69-04-01\tBOEING: Amdt. 39-723. Applies to Model 727 Series airplanes in which the battery switch is located within ten inches of the galley switch. \n\n\tCompliance required within the next 50 hours time in service after the effective date of this AD, unless already accomplished. \n\n\tAs a result of FAA evaluations of the 727 electrical system sufficient cause has been found to prevent inadvertent operation of the battery switch located on the flight engineer's panel. Inadvertent operation of the battery switch during some operating conditions could result in loss of the standby electrical system. \n\n\tTo prevent inadvertent operation of the battery switch on the flight engineer's panel on those 727 Series airplanes in which the battery switch is located within ten inches of the galley switch, accomplish one of the following: \n\n\t(1)\tInstall a guard (Grimes P/N 11170-1 or equivalent MS type painted black) on the battery switch. The guard must be installed to force the switch to the "on" position and the guard should be mounted with the hinge down. \n\n\t(2)\tReplace the battery switch with a detent lock type switch, P/N MS 25125-E3 or an equivalent MS type, provided the galley switch is a toggle type switch. \n\n\t(3)\tPerform an equivalent installation approved by the Chief, Aircraft Engineering Division, FAA, Western Region. \n\n\tIn each of the above installations, install decals as necessary to retain "bat" and "on-off" switch function and switch position identification. \n\n\tBoeing Service Bulletin No. 24-44 is forthcoming to cover same subject. \n\n\tThis amendment becomes effective upon publication in the Federal Register for all persons except those to whom it was made effective immediately by telegram dated January 31, 1969.