77-07-08: Tail Rotor Tension Torsion Bars

77-07-08 FAIRCHILD (HILLER): Amendment 39-2866 as amended by Amendment 39-2992. Applies to Model 1100 and FH-1100 type helicopters certified in all categories. Compliance required as follows: To detect improper surface finish in the bolt holes at each end of the tail rotor tension torsion bars, P/N's 24-55106 which could lead to cracking of the bar plates, accomplish the following within the next 25 hours in service after the effective date of this AD unless already accomplished. Inspect the two tail rotor tension torsion bars, P/N's 24-55106 which have serial numbers prior to 1922 or illegible serial numbers, in accordance with Fairchild FH-1100 Service Bulletin No. SBFH1100-55-2A dated 19 January 1977, Section 2 "Accomplishment Instructions" or equivalent procedure approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. If tension torsion bars are found unacceptable in accordance with the service bulletin or those procedures approved bythe Chief, Engineering and Manufacturing Branch, replace the bar with one that has been inspected and found acceptable in accordance with the service bulletin or an equivalent procedure approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. Upon submission of substantiating data by an owner or operator through an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region may adjust the inspection interval specified in this AD. Amendment 39-2866 became effective April 11, 1977. This Amendment 39-2992 becomes effective August 5, 1977.