AD 78-26-04

78-26-04 HUGHES HELICOPTERS: Amendment 39-3374. Applies to Hughes Model 269C, Serial Number 0004 through 0716, and Models 269A, 269A-1, and 269B certificated in all categories, equipped with LTS Tail Rotor Assembly P/N 269A6034, including Military Model TH-55A equipped with LTS Tail Rotor Assembly P/N 269A6034, equipped with Tail Rotor Hub Assembly Part No. 369A1725 or Tail Rotor Hub Assembly Part No. 369A1725-5, Serial No. 001 through 862.

Also, applies to Hughes Model 369H, 369HM, 369HS, 369HE and 369D, Serial Numbers 0001D through 0324D and 0331D through 0333D certificated in all categories, equipped with Tail Rotor Hub Assembly Part No. 369A1725 or Tail Rotor Hub Assembly Part No. 369A1725-5, Serial No. 001 through 862 or Tail Rotor Hub Assembly Part No. 369A1725- 501.

Compliance required as indicated.

To prevent failure of Tail Rotor Hub Assembly, Hughes P/N 369A1725, 369A1725-5, Serial No. 001 through 862 and 369A1725-501, which could result in a loss of the rotorcraft, accomplish the following:

(a) Within 100 hours time in service or six months after the effective date of this AD, whichever occurs sooner, unless already accomplished, inspect the tail rotor hub for cracks, corrosion or other damage and rework the tail rotor hub in accordance with Part II - Hub Inspection and Rework Paragraphs a through h of the following FAA approved Hughes Service Information Notices:

(1) For Hughes Model 269 Series Helicopter use Hughes Service Information Notice No. N-153, dated September 1, 1978.

(2) For Hughes Model 369H Series Helicopter use Hughes Service Information Notice No. HN-128.1, dated December 8, 1978.

(3) For Hughes Model 369D Series Helicopter use Hughes Service Information Notice No. DN-27.1, dated December 8, 1978.

NOTE: Hughes Service Information Notices of the above listed dates are the only versions of S.I.N.s suitable for compliance with this AD.

(b) Remove all cracked hubs from service prior to further flight and replace with like serviceable part. If replacement part has part number suffix identification SP, no further action is required by this AD. If replaced with part number hub affected by this AD, revert to the inspection requirements of Paragraph (c).

(c) Reinspect the tail rotor hub with a 10 power magnifying glass at each annual inspection or 300 additional hours time in service since the last inspection, whichever occurs earlier. If cracks, pits, corrosion or other damage is found, inspect and rework, per the instructions of Paragraphs (a) and (b).

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

This amendment becomes effective December 27, 1978.