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-   -   737-500 missing in Indonesia (https://www.pprune.org/rumours-news/637944-737-500-missing-indonesia.html)

toratoratora 9th Jan 2021 11:48

So it lost 7875 feet in 11 seconds-jeez.
Has to be vertical, and surely largely intact to achieve that ROD.

gearlever 9th Jan 2021 11:50

EDLB
"Debris and body parts were located in waters of about 15 meters depth near Lancang Island."

AvHerald

peterinmadrid 9th Jan 2021 11:54

Pilot suicide? If the pilot put it into a dive, we'd see a big increase in speed as the altitude decreased.
Stall? Spin? If that were the case, we'd see the speed getting dangerously low before the altitude drop and even then, it should be recoverable from that altitude. That drop in altitude would give more than enough speed to recover from a stall.

Instead the altitude and speed both suddenly dropped at the same time, which seems to indicate a sudden structural failure of the aircraft.

A320 Glider 9th Jan 2021 11:55

56 pax and 6 crew = 62 souls.

The airline's website is very basic and still fails to mention the accident or any support for families and friends of the pax and crew.

Peter, fair points. Stall can be achieved irrelevant of airspeed though. All down to AOA. Stall a 737 at 250kts no doubt. But yeah evidence is pointing toward something giving way and the aircraft nose diving into the sea below.

dr dre 9th Jan 2021 11:58


In late September (2019), quality, safety and security director Toto Soebandoro, in a leaked internal letter, recommended that Sriwijaya stop its operations until it can improve its safety standards. This was similar to what the Transportation Ministry would later decide based on factors such as a lack of engineers as well as tools, equipment and spare parts for proper maintenance of its fleet and an absence of maintenance by any MRO provider.

Last week, the aviation authority gave the airline five days to sort out its safety and security issues and threatened to totally halt its operation on Wednesday if the problem is not solved.
Sriwijaya Air eyes resumption of full operations after securing maintenance services from Garuda


DaveReidUK 9th Jan 2021 12:05


Originally Posted by peterinmadrid (Post 10963976)
If the pilot put it into a dive, we'd see a big increase in speed as the altitude decreased.

We may well see that on the FDR readout.

QDM360 9th Jan 2021 12:09

Groundspeed
 
No, again: FR24 shows "groundspeed", not IAS. When the aircraft points downwards, groundspeed automatically drops. A 90 vertical dive downwards means "groundspeed 0kts". Nothing indicates a midflight break-up. In contrary: it kept sending ADS-B data including GPS position.

Ind 9th Jan 2021 12:19

yep, data were transmitted to the impact. They had at least electrics intact, and most likely engine power due to ROD, so midair breakup unlikely.

Centaurus 9th Jan 2021 12:43

Boeing 737-300 Silkair MI185 had a similar descent profile when it went in in 1997. See: https://en.wikipedia.org/wiki/SilkAir_Flight_185

Contact Approach 9th Jan 2021 12:55

A lack of recency doesn't cause a nose dive passing FL100.

F-MANU 9th Jan 2021 13:05

PK-CLC flight profile
 
FR24 ADS-B data
Timestamp Alt GS HDG
07:39:56Z 10800;287;42
07:40:02Z 10900;287;30
07:40:05Z 10900;287;23
07:40:08Z 10725;287;6
07:40:14Z 8950;224;339
07:40:16Z 8125;192;338
07:40:20Z 5400;115;11
07:40:27Z 250;358;93



QDM360 9th Jan 2021 13:10


Originally Posted by A320 Glider (Post 10964013)
Deviation off track = aircraft turned right just after the problem occurred.

That's not the case when looking closely at the FR24 data. The aircraft remained on a stable northern course throughout the entire steep descent. It's just the very last ADS-B data point which suddenly "jumps" kilometers to the East. That's what causes the odd 90-to-the-right track in FR24 display. And this also caused the spike in groundspeed at the very end.

It's obviously a false data point, maybe caused by an incomplete/corrupted ADS-B transmission.

DaveReidUK 9th Jan 2021 13:18

Maybe.

Though the final few points are also consistent with a spiral during the last seconds of the trajectory - provided one resists the temptation to use straight lines to join the dots and infer instantaneous 90 turns ...

TFE731 9th Jan 2021 13:36

The profile looks similar to Air Sweden 294. In that case, instrument failure and spacial disorientation caused them to loose 21000 feet in one minute.

ATC Watcher 9th Jan 2021 13:40

Could you please refrain from continuing mentioning pilot suicide in here. you absolutely zero evidence for that so out of respect for the families of the victims and the pilots , turn it off. We have seen how repeating a falsehood long enough on internet can turn mobs into believing it.
Nobody has any, zero evidence to what happened a few hours ago.

derjodel 9th Jan 2021 13:41

There are not that many options IMO:
- suicide
- Somatogravic Illusion / disorientation (but the would have seen the ground, the weather doesn't seem that bad, does it?)
- some kind of H stab failure/jam
- some kind of trimming issue, misconfigured AP or siilar?

In any case, it's getting strange how Boeings are nosediving from the sky:
- Fly dubai
- Atlas
- and now this

Has there been something similar with fatal consequences involving an Airbus? Apart from Germanwings, which was (supposedly) suicide, but even that one didn't really nosedive.

alf5071h 9th Jan 2021 13:45

not appropriate in a proffesionals forum
 
andrasz, #33

You perpetuate the mistake which the FAA made in concluding that whilst a 3 person crew identified a fault, then a 2 person crew in similar circumstances would act and be capable of achieving a safe outcome.

Your views on this accident re maintenance, CB, LOC, IMC are ill founded - no evidence or reasoned argument in comparison with others experiences.

Bias, inappropriate cause and effect; not appropriate in a professional forum

TFE731 9th Jan 2021 13:50


Originally Posted by derjodel (Post 10964071)

Has there been something similar with fatal consequences involving an Airbus? Apart from Germanwings, which was (supposedly) suicide, but even that one didn't really nosedive.

Yes:
Gulf Air 072: A disorientated pilot dived into the sea with forward pressure on the side stick.
Air France 447: A disorientated pilot maintained back pressure on the stick until a stalled aircraft crashed into the sea.

In both these incidents having the two sticks physically connected together could have prevented both of these.

EDLB 9th Jan 2021 14:00

They lost 10000 feet in 19 seconds. That is no spin, more a direct nose dive. If it was not deliberate my bets are, that something on the tail got wrong.


Uplinker 9th Jan 2021 14:14

F-MANU

If this data is correct, then according to the ground speed this aircraft went from a cruise-climb at 287 kts to a descent (less horizontal speed, altitude reducing), and then finally to a ground speed of 358 kts, i.e. it had resumed horizontal travel.

An emergency descent, for whatever reason, maybe got too fast in the descent and/or then pulled out too late, almost made it, but hit the sea?

The left turn seen in the HDG data; possibly yaw caused by a No 1 engine failure?


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