The proposed plan outlined Monday by the Federal Aviation Administration (FAA) setting the requirements for the Boeing 737 MAX return to service was formally published in the Federal Register Thursday, starting the clock on a 45-day public comment period that will last through Sept. 21.

That schedule means FAA clearance for the MAX to fly passengers again is unlikely before late October.

The safety agency must assess and respond to the comments, potentially making adjustments to the requirements, before making the plan final with an Airworthiness Directive that mandates changes to the airplane and the crew procedures.

The design changes the FAA proposes will fix the flaws in the new MAX flight control system — the Maneuvering Characteristics Augmentation System (MCAS) — that went wrong on two crashes in Indonesia and Ethiopia. The proposal also requires adding a warning light to tell pilots if a sensor that initiated the crashes is not working.

The FAA also is requiring fixes to another possible vulnerability by rerouting some wiring to ensure separation. And it requires changes to operation and maintenance procedures, including revised emergency checklists for pilots.

The plan does not require broader changes to the air data and crew alert systems in the 737, which safety engineer and Boeing whistleblower Curtis Ewbank criticized as outdated and dangerous in a June submission to the U.S. Senate.

Comments are likely to come in from many interested parties, including airlines, pilot unions, engineering experts, academics with expertise in human/machine interfaces and passenger rights advocates, as well as from representatives of the victims of the MAX crashes that killed 346 people.

Comments on the FAA proposal can be submitted by:

  • Online at the Federal eRulemaking Portal at
  • By fax: 202-493-2251.
  • By mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue S.E., Washington, D.C. 20590.
  • By hand delivery to the above address.