbus 340 – will cross our flight path from right to left at lower altitude. For some reason the other aircraft continued climbing and crossed our flight path at 2 NM. We received the RA to “Climb, Climb” to avoid the collision.
We have read a lot about TCAS and seen very sad histories like the one between a Tupolev 154 and a Boeing 757 over Germany on 2002, but important is to react in a timely manner to any RA from our TCAS disregarding any previous instruction from ATC. Once the conflict has been resolved, return as soon as possible to our previous assigned altitude notifying ATC of our deviation. Remember, never argue with a traffic controller on the frequency, is not professional and you are not alone in the air, many other aircraft are sharing a common frequency. Once you have landed, there are forms at ATC offices especially designed to report this situations.
If you wish to read more about TCAS, I recommend these sources:
- Traffic Collision Avoidance System – PPT
- The Traffic Alert and Collision Avoidance System – MIT Lincoln (PDF)
By Ivan Paredes