67-22-02 BELL: Amdt. No. 39-452. Part 39, Federal Register July 29, 1967. Applies to Model 206A Helicopters, Serial Numbers 4 through 20, 22 through 48, 50 through 56, 59, 61, and 63.
Compliance required as indicated below after the effective date of this airworthiness directive, unless already accomplished.
To assure proper grounding of both fuel boost pumps and prevent a potentially explosive condition in the fuel tank due to improperly wired electric fuel boost pumps, accomplish the following inspection and modification:
(a) Before further flight, determine by either of the following methods that the white wire from each fuel boost pump is connected to the aircraft system ground wire:
(1) If the wire identification is legible, by reference to the Master Electrical Wiring Diagram in the Model 206A Maintenance and Overhaul Manual, confirm that helicopter system wires numbered Q2A18N (to the Forward Boost Pump), and Q4A18N (to the Aft Boost Pump) are connectedto the white wire from the corresponding boost pump.
(2) If the wire identification is not legible, turn all switches off and disconnect each fuel boost pump white wire from the aircraft system wire. Check each aircraft system wire thus exposed for proper grounding using an ohmmeter or continuity checking device.
If the grounding is confirmed by either of the above methods, disconnected wires may be reconnected and the helicopter returned to service for not more than 25 hours before the modification required by subparagraph 2 below is accomplished.
If grounding is not confirmed by either of the above methods, the fuel pump leads may have been reversed. Use the Master Electrical Diagram in the Maintenance and Overhaul Manual to determine correct connections, and connect the pumps to the aircraft system accordingly. The helicopter may then be returned to service for not more than 25 hours' operation before the modification required by subparagraph 2 below is accomplished.
(b) Within the next 25 hours' time in service, modify the fuel boost pump wiring in accordance with Part B, Bell Helicopter Company Service Letter, Model 206A-No. 21, Revision A, dated July 18, 1967, or an equivalent method approved by the Director, Southwest Region, Federal Aviation Administration.
This amendment effective on July 29, 1967.