Teams from the three US airlines operating 737 MAX jetliners headed to Boeing’s factory in Renton, Washington, to review a software upgrade, even as Southwest Airlines Co began taking its 34 MAXs out of service.

The factory visits indicate Boeing may be nearing completion of a planned software patch for its newest 737 following a Lion Air crash that killed 189 people in Indonesia last October, but the timing for a resumption of passenger flights on the jets remains uncertain.

Boeing and the US Federal Aviation Administration, which must approve the software fix and new training, are under US and global scrutiny since the MAX suffered a second deadly crash involving Ethiopian Airlines in Addis Ababa on March 10, which led to a worldwide grounding of the fleet.

FAA acting administrator Dan Elwell told lawmakers last week the agency expected Boeing would complete the software upgrade in a matter of days, kicking off the official approval process.

There were survivors to be pulled from the sea when the Lion Air fell out of the sky in October. Photo: AP

It remained unclear if the software upgrade, called “design changes” by the FAA, will resolve concerns that result from the ongoing investigation into the Ethiopian Airlines crash, which killed all 157 on board.

The FAA’s aviation safety chief, Ali Bahrami, briefed lawmakers on Friday about the latest information from the investigation.

The Allied Pilots Association, which represents American Airlines pilots, said it has been in talks with Boeing, the FAA and airlines to get the planes flying again as soon as possible, albeit with an acceptable level of safety.

“Right now we’re in wait-and-see mode to see what Boeing comes up with,” Captain Jason Goldberg, a spokesman for APA, said on Saturday.

“We’re hopeful, but at the same time the process can’t be rushed.”
Boeing said on Saturday it was continuing to schedule meetings with all 737 MAX operators.

APA is among a delegation of airline safety experts and pilots set to test Boeing’s software upgrade, meant to change how much authority is given to a new anti-stall system developed for the 737 MAX.

Meanwhile, Southwest said it was starting to move its entire MAX fleet to a facility in Victorville, California, at the southwestern edge of the Mojave Desert, to wait out the global grounding.

-AAP