PPRuNe Forums - View Single Post - Indonesian aircraft missing off Jakarta
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Old 29th Oct 2018, 08:01
  #55 (permalink)  
Join Date: Jul 2014
Location: Germany
Posts: 344
Originally Posted by deSitter View Post
Could be loss of one engine combined with a bad turn back and stall. Plane was pretty heavy. New type, lack of hand-flying experience on it, etc.

A stall seems unlikely as they rather seemed to be going quite fast. The data from FR24 are groundspeed data and that is of course influenced by wind too.
But still to stall at that altitude with a groundspeed of 320 kts you would probably need winds of over 100 kts so that is very unlikely.
Especially with surface winds of less than 5kts on departure.

I roughly checked the timestamps and distance between a set of coordinates and got an average ground speed of 315 kts. I used about the 5 last minutes of the track, the timestamps are not very accurate so you can't just check between two positions. Anyway this is just to check if one can suspect the ground speed data to be faulty which there is no hint that they are.

Quite the opposite: The ground speed data suggest they were going near top speed.

It's quite easy to compare it to a flight that was flying at a similar altitude and direction / position.
Marked acceleration at 10000ft on this flight might suggest they were flying at 250 kts IAS below 10000 but i don't know local departure procedures so that is speculation.

Anyway the accident airplane was going a lot faster than a similar type at that altitude in the same conditions.
Also in regards to the one engine speculation quoted I doubt they would be able to go that fast with one engine.
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