alf5071h

No I don't. I'm merely pointing out that after a flight with extraordinary events, it was not reported, not written up, with only some vague entries in the maintenance log, which were then improperly acted upon. I did not in any way blame the second crew, but the whole thing would have been preventable with a proper post-flight follow up and the aircraft rendered u/s. This does not absolve Boeing/FAA from the primary blame, but it is no coincidence either that it was the two airlines in question which brought the issue to the surface.

A Sad day again - this ASN on PK-CLC , this report is updated regularly
 

This ASN report on PK-CLC :
Type: https://cdn.aviation-safety.net/grap...Otype/B735.gifBoeing 737-524 (WL) . Operator: Sriwijaya Air , is updated regularly https://aviation-safety.net/database...?id=20210109-0

There is no indication that the ROD reduced appreciably as the aircraft descended.

https://cimg5.ibsrv.net/gimg/pprune....65ace39abc.jpg

Uplinker

Rudder hard-over?
The graph by DaveReid suggests a 40,000 ft/min descent, which suggests almost vertical.

Some old aircraft were still running with the simple hydraulic pressure-reducer mod well into the 2010s.

The Indonesian Navy says plane located and navy vessel en route to site.

I am not a great fan of social media and Boeing is not obliged to comment at this stage.

However when they do I'll be interested to see whether they demonstrate a return to openness, humility even.

derjodel

Yes. Gulf Air A320 in Bahrain on the go-around. Afriqiyah A330 in Tripoli on the go-around. Both high speed impacts due to humans being human, even if not true “nose-dives”.

Also, I’d say Germanwings was more than ‘supposedly’ suicide! The guy didn’t get confused and do it by accident.

It lost 10,650 feet in lass than 25 seconds. That is the time in which any stone would have dropped into the water from that height. Ergo it was not gliding down even if there was total engine failure. It seems pointed nose down.
Ergo debris in small area; only on impact

RUDDER?

Were not the previous rudder run-away events compounded by slow aircraft speed?

I'm waiting to see what debris is found andwhere, relative to the control surfaces on the aircraft.

I don't like waiting for black box finding and decoding before issuing some pertinent updates to other operators

The airframe belonged to Continental/United until 2012, it would have had the rudder issue fixed.

Correct. The rudder hardover theory was a low speed event. In the operational aftermath the concept of crossover speed was introduced. Above that relatively low speed lateral control was possible. Denied by Boeing to this day but very unlikely in this case anyway. Sorry for those affected. Indonesian airlines are a constant safety concern.

I'd also throw in XL 888T if we're considering multiple sensor failure and flight control law degradation.

In theory, IF the other crew member is not disorientated and intervenes in time and wins the argument, one the other hand there are many instances where the connected sticks didn't help at all - Atlas 3591 for a start (just to pick one from the "right" part of the world).

Out of interest can you point to any actual documented saves due to connected sticks after dive or stall LOC due to disorientation?

According to data from zoom.earth there were actually CBs in the area. The crosshair in the picture below is an aproximate position of the plane when it was at FL100. There is a chance that the plane was hit by lightning which led to autopilot disconnection and also temporary blindess to pilots could have made the airplane uncontrolable.

https://cimg2.ibsrv.net/gimg/pprune....e8e2034b8.jpeg

lomapaseo:

From my years dealing with Airbus they would always inform operators if urgent changes were needed.

The manufacturer is often the first to know what happened.

Wx situation at takeoff
 

Indeed, there was nothing going on at the time in the area of interest

Satellite image Jakarta area

The storm and lightning activity was to the west of the flight track.

Lightning activity in the hour before takeoff

Also 5 minutes later the acitivity was just west of the airplane

Lighnting strikes 6.45 UTC to 7.45 UTC

#72

Nothing different. Just a bad resolution sat pix.

Zoom.earth

"It was in good condition, Sriwijaya Air chief executive Jefferson Irwin Jauwena told reporters. Take-off had been delayed for 30 minutes due to heavy rain, he said."

https://www.flightradar24.com/blog/c...ajor-incident/

Watch out for dodgy timestamps and latency issues.

SOP is for the manufacturer to put out a press release, expressing condolences and stating that they will be sending representatives to help with the investigation. This is far from exclusive to Boeing - it's SOP throughout the industry. Furthermore, there will effectively be an immediate gag order prohibiting the public release of any data related to the crash or investigation by anyone besides the responsible investigative organization (presumable the Indonesians in this case).
Besides, this was an old, largely analog aircraft - it wouldn't have real time data monitoring of aircraft condition that might provide any insight into what happened (e.g. the probe icing that was reported on AF 447). So it's unlikely anyone knows any more than what's currently being discussed on this thread. That won't change until the data recorders are recovered and the data downloaded. I just hope the data recorders were functioning properly - they often don't on old aircraft, and they are not a maintenance priority.

Speed & Altitude from FR24 (Granular Data)
 

Speed and Altitude from FR24 granular data

https://cimg7.ibsrv.net/gimg/pprune....c9fca27420.jpg

https://cimg9.ibsrv.net/gimg/pprune....9e9a29f906.jpg

Thanks for that. It illustrates my earlier comment:

The momentary climbs during the descent from FL110 and the equally abrupt variations in groundspeed are artifacts as a result of timing issues: ADS-B data isn't timestamped at source, so FR24's timestamps simply record when it arrived at their servers from the various enthusiast feeds regardless of latency.

So the altitude and speed point values on the charts (and also on my earlier chart) are correct, but not all shown at the correct point in time.

I have a question: What would cause the speed to drop for half the descent before the speed drastically increased. Does this show a level of control after the initial problem?

DaveReidUK

How many enthusiast feeds is available off the coast of Java? This is why I have a problem with FR24. It is treated as the truth even if is «recording» events in the middle of an ocean with no feeds available anywhere. People simply have no idea how it works, or what it takes to get reliable information from it.

Thanks, I am fighting with Excel as well.
DaveReidUK is right with the uneven distribution over time. But still we can see that the Groundspeed is not one or two glitchy datapoints but somehow a continuous increase in the last 7 seconds (speed stops to decrease at 5600ft, starts to increase again at ~3000ft)
Why is the question. GS surely is calculated. From INS? What happened to the sources for INS? Was 735 retrofitted with GPS anyway?

I'm also (and always) sceptical with FR24 collected data, you have a first but somehow fuzzy picture.
Only the ALT drop seems to be realistic. that's "impressive" unfortunately.
I don't read more from it at this time.

Another thought: That 2nd Gen of 737 is mostly gone in the regions where people worry the most about individual safety, and it's a lower count compared to the more modern generations. So there shouldn't be too many hysteric people afraid of setting a foot in that type. If this accident was related to this type at all of course. The issue will be found I believe, changes will be recommended in time. Just no need to be hysterical.

The rudder issue is a dead end. Fixed a long time ago.
This is a loss of control accident. Why is anyones guess. We have had high speed loss of aircraft due to weather, disorientation, loss of instruments, fatal control problems, icing, suicide, computer resets and so on.
No pilots will start an emergency descent because of decompression from 11000 ft, and if you have a fire you don’t point the nose straight down.
My money is on instruments or possibly an explosion that cuts control of the tail. Pure speculation, but that is the only thing we can do at the moment.

"The only thing funnier than watching non-professionals trying to investigate an air accident, is watching dogs on youtube trying to chew toffee."

About the only things we know so far is that this aircraft 1) made a more or less ballistic dive into the ocean from about 11,000 feet, and 2) it appears to have done so in substantially one piece, which tends to rule out a major explosion.

And secondarily that there appears to be no communication. Although that is quite common - pilots try to save their lives by flying, not by telling ATC where to find the hole in the water (or ground).

That does not rule out (or in) a smaller explosion (accidental or intentional - no evidence yet), that perhaps disrupted hydraulic or control runs, or the cockpit floor, or the trim jackscrew - or something completely different. Not large enough to disassemble the airframe, but possible enough to render the controls inoperable.

There appear to be eye (or ear) witness reports of explosions (but read up on the reliability of eyewitnesses - it also make funny/sad reading).

But in any case, that is just one of many possible scenarios. Each one of which should rate an initial probability of 1% - until further evidence rules them out completely (probability = 0%) or does not. In which case they remain in the mix for continued consideration.

Not in the GulfAir case, if we're honest about the root cause. On the other side, Armavia 967 does belong on the list.

The only relevance the "boeing" label has is circumstantial. Since they have been producing aircraft longer than Airbus and their older models are less efficient. many fine aircraft are operated be companies and people who chose not to pay for something better. A little money only gets you to certain lengths, which will apply in all aspects of the operation.

The statistics of out-of-production AB are the same as BA. More importantly, creating statistics and comparisons on single (digit) data points is meaningless.

And long may it stay that fatal aviation accidents are rare, too few for statistical processing.

I read that takeoff was delayed by 40 to 90 minutes due to weather concerns. I do not have a link.

That's a fair point about events in the middle of the ocean, but this flight went down less than 20 miles from a city of 10 million people, so we shouldn't be surprised if it was being tracked by several FR24 feeds.

While it's true that some B735s are still flying around with inertially-sourced ADS-B, it's pretty clear from looking at previous tracks for the aircraft in question that it had GPS.

Groundspeed is indeed calculated by the receiving station from N-S and E-W velocity components, which are what the aircraft transmits. Those, of course, are also what is used to derive true track. As a general rule, if the track timeseries looks consistent (which it does in this case once the time jitters are corrected) then the groundspeeds are also likely to be correct.

Hi,
Fishermen overflown by plane on takeoff talk about two explosions

Ok, I averaged per second, also to get rid of the stretch of diagram-time when many values per second. I know it's still not perfect. I also removed datasets with no_position=N

https://cimg7.ibsrv.net/gimg/pprune....566423ccab.jpg

You can see that the ALT drop does not flatten out at the end. Nor is it ballistic after 07:40:17 UTC.
Somebody mentioned stallspeed warning at 4000ft. Don't forget, to deduct IAS from Groundspeed, and Stall from IAS is impossible to guess. And in case the plane nose dived, you have variable GS over descend angle. Forget the Speed. Only the GS increase at the end is somehow a mystery.

We need to be sceptical of a witnesses statement such as this, people often see things such as fire or breakups which are later on proven not to have occurred.

If the wreckage is in 15m of water at a known location then the recovery should be fairly quick.

Fishermen always come out with these claims when these things occur in Asia but none have yet to feature in any report. Remember the dozens and dozens of fishermen eyewitness claims around MH370? A lot of time was wasted investigating these false claims.

CB's around here can become very big and nasty fast ....let you know if i hear anymore.

Indonesia.......

Wet season with big nasty thunderstorms........

Low cost carrier.........

I think we’ve been here before.

Despite all the BS spouted about the B737 it is still one of the most reliable aircraft ever built.
I have thousands of hours on them.
I have also operated extensively in Indonesia.
It wont be the aircraft.

Seems to be the head scratcher for many. This could have been the point they exited a cell.

Speed seems good right up until the second the altitude heads south. Speed seems pretty accurate during climb also, data seems good so far.

Disorientation I would still not expect initially anyway, such a instantaneous fall away from a level. Loss of control entering a severe CB, I most certainly would.

Really need to know either, what they flew into, or what the engineering history is. Certainly whatever occurred, to drop like that, on the engineering front, Tail or Rear Stab something has gone wrong (or fell off as mentioned above).

krismiler

Hmm...if 15m of water, that is exactly half the fuselage length, so the wreckage would be buried deeply if the descent was as fast as it appears, making recovery a bit more difficult. But it’s been done successfully before....

Blocked Pitot-Static System?
 

Compare the FR24 data stream of accident flight with previous departure of PK-CLC and same track from RWY 25R(?) CGK two sectors back.

On accident flight, the FR24 Groundspeed readout is 20-40 knots slower during climb from 4000 to 8000 feet.
On accident flight, the FR24 Groundspeed readout "freezes" just above 280 knots climbing above about 10,000 feet instead of increasing as per previous departure CGK two sectors back.

Blocked Pitot-Static System is a possibility?

I'm not a pilot and I apologize for intruding in a professional pilot forum.
Just thinking "Occam's razor" ...
Could this be just a case of a botched stall recovery? We don't know what could have cause a stall (pilot's error, unreliable IAS reading due to obstructed pitot tube, weather). But then, the pilot didn't apply proper stall recovery technique, resulting in loss of both speed and altitude, and by the time he pushed the nose down to regain speed it was too late (not enough altitude) and basically flew the airplane into the water. This would be consistent with the GS and ALT plot, wouldn't it?