(Oct 25): Indonesian investigators found scores of problems and missteps in connection with last year’s fatal Lion Air crash, ranging from design flaws in Boeing Co’s 737 Max airplane to certification failures by US regulators and pilot error.
In a much-anticipated report released Friday, the National Transportation Safety Committee listed its significant findings in connection with the disaster and recommendations to Boeing, Lion Air and aviation authorities in the US and Indonesia. A significant amount of the report centres on a flight-control feature called the Manoeuvring Characteristics Augmentation System, which has also been implicated in an Ethiopian Airlines crash in March.
The extent that investigators faulted Boeing may add pressure on regulators to intensify scrutiny of its best-selling plane, which has turned into one of its worst crises and undermined the credibility of the US aviation regulator. Boeing Chief Executive Officer Dennis Muilenburg, who was stripped of his role as chairman earlier this month, is due to face questions from lawmakers in Washington next week.
The 737 Max has been grounded since shortly after the crash in Ethiopia, costing Boeing US$9.2 billion ($12.5 billion) and weighing on the Chicago-based company’s outlook. While Boeing says it has made significant progress in returning the 737 Max to service, no date has been set.
The US Federal Aviation Administration said it welcomed the recommendations from the report and would carefully consider them in its review of the 737 Max. “The aircraft will return to service only after the FAA determines it is safe,” spokesperson Lynn Lunsford said in a statement.
Minutes after taking off for Pangkal Pinang on the morning of Oct 29, Lion Air Flight 610 nosedived into the Java Sea, killing all 189 people on board. It was the second-deadliest airline disaster in Indonesia’s aviation history, following a 1997 crash near Medan that killed 234 people.
During testing, Boeing determined that malfunctions involving MCAS weren’t deemed serious enough — hazardous or catastrophic failures — for a more rigorous analysis, which could have identified significant problems with its design, according to excerpts of the NTSC report seen earlier by Bloomberg. Boeing also erroneously assumed that flight crew would be able to correctly deal with malfunctions within three seconds, even though they were unaware of the existence of the flight-control system, it said.
“The flight crew should have been made aware of MCAS which would have provided them with awareness of the system and increase their chances of being able to mitigate the consequences,” the report said. “Flight crew training would have supported the recognition of abnormal situations and appropriate flight crew action.”
During simulator testing, Boeing never considered a scenario that occurred in the Lion Air flight, where the flight-control system kicked in multiple times, pushing down the plane and resulting in thresholds being crossed. The Lion Air crew reacted differently to what Boeing anticipated, according to the report.
Indonesian investigators also highlighted some problems in the certification process of the 737 Max, saying the aircraft manufacturer didn’t submit required documentation and the Federal Aviation Administration didn’t adequately oversee the overall design.
“The fundamentals of the Max was that an over-sized, over-powerful engine was loaded on an air-frame that really couldn’t take it,” said Mark Martin, founder of Dubai-based Martin Consulting LLC. “This is an inherent design flaw. The software update Boeing has proposed isn’t going to be acceptable to airlines, pilots and regulators across the world.”
Boeing will likely have to install a modification kit in every 737 Max – each costing as much as US$15 million – Martin said, adding that he doesn’t see the plane flying for another year. “That’s not really a lot of money, but it’s Boeing who has to pay for this.”
The NTSC presented a slideshow summarizing its findings to families of the Lion Air crash victims in Jakarta on Wednesday. It said the MCAS was too reliant on a single angle-of-attack sensor, making it vulnerable if the sensor malfunctioned. The investigation found that a replacement sensor installed on the doomed Lion Air plane wasn’t calibrated properly during the repair.
Missed Opportunity
The report said problems with flight-data readings were initially reported on an Oct 26 flight from Tianjin in China to the Indonesian city of Manado. An examination of the angle-of-attack sensor showed it became unreliable in cold temperatures. An engineer in Manado suggested the crew continue to Denpasar in Bali for repairs.
“This indicated that the aircraft was released with known possible recurring problem,” the report said.
On a flight from Denpasar the day before the crash, the crew on the 737 Max ignored malfunctioning indicators, according to the NTSC. It said the pilot was confident about continuing because the aircraft was controllable and the weather along the route was good. The decision to keep flying was “highly unusual” after getting warnings for an imminent stall, the report said.
Previous reports have shown that an off-duty pilot traveling in the cockpit of that flight helped disable the malfunctioning control system. The NTSC said Friday that the captain had asked for the deadheading flight crew’s assistance, and kept the fasten seat-belt sign on.
“These actions indicated that the captain was aware of the need to use all available resources to alleviate the matter to complete the flight to the destination,” it said.
The problems encountered weren’t properly detailed in the post-flight report, which was filed outside office hours and not processed until the following day, the NTSC said. “The incomplete report became a hazard as the known or suspected defects were not reported which might make the engineer unable to properly maintain the airworthiness of the aircraft.”
The Crash
The crew on the doomed flight, who might not have been aware of the previous problems, failed to complete checks on the aircraft due to distractions from the flight system, increasing their stress levels, the report said. They also didn’t declare an emergency or asked for special handling, which would have helped to reduce their workload.
There seemed to be a lack of communication among the flight crew, with the captain not explicitly saying how much difficulty he was experiencing controlling the aircraft, it said. “Most of the components of effective crew coordination were not achieved, resulting in failure to achieve the common goal of flying the aircraft safely.
Both Lion Air and Indonesian regulators objected to findings in a draft of the final report on the grounds that they received too much of the blame, people familiar with the matter said last month. One of the people said at the time that 25 of 41 lapses were directed toward the airline.
