China Eastern 737-800 MU5735 accident March 2022
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In mixed fleets it's alway important to know if a 700 is referred to as a hard wing or soft wing. Slang but effective differential especially for emergency descents. Learned that flying BBJ's where all airframes were wingletted.
Rob
Rob
IIRC, all the purpose built 737-700 BBJs had the 737-800 wing (for higher gross weight/more fuel for longer range). I suspect that's what would be the 'hard wing'. If someone converted a regular 737-700 into a BBJ, then it would still have the normal -700 wing.
Only half a speed-brake
The preliminary report is out, referenced here: 关于“3•21”东航MU5735航空器飞行事故调查初步报告的情况通报 (variflight.com)
To my understanding, it does not discuss any causes at the moment, only declares the established facts that were debated here in much detail.
useful online translators:
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Be vigilant, sometimes the negative "not" can go missing without a warning.
To my understanding, it does not discuss any causes at the moment, only declares the established facts that were debated here in much detail.
useful online translators:
百度翻译-200种语言互译、沟通全世界！ (baidu.com)
https://translate.google.com/
https://www.deepl.com/translator
https://www.bing.com/translator
Be vigilant, sometimes the negative "not" can go missing without a warning.
Last edited by FlightDetent; 20th Apr 2022 at 10:57.
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???3?21???MU5735??????????????????
Use Google Chrome to get a passable translation into English.
Most interesting parts
- The trailing edge of the right wingtip winglet was found approximately 12 kilometres from the main impact point. There were traces of fire in the forest vegetation at the scene of the accident. Major wreckage including horizontal stabilizer, vertical tail, rudder, left and right engines, left and right wings, fuselage parts, landing gear and cockpit parts were found at the scene
- the qualifications of the flight crew, cabin crew and maintenance release personnel meet the requirements; the airworthiness certificate of the aircraft in the accident is valid; There is no fault report and no fault reservation before the flight and short-term parking on the same day; there is no cargo declared as dangerous goods on the plane; the navigation and monitoring facilities and equipment along the route involved in this flight are not abnormal, and there is no dangerous weather forecast
-the radio communication and control command between the crew and the air traffic control department were not abnormal, and the last normal land-air call was at 14:16; the two recorders on the aircraft were severely damaged due to the impact, and the data restoration and analysis work is still in progress .
Use Google Chrome to get a passable translation into English.
Most interesting parts
- The trailing edge of the right wingtip winglet was found approximately 12 kilometres from the main impact point. There were traces of fire in the forest vegetation at the scene of the accident. Major wreckage including horizontal stabilizer, vertical tail, rudder, left and right engines, left and right wings, fuselage parts, landing gear and cockpit parts were found at the scene
- the qualifications of the flight crew, cabin crew and maintenance release personnel meet the requirements; the airworthiness certificate of the aircraft in the accident is valid; There is no fault report and no fault reservation before the flight and short-term parking on the same day; there is no cargo declared as dangerous goods on the plane; the navigation and monitoring facilities and equipment along the route involved in this flight are not abnormal, and there is no dangerous weather forecast
-the radio communication and control command between the crew and the air traffic control department were not abnormal, and the last normal land-air call was at 14:16; the two recorders on the aircraft were severely damaged due to the impact, and the data restoration and analysis work is still in progress .
"No anomalies before they left the cruising altitude". How about afterwards? And how about showing the FDR readings?
Only half a speed-brake
On 21 March 2022, Boeing 737-800 B-1791 of Eastern Airlines Yunnan Company Limited, on flight MU5735 from Kunming to Guangzhou, was cruising in the Guangzhou control area when it descended rapidly from a cruising altitude of 8,900m and eventually crashed near Mo Pai Village, Puanan Town, Wuzhou County, Guangxi Zhuang Autonomous Region. The aircraft disintegrated after hitting the ground, killing all 123 passengers and 9 crew members on board.
According to the Convention on International Civil Aviation, within 30 days of the date of the accident, the State organising the investigation is required to send a preliminary report to ICAO and the participating States, usually containing factual information currently available, excluding an analysis of the cause of the accident and conclusions. The preliminary report on the investigation of the MU5735 flight accident has been completed, which mainly includes information on the flight, crew, airworthiness and maintenance, wreckage distribution and other facts. The main facts are as follows.
The aircraft took off from Runway 21 of Kunming Changshui Airport at 13:16 BST, rose to a cruising altitude of 8900m at 13:27, entered the Guangzhou control area at 14:17 along the A599 route, and at 14:20:55 the Guangzhou regional control radar showed a "deviation from command altitude" warning. At 14:21:40, the radar last recorded the following information: standard pressure altitude 3380m, ground speed 1010km/h, heading 117 degrees. The radar signal then disappeared.
The accident site is located in a southeast to northwest trending valley near Mo Pai Village, Puanan Town, Wuzhou City, Guangxi Zhuang Autonomous Region. A puddle with an area of about 45 square metres and a depth of 2.7 metres was visible at the scene, which was determined to be the main impact point at 23°19′25.52″N, 111°06′44.30″E. Debris from the wreckage was found mainly on the surface and underground within a bearing of 0° to 150° from the impact site. The trailing edge of the right wingtiplet was found approximately 12km from the main impact point. There were signs of overfiring of the mountain vegetation at the accident site. Major wreckage was found at the site, including horizontal stabilisation surfaces, vertical tail, rudder, left and right engines, left and right wings, fuselage components, landing gear and cockpit interior parts. All wreckage was searched and collected from the scene and transferred to a dedicated warehouse for cleaning and identification, and placed in correspondence with the actual size and position of the aircraft to facilitate subsequent inspection and analysis.
After investigation, the qualifications of the flight crew, cabin crew and maintenance and release personnel on duty met the requirements; the airworthiness certificate of the aircraft involved in the accident was valid, the last A-check (31A) and the last C-check (3C) of the aircraft did not exceed the inspection time limit specified in the maintenance programme; no faults were reported before the flight and short stop and release on that day, and no faults were retained; there was no cargo declared as dangerous goods on board; the navigation and surveillance facilities and equipment along the route involved in the flight were not abnormal. There were no abnormalities in the navigation and surveillance facilities and equipment along the route involved in the flight, and no dangerous weather forecast; before deviating from the cruise altitude, there were no abnormalities in the radio communication and control command between the crew and the air traffic control department, and the last normal land-to-air call was made at 14:16; the two recorders on board were severely damaged due to the impact, and the data repair and analysis work is still in progress.
The technical investigation team will continue to carry out in-depth investigation work such as identification, classification and inspection of the wreckage, flight data analysis and necessary experimental verification in accordance with relevant procedures to scientifically and rigorously identify the cause of the accident.
Translated with www.DeepL.com/Translator (free version)
According to the Convention on International Civil Aviation, within 30 days of the date of the accident, the State organising the investigation is required to send a preliminary report to ICAO and the participating States, usually containing factual information currently available, excluding an analysis of the cause of the accident and conclusions. The preliminary report on the investigation of the MU5735 flight accident has been completed, which mainly includes information on the flight, crew, airworthiness and maintenance, wreckage distribution and other facts. The main facts are as follows.
The aircraft took off from Runway 21 of Kunming Changshui Airport at 13:16 BST, rose to a cruising altitude of 8900m at 13:27, entered the Guangzhou control area at 14:17 along the A599 route, and at 14:20:55 the Guangzhou regional control radar showed a "deviation from command altitude" warning. At 14:21:40, the radar last recorded the following information: standard pressure altitude 3380m, ground speed 1010km/h, heading 117 degrees. The radar signal then disappeared.
The accident site is located in a southeast to northwest trending valley near Mo Pai Village, Puanan Town, Wuzhou City, Guangxi Zhuang Autonomous Region. A puddle with an area of about 45 square metres and a depth of 2.7 metres was visible at the scene, which was determined to be the main impact point at 23°19′25.52″N, 111°06′44.30″E. Debris from the wreckage was found mainly on the surface and underground within a bearing of 0° to 150° from the impact site. The trailing edge of the right wingtiplet was found approximately 12km from the main impact point. There were signs of overfiring of the mountain vegetation at the accident site. Major wreckage was found at the site, including horizontal stabilisation surfaces, vertical tail, rudder, left and right engines, left and right wings, fuselage components, landing gear and cockpit interior parts. All wreckage was searched and collected from the scene and transferred to a dedicated warehouse for cleaning and identification, and placed in correspondence with the actual size and position of the aircraft to facilitate subsequent inspection and analysis.
After investigation, the qualifications of the flight crew, cabin crew and maintenance and release personnel on duty met the requirements; the airworthiness certificate of the aircraft involved in the accident was valid, the last A-check (31A) and the last C-check (3C) of the aircraft did not exceed the inspection time limit specified in the maintenance programme; no faults were reported before the flight and short stop and release on that day, and no faults were retained; there was no cargo declared as dangerous goods on board; the navigation and surveillance facilities and equipment along the route involved in the flight were not abnormal. There were no abnormalities in the navigation and surveillance facilities and equipment along the route involved in the flight, and no dangerous weather forecast; before deviating from the cruise altitude, there were no abnormalities in the radio communication and control command between the crew and the air traffic control department, and the last normal land-to-air call was made at 14:16; the two recorders on board were severely damaged due to the impact, and the data repair and analysis work is still in progress.
The technical investigation team will continue to carry out in-depth investigation work such as identification, classification and inspection of the wreckage, flight data analysis and necessary experimental verification in accordance with relevant procedures to scientifically and rigorously identify the cause of the accident.
Translated with www.DeepL.com/Translator (free version)
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Google translate version
On March 21, 2022, the Boeing 737-800 B-1791 of China Eastern Airlines Yunnan Co., Ltd. was carrying out the MU5735 Kunming-Guangzhou flight. When cruising in the Guangzhou control area, the cruising altitude of the self-route dropped rapidly from 8900 meters, and finally crashed in Guangxi Near Mocong Village, Conan Town, Teng County, Wuzhou City, Zhuang Autonomous Region. The plane disintegrated after hitting the ground, killing all 123 passengers and 9 crew members on board.
According to the provisions of the "Convention on International Civil Aviation", within 30 days from the date of the accident, the investigating organization country must send the investigation preliminary report to ICAO and participating countries. and conclusions. At present, the "3.21" China Eastern Airlines MU5735 Aircraft Flight Accident Investigation Preliminary Report has been completed, and the report mainly includes factual information such as flight history, crew and maintenance personnel, airworthiness maintenance, and wreckage distribution. The main situations are as follows:
The aircraft took off from Runway 21 of Kunming Changshui Airport at 13:16 Beijing time, rose to a cruising altitude of 8900 meters at 13:27, entered the Guangzhou control area along the A599 route at 14:17, and at 14:20:55 Guangzhou area control radar showed a "deviation" Command altitude" warning, the aircraft left the cruise altitude, the controller called the crew immediately, but received no reply. At 14:21:40, the last recorded aircraft information by the radar was: standard pressure altitude of 3380 meters, ground speed of 1010 km/h, and heading of 117 degrees. Subsequently, the radar signal disappeared.
The accident scene is located in a valley running from southeast to northwest near Mocong Village, Conan Town, Teng County, Wuzhou City, Guangxi Zhuang Autonomous Region. A puddle with an area of about 45 square meters and a depth of 2.7 meters can be seen at the scene, which is determined to be the main impact point, located at 23°19′25.52″ north latitude and 111°06′44.30″ east longitude. The debris of the aircraft wreckage was mainly found on the ground and underground in the azimuth range from 0° to 150° of the impact point. The trailing edge of the right wingtip winglet was found approximately 12 kilometers from the main impact point. There were traces of fire in the forest vegetation at the scene of the accident. Major wreckage including horizontal stabilizer, vertical tail, rudder, left and right engines, left and right wings, fuselage parts, landing gear and cockpit parts were found at the scene. After all the wreckage was searched and collected from the scene, it was uniformly transported to a special warehouse for cleaning and identification, and placed according to the actual size and position of the aircraft, which was convenient for subsequent inspection and analysis.
After investigation
1. The qualifications of the flight crew, cabin crew and maintenance and release personnel on duty meet the requirements;
2. The airworthiness certificate of the aircraft in the accident is valid, the last A inspection (31A) and the last C inspection (3C) of the aircraft did not exceed the inspection time limit specified in the maintenance plan, and there was no fault report before the flight and short-term parking on the same day, and no fault reservation;
3. There are no goods declared as dangerous goods on board;
4. There is no abnormality in the navigation and monitoring facilities and equipment along the route involved in this flight, and there is no dangerous weather forecast;
5. Before deviating from the cruising altitude, the radio communication and control command between the crew and the air traffic control department were not abnormal. The last normal land-air call was at 14:16; the two recorders on the aircraft were severely damaged due to the impact, and the data was restored and Analysis work is still in progress.
In the follow-up, the technical investigation team will continue to carry out in-depth investigations such as wreck identification, classification and inspection, flight data analysis, and necessary experimental verification in accordance with relevant procedures, and scientifically and rigorously identify the cause of the accident.
end of translation
—/—
So a factual preliminary report as might be expected according to SOP.
Pity if they don’t publish an English version, that would limit translation errors, as pointed out above. Every languages has its specific complexities and ordinary and technical language in cases like these add to that.
No early AD’s or other statements.
At this stage, as you would expect, using a 2D layout for reference.
Damage to the recorders appears more severe than expected. IIRC one was found on the surface and the other about 2 m deep, the ‘can’ memory containers seemed quite good but had folded edges at one side, so maybe water entered the cans.
According to the provisions of the "Convention on International Civil Aviation", within 30 days from the date of the accident, the investigating organization country must send the investigation preliminary report to ICAO and participating countries. and conclusions. At present, the "3.21" China Eastern Airlines MU5735 Aircraft Flight Accident Investigation Preliminary Report has been completed, and the report mainly includes factual information such as flight history, crew and maintenance personnel, airworthiness maintenance, and wreckage distribution. The main situations are as follows:
The aircraft took off from Runway 21 of Kunming Changshui Airport at 13:16 Beijing time, rose to a cruising altitude of 8900 meters at 13:27, entered the Guangzhou control area along the A599 route at 14:17, and at 14:20:55 Guangzhou area control radar showed a "deviation" Command altitude" warning, the aircraft left the cruise altitude, the controller called the crew immediately, but received no reply. At 14:21:40, the last recorded aircraft information by the radar was: standard pressure altitude of 3380 meters, ground speed of 1010 km/h, and heading of 117 degrees. Subsequently, the radar signal disappeared.
The accident scene is located in a valley running from southeast to northwest near Mocong Village, Conan Town, Teng County, Wuzhou City, Guangxi Zhuang Autonomous Region. A puddle with an area of about 45 square meters and a depth of 2.7 meters can be seen at the scene, which is determined to be the main impact point, located at 23°19′25.52″ north latitude and 111°06′44.30″ east longitude. The debris of the aircraft wreckage was mainly found on the ground and underground in the azimuth range from 0° to 150° of the impact point. The trailing edge of the right wingtip winglet was found approximately 12 kilometers from the main impact point. There were traces of fire in the forest vegetation at the scene of the accident. Major wreckage including horizontal stabilizer, vertical tail, rudder, left and right engines, left and right wings, fuselage parts, landing gear and cockpit parts were found at the scene. After all the wreckage was searched and collected from the scene, it was uniformly transported to a special warehouse for cleaning and identification, and placed according to the actual size and position of the aircraft, which was convenient for subsequent inspection and analysis.
After investigation
1. The qualifications of the flight crew, cabin crew and maintenance and release personnel on duty meet the requirements;
2. The airworthiness certificate of the aircraft in the accident is valid, the last A inspection (31A) and the last C inspection (3C) of the aircraft did not exceed the inspection time limit specified in the maintenance plan, and there was no fault report before the flight and short-term parking on the same day, and no fault reservation;
3. There are no goods declared as dangerous goods on board;
4. There is no abnormality in the navigation and monitoring facilities and equipment along the route involved in this flight, and there is no dangerous weather forecast;
5. Before deviating from the cruising altitude, the radio communication and control command between the crew and the air traffic control department were not abnormal. The last normal land-air call was at 14:16; the two recorders on the aircraft were severely damaged due to the impact, and the data was restored and Analysis work is still in progress.
In the follow-up, the technical investigation team will continue to carry out in-depth investigations such as wreck identification, classification and inspection, flight data analysis, and necessary experimental verification in accordance with relevant procedures, and scientifically and rigorously identify the cause of the accident.
end of translation
—/—
So a factual preliminary report as might be expected according to SOP.
Pity if they don’t publish an English version, that would limit translation errors, as pointed out above. Every languages has its specific complexities and ordinary and technical language in cases like these add to that.
No early AD’s or other statements.
At this stage, as you would expect, using a 2D layout for reference.
Damage to the recorders appears more severe than expected. IIRC one was found on the surface and the other about 2 m deep, the ‘can’ memory containers seemed quite good but had folded edges at one side, so maybe water entered the cans.
Last edited by A0283; 20th Apr 2022 at 10:47.
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Perhaps this is the only concrete information that the Chinese have so far, derived only from radar observations of the flight and the FDR and CVR have not been read (or able to be read) so far. Just speculation on my part.
I presume the issue must have been that the affected -800s were already built with the provisioned wing, while the -700s were the pre-modification unprovisioned wings. According to the winglet manufacturer 300 man-hours needed for a provisioned wing, 850-1200 for an unprovisioned wing.
The phrase "deviation command altitude" sounds like a reference to Selected Altitude - a parameter that is increasingly available to ATC in many (most?) parts of the world via Mode S/EHS, intended to allow controllers to pick up discrepancies between selected FL and cleared FL.
The phrase "deviation command altitude" sounds like a reference to Selected Altitude - a parameter that is increasingly available to ATC in many (most?) parts of the world via Mode S/EHS, intended to allow controllers to pick up discrepancies between selected FL and cleared FL.
Winglets are highly susceptible to flutter. A 737-800 at cruise is already near VNE. A pushover would quickly result in putting the winglets into the flutter zone and separation from the aircraft. Flutter is primarily a TAS issue and it doesn’t take much speed increase at altitude to exceed VNE. Most aircraft with retrofit winglets have their VNE reduced for this reason. With high altitude winds the distance is very plausible.
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A useful point and something that I get the impression is rarely understood (having had to intervene from the back seat as a passenger in a light twin when the pilot decided to do a descent at VNE into Phoenix with a 45C OAT).
China Daily Report 20 April 2022
Headline: "No abnormalities yet discovered..."
"According to information disclosed by the CAAC, the exterior of the flight recorder was seriously damaged and the storage units also had a certain degree of damage. But the device remained in relatively good shape.
"It takes time to decode the flight recorder. If the storage units were damaged, it may take longer. After decoding the device, it will provide strong evidence as to the cause of the accident," said Zhu Tao, head of aviation safety for the CAAC, at an earlier news conference."
"According to information disclosed by the CAAC, the exterior of the flight recorder was seriously damaged and the storage units also had a certain degree of damage. But the device remained in relatively good shape.
"It takes time to decode the flight recorder. If the storage units were damaged, it may take longer. After decoding the device, it will provide strong evidence as to the cause of the accident," said Zhu Tao, head of aviation safety for the CAAC, at an earlier news conference."
Winglets are highly susceptible to flutter. A 737-800 at cruise is already near VNE. A pushover would quickly result in putting the winglets into the flutter zone and separation from the aircraft. Flutter is primarily a TAS issue and it doesn’t take much speed increase at altitude to exceed VNE. Most aircraft with retrofit winglets have their VNE reduced for this reason. With high altitude winds the distance is very plausible.
AFAICS, there are not any obvious situations that come to mind that a winglet that would cause a flutter event within the normal envelope of the aircraft, assuming the structure did not have a history for structural damage and a poorly conducted repair...
Caveat: The effect of a winglet is well established as far as aeroelastic effects go. TBC was aware of the effect on the early wing structure as was APB, and the structure was amended to restore the boundary to a reasonable margin. The approved envelope was also amended (by memory, a while ago) and TBC had separately published a pretty good AERO article on the subject. The aircraft meets the certification requirements and the operational boundary was set as a result. There is no "safety" issue related to having winglets that are correctly designed and certified. That flutter likely occurred indicates that the envelope was either exceeded severely, or the structure had an issue that lowered the flutter boundary, which would be something like undetected damage or am inadequate repair of known damage.
Boeing AERO 17 BLENDED WINGLETS
Last edited by fdr; 23rd Apr 2022 at 02:32.
Apologies if this has already been cited, but Xinhua (the official Chinese State Press Agency) has put out a press release that I believe is an accurate and complete English-language version of the Mandarin-only Prelimary Report.
Press release - https://english.news.cn/20220420/b3e...4da45dc/c.html
Original Mandarin CAAC Prelim Report - http://www.caac.gov.cn/XXGK/XXGK/TZT...20_212895.html
Nothing added - but better than Google Translate, I think!
Press release - https://english.news.cn/20220420/b3e...4da45dc/c.html
Original Mandarin CAAC Prelim Report - http://www.caac.gov.cn/XXGK/XXGK/TZT...20_212895.html
Nothing added - but better than Google Translate, I think!
Apologies if this has already been cited, but Xinhua (the official Chinese State Press Agency) has put out a press release that I believe is an accurate and complete English-language version of the Mandarin-only Prelimary Report.
Press release - https://english.news.cn/20220420/b3e...4da45dc/c.html
Original Mandarin CAAC Prelim Report - ???3?21???MU5735??????????????????
Nothing added - but better than Google Translate, I think!
Press release - https://english.news.cn/20220420/b3e...4da45dc/c.html
Original Mandarin CAAC Prelim Report - ???3?21???MU5735??????????????????
Nothing added - but better than Google Translate, I think!
On AvHerald it is....
On Apr 20th 2022 the CAAC released a statement indicating, the preliminary report has been submitted to ICAO. The data restoration of the data of CVR and FDR is still in progress. The aircraft left assigned cruise altitude of 8900 meters at 14:20:55L. At 14:21:40L radar recorded the last position at 3380 meters altitude, speed over ground at 1010 kph at a heading of 117 degrees, the radar signal was lost at that point. The main wreckage was found in a puddle of 45 square meters and a depth of 2.7 meters at position N23.3238 E111.1123 and included horizontal stabilier, vertical tail, left and right engines, left and right wings, fuselage parts, cockpit parts as well as landing gear. Those recovered parts were transported to a warehouse for further analysis. Traces of fire were in the forest surrounding the crash site. The trailing edge of the right winglet was recovered about 12km from the main impact site. Flight and Cabin Crew qualification and certification was without flaw, the aircraft was airworthy with no deferred entries in the tech log, there was no hazardeous cargo on board. Ground based navigation facilities all operated normally, no dangerous weather was forecast for the area when the aircraft departed its cruising altitude. Radio communication with the aircraft was normal until 14:16L (the last radio communication).
Only half a speed-brake
Original Mandarin CAAC Prelim Report - ???3?21???MU5735??????????????????