The US Federal Aviation Administration issued an "emergency airworthiness directive" warning that problems with the angle-of-attack sensor, which prevents the plane from stalling and diving, could cause pilots problems in controlling the aircraft and lead to "excessive nose-down attitude, significant altitude loss, and possible impact with the terrain".
A Lion Air plane clipped a pole as it taxied to the runway at Bengkulu airport on Sumatra island on Wednesday (Nov 7), causing its left wing to tear and forcing all passengers to disembark.
Representatives of 737 MAX operators, Singapore Airlines Ltd SIAL.SI offshoot SilkAir, Garuda Indonesia GIAA.JK and Canada's WestJet Ltd WJA.TO , said they had not yet received a bulletin from Boeing.
In the United States, Southwest Airlines now has 26 737 MAX planes in operation; American Airlines has 16.
However, it's unclear whether the warning is being issued because investigators have conclusively determined that a flight-monitoring system error was the cause of the crash. Moments earlier, the pilots radioed a request to return to Jakarta to land, but never turned back toward the airport, according to Indonesia's National Transportation Safety Committee and flight-track data.
Boeing said it is continuing to work with the Indonesian investigation into the October 29 crash.
But the preliminary result of the investigation will only be known at the end of November. He said a team had been deployed to examine the plane.
Meanwhile, authorities are still investigating what exactly happened during the Lion Air crash, which killed 189 passengers.
On Tuesday, Indonesian investigators found that the Lion Air flight had a malfunctioning air speed indicator for its last four flights and crucially, at the time of the crash.
"This is a tragedy, but (the safety bulletin) says absolutely nothing about the design of the plane and its major subsystems", TEAL Group aviation analyst Richard Aboulafia told Business Insider.
The airline said at the time that it had 61 "firm orders" for the planes.
The new details - gleaned from a recovered flight data recorder - come after the government said it was launching a "special audit" of the budget carrier's operations.
Indonesian officials said on Wednesday they would extend by three days the search for bodies.
A search for the cockpit voice recorder, the second so-called black box, remains underway.