Boeing has sought an exemption from the Federal Aviation Administration (FAA) for two Code of Federal Regulations (CFR) provisions concerning the Stall Management Yaw Damper (SMYD) system on its 737 MAX 7 and 737 MAX 10 aircraft. Neither model has yet received certification from the FAA.
The request, made public by the FAA on January 21, involves Boeing’s SMYD system on these models, as well as the enhanced angle of attack (EAOA) certification project across all 737 MAX aircraft. Boeing stated that these projects do not comply with two CFR sections.
“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.”
This period would allow for necessary certification activities to demonstrate compliance with CFR provisions and provide time to retrofit already delivered aircraft under this exemption.
According to Boeing, the SMYD is an electronics unit providing stall warning, identification, and yaw damper functions. The company modified its software for different fuselage sizes in these models to ensure consistent performance. Despite size differences, Boeing assures that performance will remain consistent.
The updated software also includes EAOA safety features designed to enhance system integrity and reduce pilot workload during air data and AOA failures. These failures were factors in two fatal crashes involving the 737 MAX 8 in Indonesia in October 2018 and Ethiopia in March 2019.
Boeing noted that once certified, the improved EAOA system would be available on all MAX aircraft without hardware changes compared to previous models like the Next Generation (NG).
“Additional certification activity will be needed to certify the SMYD to DAL A. It is proposed that the certification be completed as part of a post-ATC and post-EAOA certification project.”
Boeing argued that granting this exemption serves public interest by allowing safety enhancements while ensuring compliance with DAL A standards without compromising safety.
“Without the time-limited exemption, the EAOA safety features cannot be enabled,” delaying important safety improvements until full compliance is achieved.
The manufacturer emphasized its commitment to maintaining high integrity and reliability based on extensive service history. Boeing confirmed there are no records of yaw damper failures caused by SMYD in their database.
“The yaw damper software changes between [models] were small tuning updates…with no changes to architecture.”
Boeing tested both systems extensively, including simulator tests, confirming no adverse effects from software updates.
“Granting an exemption will enable earlier implementation of EAOA capabilities…providing industry-leading safety enhancements.”
In November 2023, Boeing requested another FAA exemption related to engine nacelle inlet structure issues but withdrew it following stakeholder pressure after a separate incident involving Alaska Airlines’ aircraft.
Boeing continues developing solutions hoping for certifications in 2025 for both models involved in current requests.
