AD/F406/16 Avionics Bus Circuit Breaker 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.

Reims Aviation F406 Series Aeroplanes

AD/F406/16 Avionics Bus Circuit Breaker Switches 8/2006

Applicability:	F406 aircraft, with serial number F406-0001 and subsequent.
Requirement:	1.    Inspect the avionics bus circuit breaker switches part number (P/N) CM3589-50 in accordance with Reims Aviation Industries Service Bulletin (SB) F406-62 dated 8 March 2006 to determine their date code.
Note 1:  The date code will have four digits.  The first two represent the year of manufacture while the last two represent the week of the same year (ie date code 0434 represents the 34th week of 2004).
2.    If, as a result of the Requirement 1 inspection, switches are found not to have a date code, replace the switches by improved design switches P/N 4061-2400-1 or CM3589-50 that have a date code of 0434 or later in accordance with SB F406-62.
3.    If, as a result of the Requirement 1 inspection, switches are found to have a date code earlier than 0434, replace the switches by improved design switches P/N 4061-2400-1 or CM3589-50 that have a date code of 0434 or later in accordance with SB F406-62.
4.    P/N CM3589-50 switches that do not have a date code, or have a date code earlier than 0434, may not be installed on any aeroplane as a replacement spare.
Later revisions of the above service bulletin approved by the European Aviation Safety Agency (EASA) may be utilised for compliance with applicable requirements of this Directive.
Note 2:  EASA AD 2006-0134 refers.
Compliance:	For Requirement 1 - Within the next 200 hours time in service (TIS) or 12 months after the effective date of this Directive or at the next scheduled inspection whichever occurs first.
For Requirement 2 - Before further flight after the requirement 1 inspection.
For Requirement 3 - Before the switches reach 1 000 hour TIS safe life limit.
For Requirement 4 - As of the effective date of this Directive.

This Airworthiness Directive becomes effective on 3 August 2006.

Background:

The United States Federal Aviation Administration (FAA) has issued AD 2005-20-25 (Australian AD/CESSNA 400/113 refers) concerning Cessna 400 series equipped with an avionics bus circuit breaker switch, P/N CM3589-50, 593-250-101,
593-250-12, W31-X2M5A-50 or W31-X1000-50.  Reims Aviation Industries has determined that switch P/N CM3589-50 is also installed on the F406 model.

This Directive intends to prevent failure of the avionics bus circuit breaker switch, which could result in smoke and a burning smell in the cockpit and lead to a reduced ability to control the airplane.  The Directive mandates an inspection to check the date code of the switches and a replacement of the switches as necessary.  It also introduces an improved design switch P/N 4061-2400-1 and a 1 000 hour TIS safe life limit for P/N CM3589-50 switches with a date code earlier than 0434.

James Coyne
Delegate of the Civil Aviation Safety Authority

21 June 2006