TCAS Descend-RA below Min Safe Alt
Hi everyone,
just coming from the SIM, where we got this TCAS-Scenario:
A/C is on downwind, 220 IAS, clean config, under radar vectors below MSA, company rules allow so (min 1000 ft above all relevant obstructions on the flightpath monitored by colour-coded contour-layer chart).
On the TCAS you abserve opposite traffic 1000ft above, which suddenly starts descending. So you get a TA, followed by a 'Descend RA'.
What do you do?
PF responded 'according to the book' by descending as TCAS said with about 1000-1500 fpm. This triggered a GPWS 'Pull Up'. While performing the GPWS Recovery Procedure (on the A320: Side Stick Full Back and Hold, TOGA Power) we ended up climbing at 4000+fpm well ABOVE the intruder, so missing him was plain luck. In the debrief the IP confirmed, that this was the very correct reaction.
I have to disagree and would say it was safer in this very case to disregard the RA, maintain level flight and watch the Intruder on the TCAS-Display.
As 'ultima ratio' I would accept to descent to the max. EGPWS-Altitude + 500 feet, if the relative altitude to the intruder becomes less than 300 ft. (EGPWS Terrain Display is switched on at TOD and displays max Terrain Elevation of the range selected on the ND).
Company Rules say TCAS has to be followed 'unless other emergency situations require appropriate action'.
Any opinions?
Cheers, MAX