U.S. aviation regulators plan to meet with airlines and pilot unions on Friday to discuss safety issues on Boeing Co.’s grounded 737 Max aircraft.

The meeting, which will include representatives of the three American carriers that fly the model, is part of the Federal Aviation Administration’s review of the plane’s safety, the agency said in a statement. The FAA is working with Boeing as it develops a software upgrade and proposes to increase the level of training that 737 Max pilots must receive.

“The purpose of this meeting is for the FAA to gather facts, information, and individual views to further understand their views as FAA decides what needs to be done before returning the aircraft to service,” the agency said in a statement.

The 737 Max was grounded March 13 after the second fatal crash in less than five months. The plane had a safety device that was automatically commanding a dive in both accidents as a result of a malfunction. The crashes off the coast of Indonesia and in Ethiopia killed a total of 346 people.

The FAA and Boeing face challenges as they attempt to restore confidence in the company’s best-selling aircraft with both the public and aviation regulators around the world, which were quicker to ground the plane.

“As part of the FAA’s overseeing the continuous operational safety of our nation’s aviation safety system, the agency continues to gather all available information and data in considering the return of the 737 Max to service,” the agency said.

Dennis Tajer, an American Airlines captain and spokesman for the Allied Pilots Association union, said he expects they’ll go over the history of the crashes, anticipated software changes and pilot training. The FAA will likely seek input and feedback on pilot training after the Max software changes are made, he said.

“We’re very pleased as an independent voice in this and stakeholders to be at the table versus pounding on the door,” Tajer said. “Consultation is the key word.”

He said the union will also ask about training for pilots at airlines based outside the U.S. even though FAA has no jurisdiction there. “Our advocacy for passenger safety does not stop at borders,” he said.

Representatives from United Airlines and Southwest Airlines Co., which also fly 737 Max aircraft, will also attend.

Boeing has been holding briefings of its own with 737 Max operators and regulators around the world, even as it works on a software upgrade for the Max and deals with the repercussions, Chief Executive Officer Dennis Muilenburg said Thursday in an address at the George W. Bush presidential center in Dallas.

“All of us feel the immense gravity of these event across our company, and these last few weeks have been the most heart-wrenching of my career,” said Muilenburg, who has spent his entire professional life at the Chicago-based planemaker.

Over the past two weeks, Boeing has conducted sessions in the United Kingdom, Singapore and China to brief them on the software update intended to safeguard against an anti-stall system linked to two fatal crashes doesn’t activating in flight. Pilots and leaders from 67 percent of Max operators have tried out the patch in flight simulators, Muilenburg said.

Meanwhile, its pilots have conducted 96 flights totaling 159 hours and 53 minutes in the air as the company works to convince regulators to certify the fix. Boeing intends to conduct additional test and production flights in the coming weeks, Muilenburg said.