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Accident Investigation Bureau embarks on second phase of crash investigation
Amdye Ayalew (Col.)

Accident Investigation Bureau embarks on second phase of crash investigation

To hire aviation consultants

The Ethiopian Accident Investigation Bureau (AIB) has embarked on the second phase of the accident investigation on the Ethiopian Airlines Boeing B737-8MAX jetliner that crashed on March 10 few minutes after takeoff.

After revealing the preliminary accident investigation report on the doomed flight number ET302 on April 4 AIB investigators have embarked on the second phase of the investigation which requires an in-depth scientific analysis. An official close to the investigation process told The Reporter that the exhaustive investigation process has already began this week. The official said an in-depth scientific analysis would be conducted on the Digital Flight Data Recorder (DFDR). “The flight data recordings would be put in a flight simulator and investigators would securitize how the aircraft behaved with the flight inputs,” he said.

“There are more than 1,600 signals that would be tested in a laboratory and flight simulator. All the inputs made by the cockpit crew would be reviewed. The recordings of the Cockpit Voice Recorder (CVR) would also be reviewed. Thousands of flight data would be analyzed,” he said.

All these scientific analysis require a special aviation accident investigation skill. Sources told The Reporter that Ethiopian aviation authorities would require foreign aviation expertise to undertake the sophisticated task. Sources said officials of the Ministry of Transport, AIB and the Ethiopian Civil Aviation Authority (ECAA) would soon sit down and discuss on the recruitment of aviation consultants. “We may invite investigators from the French BEA, the European Aviation Safety Agency (EASA) or other independent aviation agency. We may even seek assistance from Boeing,” sources said.

A senior official of the ECAA told The Reporter that the main part of the investigation process has been completed. “The aircraft manufacturer should adequately address the flight safety concerns. They should rectify the problem with the B737 MAX aircraft flight control system. They also have to work further on the flight safety manuals and pilot training programs to prevent another air disaster,” he said.

Speaking of the second phase of the accident investigation process Amdye Ayalew (Col.), chief investigator of the AIB, said that piles of documents collected from Ethiopian Airlines and the Ethiopian Civil Aviation Authority would be assessed. Amdye said all the documents related to the aircraft and the cockpit crew would be reviewed. Interviews with executives of the airlines, family members and friends of the deceased pilots will be conducted. “Data retrieved from the DFDR will be analyzed with various parameters,” Amdeye said.

The preliminary report indicated that the pilots of Ethiopian Airlines crashed B737-8MAX aircraft have applied all the emergency proceedings recommended by Boeing. The report stated that the pilots encountered problem with the flight control system. The report shows that the Angle of Attack sensor was feeding erroneous data. According the preliminary findings, though the pilots performed prescribed checklist to regain control of the aircraft they were unable to control the aircraft due to repetitive un-commanded nose dives.

“Shortly after takeoff, the Angle of Attack Sensor recorded value became erroneous and the left stick shaker activated and remained active until near end of the flight,” the report said.    

Quoting unnamed sources some international media institutions have reported that the Angle of Attack Sensor of the crashed Ethiopian Airlines B737-8MAX jetliner had been wrecked by a bird strike or another foreign object during takeoff.

The AIB dismisses the news reports. Amdye told The Reporter that all the aircraft system was sound and functioning properly until takeoff. “Shortly after takeoff the AOA sensor began feeding erroneous data. We do not yet know what caused the malfunction of the AOA sensor. We collected tons of data but none indicates that there was a bird strike or damage caused by any other foreign object,” he said.

Sources close to the investigation process told The Reporter that though there was no indication that the AOA sensor was wrecked so far the AIB will analyses various data to determine the cause for the malfunctioning of the AOA sensor. “The AOA sensor is found here. They did not take it. They did not inspect it. They are speculating on a matter that they did not conduct scientific investigation,” they said.

The report identified clear similarities between the Ethiopian B737-8 MAX plane crash and the fatal air accident that occurred in Indonesia in October 2018. Lion Air B737-8 MAX jetliner that dived into Java Sea 12 minutes after takeoff from Jakarta International Airport claimed 189 lives.  

Following the release of AIB’s preliminary accident investigation report the US aircraft manufacturer, Boeing, has conceded to the faulty flight control system dubbed Maneuvering Characteristics Augmentation System (MCAS).

Boeing’s CEO, Dennis Muilenburg commented: “The full details of what happened in the two accidents will be issued by the government authorities in the final reports, but, with the release of the preliminary report of the Ethiopian Airlines Flight 302 accident investigation, it’s apparent that in both flights the Maneuvering Characteristics Augmentation System, known as MCAS, activated in response to erroneous angle of attack information.”

He added, “It’s our responsibility to eliminate this risk. We own it and we know how to do it”.   

AIB’s report forwarded safety recommendations. “Since repetitive un-commanded aircraft nose down conditions are noticed in this preliminary investigation, it is recommended that the aircraft flight control system related to flight controllability shall be reviewed by the manufacturer. Aviation authorities shall verify that the review of the aircraft flight control system related to flight controllability has been adequately addressed by the manufacturer before the release of the aircraft to operations.”