TCAS during Emergency Descent
I read the recent thread on TCAS RA & GPWS conflicts. Enlightening, but no definitive answer. AS always, 10 pilots 10 opinions. I suspect that the trained reaction would takeover, i.e react to the RA and only realise afterwards about MSA. There's not too loong to think about an RA yes/no. I would not be surprised if there was an odour after such a rapid combination of life threatening scenarios.
May I ask another TCAS question:
Recently there was an ACAS11 bulletin N0.9. from Eurocontrol. There is a paragraph on page 3 discussing 'Degraded Performance'. This refers to the a/c. It implies that during an Emergency descent, and thus the a/c would not wish to respond to an RA climb, the TCAS should be set to TA only. Thus all avoidance will be done by other a/c. I've checked my curent SOP's and previous airline SOP's and none include setting TA only for an Emergency Descent.
The bulletin goes on to say that "the use of TA only mode is described in the following note that will included in the next version of ICAO PANS-OPS Doc. 8168 due in Nov 2007". Perhaps this is considered to become a new procedure and will take effect in 2008, hence nothing in SOP's to date.
Does anyone know more?