AD/Cessna 208/26 Autopilot Roll and Yaw Servos Bridle Cable Clamps (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.

Cessna 208 Series Aeroplanes

AD/CESSNA 208/26 Autopilot Roll and Yaw Servos
Bridle Cable Clamps 9/2009 DM

Applicability:

Model 208 aircraft, serial numbers 20800500 through 20800504.

Model 208B aircraft, serial numbers 208B1216, 208B2001, 208B2003 through 208B2023, 208B2025 through 208B2029, 208B2031 through 208B2037, 208B2040, 208B2042 and 208B2043.

Requirement:

Measure and adjust as necessary the roll bridle cable tension and yaw bridle cable tension, and torque the 12 bridle cable clamp screws, in accordance with the Accomplishment Instructions, paragraphs 2. through 7, of Cessna Aircraft Company Caravan Service Bulletin CAB08-9, dated 24 November 2008, or later FAA approved revision.

Within 10 days after accomplishment of the above inspection, record the results/information requested by the Figure 1 Inspection Report form of FAA AD 2009-15-05, and send to [email protected] unless the inspection was accomplished before the effective date of this Directive.

Note:  FAA AD 2009-15-05 Amdt 39-15968 refers.

Compliance:

Within 10 hours time in service after 27 July 2009, unless already accomplished.

This Airworthiness Directive becomes effective on 27 July 2009.

Background:

The FAA received two reported incidences of low tensioned bridle cables for the autopilot aileron servo; with the swaged balls unseated from their drum recesses.  Since the rudder autopilot interface is similar, the same condition could exist.  Loose bridle cable clamps, unless detected and corrected, could result in the swaged ball unseating from the recess in the servo drum and contacting the cable guard pin.  This failure could lead to very limited control of the rudder and/or aileron with consequent loss of control.

David Villiers
Delegate of the Civil Aviation Safety Authority

17 July 2009