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Safety Recommendation Details

Safety Recommendation A-72-006
Details
Synopsis: NORTHWEST AIRLINES FLIGHT 9, A BOEING 747-151, N607US, WAS A SCHEDULED PASSENGER FLIGHT FROM HONOLULU, HAWAII. ITS DESTINATION WAS TOKYO, JAPAN. AT DEPARTURE FROM HONOLULU, AT 1330 H.S.T., 31 REVENUE PASSENGERS AND 11 CREWMEMBERS WERE ON BOARD. AFTER TAKE-OFF AT 1,300 FEET M.S.L., A SEPARATION OF THE SECOND-STAGE TURBINE DISK OCCURRED RUPTURING THE HIGH PRESSURE TURBINE CASE AND COWLING. A FIRE WARNING AND SEVERE VIBRATION ENSUED. THE FLIGHT RETURNED TO HONOLULU AT 1351 H.S.T. THERE WERE NO INJURIES TO CREW OR PASSENGERS.
Recommendation: HOWEVER, IN VIEW OF THE POTENTIALLY SERIOUS CONSEQUENCES, THE BOARD IS CONCERNED ABOUT THE INABILITY OF PRESENT TURBINE ENGINE INSTALLATIONS TO PROTECT AIRFRAME STRUCTURE AND SYSTEM COMPONENTS ADEQUATELY FROM DAMAGE CAUSED BY TURBINE DISK FAILURE. IT URGES MANUFACTURERS AND OPERATORS OF TURBINE-POWERED AIRCRAFT, IN COLLABORATION WITH THE FEDERAL AVIATION ADMINISTRATION AND THE NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PROGRAMS, TO MAKE A CONCERTED EFFORT TO PRODUCE AN ACCEPTABLE AND EFFECTIVE ROTOR BURST PROTECTION SYSTEM.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Aviation
Location: Honolulu, HI, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA71I0004
Accident Reports: Northwest Airlines, Inc., Boeing 747-151, N607US
Report #: AAR-71-16
Accident Date: 5/13/1971
Issue Date: 12/15/1971
Date Closed: 11/28/1973
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s):

Safety Recommendation History
From: FAA
To: NTSB
Date: 1/26/1972
Response: THE FAA RESPONDED STATING THAT FOR A NUMBER OF YEARS THEY HAVE BEEN CONCERNED WITH THIS PROBLEM. FAR PART 25, SECTION 25.903(D)(I), REQUIRES THAT "DESIGN PRECAUTIONS MUST BE TAKEN TO MINIMIZE THE HAZARDS TO THE AIRPLANE IN THE EVENT OF AN ENGINE ROTOR FAILURE ---." THESE DESIGN PRECAUTIONS HAVE NOT PREVENTED AIRCRAFT DAMAGE, BUT THE LOCATIONS OF ENGINE MOUNTING, FLAMMABLE FLUID SHUTOFF VALVES AND CONTROLS, FUEL TANKS, SEPARATION AND REDUNDANCY OF VITAL FLIGHT CONTROLS, AND PROTECTION FOR FLIGHT STATION AND CREW AS WELL AS OTHER AIRCRAFT CONFIGURATION AND DESIGN FEATURES, ALL RELATIVE TO THE POSITION OF THE ENGINE ROTATING PARTS, ARE PART OF THE AIRCRAFT DESIGN CHARACTERISTICS DEVELOPED IN THE DESIGN OF THE AIRCRAFT AND EVALUATED BY THE FAA DURING THE AIRPLANE CERTIFICATION PROCESS. IT IS BORNE OUT THAT THESE DESIGN CONSIDERATIONS HAVE BEEN EFFECTIVE BY THE FACT THAT NO CATASTROPHIC RESULTS HAVE BEEN OCCASIONED BY THE ROTOR FAILURE EXPERIENCED. A TURBINE ENGINE ROTOR BURST PROTECTION PROGRAM HAS BEEN ESTABLISHED AND FUNDED BY NASA AND IS BEING CONDUCTED BY THE NAVAL AIR PROPULSION TEST CENTER. THE PROGRAM HAS BEEN UNDERWAY FOR SEVERAL YEARS, AND IS INTENDED TO RESULT IN THE DEVELOPMENT OF TECHNIQUES THAT WILL ASSIST IN THE PREVENTION OF ROTOR FAILURES. THE FAA IS FOLLOWING THIS PROGRAM AND WILL CONTINUE TO PROMOTE NEW DEVELOPMENTS IN THE STATE OF THE ART.