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.