WASHINGTON – Boeing is getting new questions from United States aviation regulators about the Max 7 aircraft, making it more likely the company will be unable to complete the certification process by late December and have to undertake a costly redesign. 

In an Oct 12 letter, the Federal Aviation Administration (FAA) ordered the planemaker to study the impact of pilot performance on a broader range of potential failures than had been agreed to previously. The FAA letter, which was reviewed by Bloomberg, also repeated warnings from September that Boeing had additional work to perform on safety analyses it submitted to the agency. 

“We request Boeing to review all of the catastrophic hazards” to ensure that potential actions by pilots had been taken into account, the letter said. 

The letter is the latest indication that the process of approving the last two 737 Max models is behind schedule and that there are tensions between Boeing and its federal regulator. Earlier versions of the Max are in service, while others are awaiting certification.

“Boeing is focused on meeting all regulatory requirements to certify the 737-7, and safety remains the driving factor in this effort,” the company said. “We will continue to prioritise being thorough and transparent in our documentation and interactions with the FAA and following established processes to ensure safety and compliance above all else.” 

Once the original model in a family of airliners is approved, it has traditionally been relatively easy for later versions featuring nearly identical engines and other systems to receive certification. But legal changes ordered by Congress after two fatal Max crashes in 2018 and 2019, combined with caution by FAA officials, have dramatically complicated work on the remaining Max approvals. 

In September, the FAA sent a letter to Boeing saying for the first time that the Max 7 was in danger of not being certified by the end of the year. Earlier this month, the agency sent a letter to a senator saying it did not expect to conclude certification of the larger Max 10 until next summer. 

Congress, in a 2020 law passed in response to the Max crashes, said all new airliners must have modern alerting systems for emergencies, but gave Boeing two years to complete the process of certifying the remaining two Max jets. 

Unless Congress changes the law, Boeing would have to add the alerting system to the Max 10 and Max 7, which the company says would be costly and unnecessary. BLOOMBERG