AD/B747/374 - Korry Pushbutton 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.

Boeing 747 Series Aeroplanes AD/B747/374 Korry Pushbutton Switches 4/2008

Applicability: Model 747-400, -400D and -400F series aeroplanes as identified in Boeing Alert Service Bulletin (ASB) 747-33A2280, Revision 1, dated 25 September 2003. Requirement: 1. Either: a. Carry out a general visual inspection of the switches identified for the panel assemblies specified in ASB 747-33A2280, Revision 1 to identify configuration `D' master modules and the part number (P/N) of the switch; or b. Inspect the panel assemblies identified in ASB 747-33A2280, Revision 1 to determine the part number (P/N). If the P/N is identified as a new P/N in Appendix B of the service bulletin, no further action is required. Note 1: For the purposes of this Directive, a general visual inspection is "A visual examination of a interior or exterior area, installation or assembly to detect obvious damage, failure or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normal available lighting conditions such as daylight, hangar lighting, flashlight or drop-light and may require removal or opening of access panels or doors. Stands, ladders or platforms may be required to gain proximity to the area being checked.'' Note 2: ASB 747-33A2280, Revision 1 refers to Korry Service Bulletin (SB) 433-33-05, dated 23 July 2001, as an additional source of service information for finding configuration `D' switches, for replacing the switch master module with a configuration `D' master module, and for doing various operational tests after the replacement. 2. If, as a result of the Requirement 1.b. inspection, the P/N is not identified as a new P/N, the inspection required by Requirement 1.a. must be accomplished. 3. If, during any Requirement 1.a. inspection, any switch is found that does not have a configuration `D' switch master module and the switch P/N is not specified Table 1, carry out either of the following and do the part number revision in accordance with Requirement 3.c: