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China Eastern 737-800 MU5735 accident March 2022

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China Eastern 737-800 MU5735 accident March 2022

Old 22nd Apr 2022, 13:33
  #461 (permalink)  
 
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Originally Posted by FlightDetent
This looks the same as post 437. Which is a press release not the report itself, which is said to be 'sent to ICAO'.
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Apologies - it is indeed the press release concerning the report sent - as per regs - to ICAO. Though the prerss release does contain a summary of findings so far, there's no obligation for the Chinese to publish the actual submitted report, and ICAO can only do so if the submitting power asks.

It is a tad odd that the Madarin and English press release summaries of the report have some small but significant differences (which I had not spotted!). My sense of course would be that the Mandarin is the better version, and the AV Herald summary of the that report is (so far as I can tell) pretty accurate as to its contents. Either the "official" English version is simply slightly incorrect (which, even in China, is not unknown!) or we must await news of any significance in the differences.
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Old 22nd Apr 2022, 22:00
  #462 (permalink)  
 
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@gearlever - “Interesting, the horizontal stabiliser is not mentioned. On AvHerald it is....”

Finding the horizontal stabiliser was reported, first by journalists on-site and then by officials involved in the investigation, from early on and repeated since.
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Old 24th Apr 2022, 05:33
  #463 (permalink)  
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For the impact that occurred here, it is not surprising that the horizontal stab was identified in the wreckage. It will have less fragmentation than the forward parts of the aircraft. The wings would have substantial fragmentation, but inner span sections of the spar will be identifiable, The engine cores (shafts, gears, not necessarily aux cases) actuators, control, gear, flap drives etc, would be usually in identifiable components, the further back in the structure the less fragmentation of associated quadrants/cranks etc.

The presence of the stabilizer doesn't rule out some control issues, but it still remains a remote possibility for initiating events. Had parts of the stab been found 12km away it would be a point of interest, but absent that it is not indicative of cause. Even if found 12km away, the failure mode would be of significance, as would be the trajectory analysis of the part to determine when it would have separated. Controls are not indicating a factor as yet other than the obvious fact that the plane didn't get to its destination, so presumably, at some point, the flight path was not as desired, or not.
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Old 28th Apr 2022, 06:55
  #464 (permalink)  
 
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I don't know what was the cause of the accident. What I DO know is the Chineses already know the cause of the accident, for two reasons:

1.I flew 10 years in China until the pandemic came, and, I know that all airplanes in China continually download both CVR and FDR through out the flight and send it to the cloud. They then keep it for 3 month. So, the bulls..t that the "black boxes"are severely damaged is just an excuse to not spread the real causes of this accident.
I had a small incident during the taxi departing for an 8 hour flight. By the time I landed (8 hours afterwards) they already had both fdr and cvr data in hands.

2. IF they had any doubt it was a plane failure , they would never have put the 738 back in service again.



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Old 28th Apr 2022, 07:21
  #465 (permalink)  
 
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Originally Posted by A-3TWENTY
I know that all airplanes in China continually download both CVR and FDR through out the flight and send it to the cloud.
Assuming that's true, why don't all airlines/countries do that? It would avoid some of the recent situations where there was fear that a recorder might not be found following an accident.

Do all the Boeings and Airbuses flying in China have custom modifications that allow them to stream CVR/FDR data?
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Old 28th Apr 2022, 08:51
  #466 (permalink)  
 
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All this conspiracy about the Chinese release of the FDR/CVR findings when both are in Washington (have been for weeks) being analysed by the US. As for streamed CVR/FDR, yeah good one.... pretty good evidence that you may have no idea what FOQA /FDM or ACARS is.
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Old 28th Apr 2022, 09:53
  #467 (permalink)  

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Originally Posted by DaveReidUK
Assuming that's true, why don't all airlines/countries do that?
After the MAS disappearance which has become a bit of a 'landing on the moon' conspiracy event in E Asia, PRC implemented 4D/15 mandate.
4D is the position and 15 min s the maximum or target reporting latency. For the 737 class and above, sure all B-reg have it, national security matters. Airborne connectivity is not a problem, definitely not on widebodies.

QCVR is also a fact since around 2019 at the latest. During the various Safety Warfare Weeks (=bonus punishment periods) the culprits breaching sterile flight deck with chatter would be named and shamed with an internal memo, for instance.

Wireless QARs (LTE modems) have been the standard on Airbii for at least 10 years. The units I was familiar then with had 3 SIM card slots BTW.

The story above may have a more trivial explanation if the taxi mixup was in China. Viewed as a breach of an ATC command this lands the pilot in very hot water. It's not beyond imagination the report from ATC reached the company and the 8 hours of elapsed time was used to plan exactly what to do. After landing the standard LTE WQAR+CVR sent the data to the mothership and decision was reached swiftly, especially with a foreigner pilot to blame.. ATC supplying their audio inside the given time frame is also very feasible.


Having said that, linking the DMU to the SATCOM communication channel does only need technology that is presently available. Pulling larger data on request can also be done, on top of the regular 4D/15. Still, indicriminate streaming broadcast is not realistic, from my point of view. This comes back to the crash discussed, data is in the US and the rest ADS-B is public domain. Probably nothing in between.

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Last edited by FlightDetent; 28th Apr 2022 at 10:08.
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Old 28th Apr 2022, 17:06
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Originally Posted by FlightDetent
After the MAS disappearance which has become a bit of a 'landing on the moon' conspiracy event in E Asia, PRC implemented 4D/15 mandate.
4D is the position and 15 min s the maximum or target reporting latency. For the 737 class and above, sure all B-reg have it, national security matters. Airborne connectivity is not a problem, definitely not on widebodies.

QCVR is also a fact since around 2019 at the latest. During the various Safety Warfare Weeks (=bonus punishment periods) the culprits breaching sterile flight deck with chatter would be named and shamed with an internal memo, for instance.

Wireless QARs (LTE modems) have been the standard on Airbii for at least 10 years. The units I was familiar then with had 3 SIM card slots BTW.

The story above may have a more trivial explanation if the taxi mixup was in China. Viewed as a breach of an ATC command this lands the pilot in very hot water. It's not beyond imagination the report from ATC reached the company and the 8 hours of elapsed time was used to plan exactly what to do. After landing the standard LTE WQAR+CVR sent the data to the mothership and decision was reached swiftly, especially with a foreigner pilot to blame.. ATC supplying their audio inside the given time frame is also very feasible.


Having said that, linking the DMU to the SATCOM communication channel does only need technology that is presently available. Pulling larger data on request can also be done, on top of the regular 4D/15. Still, indicriminate streaming broadcast is not realistic, from my point of view. This comes back to the crash discussed, data is in the US and the rest ADS-B is public domain. Probably nothing in between.

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The incident I had was in Australia. Australia authorities called the company during the flight and when I landed in China 8 hours afterwards , the quality control already had the transcription of the CVR. THE DAY AFTER,I was there listening to my voice and the FO's. Just reminding that according to the manual, the CVR records the last 120 minutes. Not in China. In this case it was good, because thanks to that, I was considered not guilty


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Old 28th Apr 2022, 19:28
  #469 (permalink)  

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Thanks for the details, one piece of info actually is a bit of a surprise.

Not about technology though.
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Old 29th Apr 2022, 17:36
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I checked a couple local news sources, it seems that at least some Chinese airlines have started to use a system called "X-CVR", which can record up to 8000hrs of cockpit voice recordings with "quality higher than MP3".
It has also been suggested that the so-called X-CVR system supports downloading the recordings directly to USB drive, and can even transmit the recordings via 3G/4G wireless network automatically to specific servers.
Reports say Hainan Airlines has started to fit its 737 and A320 fleets with X-CVR as early as 2018. So it looks like such technology already exists in China, although it's unclear whether MU has started to fit their 737s with the system.
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Old 29th Apr 2022, 20:19
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Originally Posted by menphix
I checked a couple local news sources, it seems that at least some Chinese airlines have started to use a system called "X-CVR", which can record up to 8000hrs of cockpit voice recordings with "quality higher than MP3".
It has also been suggested that the so-called X-CVR system supports downloading the recordings directly to USB drive, and can even transmit the recordings via 3G/4G wireless network automatically to specific servers.
Reports say Hainan Airlines has started to fit its 737 and A320 fleets with X-CVR as early as 2018. So it looks like such technology already exists in China, although it's unclear whether MU has started to fit their 737s with the system.
We've already been told that all Chinese airlines are already continuously streaming FDR and CVR data - is that not the case ?
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Old 29th Apr 2022, 21:54
  #472 (permalink)  

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Originally Posted by DaveReidUK
We've already been told that all Chinese airlines are already continuously streaming FDR and CVR data - is that not the case ?
Regardless of once or twice, it is not the case. :-) And the anecdotal evidence has a technological explanation without broadcast streaming....
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Old 30th Apr 2022, 06:40
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Originally Posted by menphix
I
It has also been suggested that the so-called X-CVR system supports downloading the recordings directly to USB drive, and can even transmit the recordings via 3G/4G wireless network automatically to specific servers.
Mobile networks system are dimensioned and designed to provide maximum coverage and capacity on land, not in the air. The antenna are orientated at an angle downwards. (Not necessarily the physical antenna, that might be vertical, but it will transmit downward).

At a typical cruising altitude you won’t have any coverage. Even at much lower cruising altitudes, the coverage would be patchy and handovers (when you move from one cell to the next) can be troublesome. So I doubt 3G/4G or any G for that matter has the capability to provide continues streaming capabilities for planes. It doesn’t do so, when I fly my little single prop planes at much lower altitudes.

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Old 30th Apr 2022, 07:58
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just thinking …

If you record while airborne and store while airborne, then you could start to transfer that data from a position that puts you in reach of the ground station.

From the ground station you can then distribute it over higher volume networks.

That would make it possible to have data for analysis before the plane arrives at the gate.

So precise language is needed here … is it continuous any altitude air to ground streaming… or batch/burst when in reach…

the functionality is similar but the performance quite different… bandwidth and range …

the crash area is quite remote and rough by the way and even the SAR had Comms issues …
so even a working batch system would have had coverage issues,


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Old 30th Apr 2022, 08:39
  #475 (permalink)  
 
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Originally Posted by DaveReidUK
We've already been told that all Chinese airlines are already continuously streaming FDR and CVR data - is that not the case ?
Not streamed, but easily downloadable by 4G as soon as the aircraft is on the ground:
QACVR Solution-DONICA

It’s little wonder that China has a reputation as a ‘surveillance State’. 🙄

Perhaps in-flight 4G is also possible:
IN-FLIGHT BROADBAND REACHES NEW HIGHS WITH 4G SOLUTION FROM THALES

Last edited by BuzzBox; 30th Apr 2022 at 09:27. Reason: Added in-flight broadband
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Old 30th Apr 2022, 09:37
  #476 (permalink)  
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DONICA stuff : very interesting , especially this part :
helping to provide evidence for the safety investigation pilot evaluation and responsibility partition.
Totally against the spirit of ICAO incident investigations . and if I read correctly it goes far beyond 3 hours and the CB cannot be pulled on that one ..
I guess the video camera will be next..
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Old 30th Apr 2022, 09:50
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Originally Posted by ATC Watcher
Totally against the spirit of ICAO incident investigations . and if I read correctly it goes far beyond 3 hours and the CB cannot be pulled on that one ..
I guess the video camera will be next..
Absolutely. Too easily abused, especially in that country.

I wonder what their unions had to say about it. LOL 🤣
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Old 30th Apr 2022, 10:22
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If I, as slf, can us the free wifi on QANTAS flights to send text and much larger image files then why is it difficult to send CVR and FDR info back to base?
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Old 30th Apr 2022, 12:01
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Originally Posted by CBD3000
If I, as slf, can us the free wifi on QANTAS flights to send text and much larger image files then why is it difficult to send CVR and FDR info back to base?
I think there are two major reasons. First, there simply isn't enough bandwidth available using 'traditional' systems such as VHF datalink and SATCOM. CVRs and FDRs generate a huge volume of data and when you multiply that by the large number of aircraft that might be airborne in the same area at the same time, the available bandwidth isn't sufficient to reliably support data streaming. Second, is cost. Data streaming is expensive and nobody's been able to justify the extra cost on safety grounds. That said, technology is constantly changing and there will no doubt come a time when streaming of CVR and FDR becomes feasible. Mind you, international regulatory change normally take years so it will no doubt be a long time before data streaming becomes the 'norm'.
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Old 1st May 2022, 05:29
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XCVR technology long implemented in China Eastern. This XCVR with certain software, can detects words that are sensitive to managements.
I do not think the CAAC will review the information on the CVR. Face reason they would rather damage it and sent it back to boeing for the analysis.
They will come up with a story like unlawful interference rather what was speculated previously. Sorry for all. I know this is disappointing but this is how it works in china.
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