boeingboy wrote: ↑Mon Mar 21, 2022 7:35 pm
No dive recovery...the speed apparently decreased momentarily at 9000 feet and then climbed back - so maybe some reporter confused the 2 scales. It was probably a glitch in the data due to speed, decent, and terrain.
boeingboy wrote: ↑Mon Mar 21, 2022 7:35 pm
No dive recovery...the speed apparently decreased momentarily at 9000 feet and then climbed back - so maybe some reporter confused the 2 scales. It was probably a glitch in the data due to speed, decent, and terrain.
boeingboy wrote: ↑Mon Mar 21, 2022 7:35 pm
No dive recovery...the speed apparently decreased momentarily at 9000 feet and then climbed back - so maybe some reporter confused the 2 scales. It was probably a glitch in the data due to speed, decent, and terrain.
discussion of a climb comes from this plot of adsb data available at the dailymail.
29,000 to impact in 2 minutes is a significant vertical speed, have no idea how the overall airspeed looked.
Weird - looks much different than the flight radar data I linked...and the time and speed dont match either.
Like I said, all the data is a little spotty still. I believe that level off ( if true) more or less rules out aircraft structural failure as the initial cause
Itss reported as a -800 modle (which would rule out mcas issues)
the -800 has no history of any accident like this in it's almost 30 years of flying.
Also no reportable weather to speak of
So my mind now goes to intentional CFIT. Perhaps the brief level off was due to who ever was at the controls having a change of heart, but the subsequent level off lead to structural failure. Which, afterwards led to that crazy nose dive that was captured in the video above?
That's my best, any other crazy theories out there?
boeingboy wrote: ↑Mon Mar 21, 2022 9:06 pm
We will just have to wait for the recorder data....
Flightradar24 data below...
I think your misreading the graph, I had to take a second look at it aswell. At about 6:21 and 40 seconds, it starts to level off, and at 6:22 and 40 seconds it disappears. So from the level off to crash 1 minute passes. About 2 minutes for the whole incident
jpilot77 wrote: ↑Mon Mar 21, 2022 7:17 pm
The Alaska Air crash stopped the dive momentarily as well before diving again.
My understanding of that one, pulling up wasn't working so they tried to push to inverted, that sort of worked, then they ended up back into the vertical dive.
The adsb plot from dailymail has a similar set pof data points.
There's an initial "jump to the left" in the track, followed by a rough arc down and to the right. If the rudder had been kicked to one side, it could have rolled left and ended up in a counter-clockwise spiral dive that recovered down near 7000' and over Vne... The g-forces in the pull causing wing failure? Or maybe a rudder actuation caused the vertical stab to separate, and they lost it before they could get it stable with asymmetric thrust?
There's an initial "jump to the left" in the track, followed by a rough arc down and to the right. If the rudder had been kicked to one side, it could have rolled left and ended up in a counter-clockwise spiral dive that recovered down near 7000' and over Vne... The g-forces in the pull causing wing failure? Or maybe a rudder actuation caused the vertical stab to separate, and they lost it before they could get it stable with asymmetric thrust?
Could this be another accidental rudder trim activation instead of flight deck door unlock? It has happened before
Looking at the drone footage of the crash site, not sure there will be any recorder data.
Both Silk air 185 and PSA 1771 were put into vertical dives and exceeded the speed of sound before disintegrating on impact with the ground. The recorders were recovered in both cases.
PSA 1771 (BAE 146)...
Shutterstock_6571944b.jpg (316.6 KiB) Viewed 4020 times
I've seen a few posts on PPrune that suggest there are always 3 pilots in the flight deck of Chinese majors; can anybody confirm or deny this? If so, the Silkair/Germanwings cause strikes me as more unlikely.
Fingers crossed for good news about CVR/FDR memory soon.
Maritimer wrote: ↑Tue Mar 22, 2022 8:33 am
Could this be another accidental rudder trim activation instead of flight deck door unlock? It has happened before
I had never read or heard about that case. I've also never seen a 737 with that layout for the location of the rudder trim and door lock switch, but I'll certainly be aware of it. The 737 has lots of switches and knobs that look nearly identical. I've heard first hand of people accidentally turning the electric hydraulic pumps off by mistake instead of the engine anti ice, as well as turning the ignition switches on by mistake instead of the wind shield wipers. Neither of those cause control problems though.
co-joe wrote: ↑Tue Mar 22, 2022 9:39 pm
I've heard first hand of people accidentally turning the electric hydraulic pumps off by mistake instead of the engine anti ice
I had a FO do exactly this on the climb out on a 737-300.
The moment he moved the electric pump switch to off he immediately moved it back on. The power spike tripped the left generator and caused a loss of all EFIS displays on my side and tripped off the autopilot.
I had to transfer control to the FO and he had to fly manually while I sorted things out.
The left generator could not be re-connected - I finally needed to start the APU and connect that to the left side of the electrical system. After 10 minutes I was able to replace the APU with the left generator.
As stated earlier - no issues with flight controls - but a potential high workload situation requiring manual flight.
No idea if the 737-800 electrical architecture is the same.
The captain had accumulated 6,709 flight hours total, the first officer 31,769 flight hours, the second officer 556 hours, all of them in good family relations. The aircraft was in an airworthy condition, all maintenance had been done in strict compliance with regulations and requirements.
In a third press conference the CAAC reported although the black box is badly damaged, the storage unit looks intact and has been determined as the Cockpit Voice Recorder CVR. It has been sent to Beijing for download and decoding. The second officer was an observer to increase experience.
digits_ wrote: ↑Wed Mar 23, 2022 9:19 pm
Now the question becomes, who do we trust more to accurately report whatever is on the cvr: Boeing or China?
This is a very high profile incident. When the device is opened there will be reps from the Chinese regulator, the American regulator, and Boeing present. There will likely be reps from the engine manufacturer and the device manufacturer as well.
Mick G wrote: ↑Thu Mar 24, 2022 9:00 pm
Wonder if the pitot tube were blocked?
By what? They were reportedly at cruise in VMC conditions…
I’ve unfortunately had both of mine blocked after encountering unforcasted severe icing. It was an “affair” down low… I highly doubt that this crew made it this far along their flight profile with a blocked system without saying a damn thing. Speaking of which… no distress call, zip, nada, niet. It’s boggling my mind!
Mick G wrote: ↑Thu Mar 24, 2022 9:00 pm
Wonder if the pitot tube were blocked?
By what? They were reportedly at cruise in VMC conditions…
I’ve unfortunately had both of mine blocked after encountering unforcasted severe icing. It was an “affair” down low… I highly doubt that this crew made it this far along their flight profile with a blocked system without saying a damn thing. Speaking of which… no distress call, zip, nada, niet. It’s boggling my mind!
TPC
Yeah i know its unlikely, I'm just trying to rationalize what looks like an intentional act. If they were lower, one could surmise a similar incident like Atlas Air 3591 or pitot tube
The unfortunate reality of intentional acts are we end up with both cover-ups and blame. Egypt Air and Malaysian come to mind and it is important that the chain of evidence is maintained throughout. It would be more beneficial if a third party country is involved where it concerns both black boxes.
boeingboy wrote: ↑Wed Mar 23, 2022 9:14 pm
CVR has been found.
From Avherald...
The captain had accumulated 6,709 flight hours total, the first officer 31,769 flight hours, the second officer 556 hours, all of them in good family relations. The aircraft was in an airworthy condition, all maintenance had been done in strict compliance with regulations and requirements.
“All of them in good family relations” so I guess that rules out this being an intentional act…
Also, was the maintenance done in strict compliance with regulations and requirements with real or counterfeit parts?
Seems a little premature to be making either of those claims.
Haven't read through this thread yet(just the one on PPrune), but I think this article says it all for this accident and so many more......
Clamour for China Eastern crash theories is at odds with reality
By Lewis Harper24 March 2022
Few incidents prompt greater focus on the airline industry than a fatal crash.
Following the tragic loss of a China Eastern Airlines Boeing 737-800 on Monday, the scrutiny – informed or otherwise – has been intense, in general reporting and particularly on social media.
The internet is awash with theories regarding the cause of the crash, notably including those carelessly based on imagery from a computer reconstruction of an incident that happened 25 years earlier.
During such times, the commentators worth listening to tend to be those urging people to wait for further evidence to emerge.
So far, aside from flight-tracking data, the few fresh details released via official channels include acknowledgements of failed attempts by air traffic control to contact the aircraft as the incident occurred and of the damaged cockpit voice recorder being recovered.
One certainty is that in China’s huge aviation market, the incident marks the first fatal crash since 2010.
And within the wider context of airline safety, the crash has occurred in an industry that has a remarkable safety record, as was reflected in IATA’s recent summary of 2021 data.
None of that is, of course, any comfort to those who have lost loved ones this week.
As ever, commercial’s aviation licence to connect the world is contingent on it doing everything within its power to establish why catastrophic incidents have occurred, before acting promptly on any recommendations. The first part of that process may take some time.
As investigators continue their work, many commentators will already be tired of having to point out that the crash is unrelated to the safety issues with the 737 Max programme. The requirement to do so undeniably reflects that the latter programme and Boeing’s reputation are still very much in the public consciousness, even as hundreds of Max jets fly without fanfare in markets around the world.
On the latter point, it is not unreasonable to question whether this week’s crash might further extend the long wait for Max jets to fly again in China, on the grounds of optics alone.
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Last edited by pelmet on Fri Mar 25, 2022 9:25 pm, edited 1 time in total.
Circling back to that adsb data, have a question for those a bit more 'in the know' on how the avionics work on the -800. Is the altitude reported on that adsb track coming from a pressure source, or from a gps source ?
After putting a bunch of thought into it, I have realized a few ways the apparent 'climb' could show up as simply bad data. If it's coming from a pressure source, and speeds were such that shock waves have developed, then there will be abnormal areas of high pressure. A scenario then that can product that trace, even without an actual climb, with high pressure behind a shock wave affecting a static source, it'll show a much more rapid descent than what was actually happening. As the aircraft hits thicker air below, some deceleration, shock wave dissipates, pressure drops, which will register as a climb if the data comes from a static pressure source.
If the data comes from a civilian gps source, they have a top end speed limit coded in, above which they report garbage data. This is an intentional thing to ensure 'off the shelf' gps equipment cant be used for targetting missles etc. If the aircraft was really in a vertical dive and approaching transonic or even supersonic speeds, then the data from a civilian gps cannot be relied on to be accurate, and in fact if it's is erronously reporting altitudes incorrectly the system designers will tell you 'working as intended'.
If indeed the aircraft basically did a power on vertical descent from 29,000 feet as suggested, it's quite possible, and actually realistic, for that adsb trace to be a huge big red herring.
I watched a YouTube video and the claim was that the ADSb speed is GPS ground speed. Therefore, if the plane is almost vertical, the ground speed will be WAY lower than the actual AS.