77-15-04 ENSTROM: Amendment 39-2973. Applies to Enstrom Models F28C and 280C helicopters with wide chord (4.4 inch) tail rotor blades certificated in all categories.
Before further flight perform a dye penetrant inspection around the circular hub including the arm base of the pitch link retainer assembly P/N 28-16320 unless already accomplished in the last ten hours time in service. Within ten (10) hours time in service after the receipt of this airmail letter, unless already accomplished, replace the wide chord tail rotor pitch link assembly P/N 28- 16320 and two (2) guide bolts P/N 28-16307 with a new wide chord tail rotor pitch link retainer assembly P/N 28-16325 and two (2) guide bolts P/N 28-16324. Enstrom Service Directive Bulletin Number 0040 pertains to this same subject.
This amendment is effective July 26, 1977, and was effective immediately for all recipients of airmail letters dated June 15, 1977 which contained this amendment.