The Federal Aviation Administration (FAA) on Monday issued a preliminary report on its review of the Boeing 737 MAX. The report provides a detailed technical account of the lessons learned since the two fatal accidents involving the Boeing 737 MAX aircraft, as well as the actions by the U.S. Federal Aviation Administration (FAA) to ensure the airplane’s safe return to service.
As the State of Design agent, the FAA is providing this report to all States of Registry of the 737 MAX and to the general public to assist in their understanding of how the agency identified and is addressing the safety issues affecting the aircraft.
The FAA intends to assure the global community that when the work is completed, the 737 MAX will be safe to operate and meet FAA certification standards.
The report contains details of the FAA’s comprehensive review of the manufacturer’s proposed changes to the airplane’s Maneuvering Characteristics Augmentation System (MCAS), including associated system parts, software and mechanical characteristics, safety assumptions,
and systems assessments.
Additionally, the report addresses the design, operation, proposed training, and maintenance changes that will effectively address the causes of the Lion Air Flight 610 (JT610) and Ethiopian Airlines Flight 302 (ET302) accidents.
During its evaluation of Boeing’s proposed modifications, the FAA has retained all compliance findings and approvals associated with the design changes related to MCAS.
FAA’s review took more than 18 months and included the full-time work of more than 40 engineers, inspectors, pilots, and technical support staff. The effort represents more than 60,000 FAA hours of review, certification testing, and evaluation of pertinent documents. This has so far included approximately 50 hours of FAA flight or simulator tests and FAA analysis of more than 4,000 hours of company flight and simulator testing.
The FAA has a longstanding commitment to transparency, continuous improvement, and information sharing to encourage increased aviation safety worldwide. To these ends, the agency supported numerous reviews, investigations, and robust international engagement with fellow Civil Aviation Authorities (CAA).
The FAA took into account the final recommendations of the U.S. National Transportation Safety Board (NTSB) and Indonesia’s Komite Nasional Keselamatan Transportasi (KNKT), as well as all available preliminary information from the accident investigations.
The FAA and other U.S. bodies commissioned a number of studies to evaluate the initial certification of the 737 MAX, as well as the certification process itself.
The FAA invited nine other CAAs to be a part of the Joint Authorities Technical Review (JATR), which assessed the certification of the 737 MAX flight control system. The FAA is considering all relevant findings of the JATR, as well as those of the U.S. Department of Transportation Special Committee, the U.S. Department of Transportation Office of the Inspector General (OIG), and other available preliminary findings.
The FAA also commissioned a Technical Advisory Board (TAB) to independently review Boeing’s proposed corrective actions. The TAB consisted of a number of technical experts with no involvement in the initial certification of the 737 MAX. Several of these experts were from other U.S. government agencies. The actions by the FAA and Boeing, summarized in this report, fully incorporate the TAB’s recommendations to date.
The Preliminary Summary is part of FAA’s extensive outreach to technical experts from CAAs around the globe to keep them apprised of the agency’s progress and address their concerns about the aircraft. The FAA is also actively supporting concurrent validation activities of the aircraft by the CAAs of other States of Design of large transport airplanes. Each authority will make its own assessment of the FAA’s process and findings, as well as Boeing’s actions to address the findings.
Due to the nature of the certification process, there is continuous engagement with the CAAs on all aspects of the review. Likewise, all of the CAAs are reviewing identical data from Boeing to make their respective findings.
Proposed Airworthiness Directive
The preliminary report also includes the proposed airworthiness directive that lists six tasks airlines (or Boeing, for undelivered aircraft) will need to perform before their 737 MAX are allowed to return to service:
- require installing new flight control computer (FCC) software,
- revising the existing Airplane Flight Manual (AFM) to incorporate new and revised flightcrew procedures,
- installing new MAX display system (MDS) software,
- changing the horizontal stabilizer trim wire routing installations,
- completing an angle of attack sensor system test,
- performing an operational readiness flight