Originally Posted by
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-200 ft (as in minus)? This is presumably the 1013 value?
Yes. Transponders send altitude code in mode C referenced to 1013,25 / 29.92, technically it is Flight level and not altitude. The sent data give no reference to acual selected altimeter baro setting. (I have no idea if perhaps it may be available through mode S coding).
Also one other information I found possibly confusing in the thread is that there would be no terrain warining in landing configuration via GPWS. That is correct, GPWS would only have (loud enough) "GlideSlope" alert. On the other hand, Enhanced GPWS which I believe had been made mandatory for the likes of this 738 operated from Turkey, does have a mode called Terrain Clearance Floor which could have been activated. One way or another, the situation probably triggered several warnings; whichever took priority I cannot guess with my limited tech knowldege but CVR will surely reveal. Niether do I suggest that once the crew is made aware more warnings are automatically better help to solve the situation.
FD (the un-real)