Doomed Lion Air jet was ‘not airworthy’
Preliminary report on crash does not give cause
JAKARTA (Reuters) – A Lion Air jet that crashed into the sea off Indonesia last month was not in an airworthy condition on its second-tolast flight, when pilots experienced similar problems to those on its doomed last journey, investigators said on Wednesday.
Contact with the Boeing 737 MAX jet was lost 13 minutes after it took off on October 29 from the capital, Jakarta, while heading north to the tin-mining town of Pangkal Pinang.
In a preliminary report, Indonesia’s transport safety committee (KNKT) focused on the airline’s maintenance practices and pilot training and a Boeing anti-stall system, but did not provide a cause for the crash that killed all 189 people on board.
The report unveiled fresh details describing efforts by pilots to steady the jet as they reported a “flight control problem,” including the captain’s last words to air traffic control asking to be cleared to 5,000 feet.
On Wednesday evening, Lion Air CEO Edward Sirait rejected some media reports quoting KNKT that the airline’s Boeing 737 passenger jet that crashed was not airworthy since its second-last flight from Denpasar to Jakarta.
It had been cleared as airworthy by Lion Air engineers on that day, KNKT investigator Nurcahyo Utomo said earlier in the day.
“I think pilots can judge for themselves whether to continue,” said Lion Air Managing Director Daniel Putut, a former pilot.
Utomo, in contrast, pointed to multiple problems, including the “severe” issue of stall warnings, which occurred in tandem on the Bali-Jakarta flight that were enough for the KNKT to determine that the flight should not have continued.
Information retrieved from the flight data recorder showed that the “stick shaker” was vibrating the captain’s controls, and warned of a stall throughout most of the flight. The captain was using his controls to bring the plane’s nose up, but an automated anti-stall system was pushing it down.
Pilots who flew the same plane a day earlier had experienced a similar problem, en route from Denpasar, Bali to Jakarta, until they used switches to shut off the system and used manual controls to fly and stabilize the plane.
“The flight from Denpasar to Jakarta experienced stick shaker activation during the takeoff rotation and remained active throughout the flight,” the committee said. “This condition is considered un-airworthy” and the flight should have been “discontinued.”
The pilots of that flight reported problems to Lion Air’s maintenance team, which checked the jet and cleared it for take-off the next morning.
Former Boeing flight control engineer Peter Lemme said that the stick shaker activation was “very distracting and unnerving.”
“It’s not something you ever want to have happen as a pilot,” he said.
Utomo said the agency had not determined if the anti-stall system – which had not been explained to pilots – was a contributing factor.
“We still don’t know yet, if it contributed or not,” he said in response to a question. “It is too early to conclude.”
BOEING DREW attention in detail to a list of airline maintenance actions set out in the report but stopped short of blaming ground workers or pilots for the accident.
The manufacturer has said that procedures for preventing an anti-stall system, were already in place. Pilots of the penultimate flight had used that drill, but noted that it was unclear whether pilots of the doomed flight did so.
Boeing’s statement did not make any reference to a revised anti-stall system introduced on the 737 MAX, which US pilots and Indonesian investigators say were missing from the operating manual.
Boeing says the procedure for dealing with a so-called runaway stabilizer, under which anti-stall systems push the nose down even when the plane is not entering a stall or losing lift, had not changed between earlier versions of the 737 and the newly delivered 737 MAX.
Indonesia’s director general of aviation, Polana Pramesti, said the agency planned to require pilots in Indonesia to be trained on simulators for the MAX series.
Pramesti also said a new regulation was being planned to limit the risk of pilot fatigue occurring and should be issued in the “near future.”
A source at the US Federal Aviation Administration said a number of factors were likely to be cited as causes of the crash, including pilot training and maintenance.
It was still to be determined how much the plane design was faulted. The report provided new recommendations to Lion Air on safety on top of earlier recommendations about the flight manual that have already been implemented by Boeing.
Lion Air CEO Sirait said the airline would comply with KNKT’s recommendations. Authorities have downloaded data from the flight data recorder, but are still looking for the cockpit voice recorder (CVR).
Indonesia plans to bring a ship from Singapore, which will be able to help with the search.
Asked what was needed from the CVR, Utomo said: “A lot. Discussions between the left and right pilots were about what? What procedures did they carry out. Were there any strange noises?”
Without it, he said there would be “a lot of guessing.”