IIRC one of the incidents in
‘EPGWS events and analysis’ occurred in India; does anyone have a link to the Lahore approach chart that can be used to see if there are any similarities?
Propeller, I have posted comments on the use of ‘an intermediate altitude’ in
http://www.pprune.org/forums/showthr...=312341&page=3. I agree with your implication that an immediate climb is required without thought of why the warning has occurred, why an error has occurred, or where the aircraft might be; these can be considered later at a safe altitude or on the ground after flight.
I also agree that an in-depth investigation is required, preferably by the national authority so that we might all learn from the event. However, I wonder if the national culture, or indeed the operator’s culture will permit identification of the ‘interesting’ contributions to the crew’s error.
A training / operational issue is that many pilots do not appreciate the amount by which EGPWS has been improved over GPWS. I am mildly irritated in this respect by the continuing use of GPWS as a generic term for the Enhanced system - no blame ascribed. The use of incorrect terminology can contribute to misunderstandings and incorrect use of systems. In this instance TAWS is the generic term, but “Enhanced GPWS” (EGPWS) means much more - that the aircraft is fitted with a highly reliable system which leaves no doubt at all about the validity of any warning.
Molokai, I agree with your points. One of the common sources of error in the use of modern technology for non-precision approaches is the use of pressure altitude. A simple mistake in altimeter pressure setting can affect both the instrument displays and VNAV path calculations, thus the crew have no immediate means of checking for an error. Similarly altitude miscalculation can induce errors, but if the pressure setting was correct, then someone should have detected the error with the basic crosschecks as you indicate. Thus the problem might be with the procedures / checking process, or even the altimeter setting procedure / crosschecking and subsequent monitoring of the critical parameters during the approach.