AD 78-22-02

78-22-02 HILLER HELICOPTER: Amendment 39-3320. Applies to Hiller Model UH- 12D, UH-12E, and UH-12E(4 Place) certificated in all categories including Military Models UH- 23D, UH-23G, H-23F and turbine powered models, equipped with main rotor blades assembly, Parson Part No. 2253-1101-03 or 2253-1101-04.

Compliance required as indicated.

To prevent failure of the main rotor blade Parson Part No. 2253-1101-03 and 2253-1101- 04 antinode outboard retention system, which could result in a loss of the rotorcraft, accomplish the following:

(a) Before further flight after receipt of this AD, unless already accomplished, inspect the threaded end of the antinode bar outboard of the antinode weight anchor nut according to the following instructions:

(1) Remove the antinode bar assembly per paragraph 4.53 of UH-12E/UH- 12L Series Structural Repair Manual.

(2) Clean thread outboard of the antinode weight anchor nut with a suitable wire brush.

(3) Using a micrometer, measure the thread major diameter.

(i) If the rod thread major diameter is between .3678 and .3750 inches, no further action is required for this AD and the rod may be reinstalled per instructions contained in the Structural Repair Manual.

NOTE: CAUTION. Use extreme care in reinstalling the antinode bar assembly to ensure that the screws attaching the anchor nut to the antinode bar are not sheared. Hand pressure is the maximum force allowed.

(ii) If the rod thread major diameter measures .3677 inch or less, before returning to service:

(A) Return the rotor blade(s) to Hiller Aviation or an FAA approved repair station to replace the antinode bar assembly, or

(B) Replace the antinode bar assembly per Hiller Service Bulletin 51-4 dated September 26, 1978.

NOTE: Hiller Service Bulletin 51-4 dated September 26, 1978 is the only version of the service bulletin suitable for compliance with this AD.

(b) Special flight permits may beissued in accordance with FARs 21.197 and 21.199 to operate aircraft to a base for accomplishment of the repair required by paragraph (a) of this AD.

(c) Equivalent inspection procedures and repairs may be used when approved by the Chief, Aircraft Engineering Division, FAA Western Region.

(d) Record the rod thread major diameter on the appropriate blade record card.

(e) Report the helicopter serial number, blade serial number, blade total time and the antinode rod thread major diameter to the Chief, Aircraft Engineering Division, FAA Western Region, P.O. Box 92007, World Way Postal Center, Los Angeles, Ca 90009. (Reporting approved by the Bureau of the Budget under BOB No. 04-R0174.)

This amendment is effective October 27, 1978 and was effective upon receipt for all recipients of the priority mail letter dated September 22, 1978 which contained this amendment.