Boeing 737 MAX airplanes are parked along the west side of Boeing Field in Seattle as the company awaits FAA approval for the jets to return to service.

Thursday brought more strong hints that Boeing and the Federal Aviation Administration are moving steadily toward ungrounding the 737 Max as soon as October.

The FAA said Thursday it’s inviting “a cross-section of line pilots from carriers that operate the aircraft around the world” to participate in simulator testing “as part of the overall testing and validating of new procedures on the Boeing 737 Max.”

And according to two sources with knowledge of the matter, the FAA’s Flight Standardization Board that determines U.S. pilot-training requirements aims to issue in early September new recommendations for exactly what Max pilot training is needed before U.S. airlines can fly passengers on the airplane again.

Meanwhile, Boeing gave suppliers a new 737 production schedule reflecting “timing assumptions for the 737 Max return to service plan.”

The updated schedule is aggressive. Assuming FAA clearance in October, Boeing plans to begin the ramp-up immediately, moving from the current 42 planes per month to the pre-crash production level of 52 jets per month by February and reach a new high of 57 jets per month by next summer.

The simulator sessions the FAA plans for line pilots will test new procedures related to Boeing’s the updated Maneuvering Characteristics Augmentation System (MCAS) flight control software, the original version of which went haywire in the two fatal Max crashes in Indonesia and Ethiopia and repeatedly pushed the nose of each jet down.

Because of a potential new computer glitch discovered in June, pilots may also run through separate procedures handling uncommanded nose-down movements unrelated to MCAS.

Boeing and FAA pilots have been testing the updated MCAS software for months. What’s significant is that the FAA is now inviting regular 737 Max line pilots to do the same.

The assumed response time of pilots to an emergency, whether due to MCAS or not, has been under scrutiny since the crash of the Ethiopian Airlines Max in March, when the pilots tried and failed to follow a standard recovery checklist.

FAA guidelines say that if an emergency arises on a plane flying by autopilot, the assumption is that a pilot will begin to respond within three seconds. If the plane is being flown manually, the assumption is one second. When FAA test pilots deliberately delayed their responses in a simulation in June, one of the pilots crashed the plane.

The safety agency said the line pilots now being invited to the new simulator tests will be pilots with “previous experience at the controls of the Boeing 737 Max.”

“A firm schedule for these tests has not been set, although they must be completed before the aircraft is approved for return to service,” the FAA said in a statement.

Those simulator sessions are designed to validate the safety of the Max with a regular pilot at the controls.

Dennis Tajer, an American Airlines captain and spokesman for the Allied Pilots Association union, said that “anything that gets the average line pilot in to test that system — not the top test pilot at Boeing but an average 737 pilot — that’s realistic analysis and we’re encouraged to hear that.”

At the same time, the FAA’s Flight Standardization Board (FSB) is preparing to issue new guidelines early next month for the training that all U.S. airline pilots must receive before flying the Max again.

The report by FAA’s Flight Standardization Board coming in September will have a comment period no longer than 30 days to gather input from the airlines and pilots before it’s finalized and made mandatory. This timeline meshes with Boeing’s publicly stated hope to get the Max flying again commercially “in the early fourth quarter.”

Even if the FAA doesn’t mandate simulator training before the Max returns to flight, there’s no guarantee for Boeing that some overseas regulators won’t come up with different requirements. But most foreign safety agencies seem likely to follow the FAA’s lead.

Separately, Boeing said Thursday that, contingent upon FAA clearance, it has come up with a new 737 Max production schedule that can meet the target set by Boeing Chief Executive Dennis Muilenburg in July: ramping up to a new production level before the end of 2020.

Boeing said the production plan, which has been communicated to suppliers, “assumes a gradual increase in the 737 production rate from the current 42 per month to 57 per month in 2020.”

The Seattle Times