A Sukhoi superjet 100 is missing

[ATC Watcher]

A few confirmed facts but still a few questions :

Fact : Flight rules/PLN was IFR. Req alt was 10.000
MSA was 6.9 until 25 NM. Radius HLM impactwas 28 NM .
Question 1 : what was the MSA at that point ?
fact :a/c was not under radar vector : reponsibility terrain clearly PIC.
Fact : discrepancy in the report on the ATC R/T phraseology used for the a/c to descend to 6000 ( below MSA)
Question2 :was the PLN vertical request made to descend below MSA followed by an ATC instruction ( XX descent to 6000 ) or was the request made in such a way that it was understood to be going down visually ? then the " 6000 copy" mentioned at the begining of the report could be understood.

It would be nice to see the R/T transcript.

[Heathrow Harry]

I suspect that you're asking a great deal for perfect dialogue from Jakarta Radar Control

What I'd like to see is the transcript for the 07:28 UTC conversation when the pilot asked for approval to make a right turn "the Controller approved the flight to make an orbit to the right at 6,000ft"

If he did say 6000ft then the crew probably thought (wrongly) they were OK

[ATC Watcher]

I suspect that you're asking a great deal for perfect dialogue from Jakarta Radar Control

yes but I fly as well, and when in IFR ( or VFR in controlled airsace ) if I request a descend and I hear back : " copied " I am never going to start decending , and would ask again if we are cleared to descend. Anywhere on the globe. Therefore I think the full exact R/T exchange would be helping us understand why ( and if) they did take this " copy" as an ATC instruction .

If he did say 6000ft then the crew probably thought (wrongly) they were OK

Normally not the kind of assumption a 57 years old test pilot with over 10.000 h would do. In this situation (outside radar vectoring) The ATC clearance / responsibilty is only with regard to separation with other traffic, not with terrain.
A guy like this would know that for sure.

The clue(s) are somewhere else I would say.

[Green Guard]

if you mean orbit=2x Radius then here it is:

(Turn Radius) NM = TAS↑2 / 68652 / tg φ

( φ = Bank Angle)

[PJ2]

Couple of points regarding the report...

Below is a summary of the main crash site coordinates, with sources, (copy/paste into your browser examine original sources).

Interestingly, the Indonesian NTSC has two different coordinates in their "Immediate Recommendations" document and their "Preliminary Report" document.

The estimate from PPRuNe member sledge1984 coincides very closely with Sergei Dolya's estimated position and the NTSC Preliminary Report position.

The estimate from mcgyvr61 which had the aircraft flying up the valley and striking the almost-vertical face is, to me, the most viable crash site estimate. I believe this because the terrain on the east side of the valley, is not an "85deg" vertical face as seen in crash-site photographs, and Google Earth images which seem to fit the site photographs.

The discussion on TAWS by A Van (with some contributions by others) is a must-read if only to further understand the workings and limitations of TAWS/EGPWS and T2CAS.

There are a number of theories which have been discussed in the thread concerning the TAWS - that it was intentionally ignored/turned off, that it may not have had database information for the area, or, according to A Van, may possibly not have had sufficient "granularity" to sense the mountain peak, (you have to read the post and take a look at the links to understand this interesting and important point).

The preliminary report makes no mention of the TAWS so we will have to wait for the final report.

First, a contour map supplied earlier in the thread:



Here's an image summarizing a few of the crash site estimated coordinates, with sources:

NTSC Immediate Recommendations document crash site coords

NTSC Preliminary Report crash site coords

Dolya/Map crash site coords

PPRuNe mcgyvr61 probable crash site coords

PPRuNe Sledge1984 est crash site coords

[Heathrow Harry]

Unfortunately you are using the map (which is pretty small scale for this sort of thing - looks like 1:100,000) as evidence for the detailed local terrain

You'll find that even the Ordnance Survey get it wrong in areas of steep terrain - it's very difficult to render accurately - if you ever read Wainwrights Lakeland Guides he points this out all the time - especially on places such as Scafell Pike or Great Gable

You'd probably have to map at 1:10000 or even 1:5000 to accurately show the terrain on Salak - note the map shows no "sharp ridges" whereas all the photographs of the mountain ( not just at the crash site) show steep ridges all over the place- essentially they are below the resolution of the mapping

which is another reason to stay clear of rapidly rising terrain

[Karel_x]

More detailed terrain on OpenStreetMap:
OpenStreetMap

[Heathrow Harry]

thanks - looks a horrible place to be flying around

[Torquelink]

Not necessarily related but following in Aviation News today:

Armavia cancels SuperJet order

Armavia has cancelled its order for two Sukhoi SuperJet 100 aircraft due to safety concerns. The national airline of Armenia had agreed in principle to purchase two aircraft in an agreement signed with Sukhoi in 2007.
Armavia has operated the first SuperJet 100 since April 2011 although earlier this year, the aircraft was grounded and had to undergo urgent repairs in Russia. The airline has stated that the fact the aircraft needed repairs after just one year of service casts serious doubts on its quality and technical characteristics.
Armavia has already stated that it will not be taking delivery of a second SuperJet.

[Karel_x]

I read that Armavia has financial problems and economy issues are true reason for effort to return the a/c. As far as I know, there is the only one safety issue at first several SSJ - some sensor in climatisation system - if not absolute accurate mounting an cabling it gives false alarm of dehermetisation of cabine.

There are several non technical problems for foreign air companies - for example, when flying from Armenia to Russia for technical check they reportedly wait 2 days for Russian customs formalities. Russia also have not a scheme of financing the supply of a/c to a foreign companies by providing government guarantees for lower rates for loans.

It could be only teething.

[smiling monkey]

This is slightly off topic, but relevant. Sky Aviation of Indonesia who had the highest number of employees on board (the majority as flight attendants) has just acquired their first jet aircraft which is a B733. I wonder what the status of their Sukhoi orders are now? Will they cancel all orders and now pursue with the 737? As much as the Sukhoi aircraft itself was most probably not to be blamed for the crash, it will cause a stigma for Sky flight crew and potential passengers as well. Indonesians are quite superstitious.

[India Four Two]

Indonesians are quite superstitious.

For 'quite' read 'very'.

When I worked in Jakarta, one of the lifts in my office building was thought to be haunted and the local staff would not use it. As a consequence, it was the fastest and most convenient lift in the building.

[Heathrow Harry]

if you used it I can see why the the locals gave it a wide berth..............

[Karel_x]

Russian delegation will fly to Indonesia next Wednesday to discuss the final report. Group will be led by Deputy Minister of Industry and Trade and the visit will spend several days. Final report is supposed about half of October.

[angels]

Was just on here to look for an update on this.

Thanks for the info Karel.

[Karel_x]

Russian group of specialists finished negotiations in Jakarta and together with Indonesian side signed the protocol that fixed "agreed positions about results of investigations and determines the content of the future conclusions".

Indonesian side works on the report and will negotiate it with many instances, incl. NTSB (USA) and BEA (France).

Final report is not supposed before end of October.

[Heathrow Harry]

Given that international relations between Indonesia and Russia were fraught for many years I doubt they'll be too accomodating to any "pressure"

on the other hand they absolutely HATE a fuss so there may be some changes made

[DaveReidUK]

I doubt they'll be too accomodating to any "pressure"

Pressure by whom, on whom ?

Why would you think that the parties involved aren't going to agree on probable cause on this occasion ?

[Karel_x]

I believe that Russian point of view could be useful for Indonesian investigators. They know very well the aircraft, they very carefully analysed FDR and CVR records, they understand Russian mentality, they know differences in air traffic customs and rules in Russia. Let as remember that captain was not much experienced in foreign flights.

By my opinion Russians would like to read clearly in final report that there is no reason to suppose that there was any problems with SSJ. They understand that it was caused by human factor, mostly by pilots, maybe they suggest that captain was a little confused by non standard reactions by ATC. There is no conflict with known facts.

I don't think that "pressure" is the best word for discussions with Russian or with NTSB and BEA.

[Heathrow Harry]

"Pressure by whom, on whom ?"

Dave, Dave

EVERY time there is an accident report released this forum explodes with people alleging "pressure" by one side or the other or by the Masons or the Templars or little green men from New Mexico

I just thought I'd get in first