NTSB · Safety Recommendation
Safety Recommendation A-80-029
Recommendation
THE NTSB RECOMMENDS THAT THE FEDERAL AVIATION ADMINISTRATION: EXPEDITE THE DEVELOPMENT AND INSTALLATION OF A METHOD OF RESTRAINING AND VENTING OVERBOARD, FUEL AND FUEL VAPORS THAT MAY LEAK FROM THE MOTIVE FLOW VALVE DURING ITS NORMAL OPERATIONS.
Safety Issue and Context
THE NTSB HAS LEARNED OF AN INCIDENT WHICH OCCURRED JANUARY 1, 1980, WHEREIN A FUEL LEAK WAS DISCOVERED IN THE TAILCONE SERVICE AREA OF A LEARJET-36 DURING A POSTFLIGHT INSPECTION. THE LEAK WAS TRACED TO THE LEFT MOTIVE FLOW VALVE (PN AV16E1182) (SNH46478) WHICH IS LOCATED IN THE TAILCONE SERVICE AREA WHERE THE BATTERIES AND OTHER ELECTRICAL COMPONENTS ARE POSITIONED. THE VALVE HAD OPERATED ABOUT 1,663 HOURS. IT WAS REPORTED THAT, WHEN THE VALVE WAS PRESSURIZED, FUEL SPURTED ABOUT 5 INCHES INTO THE AIR AND SPRAYED INTO THE SERVICE AREA IN SUFFICIENT QUANTITY TO WASH SOOT FROM INSTALLED EQUIPMENT IN THE COMPARTMENT.
PORTIONS OF THE ELECTRICAL JUNCTION BOX ADJACENT TO THE VALVE WERE SATURATED WITH FUEL.
Response History
May 12, 1981 · NTSB Correspondence · FAA
With regard to a-80-29, we note that the faa has issued ad, revision 80-19-09 r1, gates learjet, which requires the installation of motive flow valve shrouds and drain lines before february 13, 1981. This complete actions on a-80-29 which we now classify in a closed--acceptable action status.
September 8, 1980 · NTSB Correspondence · FAA
We note that this recommendation is in proces of fulfillment and that we will be advised when action is complete. Pending the faa's further response, a-80-29 is classified in an open--acceptable action status.
July 8, 1980 · Recipient Response · FAA
FAA LTR: GATES LEARJET INVESTIGATED THE POSSIBILITY OF A DESIGN CHANGE TO PRECLUDE FUEL LEAKING FROM THE MOTIVE FLOW VALVE FROM BEING SPRAYED INTO THE TAILCONE AREA. TO ACCOMPLISH THAT OBJECTIVE, THE VALVE MANUFACTURER IS PROCESSING A DESIGN CHANGE TO ENCLOSE THE VALVE IN A SHEET METAL ENCLOSURE WITH A DRAIN LINE TO PERMIT ANY LEAKAGE TO BE DRAINED OVERBOARD. WHEN THIS DESIGN BECOMES AVAILABLE IN THE FIELD, AD 80-09-06 WILL BE REVISED TO EXEMPT THOSE AIRPLANES HAVING THE CHANGE INCORPORATED FROM THE POST-FLIGHT INSPECTION REQUIREMENT.
COMMENT: WITH REGARD TO SAFETY RECOMMENDATION A-80-29, NTSB NOTES THAT THE FAA HAS ISSUED AIRWORTHINESS DIRECTIVE, REVISION 80-19-09 R1, GATES LEARJET, WHICH REQUIRES THE INSTALLATION OF MOTIVE FLOW VALVE SHROUDS AND DRAIN LINES BEFORE FEBRUARY 13, 1981. THIS COMPLETES ACTIONS FOR A-80-29.