Ad/Beech 77/16 - Circuit Breaker Toggle Switches (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.

Beechcraft 77 (Skipper) Series Aeroplanes

AD/BEECH 77/16 Circuit Breaker Toggle Switches 10/2008

Applicability:	Aeroplane models and serial numbers listed in Table 1 that have any circuit breaker toggle switch with a part number (P/N) 35-380132-1 through 35-380132-53 installed.
Table 1
Model	Serial Number Range
77	WA-1 through WA-312
Requirement:	1.    Unless previously accomplished, replace all circuit breaker toggle switches P/N 35-380132-1 through 35-380132-53 with an improved circuit breaker toggle switch, P/N 35-380132-61 through 35-380132-113, as applicable, as specified in Raytheon Aircraft Company (RAC) Recommended Service Bulletin SB 24-3735, Issued: August 2005.
2.    Circuit breaker toggle switches P/N 35-380132-1 through 35-380132-53 may not be installed on any aeroplane as an initial fit or as a replacement spare.
Later revisions of the above SB, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2008-13-17, are considered acceptable for compliance with the equivalent Requirements of this Directive.
Note:  FAA AD 2008-13-17 Amdt 39-15580 refers.
Compliance:	For Requirement 1 - Within the next 24 months after the effective date of this Directive.
For Requirement 2 - Before further flight after the circuit breaker toggle switch has been replaced in accordance with Requirement 1.
This Airworthiness Directive becomes effective on 25 September 2008.
Background:	The FAA has received reports of certain circuit breaker toggle switches used in various electrical systems throughout Beech F33, F33A, F33C, G33, V35B, A36, A36TC, B36TC, 95-B55, D55, E55, A56TC, 58, 58P, 58TC, G58 and 77 model aeroplanes overheating. Failure of the circuit breaker toggle switch could result in smoke in the cockpit and the inability to turn off the switch.

This Directive follows the intent of the FAA Directive, requiring the replacement of circuit breaker toggle switches with a P/N 35-380132-1 through 35-380132-53.  However, it is revised to allow prior accomplishment, as the RAC service bulletin was issued in 2005 and may have already been accomplished.  The Directive also extends compliance by 13 months until 25 September 2010, the final compliance time required by the FAA was 6 August 2009.

A draft version of this Directive was posted for public comment on the Civil Aviation Safety Authority (CASA) internet site on 9 July 2008.  As of the date that this Directive was made, no comments or objections have been received by CASA.

James Coyne
Delegate of the Civil Aviation Safety Authority

8 August 2008