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Safety Recommendation Details

Safety Recommendation A-93-139
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: REQUIRE ANY FUTURE STRUCTRUAL MODIFICATIONS OF EXISTING ENGINE PYLONS TO CONSIDER MULTIPLE AXIS LOADING.
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):

Safety Recommendation History
From: NTSB
To: FAA
Date: 4/16/1997
Response: ALSO, THE BOARD NOTES THAT THE MODIFICATION PROGRAMS FOR B-747 ENGINE PYLONS PROVIDED IN AIRWORTHINESS DIRECTIVES 95-10-16, 95-13-05, 95-13-06, & 95-13-07 DID NOT CONSIDER MULTIPLE AXIS LOADING. THE INTENT OF THIS RECOMMENDATIOIN WAS TO ENSURE THAT ANY FUTURE MODIFICATION PROGRAMS INTENDED TO IMPROVE IN-SERVICE ENGINE PYLON DAMAGE TOLERANCE CAPABILITY & DURABILITY MULTIPLE AXIS LOADING. BECAUSE THE FAA PLANS NO FURTHER ACTION ON THIS ISSUE, A-93-139 IS CLASSIFIED "CLOSED--UNACCEPTABLE ACTION."

From: FAA
To: NTSB
Date: 1/8/1997
Response: THE FAA RESPONSE INDICATES THAT THE NEW TUNED GUST REQUIREMENT MAY BE IMPOSED ON DERIVATIVE AIRPLANE CERTIFICATION PROGRAMS ON A CASE-BY-CASE BASIS. THE NEW TUNED GUST REQUIREMENT WILL NOT BE APPLIED TO THE MODIFICATION OF PYLONS THAT ARE CURRENTLY IN SERVICE.

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 PERTAINED 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 IS ADDRESSING THIS RECOMMENDATION THROUGH THE ONGOING RESEARCH PROGRAM AT THE FAA'S TECHNICAL CENTER. THIS PROGRAM CALLS FOR THE 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, AS OUTLINED IN A-93-139. BASED ON THIS INFO, THE BOARD CLASSIFIES A-93-139 "OPEN--ACCEPTABLE ALTERNATE RESPONSE."

From: FAA
To: NTSB
Date: 2/24/1994
Response: I BELIEVE THAT THE ACTION BEING TAKEN TO ADDRESS RECOMMENDATION A-93-137 WILL RESULT IN STRUCTURAL DESIGNS WHICH WILL BE CAPABLE OF WITHSTANDING THE MULTIPLE AXIS LOAD. I WILL KEEP THE BOARD APPRISED OF THE FAA'S PROGRESS ON THIS SAFEY ISSUE.