74-20-04 HUGHES HELICOPTERS: Amendment 39-1968. Applies to Hughes Model 369, 369A, 369H, 369HE, 369HS and 369HM helicopters certificated in all categories.
Compliance required within the next 25 hours' of helicopter operation after the effective date of this AD, unless already accomplished within the last 75 hours' of helicopter operation, and thereafter at intervals not to exceed 100 hours' of helicopter operation from the last inspection.
To detect cracks, gouges, nicks and scratches in the main rotor blade trailing edge, accomplish the following:
(a) Inspect the main rotor blade trailing edge in accordance with Hughes Service Information Notice. No. HN-73, dated August 19, 1974, or later FAA-approved revisions.
(1) If cracks are found remove blade from service prior to further flight.
(2) If gouges, nicks and/or scratches are found replace or repair blade prior to further flight in accordance with Hughes Service Information Notice, No. HN-73.
(b)Equivalent inspection and repair procedures may be approved by the Chief, Aircraft Engineering Division, FAA Western Region upon submittal of adequate substantiating data.
(c) Aircraft may be flown to a base for performance of the inspections required by this AD per FAR's 21.197 and 21.199.
This amendment becomes effective September 25, 1974.