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Safety Recommendation Details

Safety Recommendation A-79-098
Details
Synopsis: THE NATIONAL TRANSPORTATION SAFETY BOARD HAS COMPLETED ITS DETERMINATION OF PROBABLE CAUSE AND FINAL REPORT ON THE AMERICAN AIRLINES DC-10 ACCIDENT IN CHICAGO ON MAY 25, 1979. THE SAFETY BOARD'S ANALYSIS OF THE EVIDENCE, AND RECOMMENDATIONS SUBMITTED TO THE BOARD BY THE OTHER PARTIES WHO PARTICIPATED IN THE INVESTIGATION AND PUBLIC HEARING, HAVE IDENTIFIED SEVERAL AREAS WHICH WE BELIEVE REQUIRE THE FEDERAL AVIATION ADMINISTRATION'S EARLY ATTENTION.
Recommendation: THE NTSB RECOMMENDS THAT THE FEDERAL AVIATION ADMINISTRATION: INCORPORATE IN TYPE CERTIFICATION PROCEDURES FULL CONSIDERATION OF: (A) FACTORS WHICH AFFECT MAINTAINABILITY, SUCH AS ACCESSIBILITY FOR INSPECTION, POSITIVE OR REDUNDANT RETENTION OF CONNECTING HARDWARE AND THE CLEARANCES OF INTERCONNECTING PARTS IN THE DESIGN OF CRITICAL STRUCTURAL ELEMENTS; AND (B) POSSIBLE FAILURE COMBINATIONS WHICH CAN RESULT FROM PRIMARY STRUCTURAL DAMAGE IN AREAS THROUGH WHICH ESSENTIAL SYSTEMS ARE ROUTED.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Aviation
Location: Chicago, IL, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA79AA017
Accident Reports: American Airlines, Inc., DC-10, N110AA
Report #: AAR-79-17
Accident Date: 5/25/1979
Issue Date: 12/21/1979
Date Closed: 5/17/1983
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s):

Safety Recommendation History
From: NTSB
To: FAA
Date: 5/17/1983
Response: The safety board has reviewed the advisory circular (ac) 25.1309.1, system design analysis issued september 7, 1982, and we concur that the guidance material provided therein along with the contents of ac 25.571.1, damage-tolerance and fatigue evaluation of structure issued september 28, 1978, should enhance the consideration of failure modes during an airplane's design and certification program. The safety board considers the faa's actions as responsive and is classifying safety recommendation a-79-98 as closed--acceptable action.

From: FAA
To: NTSB
Date: 10/5/1982
Response: FAA LETTER: THE FAA, WITHIN A VERY SHORT TIME, PLANS TO RELEASE ADVISORY CIRCULAR 25.1309.1 SYSTEM DESIGN ANALYSIS DIRECTLY ADDRESSING THE FAILURE MODE AND EFFECTS ANALYSIS APPROACH TO AIRCRAFT DESIGN. ALSO, THE FAA HAS UNDER WAY A REGULATORY PROJECT FOR THE DEVELOPMENT OF STANDARDS TO ASSURE THAT AN AIRCRAFT IS DESIGNED TO FLY AFTER STRUCTURAL FAILURES WHICH, OF THEMSELVES, DO NOT PRECLUDE CONTINUED FLIGHT. THE FAA INTENDS TO ISSUE AN ADVANCE NOTICE OF PROPOSED RULEMAKING ON THIS SUBJECT. IN SUMMARY, THE FAA BELIEVES THAT THE ABOVE ACTIONS, COUPLED WITH THE RESPONSIBILITIES INHERENT IN A CERTIFICATION ENGINEER'S BASIC FUNCTION, ARE THE ONLY PRACTICABLE MEANS FOR ASSURING CONSIDERATION OF COMBINED FAILURE CASES DURING TYPE CERTIFICATION. IT IS THE FAA'S POSITION THAT THE COMPLEXITY OF AIRFRAMES/SYSTEMS AND RAPID EVOLUTION OF AIRCRAFT TECHNOLOGY WOULD RENDER MEANINGLESS ANY ATTEMPTS TO SPECIFY "GUIDANCE MATERIAL" TO COVER ALL "POSSIBLE RISKS".

From: NTSB
To: FAA
Date: 6/7/1982
Response: Your response provided a reasonable clarification regarding maintainability factors addressed in part (a) of this recommendation; however, the consideration of combined failures recommended in part (b) was not mentioned in the letter. The safety board is aware that far's cited by faa make provision for considering certain combine failure cases during aircraft certification. However, the safety board remains concerned about the lack of detailed guidance material available from faa to provide some uniformity and consistency in establishing regulatory compliance requirements during design and certification of aircraft. . . . the safety board requests a clarification regarding the faa's position on providing regulatory guidance material for the consideration of combined failure cases during type certification. This recommendation is classified as open--acceptable action.

From: FAA
To: NTSB
Date: 6/10/1981
Response: FAA LTR: AS PREVIOUSLY INDICATED, FAA FULLY AGREES WITH THE BOARD'S STATEMENT OF THE IMPORTANCE OF EMPHASIZING MAINTAIN ABILITY FACTORS IN THE AIRCRAFT DESIGN PHASE. IN SUMMARY, WE BELIEVE THAT THE RECENT AMENDMENT TO FAR 25.571 AND THE REQUIREMENT FOR A MAINTENANCE MANUAL AS SET FORTH IN 25.529, TAKEN TOGETHER WITH THE MANDATORY PARTICIPATION OF MAINTENANCE SPECIALISTS IN THE TYPE CERTIFICATION PROCESS, EXISTING GUIDANCE MATERIAL, AND SERVICE DIFFICULTY REVIEW PRACTICES PROVIDE FULL COMPLIANCE WITH THE INTENT OF THE BOARD'S RECOMMENDATION, AND WE PLAN NO ADDITIONAL ACTION ON THIS RECOMMENDATION.

From: NTSB
To: FAA
Date: 6/13/1980
Response: . . . in the case of this accident, the ntsb investigation indicated that the procedures used to demonstrate compliance with regula- tions were lacking in the areas cited in the recommendation; the regulations were not faulted. This recommendation was directed at the inclusion of specific considerations in certification and design procedures; however, the reply only cites regulations rather than discussing the method in which they are applied. We would appreciate clarification regarding the methods which will assure that the factors cited in this recommendation receive appropriate consideration during certification. An advisory circular, similar to the re- cently issued draft ac 25.1309-x, airplane system design analysis might provide the explicit guidance to assure proper consideration of maintainability factors and failure combinations during the aircraft certification process. Until a clarification is obtained, this recommendation will be placed in an open--unacceptable action status.

From: FAA
To: NTSB
Date: 3/20/1980
Response: FAA LTR: OUR CURRENT TYPE CERTIFICATION PROCEDURES INCLUDE MAINTENANCE PARTICIPATION IN ASSESSING ALL AREAS OF THE DESIGN WHICH ARE AFFECTED BY MAINTENANCE. WE INTEND TO FURTHER AMEND THESE PROCEDURES TO ASSURE AND EMPHASIZE THAT MAINTENANCE SPECIALISTS, INCLUDING OUR NATIONAL RESOURCE SPECIALISTS, WILL PARTICIPATE IN APPROVAL OF ALL FEATURES OF A DESIGN WHICH INVLOVE MAINTENANCE CONCERNS. COMMENT ON A-79-98(A): WITH REGARD TO MAINTAINABILITY, FAR 25.611 COVERS THE FACTOR OF ACCESSIBILITY; FAR 25.607(A) AND (B) COVER THE FACTOR OF RETENTION OF CONNECTING HARDWARE; AND FAR 25.601 AND 25.571 COVER CLEARANCES OF INTERCONNECTING PARTS IN THE DESIGN OF CRITICAL STRUCTURAL ELEMENTS. COMMENT ON A-79-98(B): DESIGN ASPECTS OF FAILURE COMBINATIONS WHICH CAN RESULT FROM PRIMARY STRUCTURAL DAMAGE IN AREAS THROUGH WHICH ESSENTIAL SYSTEMS ARE ROUTED ARE COVERED BY FAR 25.571, 25.601, 25.671, AND 25.1309.