Boeing officially confirmed on Wednesday, November 7, that it has issued an Operations Manual Bulletin (OMB) directing operators of its Boeing 737 MAX airliners to existing flight-crew procedures for addressing circumstances where there is erroneous input from an angle of attack (AOA) sensor, the Interfax news agency reports.

The Bloomberg news agency reported earlier on Wednesday that erroneous readings from a flight-monitoring system could cause Boeing 737 MAX aircraft to abruptly nosedive.

The warning is based on preliminary findings from the crash of a Lion Air jetliner off the coast of Indonesia on October 29. According to a press release from Boeing, the Indonesian National Transportation Safety Committee, which is investigating the crash, has indicated that the Lion Air airliner experienced erroneous input from one of its AOA sensors.

The Lion Air airline’s Boeing 737 MAX-8 crashed into the sea off the west coast of the island of Java on October 29 with 189 people on board. Contact with the airliner was lost 13 minutes after its departure from the Jakarta airport. The airliner’s pilot requested and received permission to return to the airport shortly before loss of contact.

One of the airliner’s black boxes was recovered on November 1. It was reported on November 5 that the Lion Air airliner had a defective sensor.