AD 77-07-05 R1

77-07-05 HILLER AVIATION: Amendment 39-2862 as amended by Amendment 39-2917. Applies to Hiller Model UH-12, UH-12A, UH-12B, UH-12C, UH-12D, UH-12E UH-12E (4- place), (including military Models H-23A, H-23B, H-23C, H-23D, H-23F, OH-23G, HTE-1, HTE-2, and CH112) helicopters, certificated in all categories.

Compliance required as indicated, unless already accomplished.

To detect cracks in the control rotor blade spar tube and cuff and to establish a service life of 6860 hours for Hiller P/N 36124 cuff used with unfaired paddles accomplish the following:

(a) Within the next 100 hours time in service after the effective date this AD, unless already accomplished within the last 100 hours time in service and thereafter at intervals not to exceed 100 hours time in service from the last inspection, inspect, replace or repair the control rotor blade spar tube and cuff in accordance with Hiller Aviation Service Bulletin No. 36-1, Revision 2, dated June 19, 1974, or later FAA-approved revisions.

(b) After any repair is accomplished in accordance with Hiller Aviation Service Bulletin No. 36-1, Revision 2, dated June 19, 1974 or later FAA-approved revisions, the control rotor blade spar tube (faired and unfaired) and cuff must be retired before 2500 additional hours time in service after rework or when the current approved total service life (total service life before repair plus service life after repair) is reached, whichever comes first.

(c) Fabric covered, metal covered, faired and unfaired control rotor blades are not interchangeable and must not be intermixed.

(d) For Hiller P/N 36124 cuffs used with unfaired paddles

(1) Cuffs with more than 6660 hours time in service, remove and replace with a serviceable part within 200 hours time in service after the effective date of this AD.

(2) Cuffs with less than 6660 hours time in service, remove and replace with a serviceable part prior to 6860 hours time in service.

(3) For cuffsfor which the prior service history cannot be documented, within the next 25 hours time in service, unless already accomplished within the last 25 hours time in service prior to the effective date of this AD and at intervals not to exceed 50 hours time in service, perform a dye penetrant inspection of the cuff per Hiller Aviation Service Bulletin, No. 36-1, Revision 2, dated June 19, 1974, or later FAA approved revisions. Remove cracked cuffs from service prior to further flight. Cuffs for which the prior service history cannot be documented cannot be used as a replacement part. Remove from service all cuffs prior to the accumulation of 225 hours total time in service since April 7, 1977.

(e) Equivalent inspection procedures and repair procedures for Hiller P/N 36124 cuff when used only with unfaired paddles may be approved by the Chief,Aircraft Engineering Division, FAA Western Region.

(f) Special flight permits may be issued in accordance with FAR's 21.197 and 21.199 to operate helicopters to a base for accomplishment of the inspections required by this AD.

Amendment 39-2862 superseded Amendment 39-1990 (39 F.R. 36855), AD 74-21-05.

Amendment 39-2862 became effective April 7, 1977.

This amendment 39-2917 becomes effective June 20, 1977.