NTSB · Safety Recommendation
Safety Recommendation A-06-036
Recommendation
TO THE FEDERAL AVIATION ADMINISTRATION: Compile a list of safety-critical systems derived from the safety assessment process for each type certification project, and place in the official type certification project file the documentation for the rationale, analysis methods, failure scenarios, supporting evidence, and associated issue papers used to identify and assess safety-critical systems.
Safety Issue and Context
Certification of systems that are critical to safety of flight has been an issue in several National Transportation Safety Board accident investigations of transport-category airplanes. In 1999, the Safety Board expressed concern about the Federal Aviation Administration's (FAA) certification process during its investigation of the rudder actuator in USAir flight 427. In 2000, the Board suggested the need for a directed examination of the certification process in the investigation of the center wing fuel tank in TWA flight 800.
Subsequent investigations of the horizontal stabilizer jackscrew in Alaska Airlines flight 26 1 and the rudder system in American Airlines flight 5874 also raised questions about the certification process used by the FAA to determine compliance with airworthiness standards. These four accidents resulted in 715 fatalities and accounted for 60 percent of the air carrier fatalities that occurred from 1994-2001 . In each of these accidents, the Board identified a safety-critical system that suffered a catastrophic failure, and issued certification-related recommendations to address system-specific design, operational, or maintenance issue.
Response History
November 2, 2015 · NTSB Correspondence · FAA
We reviewed the existing FAA regulations, advisory material, and processes that you discussed in your letter including the requirements contained in Title 14 Code of Federal Regulations Part 25.1309, which requires the development of system safety assessments (SSA) that identify safety critical systems, describes the failure conditions associated with these systems, and classifies the hazards associated with failure conditions as catastrophic, hazardous, or major.
On December 9, 2014, we said that the procedures used under FAA Order 8110.4C, “Type Certification,” to retain the information in the SSA satisfy the part of this recommendation concerning the availability of the information in the type certification project file. We agree with you that current regulations, advisory material, and processes identify safety-critical systems during certification; therefore, Safety Recommendation A-06-36 is classified CLOSED—ACCEPTABLE ACTION.
September 2, 2015 · Recipient Response · FAA
-From Michael P. Huerta, Administrator: In our October 28, 2013, response, we conveyed our plan to resume issuance of a Key Safety Information (KSI) advisory circular (AC) for Title 14, Code of Federal Regulations (14 CFR) Part 25 products after several years on hold, while we considered the benefits of application to a broader group of type certificated products. Upon further review, we believe the objectives of this recommendation are met using our current certification regulations, advisory material, and processes; some were developed or have evolved since 2007, when we first informed the Board of the KSI concept.
The FAA believes these existing regulations, advisory material, and processes are sufficient to identify safety-critical systems during certification. Therefore, we no longer see a benefit in pursuing the KSI AC concept. Existing regulations, advisory material and processes that address the Board' s recommendation are described below: