A Sukhoi superjet 100 is missing

[Karel_x]

Семь последних миль ... по данным бортовых самописцев, система T2CAS несколько раз предупредила экипаж об опасности. Яблонцев лично испытывал работу этой системы на Северном Кавказе и, составляя руководство по летной эксплуатации SSJ-100, написал, что при срабатывании сигнализации нужно «незамедлительно начать набор высоты». Однако в Индонезии пилот почему-то не поверил системе: он был уверен, что летит над равниной к аэропорту и даже проигнорировал собственные рекомендации, снизившись на 800 футов.

7 last miles ... according to flight data recorders, T2CAS several times warned the crew about the dangers. Yablontsev personally tested this system in the North Caucasus and preparing Flight Operation Manual for SSJ-100, he wrote that reaction for the alarm should be "immediately begin to climb." However, in Indonesia for some reason the pilot did not believe the system: he was convinced that they flies over a flat terrain toward the airport and even ignored the recommendations of its own, when descenting to 800 feet.

[henra]

Originally Posted by Karel_x

he was convinced that they flies over a flat terrain toward the airport and even ignored the recommendations of its own, when descenting to 800 feet.

And they never saw the sides of the canyon which were maximum 3-500m away?. It would mean they accidentally and unknowingly always flew pretty much in the middle of that canyon for almost 5 miles without ever getting close enough to one side to see it and ask themselves wtf???
Plus a shouting TCAS where there should be flat terrain underneath when returning to Jakarta ?
Sorry, This sounds a bit strange for my taste.
I rather prefer to wait for the official report hoping it will be published and be objective without cover up.

[Heathrow Harry]

Henra - some of the earlier posts and pictures show how easy it is to have mist & cloud around the crash site - he could probably see the mountain out of one window and thought he was in over flat land to the north - couldn't see the other ridge coming up fast on the other side..........

[hetfield]

Why not to put it simple?

IFR?
Check your plates for MSA.

VFR?
Have a look out, stay clear of clouds/traffic and obstacles, but don't blame any other person e.g. ATC.

[henra]

Originally Posted by Heathrow Harry

he could probably see the mountain out of one window and thought he was in over flat land to the north - couldn't see the other ridge coming up fast on the other side..........

But there shouldn't have been any mountain to any side of the aircraft if they had just made the mentioned reciprocating error.
They would have been North of the mountain range all the time. In that scenario any green solid mass of terra firma reaching up to their flight level, be it to the left or to the right, should have initiated instant concern - and action.
As they were released to FL60 and hit the mountain at ~FL62 I see no indication for a vigorous attempt to climb until maybe the last 5 or 10 seconds.

[BOAC]

Can we review for a moment? Looking at PJ's post #288 the crash appeared to be south to north. How does that fit with a 'reciprocal error' heading south?

[henra]

Originally Posted by BOAC

Can we review for a moment? Looking at PJ's post #288 the crash appeared to be south to north. How does that fit with a 'reciprocal error' heading south?

If I remember correctly that was one of two possible scenarios proposed by him based on the originally reported coordinates which were not quite exact.
The other was North to South. The latter one seems to be the more likely and generally accepted one. That second one is also the basis for the speculation about this reciprocal error.

[Karel_x]

If this map is correct:
Файл:SSJ100 crash on Salak ru.png — Википеди�
(red point = crash site, 2211 - Mt Salak)
it is unlikely that plane flew from South to Nord. The crash site lies behind the peak in this direction. The crash site lies in the end of canyon which heading is ca 200, opposite to the direction to the airport.

[aterpster]

henra:

Plus a shouting TCAS where there should be flat terrain underneath when returning to Jakarta ?

There was discussion much earlier that the TCAS(TAWS) may have had a regional terrain database, which did not include the area in question.

[henra]

Originally Posted by aterpster

henra:
There was discussion much earlier that the TCAS(TAWS) may have had a regional terrain database, which did not include the area in question.

Agreed! As single Issue I would agree it may not have been very reliable and there could be an explanation why to diregard it.
It is just the combination with other Issues that makes it -in my Eyes- not the most likely overall scenario.
Looking back at most accidents Occam's Razor has an excellent hit rate. Maybe this is one óf the exceptions.
But I only tend to believe it if there is substantial evidence pointing in the direction of a scenario that needs (too) many assumptions. So far I don't.

[Karel_x]

....Occam's Razor has an excellent hit rate

What scenario prefers Occam's Razor in this case?

[India Four Two]

What scenario prefers Occam's Razor in this case?

CFIT - They lost situational awareness and flew into a mountain they weren't expecting to be there.

[etrang]

Yes, of course. Obviously they didn't expect the mountain to be there. But how did they come to lose situational awareness?

[PJ2]

Henra, you are quite correct - my original scenario, south-to-north, is incorrect.

The flight path was north to south, striking the other side of the ridge where I thought the original site was - everything fits. This knowledge and mapping actually came from a German site and it is worth re-reading this thread to see their work, which I think is correct.

Edit - here's as good a map and theory as any, posted by mcgyvr81

[BOAC]

Thanks for that link, PJ. We sum this up, as I and many others said earlier as
'LOST'. Why? I sure reams of PDFs can be written on the psychology of this, but I still think my post#591 says it all and we should close the folder and go 'WHAT?!!!?

[PJ2]

BOAC;

but I still think my post#591 says it all and we should close the folder and go 'WHAT?!!!?

Yes, fully agree.

I haven't read it yet, (haven't covered all recent posts here) if the TAWS database included this area. Anyone?

[henra]

Originally Posted by Karel_x

What scenario prefers Occam's Razor in this case?

I really hate to say this but I honestly believe it is something along the lines: Sightseeing gone wrong.
Lost situational awareness and maybe thought they were in a different valley. One they saw before where you could fly through. Or thinking they were on the outside of the mountain range and flying alongside it (while the outer ridge being obscured).

This would explain why they did not initiate a climb once entering the canyon, without requiring total obscuration of both ridgelines while accidentally following exactly the direction of the canyon without seeing it.

Happy to stand corrected by the official report, though

[training wheels]

The Indonesian NTSC has just released the Preliminary Report in to the investigation of this crash.

http://www.dephub.go.id/knkt/ntsc_av...4_Released.pdf

[Radix]

Re the report, ATC never delegates Responsibility for Terrain Clearance to the pilot.

The keyword "visual" is found wanting when the pilot & atc agree on 6,000'.

Also ATC doesn't give a 'clearance' to 6,000'. He says '6,000 copied'. Doesn't sound like a clearance to me. Have to say they approved the right orbit after that.

[Heathrow Harry]

you wonder if the pilot misread the MSA as 6000 ft??

had it been 7000ft instead of 6900ft he might have noticed it ..........