68-08-03 FAIRCHILD-HILLER: Amdt. 39-583. Applies to all F-27 type aircraft Serial Nos. 1 to 95 inclusive incorporating a combustion heater system.
Compliance required as indicated unless already accomplished, or unless installed heaters are rendered electrically inoperative and heater controls are placarded to prohibit operation prior to compliance with this AD.
To preclude the possibility of residual fuel fire in the heater outer air passage due to lack of adequate drainage, accomplish the following:
(a) Within the next 400 operational heater hours after the effective date of this AD, incorporate a heater outer pass drain installation in accordance with Fairchild Service Bulletin No. 21-68 Revision No. 1 dated November 10, 1964, or later FAA-approved revision, or an equivalent modification approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region.
(b) Upon the effective date of this AD heater operational hours will be logged until such time as the AD has been complied with.
This amendment effective May 19, 1968.