Posted on 06/02/2010 2:28:49 AM PDT by ErnstStavroBlofeld
Newly-released cockpit voice-recorder transcripts from the crashed Polish presidential Tupolev Tu-154M show that the terrain-awareness system sounded a 'pull up' warning eight times before the jet collided with trees and disintegrated.
The first warning at 10:40:42, about 20s before the accident, came almost immediately after the crew had called the aircraft's height as 100m. This also happened to be the decision height for the approach, which was being attempted in dense fog.
Transcripts from the accident also show that, although the aircraft was descending, the height was still being called as 100m seven seconds later at 10:40:49. This could indicate that the reading was not the aircraft's height above the runway, but rather the immediate height above terrain as given by the radio altimeter.
Radio altimeter readings provide a 'snapshot' height above ground and can give a false impression of clearance margins in regions where terrain rises sharply ahead of the aircraft. The approach to Smolensk taken by the Tu-154 features a rising valley wall about 1km from the runway threshold.
The transcript reveals that the Tu-154 continued to descend through the 100m decision height, the navigator calling 10m intervals, with no apparent comment from the crew until at 80m the co-pilot said, "Odchodzimy" - or "We're leaving" - which may have been a reference to a missed approach. There is no subsequent evidence, however, that the crew opted to abort the landing.
(Excerpt) Read more at flightglobal.com ...
I suppose Putin must have hypnotized the pilot.
Smolensk airfield area was not in the TAWS system database.
So - even if the weather was perfectly clear - the system would be shouting “pull up! pull up!”, because it would read, that they’re descending towards some uidentified terrain, not an airfield.
There is no DH on a non precision approach. There is a minimum decision altitude, and they obviously descended past it. It sounds like that were using DH when they should have been using MDA. This is exactly why MDA is used on non precision approaches. If the transcripts are true, they managed to kill themselves.
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