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Safety Recommendation Details

Safety Recommendation A-93-137
Details
Synopsis: ON MARCH 31, 1993, THE NO.2 ENGINE AND ENGINE PYLON SEPARATED FROM JAPAN AIRLINES, INC., FLIGHT 46E, A BOEING 747-121, THAT HAD BEEN WET-LEASED FROM EVERGREEN INTERNATIONAL AIRLINES, INC., SHORTLY AFTER DEPARTURE FROM ANCHORAGE INTERNATIONAL AIRPORT, ANCHORAGE, ALASKA. THE ACCIDENT OCCURRED ABOUT 1234 ALASKA STANDARD TIME. THE FLIGHT WAS A SCHEDULED CARGO FLIGHT FROM ANCHORAGE TO CHICAGO-O'HARE INTERNATIONAL AIRPORT, CHICAGO, ILLINOIS. ON BOARD THE AIRPLANE WERE THE FLIGHTCREW, CONSISTING OF THE CAPTAIN, THE FIRST OFFICER, AND THE SECOND OFFICER, AND TWO NONREVENUE COMPANY EMPLOYEES. THE AIRPLANE WAS SUBSTANTIALLY DAMAGED DURING THE SEPARATION OF THE ENGINE. NO ONE ON BOARD THE AIRPLANE OR ON THE GROUND WAS INJURED.
Recommendation: THE NTSB RECOMMENDS THAT THE FEDERAL AVIATION ADMINISTRATION: AMEND THE DESIGN LOAD REQUIREMENTS OF 14 CFR PART 25 TO CONSIDER MULTIPLE AXIS LOADS ENCOUNTERED DURING SEVERE TURBULENCE.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Unacceptable Action
Mode: Aviation
Location: ANCHORAGE, AK, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA93MA033
Accident Reports: In-Flight Engine Separation Japan Airlines, Inc., Flight 46E Boeing 747-121, N473EV
Report #: AAR-93-06
Accident Date: 3/31/1993
Issue Date: 11/15/1993
Date Closed: 4/16/1997
Addressee(s) and Addressee Status: FAA (Closed - Unacceptable Action)
Keyword(s): Weather, Turbulence

Safety Recommendation History
From: NTSB
To: FAA
Date: 4/16/1997
Response: THE BOARD NOTES THAT THE FAA HAS ASKED THE AVIATION RULEMAKING ADVISORY COMMITTEE (ARAC) A NOTICE OF PROPOSED RULEMAKING TO ADDRESS CONTINUOUS TURBULENCE FIELDS, WHICH MAY ADDRESS CONTINUOUS DYNAMIC RESPONSE. THE ANALYSIS OF ENGINE PYLON LOADS AS A RESULT OF CONTINUOUS TURBULENCE FIELDS DOES NOT ENSURE THAT SIMULTANEOUS MULTIPLE AXIS LOADING WILL BE CONSIDERED IN FUTURE DESIGNS. BECAUSE THE FAA HAS NOT PROCEEDED WITH ADDITIONAL RULEMAKING THAT WOULD BE RESPONSIVE TO THE INTENT OF RECOMMENDATIONS A-93-137 & -139 IMPOSING MULTIPLE AXIS LOADING REQUIREMENTS, A-93-137 IS CLOSED--UNACCEPTABLE ACTION."

From: FAA
To: NTSB
Date: 1/8/1997
Response: THE FAA ACTION OF ISSUING AMENDMENT 25-86 PROVIDES A CRITERION FOR A DISCRETE-TUNE GUST & THAT IMPLEMENTATION OF THIS CRITERION MAY PROVIDE AN INCREASE IN DESIGN LOADS IN CERTAIN AREAS THAT ARE SUBJECT TO DYNAMIC AMPLIFICATION SUCH AS ENGINE PYLONS. HOWEVER, THE FAA ACTION DOES NOT CONSIDER SIMULTANEOUS MULTIPLE AXIS LOADING OF ENGINE PYLON WHICH WAS THE INTENT OF THIS RECOMMENDATION.

From: NTSB
To: FAA
Date: 10/1/1996
Response: THE BOARD NOTES THAT ON 2/2/96, THE FAA ISSUED A FINAL RULE TO AMEND 14 CFR PART 25 TO INCLUDE A CRITERION FOR A DISCRETE-TUNED GUST. HOWEVER, THE BOARD NOTES THAT THE FINAL RULE DOES NOT ADDRESS MULTIPLE AXIS LOADING, WHICH WAS THE PRIMARY INTENT OF THESE TWO RECOMMENDATIONS. ADDITIONALLY, THE RULE WOULD ONLY BE APPLICABLE TO NEWLY CERTIFICATED AIRCRAFT & NOT STRUCTURAL MODIFICATIONS TO EXISTING ENGINE PYLON DESIGNS, WHICH WAS THE INTENT OF A-93-139. THE BOARD FOUND DURING ITS INVESTIGATION OF THE ACCIDENT INVOLVING JAPAN AIRLINES FLIGHT 46E THAT 14 CFR PART 25 ALLOWS MANUFACTURERS TO ANALYZE EACH AXIS OF LOADING INDEPENDENTLY WHEN DETERMINING HOW STRONG A STRUCTURE SHOULD BE TO WITHSTAND ULTIMATE LOAD. MANUFACTURERS ARE NOT REQUIRED TO DESIGN THE STRUCTURE TO WITHSTAND ULTIMATE LOADS FROM MULTIPLE DIRECTIONS AT THE SAME TIME. THE BOARD FINDS THAT THE FAA'S FINAL RULE DOES NOT PROVIDE A REQUIREMENT FOR ANALYZING THE EFFECTS OF MULTIPLE AXIS LOADS WHEN MODIFYING EXISTING DESIGNS OR IN THE CERTIFICATION OF NEW DESIGNS. ALTHOUGH THE FAA'S RESPONSE STATES THAT IT PLANS NO FURTHER ACTION ON THESE RECOMMENDATIONS, THE BOARD NOTES THAT THE FAA STATED IN ITS FINAL RULE TO AMEND 14 CFR PART 25 THAT IT WOULD CONSIDER FUTURE RULEMAKING ACTIONS, IN PART, BASE ON COMMENTS RECEIVED IN CONNECTIONS WITH THE NOTICE OF PROPOSED RULEMAKING THAT LED TO THE FINAL RULE. THE COMMENTS PERTAINTED TO THE FACT THAT THE TUNED GUST CRITERIA DEVELOPED AS PART OF THE FINAL RULE DO NOT FULLY ACCOUNT FOR THE DYNAMIC RESPONSE OF THE AIRPLANE & THEREFORE COULD PRODUCE UNCONSERVATIVE RESULTS & COULD SERIOUSLY UNDERPREDICT GUST LOADS. THE BOARD WOULD LIKE TO HAVE FORMAL ACKNOWLEDGMENT FROM THE FAA WHETHER IT INTENDS TO PROCEED WITH ADDITIONAL RULEMAKING THAT WOULD BE RESPONSIVE TO THE INTENT OF RECOMMENDATIONS A-93-137 & -139 BY IMPOSING MULTIPLE AXIS LOADING REQUIREMENTS. PENDING FURTHER CORRESPONDENCE FROM THE FAA, RECOMMENDATIONS A-93-137 & -139 ARE CLASSIFIED "OPEN--UNACCEPTABLE RESPONSE."

From: FAA
To: NTSB
Date: 5/14/1996
Response: THE FAA, IN COOPERATION WITH THE EUROPEAN JOINT AVIATION AUTHORITIES & THE AVIATION RULEMAKING ADVISORY COMMITTEE, DEVELOPED A FINAL RULE THAT AMENDED 14 CFR PART 25 TO INCLUDE CRITERION FOR A DISCRETE TUNED GUST. THE FINAL RULE WAS ISSUED ON 2/2/96.

From: NTSB
To: FAA
Date: 6/17/1994
Response: THE BOARD NOTES THAT THE FAA, IN CONJUNCTION WITH THE EUROPEAN JOINT AIRWORTHINESS AUTHORITY & UNDER THE DIRECTIONS OF THE AVIATION RULEMAKING ADVISORY COMMITTEE, HAS DEVELOPED A PROPOSAL TO AMEND THE AIRWORTHINESS PROVISIONS OF 14 CFR PART 25 TO INCLUDE A CRITERION FOR TUNED DISCRETE GUST. THIS CRITERION WILL USE MORE RECENT MEASUREMENTS OF GUST VELOCITY & WILL REQUIRE THE GUST GRADIENT TO BE TUNED TO DEVELOP THE MAXIMUM DYNAMIC RESPONSE IN THE STRUCTURE. THE FAA ANTICIPATES THAT THIS RULEMAKING ACTION WILL BE PUBLISHED DURING THE THIRD QUARTER OF FISCAL YEAR 1994. THE BOARD FURTHER NOTES THAT THE FAA'S TECHNICAL CENTER IS ENGAGED IN A RESEARCH PROGRAM DESIGNED TO IMPROVE THE KNOWLEDGE OF THE GUST ENVIRONMENT. THE PROGRAM, ENTITLED "MEASUREMENTS & ANALYSIS OF FLIGHT LOADS FOR TRANSPORT AIRPLANES." CALLS FOR INSTRUMENTATION OF IN-SERVICE TRANSPORT AIRCRAFT WITH STATE-OF-THE-ART DATA ACQUISITION EQUIPMENT TO ACQUIRE NEW LOAD DATA FOR THE DESIGN OF FUTURE GENERATIONS OF LARGE TRANSPORT AIRPLANES. PENDING FURTHER INFO THE BOARD CLASSIFIES A-93-137 "OPEN--ACCEPTABLE RESPONSE."

From: FAA
To: NTSB
Date: 2/24/1994
Response: THE FAA, IN COOPERATION WITH THE EUROPEAN JOINT AIRWORTHINESS AUTHORITY & UNDER THE DIRECTION OF THE AVIATION RULEMAKING ADVISORY COMMITTEE, HAS DEVELOPED A PROPOSAL TO AMEND THE AIRWORTHINESS PROVISIONS OF 14 CFR PART 25 TO INCLUDE A CRITERION FOR TURNED DISCRETE GUST. THIS AMENDMENT IS A COOPERATIVE EFFORT IN CONJUCTION WITH THE EUROPEAN JOINT AIRWORTHINESS AUTHORITY & UNDER THE DIRECTION OF THE AVIATION RULEMAKING ADVISORY COMMITTEE. ADDITIONALLY, THE FAA'S TECHNICAL CENTER IS ENGAGED IN A RESEARCH PROGRAM DESIGNED TO IMPROVE THE KNOWLEDGE OF THE GUST ENVIRONMENT. THE PROGRAM, ENTITLED "MEASUREMENTS & ANALYSIS OF FLIGHT LOADS FOR TRANSPORT AIRPLANES," CALLS FOR THE INSTRUMENTATION OF IN-SERVICE TRANSPORT AIRCRAFT WITH STATE-OF-THE-ART DATA ACQUISITION EQUIPMENT TO ACQUIRE NEW LOADS DATA FOR THE DESIGN OF FUTURE GENERATIONS OF LARGE TRANSPORT AIRPLANES.