Weeks after a Lion Air jet crashed in the Java Sea, killing all 189 aboard, an airline employee gave investigators photographs meant to show that a crucial repair had been properly performed the day before the disaster.
Yet the photos may not show what was claimed.
The time displayed in photos of a computer screen in the cockpit of the Boeing 737 MAX indicated they actually had been taken before the repair was performed, according to a draft of the final crash report being prepared by Indonesia’s National Transportation Safety Committee (NTSC), portions of which were reviewed by Bloomberg News.
Investigators were similarly unable to confirm the authenticity of other photos in the packet, which were supposed to show how a piece of equipment near the jet’s nose had been calibrated, according to the report. There were indications that the pictures depicted a different plane, according to two people familiar with the investigation.
The draft report doesn’t say whether anyone falsified or misrepresented the photos — which would be considered a serious breach of protocol — but concludes that they may not be valid evidence.
The incident injected additional tension into the already fraught international investigation in which billions of dollars and the reputations of airlines, manufacturers and entire nations are on the line.
According to one person briefed on the matter, the Indonesia-based airline has told investigators that the allegations about the photos are unsubstantiated and shouldn’t be mentioned in the final report of the October 2018 crash. But to others involved in one of the most significant accident probes in decades, it could represent an attempt to mislead investigators about a critical aspect of the case and needs to be documented, said two other people who were briefed about the existence of the photos.
Lion Air spokesman Danang Prihantoro said that he could not comment on the investigation. Representatives of the U.S. Federal Aviation Administration, Boeing and National Transportation Safety Board (NTSB) declined to comment on the existence of the photos.
Indonesia’s NTSC, which is overseeing the investigation, is finalizing the report and expects to release it by early November. Anggo Anurogo, a spokesman for the investigation agency, said it wouldn’t comment on the report before its release.
Portions of the draft reviewed by Bloomberg News say an engineer gave the photos to investigators to show that the replacement of a sensor on the plane on Oct. 28 had been done properly. The sensor, known as an “angle-of-attack” vane, was malfunctioning on the very next flight as well as the one the next day that crashed and is at the heart of the investigation, according to an NTSC preliminary report released last November.
Some of the images were taken of the inside of an equipment compartment where the faulty sensor was attached, according to the people familiar with the investigation. Part of the calibration process occurs in that location.
Visible in the background of these photos was other equipment with identification marks, the people said. Officials at Boeing were able to trace at least one of the devices to a different 737 MAX jet operated by Lion Air, they said.
Other photos were shot in a 737 MAX cockpit, where mechanics check to see that the sensor is providing accurate readings, the people said. Those photos showed the captain’s flight display, but the time shown on its digital clock was before the repair being performed, according to the draft report.
Lion Air, which already was pushing back on preliminary conclusions by investigators, has challenged assertions that the photos were falsified and asked the NTSC not to include the pictures and any reference to them in its final report, according to one person familiar with the airline’s view of the matter.
The airline further said the photos didn’t come from the carrier, the person said. The pictures were blurry, and the airline couldn’t understand how equipment markings could have been identified, the person said.
Investigative reports of crashes often contain hundreds of pages and document evidence collected and significant issues faced during the probe.
The repair depicted by the photos is central to the investigation. A malfunction of the angle-of-attack sensor is believed to have triggered an automated system on the plane to repeatedly force its nose down, eventually causing the pilots to lose control and crash at high speed into the ocean.
Documents reviewed by Bloomberg News show the repair station XTRA Aerospace in Miramar, Florida, had worked on the sensor. It was installed on the Lion Air plane on Oct. 28 in Denpasar, Indonesia, after pilots on earlier flights had reported problems with instruments displaying speed and altitude. XTRA has said it is cooperating with the investigation.
For months, examinations of the Lion Air crash and the second, similar accident March 10 of a 737 MAX operated by Ethiopian Airlines have focused on the angle-of-attack sensors and their role in the functioning of a feature built into the jet known as Maneuvering Characteristics Augmentation System.
MCAS, designed to keep the nose of the plane from drifting too far up in flight, was fed data from one of the plane’s two angle-of-attack sensors, devices that protrude from the jet’s nose and resemble a weather vane.
When it senses the nose has risen too far, it automatically pushes it back down, reducing the risk of an aerodynamic stall. Investigators believe a malfunction of the sensor on board the Lion Air flight mistakenly forced the nose of the plane down repeatedly until the pilots lost control.
The same failure occurred Oct. 28 immediately after the repair on the Lion Air jet, but pilots on that flight were able to recover and fly to their destination. Not so on the final flight of the jet, when the pilots began fighting for control shortly after takeoff.
The plane hit the water in a high-speed dive, shattering into pieces. While investigators haven’t said whether they’ve recovered the angle-of-attack sensor from the bottom of the sea, the plane’s black-box flight recorder was brought up and confirmed the sensor was malfunctioning.
The crash, and the Ethiopian Airlines disaster months later, prompted a worldwide grounding of Boeing’s best-selling jet, leading to billions of dollars in losses and international investigations into how the system was designed and approved.
The mechanic who worked on the Lion Air jet before the crash reported the new device was installed according to the maintenance procedure, the November 2018 preliminary report said.
“Installation test and heater system test result good,” said an entry in the plane’s maintenance log included in the report. The mechanic also told a pilot about to fly the plane that the sensor “had been tested accordingly,” the report said.
However, data in the report suggest the calibration wasn’t done properly or at all, said John Goglia, a former airline mechanic who used to serve on the NTSB.
Such processes are routine and relatively simple, Goglia said. The procedure is designed as a fail-safe to ensure that a mechanic can quickly determine whether a newly installed sensor isn’t working.
“They were given an unairworthy airplane because the maintenance was incomplete and didn’t correct the problem,” he said.