Thai Airlines Urged to Conduct Inspection of Boeing 737-800

[aussiexpat]

2 hours ago, TropicalGuy said:

Defect or Characteristic ? Boeing and/ or Airlines ? Will research findings made by the US Safety Board ……

Actually it was a significant engineering design error. In simple terms, they fitted new larger engines to the existing airframe and to avoid hitting the ground they had to move the engines forward and higher on the wing. This changed the critical flight characteristics of the aircraft so new software (infamous MCAS) had to be added to make it handle like the existing 737 (nose would pitch up suddenly so software drove the nose down). Unfortunately this software was controlled by only one sensor, so when it failed, nose pitched down.

 

All critical aircraft systems have multiple redundancy, so if one fails you have at least two back-ups. Boeing decided one sensor for MCAS was enough....

[Moonlover]

On 3/26/2022 at 11:23 AM, OccamsRazor said:

The flaw in that is it plummeted from around 30k then leveled off around 7k feet then plummeted again.  If no tail it would never been able to level off.  If suicide, the leveling off could be the other pilot trying to wrestle control back from the pilot.  But of course this is totally conjecture.  ????

There was a very similar occurrence in 1999 when an Egyptair 767 plunged into the north Atlantic. It too went  into steep dive and then briefly pulled out of it again. The NTSB and the FBI established that there had been a tussle between two of the crew members wrestling for control.

 

Egyptair Flight 990 1999

[Isaan sailor]

On 4/1/2022 at 2:54 PM, aussiexpat said:

Actually it was a significant engineering design error. In simple terms, they fitted new larger engines to the existing airframe and to avoid hitting the ground they had to move the engines forward and higher on the wing. This changed the critical flight characteristics of the aircraft so new software (infamous MCAS) had to be added to make it handle like the existing 737 (nose would pitch up suddenly so software drove the nose down). Unfortunately this software was controlled by only one sensor, so when it failed, nose pitched down.

 

All critical aircraft systems have multiple redundancy, so if one fails you have at least two back-ups. Boeing decided one sensor for MCAS was enough....

A good analysis of 737Maxx.  But this accident involved the 737-800, a very different and very safe plane.

[aussiexpat]

10 hours ago, Isaan sailor said:

A good analysis of 737Maxx.  But this accident involved the 737-800, a very different and very safe plane.

Yep, I defended the safety record of the B737-800 earlier in the thread. Was just answering a question on the Max

[aussiexpat]

China Eastern B737-800's back flying again so I assume the FDR showed no technical issues?

 

https://www.channelnewsasia.com/asia/china-eastern-resumes-boeing-flights-crash-2630381

 

[jacko45k]

7 hours ago, aussiexpat said:

China Eastern B737-800's back flying again so I assume the FDR showed no technical issues?

 

https://www.channelnewsasia.com/asia/china-eastern-resumes-boeing-flights-crash-2630381

 

Any other news as to why the other one nose-dived? I always fear the truth will be held back in these cases. 

[stratocaster]

The primary inquiry to Malaysian 737-800 losing altitude was due to an incorrect airspeed signal received by the auto pilot which disengaged. The plane lost approximately 2000 feet before the pilots took control. The plane losing 7000 feet/min was an account from a passenger. The crew did a controlled descent to, I think, 13000 feet and returned to KL flying the plane manually. The aircraft was flying through heavy turbulence at the time of the incident so a frozen up pitot static tube is suspected. Because Boeing don't want to re certify the cockpit of 737 the plane is one of the few aircraft flying where the the heat for the pitot must be manually turned on by a switch not done automatically.

[aussiexpat]

Chinese Preliminary report is out

 

https://yenei.variflight.com/club/item/?id=3xcsz6lzz6xKddd256026b

 

Using Google translate, only thing of interest seems the right wing tip Winglet was found 12km from the crash site ( so rest of plane intact at impact). No black box data yet.

 

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. 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 plane 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 the Guangzhou area control radar appeared "deviation" at 14:20:55. 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 was 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. Main 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 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.

 

Edited April 20, 2022 by aussiexpat

[aussiexpat]

It took a long time, but....

 

Chinese plane crash that killed 132 people in March 'was caused intentionally by someone in the cockpit', data from the black boxes suggests

https://www.dailymail.co.uk/news/article-10826335/Chinese-plane-crash-caused-intentionally-cockpit-black-box-suggests.html