90-10-05 CALIFORNIA DEPARTMENT OF FORESTRY; GARLICK HELICOPTERS; HAWKINS AND POWERS AVIATION, INC.; HERCULES; INTERNATIONAL HELICOPTERS, INC.; OFFSHORE CONSTRUCTION; OREGON HELICOPTERS; PILOT PERSONNEL INTERNATIONAL, INC.; SMITH HELICOPTERS; SOUTHERN AERO CORPORATION; SOUTHWEST FLORIDA AVIATION; AND WEST COAST FABRICATIONS (these helicopters were manufactured by Bell Helicopter Textron, Inc under military contract): Amendment 39-6596. Docket No 89-ASW-52.
Applicability: Model UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and TH-1L helicopters, certificated in any category.
Compliance: Required as indicated, unless already accomplished.
To prevent failure of the tail rotor duplex bearing which could result in loss of tail rotor control and subsequent loss of the helicopter, accomplish the following:
(a) Within the next 100 hours' time in service after the effective date of this AD, determine if the tail rotor gearbox duplex bearing sets, P/N 204-040-424-001, havingthe following serial numbers are installed in the tail rotor gearbox output quill, P/N 204-040-012-009:
Serial Numbers
1 thru 182
MB183 thru MB382
MB442
MB486
MB513
MB518
MB519
MB524
MB530
MB531
MB544
MB545
MB548
MB549
MB551
MB553
MB554
MB561
MB659
MB743
MB744
MB760 thru MB769
MB927 thru MB936
If a part with any of the listed serial numbers is installed, replace with a serviceable part before further flight.
(b) In accordance with FAR Sections 21.197 and 21.199, the helicopter may be flown to a base where the requirements of this AD may be accomplished.
(c) An alternate method of compliance or adjustment of the compliance time that provides an equivalent level of safety may be used when approved by the Manager, Rotorcraft Certification Office, ASW-170, Rotorcraft Directorate, FAA, Southwest Region, Fort Worth, Texas.
This amendment (39-6596, AD 90-10-05) becomes effective on June 5, 1990.