1AD/BELL 412/39 Amdt 1 - Tail Rotor Yoke and Tail Rotor Flapping Stop/Indicator

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Bell Helicopter Textron 412 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/BELL 412/39 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/BELL 412/39

Amdt 1

Tail Rotor Yoke and Tail Rotor Flapping Stop/Indicator

8/2001

Applicability: All Model 412, 412CF, and 412EP helicopters, with tail rotor yoke assembly, part number 212-011-702-all dash numbers, installed.

Requirement: 1. Review the historical records of the yoke assembly, for any static or dynamic overload damage that could have imposed a bending load on the yoke. The damage may not have required replacing the yoke assembly; for example, an incident in which a damaged tail rotor blade was replaced due to a blade strike. If the records indicate that overload damage may have occurred, replace the yoke with a serviceable yoke.

2. (a) Install a Never Exceed Velocity (Vne) red line at 120 knots indicated airspeed (KIAS) on the pilot and copilot airspeed indicators using red tape or paint, and a slippage indicator on the instrument case and glass.

(b) Install a placard made of material that is not easily erased, or disfigured, or obscured on the instrument panel in clear view of the pilot and copilot:

“Observe temporary Maximum Never Exceed (Vne) airspeed red line (marked at 120 knots indicated airspeed (KIAS). Vne is 20 KIAS less than the value presented on the airspeed limitation placard for each ambient condition”.

(c) A Rotorcraft Flight Manual Temporary Revision, dated 16 August 1996 is required.

3. (a) Remove rotor yoke assembly, part number 212-011-702-all dash numbers, and replace it with a serviceable yoke assembly, part number 212-011-702-all dash numbers, with zero hours time in service, or an airworthy yoke that has passed a one-time x-ray diffraction inspection in accordance with Bell Helicopter Textron Alert Service Bulletin (ASB) 412-96-89 Revision A, dated 17 October 1997, or ASB 412CF-96-01, dated 3 September 1996, as applicable.

(b) Install a serviceable tail rotor flapping stop, part number 212-011-713-103.