AD 86-22-04

86-22-04 ROGERSON HILLER CORP.: Amendment 39-5430. Applies to Model UH-12D, UH-12E, and UH-12E4 series helicopters, including military Models OH-23F and OH-23G, and all those converted in accordance with STC's SH177WE and SH178WE, certificated in any category, equipped with main rotor blade assembly Parson's P/N 2253-1101-04 or 2253-1101-03. This AD supersedes AD 80-14-12, Amendment 39-3836.

Compliance is required as indicated, unless already accomplished.

To prevent main rotor blade failure due to cracking of the spar or delamination of the trailing edge skin from the spar, accomplish the following:

(a) Prior to the first flight of each day after the effective date of this AD, visually check the main rotor blades (P/N 2253-1101-04 or -03) for cracks in the leading edge area identified in figure 1 of Rogerson Hiller Service Bulletin (SB) No. UH12-51-6, dated December 19, 1985.

(b) Within the next 25 hours' time in service after the effective date of this AD and thereafter at intervals not to exceed 25 hours' time in service from the last inspection, conduct a dye penetrant or magnaflux inspection of the blade for cracks in accordance with paragraph IIB of Rogerson Hiller SB No. UH12-51-6, dated December 19, 1985.

(c) Within the next 100 hours' time in service after the effective date of this AD and thereafter at intervals not to exceed 100 hours' time in service from the last inspection, conduct a visual and coin tap inspection of the spar to trailing-edge-skin bond line for corrosion and voids in accordance with paragraph IIC of Rogerson Hiller SB No. UH12-51-6, dated December 19, 1985.

(d) If the blade has not been overhauled and has over 1,000 hours' time in service, or has had the 2,500-hour overhaul and has more than 3,500 hours' time in service, overhaul the blade within the next 100 hours' time in service and thereafter at intervals not to exceed 1,000 hours' time in service.

(e) When the overhauls required by paragraph (d) have been accomplished, conduct the dye penetrant checks required by paragraph (b) at intervals not to exceed 100 hours' time in service.

NOTE 1: The overhauls required by paragraph (d) may be accomplished by an FAA authorized repair station whose certificate indicates approval for overhaul or major repair of Fairchild Hiller main rotor blades.

NOTE 2: A maintenance record entry showing compliance with this AO is required by FAR Section 91.173.

(f) If discrepancies are found as a result of compliance with this AD which exceed the limitations specified in Rogerson Hiller SB No. Uh12-51-6, dated December 19, 1985, replace the blade prior to further flight.

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

(h) Alternative inspections, modifications, blade overhaul methods, or other actions which provide an equivalent level ofsafety may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region.

This procedure shall be done in accordance with Rogerson Hiller Service Bulletin UH12- 51-6, revised December 19, 1985. This incorporation by reference was approved by the Director of the FEDERAL REGISTER in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from Rogerson Hiller Corporation, 2140 West 18th Street, Port Angeles, Washington 98362-0262.

Copies may be inspected at the Office of Regional Counsel, FAA, 4400 Blue Mound Road, Fort Worth, Texas or at the Office of the FEDERAL REGISTER, 1100 L Street, NW., Room 8401, Washington, D.C.

This amendment supersedes Amendment 39-3836 (45 FR 46345), AD 80-14-12. This amendment becomes effective November 3, 1986.