AD/PHS/24 Propeller System Actuator Yoke Arms (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(1) of CASR 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.

Propellers - Variable Pitch - Hamilton Standard

AD/PHS/24 Propeller System Actuator Yoke Arms 8/2006

Applicability:

Hamilton Sundstrand Model 14RF-19 propellers with propeller system actuator yoke arms, part number (P/ N) 810436-2, which might be installed in actuator assemblies P/N 790119-6.

Note 1:  These propellers are installed on, but not limited to, SAAB 340 airplanes.

Requirement:

1.    Replace all actuator yoke arms, P/N 810436-2 with improved actuator yoke arms, P/N 810436-3 in accordance with the Accomplishment Instructions of Hamilton Sundstrand Service Bulletin 14RF-19-61-113, Revision 1, dated 2 September 2003 or later FAA approved revisions.

2.    Mark newly installed actuators in accordance with the Accomplishment instructions of Hamilton Sundstrand Service Bulletin 14RF-19-61-113, Revision 1, or later FAA approved revisions.

3.    Do not install any actuator yoke arms, P/N 810436-2, into any propeller assembly.

Note 2:  FAA AD 2006-12-19 Amdt 39-14645 dated 6 June 2006 refers.

Compliance:

1.    Within 60 days after the effective date of this AD, unless previously accomplished.

2.    Within 60 days after the effective date of this AD, unless previously accomplished.

3.    From the effective date of this AD.

This Airworthiness Directive becomes effective on 3 August 2006.

Background: This AD results from propeller system actuator yoke arms breaking during flight.  The requirements of this AD are intended to prevent actuator yoke arms breaking during flight, which could cause high propeller vibration and contribute to reduced controllability of the airplane.

James Coyne
Delegate of the Civil Aviation Safety Authority

20 June 2006