77-06-04 ENSTROM: Amendment 39-2855. Applies to Enstrom Model F28C helicopters with serial numbers 364, 367, 373 and 374 and Model 280C with serial numbers 1007, 1020, 1060, 1062, 1065 certificated in all categories.
Before further flight, unless already accomplished, remove from service the tail rotor assembly P/N 28-150000-3 and replace with an airworthy assembly which has been assembled using forged blade grip fittings P/N 28-150013-11.
The removed tail rotor assembly should be returned to Enstrom Helicopter Corporation, Menominee, Michigan 49858.
This amendment becomes effective March 31, 1977, to all persons except those to whom it was made effective earlier by air mail letter dated March 2, 1977.