Lion Air Boeing 737 Max crash investigation faults flight-control feature, regulatory lapses and pilot error


Lion Air Boeing 737 Max crash investigation faults flight-control feature, regulatory lapses and pilot error

The crash prompted Boeing to make changes to the 737 Max, the manufacturer said in a statement Friday as the report was released. The fixes included changing how the angle-of-attack sensors feed information to the cockpit and improving crew manuals and pilot training. 

“These software changes will prevent the flight control conditions that occurred in this accident from ever happening again,” Boeing said. 

 Lion Air Flight 610 crashed into the Java Sea on Oct. 29, shortly after taking off from Jakarta. All eight crew members and 181 passengers were killed.

The crash was soon tied to a new automated feature that Boeing had included on the 737 Max, a new version of its popular jet with larger, more fuel-efficient engines. Investigators say the feature was mistakenly triggered by faulty information from an external sensor.

On Friday, officials from Indonesia’s transportation safety regulator said nine factors worked together to doom the Lion Air jet. 

“These items were connected to each other. If one of them was not occurring on that day, the accident may not have happened,” said Nurcahyo Utomo, an investigator at the National Transportation Safety Committee.

Those factors included incorrect assumptions by Boeing about how pilots would respond to the new flight-control system, known as the Maneuvering Characteristics Augmentation System, or MCAS. Investigators highlighted how the MCAS design relied on a single sensor and was therefore vulnerable to errors.

“One [angle of attack] affected the whole system,” Nurcahyo said. A false reading on that sensor redirected the plane’s nose downward, leaving the cockpit crew unable to override the auto­pilot commands.

Other fatal mistakes included a lack of training for pilots in the new system, a lack of documentation about problems in previous Lion Air flights involving the same jet and ineffective coordination between flight crews. Investigators concluded that the plane should have been grounded after an earlier fault.

The report offered stark new details on the backstory of an external sensor involved in the crash, pointing at the role of a maintenance firm in Florida and oversight by U.S. regulators.

A dirty angle-of-attack sensor was sent to a Miramar-based company, Xtra Aerospace, for maintenance in 2017. It was then sent back and installed on the left side of the Lion Air flight the day before it plunged into the Java Sea, the report said.

Angle-of-attack sensors are supposed to give pilots, and airplane systems, reliable information to help understand how the aircraft’s nose is pointed in relation to oncoming wind.

But shortly after takeoff, the newly installed left sensor showed a reading that was different, by 21 degrees, from the one on the right. Investigators say that inaccurate reading caused Boeing’s automated feature to mistakenly fire, again and again, before the plane eventually crashed.

The “sensor was most likely improperly calibrated at Xtra Aerospace,” the Indonesian crash report said, noting that tests have been performed for the FAA and National Transportation Safety Board indicating that certain actions during the calibration process “could potentially introduce a bias” in parts of the sensor.

The report said Xtra should have had a written procedure regarding the part of the process that may have gone wrong. The lack of such a written procedure was not detected by a relevant FAA office, the report said, and “this indicates inadequacy of FAA oversight.”

The FAA said it issued an order revoking Xtra Aerospace’s repair station certificate Friday, saying the company had “failed to comply with requirements to repair only aircraft parts on its list of parts acceptable to the FAA that it was capable of repairing.” The FAA said it began investigating the company in November 2018, shortly after the Indonesia crash.

An Xtra employee in Florida referred questions to legal counsel at corporate parent Wencor Group, in Peachtree City, Ga. An employee at Wencor would not answer questions. A representative at an outside public relations firm said there would be “no comment at this time.”

The Indonesian report called for improved oversight by the FAA more broadly, and changes at Boeing as well as Lion Air. 

Indonesian investigators said their report was not aimed at pinpointing culpability but at ensuring passenger safety and preventing a similar accident. The report cannot be used for liability or compensation issues in court.

In a statement, Lion Air said it was essential to take “immediate corrective actions to ensure that an accident like this one never happens again.”

Charles Herrmann, a Seattle attorney representing the families of 46 Lion Air crash victims, said the crash anniversary and the release of the report are “a double wounding” for his clients.

“This is a devastating experience for these people,” Herrmann said. “It involves not only tremendous sorrow and grief. There’s a lot of anger.”

Since the crashes, Boeing’s decision to adopt MCAS and the FAA’s role in certifying the plane have come under intense scrutiny from the Justice Department, congressional investigators and lawyers representing the families of dozens of those who died.

Ahead of Friday’s release of the crash investigation report, a review by the NTSB found that Boeing underestimated the risk posed by MCAS and made bad assumptions about how pilots would respond to a barrage of alerts in the cockpit if something went wrong.

And an international group of aviation regulators and U.S. experts concluded that Boeing shared information with the FAA in a fragmented way, resulting in insufficient scrutiny of the new feature.

MCAS was designed to kick in when pilots were flying manually, repeatedly pushing the plane’s nose down if sensor data indicated that the aircraft was at risk of stalling. But the data that the system received in both the Lion Air and Ethio­pian Airlines flights was faulty, causing the feature to kick in repeatedly while the pilots struggled to regain control of the aircraft.

The protracted grounding of the Max has battered Boeing’s finances and its stock price. This week, the company reported that its revenue fell to $20 billion in the third quarter, down 21 percent from a year earlier. Profits were down 51 percent to $1.17 billion.

The company also announced the resignation this week of Kevin McAllister, head of the Boeing division that made the Max.

The company’s fortunes rest on it winning approval from aviation regulators in the United States and abroad for the Max to resume flights.

Boeing has redesigned the MCAS feature in a way that it says is safer, and the changes are being reviewed by aviation authorities. FAA officials say they have several more weeks’ work to do, and airlines have said they are keeping the Max off their schedules into January and February.

Boeing’s chief executive Dennis Muilenberg, who was stripped of his role as chairman of the company’s board this month, is scheduled to testify about the Max before Senate and House committees next week. Lawmakers are weighing whether there ought to be changes to an FAA program that turns over to industry much of the responsibility for certifying that safety standards are being met.

Lion Air is Indonesia’s largest budget airline, operating in a fast-growing industry across an archipelago where air travel is a necessity. But even before the crash a year ago, the country had a spotty safety record, and its carriers were banned from flying to the United States between 2007 and 2016.

The Max involved in the crash had entered service just months before. Lion Air was a major international customer for Boeing.

The pilot, 31-year-old Bhavye Suneja, was a native of India who had logged 6,000 flight hours. He was joined in the cockpit by a first officer who used only the single name Harvino and who had 5,000 hours of experience. 

Vini Wulandari, Harvino’s sister, said the investigation reinforced her family’s belief that her brother was not to blame for the crash, and she demanded that Boeing take more responsibility for the loss of life.

“From the beginning, I’m sure that Harvino was innocent because he had done everything according to procedure,” Vini said in an interview Friday. Her family is among those suing Boeing.

“Someone must be held responsible for what has happened,” she added.

Mahtani reported from Hong Kong and Duncan reported from Washington.


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