72-13-08 FAIRCHILD-HILLER: Amendment 39-1471 as amended by Amendment 39-1539.
Applies to Fairchild Hiller UH-12L, UH-12L4, and UH-12E-L helicopters certificated in all categories.
1. Within 10 hours in service after effective date of this airworthiness directive remove from service P/N 53100-01 main rotor blades S/N's 5, 21, 29, 66, 71, 74, 88, 125, 129, 130, 132, 142, 143, 158, 159, 160, 161, 162, 171, and 176, and replace with blades P/N 53100-01 with S/N's other than those listed.
2. Within 30 hours time in service after the effective date of this airworthiness directive, inspect and alter all other main rotor blades in accordance with Fairchild Hiller Service Bulletin SBUH12L-51-1, 7/31/72, Para. 2A thru 2K, or equivalent method approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region.
Amendment 39-1539 was effective June 27, 1972, and was effective for all recipients of the air mail notice dated May 11, 1972 which contained this airworthiness directive.
This amendment 39-1539 is effective October 19, 1972.