9 problems led to Lion Air crash, report says
Investigators fault Boeing, maintenance, inadequate training
JAKARTA, Indonesia — AnIndonesian investigation found that a combination of design flaws by Boeing and inadequate pilot training and maintenance lapses by Lion Air doomed a Boeing 737 Max jet that plunged into the Java Sea a year ago, killing 189 people.
The final accident report released Friday said Lion Air Flight 610, fromIndonesia’s capital Jakarta to the nearby town of Pangkal Pinang off Sumatra island, crashed partly because the pilots were never told how to quickly respond to malfunctions of the Boeing jet’s automated flight- control system.
Investigators, however, indicated there was plenty of blame to go around. They said nine critical problems were responsible for the tragedy.
“If one of the nine hadn’t occurred, maybe the accident wouldn’t have happened,” chief investigator
Nurcahyo Utomo said at a news conference.
Budget carrier Lion Air’s jet vanished from radar after air traffic control was told the plane had altitude and air speed troubles. It plunged into the sea 13 minutes after takeoff Oct. 29, 2018.
Five months later, a similar malfunction caused a Max jet to crash inEthiopia, killing all 157 people on board.
That led to the grounding of all 737 Max jets and put Boeing under intense pressure to explain problems associated with the flightcontrol system, known as MCAS. The aircraft still has not resumed flying. Boeing officials say the company is nearly finished with changes to flight software and computers.
The troubles with the
Max jets have also raised questions about the safety certification process in the United States.
Indonesia’s National Transportation Safety Committee said the MCAS on the Lion Air flight relied on a single “angle of attack” sensor that gave erroneous information, triggering an automatic nose-down pitch of the plane.
“The investigation considered that the design and certification of this feature was inadequate,” according to a statement issued by the head of the committee, Soerjanto Tjahjono. “The aircraft flight manual and flight crew training did not include information about MCAS.”
The report released Friday outlined various missteps.
The aircraft, only in use for two months, began having problems a few days before it crashed. A new angle of attack sensor was installed while the aircraft was on the Indonesian island of Bali a day before the crash, but it had been miscalibrated during an earlier repair, leaving it 21 degrees out of alignment. The problemwas missed when itwas installed, and the investigators said they were unable to find out if the new sensor was properly tested.
Shortly after takeoff on a flight later that day from Bali to Jakarta, the airspeed and altitude warnings went off, activating the captain’s stick shaker and signaling an impending stall. The captain and co-pilot regained control of the aircraft by manually over riding the automated system with help from a third Lion Air pilot who was hitching a ride in the cockpit jump seat.
Instead of turning around, the plane continued to Jakarta and landed safely and the pilot did not report fully about the problems, including the activation of the stickshaker, thesummary said. This oversight kept maintenance crews from investigating, and the critical information was not shared with the pilots of the flight that crashed.
Investigators said the Indian captain and the Indonesian co-pilot were unaware of the entire situation because a warning function that should have told the pilots the two angle of attack sensors were out of sync was not installed on the aircraft.
“Let’s just say, that flight from Bali to Jakarta was very lucky,” said Indonesian aviation expert Gerry Soejatman, who says most of the blame for the crash should be placed on Boeing.
“HowBoeing could allow theMCASto rely on a single source of data and act upon that single source without cross checking the other angle of attack indicator is anyone’s guess,” he said.