89-17-03 CALIFORNIA DEPARTMENT OF FORESTRY; GARLICK HELICOPTERS; HAWKINS AND POWERS AVIATION, INC; HERCULES; INTERNATIONAL HELICOPTERS, INC; OREGON HELICOPTERS; PILOT PERSONNEL INTERNATIONAL, INC; SMITH HELICOPTERS; SOUTHERN AERO CORPORATION, AND WEST COAST FABRICATIONS (these helicopters were manufactured by Bell Helicopter Textron, Inc., under military contract): Amendment 39- 6251. (Airworthiness Docket No. 88-ASW-33)
Applicability: Model UH-1A, UH-1B, UH-1E, UH-1F, UH-1L, and TH-1L helicopters certificated in any category.
Compliance: Required as indicated, unless already accomplished.
To prevent possible fatigue failure of the main rotor masts, part number (P/N) 204-011- 450-001, -005, -007, -101, -105, -109, and -113, and main rotor trunnion, (P/N) 204-011-105-001, which could result in a catastrophic failure of the main rotor system and subsequent loss of the helicopter, accomplish the following:
(a) Within 10 days after the effective date of this AD,create a historical service record for the main rotor mast, (P/N) 204-011-450-001, -005, -007, -101, -105, -109, and -113, and main rotor trunnion, (P/N) 204-011-105-001, and record the hours' time in service accumulated on the main rotor mast and trunnion. If the time in service cannot be determined, enter 900 hours for each year from the date the mast and trunnion were installed.
(b) For masts and trunnions with more than 14,900 hours' time in service on the effective date of this AD, remove the masts and trunnions from service within the next 100 hours' time in service.
(c) For masts and trunnions with less than 14,900 hours' time in service on the effective date of this AD, remove the masts and trunnions from service at 15,000 hours' time in service.
(d) An alternate means of compliance which provides an equivalent level of safety with this AD may be used when approved by the Manager, Rotorcraft Certification Office, ASW-170, Federal Aviation Administration, Fort Worth, Texas 76193-0170.
This amendment (39-6251, AD 89-17-03) becomes effective on September 5, 1989.