73-17-04 BELL: Amdt. 39-1704. Applies to Bell Model 204B and 205A-1 helicopters certificated in all categories.
Compliance required within 5 hours time in service after the effective date of this A.D. for tail rotor grips with 495 or more hours total time in service on the effective date of this A.D., and prior to attaining 500 hours time in service for tail rotor grips with less than 495 hours total time in service on the effective date of this A.D., except that the aircraft may be flown in accordance with FAR 21.197 to a base where the inspections can be performed.
To prevent possible failure of the tail rotor grips, P/N 204-011-706 or 204-011-728, as applicable, to preclude corrosion in the retaining threads of the tail rotor grip, and to assure serviceable condition of the tail rotor grip bearings, accomplish the following:
(a) Remove the tail rotor hub and blade assembly from the helicopter, remove the blades from the grips, and remove the grips from the hub assembly in accordance with the appropriate model maintenance manual.
(b) Remove the tail rotor grip bearings from each yoke spindle and inspect the bearings for roughness or seizure. If the bearings are rough and unserviceable, replace the bearings prior to next flight.
(c) Replace the tail rotor grips prior to next flight.
(d) Assemble the tail rotor hub and blade assembly as noted in Section VI of Model 204B Maintenance and Overhaul Instruction Manual, or Section III of Model 205A/205A-1 Maintenance and Overhaul Instruction Manual, as applicable. Apply sealant to the inboard end of each grip as specified in Bell Helicopter Co. Service Letter No. 204B-86/205A-68, dated 12 February 1971, or later FAA approved revision, or as specified by an equivalent method approved by the Chief, Engineering and Manufacturing Branch, Flight Standards Division, Southwest Region, FAA. Balance the assembly as noted in the appropriate model maintenance manual.
(e) Install and track the tail rotor hub and blade assembly as noted in Section VI of Model 204B Maintenance and Overhaul Instruction Manual, or Section III of Model 205A/205A- 1 Maintenance and Overhaul Instruction Manual, as applicable.
(f) The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to the Service Manager, Bell Helicopter Company, P.O. Box 482, Fort Worth, Texas 76101.
These documents may also be examined at the Office of the Regional Counsel, Southwest Region, FAA, 4400 Blue Mound Road, Fort Worth, Texas, and at FAA Headquarters, 800 Independence Ave., S.W., Washington, D.C. A historical file on this A.D. which includes the incorporated material in full is maintained by the FAA at its headquarters in Washington, D.C., and at the Southwest Region Office in Fort Worth, Texas.
(Bell Helicopter Company Service Bulletin Nos. 204-05-73-2, Rev. A, and 205-05-73-4, Rev. A, dated July 25, 1973, pertain to this subject.)
This supersedes Amendment 39-1470, 37 F.R. 12308, A.D. 72-13-06.
This amendment becomes effective August 20, 1973.