Boeing 737 Max Recertification Testing - Finally.

[Dave Therhino]

To elaborate on what Wrench1 wrote, the law in the US driving this is the Administrative Procedures Act, which requires public notice and opportunity for comment, and requires agencies to address comments received, for all changes to regulations unless there is an emergency as defined in the Act. That includes airworthiness directives issued under 14 CFR part 39. The airplanes are grounded, so there is no emergency from a safety standpoint.

There also is a requirement in the FAA authorization statute for any emergency orders by the FAA Administrator to be followed by a public proceeding as defined in the law, which was not done after the grounding order. The FAA theoretically can't simply rescind or revise the order at this point without holding such a proceeding or they'd be violating that law.

Failure to follow either of these requirements in this case seems likely to invite court challenges by various parties, so I suspect the FAA is going to be careful to follow the law. This is a situation where trying to skip steps may cause additional delay versus following the required steps.

Whenever an AD requires a change in design to be incorporated, both the certification procedures of 14 CFR part 21 (which requires evaluation of compliance with airworthiness standards) and the regulatory promulgation process requirements of 14 CFR part 39 and the Administratve Procedures Act are required to be followed. Normally this is done sequentially, but it can be done in parallel or even in reverse (resulting in ADs that say "fix in a manner acceptable to the FAA"). The design changes to address the issues with the Max are apparently in the late stages of the certification process. It sounds like the FAA's plan is that, once the design changes are approved, the AD process will begin with issuance of an NPRM. The process for promulgating an AD when public notice and opportunity for comment prior to the final rule are provided typically takes at least six months. There are likely to be many comments, so I doubt the process will be faster than that in this case.