AD 59-25-03

59-25-03 HILLER: Applies to Hiller UH Series Helicopters As Follows:

(a) UH-12 and UH-12A - incorporating both P/N 34126 wobble plate shield and P/N 34158 forged lower cyclic scissors. (b) UH-12B and UH-12C - incorporating the P/N 34158 forged lower cyclic scissors. (c) UH-12D - all Serial Numbers. (d) UH-12E - Serials 942, 954, and 2001 through 2018.

Compliance required as indicated.

To prevent contact between the lower cyclic scissors and the filister head screws attaching the wobble plate shield, which can result in damage to the lower scissors and subsequent loss of cyclic control, the following inspection and rework are required.

(1) Daily inspect the lower cyclic scissors P/N 34158 on all models, or P/N 34141 on Models UH-12D and UH-12E for damage due to striking the wobble plate shield attachment screws. Damaged scissors must be replaced prior to next flight.

(2) Not later than January 1, 1960, replace the filister head screws attaching thewobble plate shield with AN 509-8R4 flush head screws in accordance with the procedures in Hiller Service Bulletins No. 87 or No. 2004.

(3) Upon accomplished of item (2) the inspections of item (1) may be discontinued.