64-22-01\tBOEING: Amdt. 815 Part 507 Federal Register September 19, 1964. Applies to Models 707 and 720 Series Aircraft. \n\n\tCompliance required as indicated. \n\n\tThere have been failures of the fuel tank vent float valve arms causing the float to break loose from the main valve assembly. This permits the vent valve (which is normally float actuated to the closed position by a high fuel level) to remain open and allow (under some flight conditions) fuel to fill the surge tank and spill out the wing tip vent scoop. To correct this condition, accomplish the following: \n\n\t(a)\tWithin 500 hours' time in service after the effective date of this directive, unless already accomplished in the previous 500 hours' time in service and within every 1,000 hours time in service thereafter until compliance with (b) has been accomplished, visually inspect the reserve fuel tank vent valve assemblies in each wing for cracks or deformation. If the valve assembly is in a failed condition, or if cracks or deformed parts are found, replace the parts before further flight. \n\n\t(b)\tWithin 6,000 hours' time in service after the effective date of this directive modify all fuel tank vent valve assemblies in each tank by installing a float stop bracket assembly, Boeing P/N 69-31399-1, in accordance with Boeing Service Bulletin No. 1958 or an equivalent method processed through the Aircraft Engineering Division, FAA Western Region, Los Angeles, California. When this modification has been accomplished the repetitive inspection of (a) may be discontinued. \n\n\t(c)\tUpon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Aircraft Engineering Division, FAA Western Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for such operator. \n\n\t(Boeing Service Bulletin No. 1958 covers thissubject.) \n\n\tThis directive effective October 22, 1964.