53-21-02 GRUMMAN: Applies to All Model G-21A (Converted OA-9, JRF-1 Through JRF-5 and JRF-6B) Aircraft.
Compliance required as indicated.
1. Inspect the threaded portion of the horizontal stabilizer strut lower adjustable end fitting P/N 12561-3, by a magnetic particle inspection method, as soon as practicable, but not later than November 15, 1953, and at 1,000-hour intervals thereafter. Replace fitting if crack is found.
2. Replace these fittings every 3,200 hours. If 3,200 hours is reached before the first inspection, fittings may be used for 50 hours after this inspection provided no cracks are found.
(Grumman Aircraft Engineering Corp. Customer Bulletin G-21A No. 3, dated March 20, 1953, covers this same subject.)