A Van ... on the accuracy of terrain maps
Thanks for the very informative "response". [Actually I think we posted simultaneously. I certainly didn't see yours before I posted, and I doubt that you saw mine.]
Capn Bloggs
I think you guys are on the wrong track with all the "ATC clearance" and GPWS talk. I have no doubt that a standard EGPWS would be going ape down in amoungst those mountains.
I think it is highly likely they were fully VFR, sightseeing, when they got badly caught-out. EGPWS (or whatever the equiv is in the Sukhoi) is not designed to provide terrain avoidance
guidance during low-altitude sightseeing flights. I can even imagine that the system had been disabled, as one would do during a handling demonstration, to prevent the annoying
"nuisance" warnings that would be going off eg "bank angle", Too low gear", terrain ahead".
You may very well be right, but you misunderstand the purpose of my post.
From ideas thrown up in this thread there seem to be a variety of possible scenarious, all with some plausibility:
a) A "demonstration" of T2CAS.
b) A "white knuckle" ride intentionally at or below T2CAS warning levels, with T2CAS turned off.
c) A "highly scenic" ride intended to be near but above T2CAS warning levels, with T2CAS left on.
d) A "scenic" ride intended to be well above T2CAS warning levels, T2CAS on.
e) An intentional flight into a mountainous region flying below the peaks, with no intention of getting near the ground, T2CAS on.
f) A flight planned to be well way from the mountains, which strayed into them, T2CAS on.
To me it seems worth exploring all of these scenarios, and testing them all against the evidence -- as and when it appears.
I was simply exploring scenario (f).
I am certain that scenario (b) would greatly appeal to some salespeople, and accept your belief that some pilots would go along with the idea.
vovachan ... reported [a press release?] which, after google translation, states:
the warning system on dangerous ground proximity TAWS has been enabled and working.
If true, this argues against scenario (b) being the case
for this flight.
In the spirit of full reporting ..The press release goes on to say:
"Preliminary analysis of the received speech to the registrar of the board 97 004 information shows that the premature failure of systems and
units of the SSJ-100 aircraft before the collision with Mount Salak, according to the decoded data to date, have been identified,"
Which I read as saying that there were [unspecified] system failures. At the moment I choose the believe that this is simply a translation error.