WASHINGTON — A faulty sensor on a Lion Air 737 Max that has been linked to the jetliner’s deadly crash last October and a harrowing ride the previous day was repaired in a U.S. aircraft maintenance facility before the tragedy, according to investigative documents.
The sensor was made by Rosemount Aerospace, of Minnesota, a subsidiary of United Technologies Corp., the parent company of Collins Aerospace, Cedar Rapids’ largest employer.
United Technologies declined to comment, citing the investigation.
Accident investigators in Indonesia, home of Lion Air, and the United States, where Boeing, the plane’s manufacturer, is based, have been examining the work that a Florida repair shop previously performed on the so-called angle-of-attack sensor, according to briefing documents prepared for Indonesia’s parliament.
Erroneous signals from that sensor triggered the repeated nose-down movements on the Oct. 29 flight that pilots struggled with until the jet plunged into the Java Sea, killing all 189 people aboard, according to a preliminary accident report by Indonesian investigators.
The Lion Air crash and a similar one about five months later involving an Ethiopian Airlines 737 Max together prompted the grounding of Boeing’s best-selling jet March 13 and touched off a global rebellion against U.S. aviation regulators. Investigators have focused on the sensor’s role in the two disasters.
Documents obtained by Bloomberg show the repair station XTRA Aerospace in Miramar, Fla., had worked on the sensor. It was later installed on the Lion Air plane on Oct. 28 in Bali, after pilots had reported problems with instruments displaying speed and altitude.
There’s no indication the Florida shop did maintenance on the Ethiopian jet’s device.
The Indonesian National Transportation Safety Committee is seeking data “from repair station in Florida” where the unit was worked on, the investigative agency said in a briefing to parliament last November and contained in a presentation.
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Nurcahyo Utomo, lead investigator at the Indonesia NTSC, said the U.S. National Transportation Safety Board was conducting a review of the work performed on the sensor, but hasn’t yet reported back on its findings.
The sensor involved in the crash wasn’t working from the time it was installed, according to the NTSC’s preliminary report on the accident.