76-25-03 BOEING VERTOL: Amendment 39-2784. Applies to Boeing Vertol Model 107-11 Helicopters Certificated in all Categories.
Compliance required as follows:
To detect corrosion which could lead to cracking of the main rotor blade spars accomplish the following within the next 60 days unless already accomplished within the past 34 months and every 36 months thereafter.
a) Inspect for corrosion, and alter if necessary, main rotor blades P/N's 107R1202 and SK24790 series in accordance with Boeing Vertol Company Service Bulletin No. 107-333 (R-1) dated July 1, 1976, Section 2 (Accomplishment Instructions" or Boeing Vertol Company Service Bulletin No. 107-334 dated October 29, 1976, Section 2 "Accomplishment Instructions" or equivalent procedure approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region.
b) If spar corrosion exceeds the limits in either of the above service bulletins or those approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region, replace the main rotor blade with one that has been inspected and altered if necessary, in accordance with one of the above service bulletins and/or an acceptable equivalent procedure.
This amendment is effective December 10, 1976.