Manufacturer’s Requests Delay for Stall Management Yaw Damper Fix

The FAA recently published Boeing’s exemption request involving the Stall Management Yaw Damper (SMYD) system on its uncertified 737 MAX 7 and MAX 10 airliners. If the appeal is somehow approved, Boeing will be able to deliver the jets as-is through October 2028.

“Boeing is requesting a time-limited exemption that allows for certification and delivery of SMYD [for the 737 MAX 7 and 737 MAX 10] through October 31, 2028,” it said. The additional time would allow it to jump through all the necessary hurdles to get the SMYD in compliance and then retrofit delivered jets with the updated system.

The SMYD system increases an aircraft’s stability when nearing stalls by providing warnings, identifying stall conditions, and actively controlling the aircraft's yaw. The version that Boeing used on the 737 MAX 9 was modified to fit the MAX 7 and then again for the MAX 10 to accommodate their different fuselage sizes.

The new software also implements enhanced angle of attack (EAOA) features to reduce pilot workload and improve system integrity, specifically during air data and AOA system failures. This change addresses two accidents in 2018 and 2019 that caused 346 fatalities and were partially attributed to said failures.

While the FAA likely appreciates the plane maker’s upgrades, it can’t ignore the fact that the new SMYD system is out of compliance with two CFR sections. The SMYD also does not qualify for Level A (DAL A) certification under the Radio Technical Commission for Aeronautics’s (RTCA) standards since it was previously only approved under Level B.

However, with Boeing already being behind schedule on getting the 737 MAX 7 and MAX 10 certified, it has requested that the FAA grant an exemption.

“Granting an exemption will enable earlier implementation of the EAOA capabilities to production airplanes and the 737 MAX fleet, providing industry-leading safety enhancements,” Boeing continued. “An exemption will deliver the 737-7 and 737- 10 airplanes to customers sooner with enhanced safety.”

FMI: www.boeing.com