1AD/HU 269/28 Amdt 3 - Main Rotor Thrust Bearing P/N 269A5050-50 or -51 Nut and Mast - Inspection and Modification

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Schweizer (Hughes) 269 Series Helicopters

AIRWORTHINESS DIRECTIVE

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For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/HU 269/28 Amdt 2 and issues the following AD under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

AD/HU 269/28

Amdt 3

Main Rotor Thrust Bearing P/N 269A5050-50 or

-51 Nut and Mast - Inspection and Modification

8/2000

Applicability: Model 269A helicopters, S/N 0011 to 1109, Model 269A-1 helicopters, S/N 0001 to 0041, Model 269B helicopters, S/N 0001 to 0444 and model TH-55A with main rotor thrust bearing P/No 269A5050-50, -51 or -73 installed.

Requirement: 1. Examine the helicopter records to determine P/N of main rotor thrust bearing.

(a) If bearing P/No 269A5050-50 or -51 is fitted, inspect in accordance with Step II, paragraph b. of Schweizer Service Notice (SSN) No N-59, dated October 9, 1968.
(b) If bearing P/No 269A5050-73 is fitted. Inspect for corrosion, rust, freedom of rotation, looseness, binding, nicks, burrs, cracks and lubrication. Repack the bearing cavity in accordance with Schweizer Aircraft Corporation CKP-C-41 “Installation Instructions for 269 Series Helicopters, SA-269K-057-1 Main Rotor Thrust Bearing Kit,” dated June 9, 1994.

Note 1: Bearing P/N 269A5050-50 and 269A5050-51 have a 300 hour retirement life while bearing P/N 269A5050-73 has a 3000 hour retirement life.

2. Inspect the thrust bearing nut P/N 269A1306-5 for corrosion and physical damage and confirm nut has been modified in accordance with Step III of SSN No 59. Replace any nut found damaged, corroded or not modified.
3. Inspect interior of main rotor mast for corrosion, damage, foreign material, moisture or inadequate drainage due to a build up of zinc chromate paste and determine whether the mast has been modified in accordance with Step II of SSN No 59. If mast has not been modified, modify mast in accordance with Step III of SSN No 59.