AD/B747/359 - Flight Deck Humidifier (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/B747/359 Flight Deck Humidifier 9/2007

Applicability: Boeing Model 747-400 series aeroplanes as identified in Boeing Service Bulletin 747-21A2414, Revision 3, dated 12 May 2006. Requirement: 1. For Model 747-400 series aeroplanes identified as Group 1 in Boeing Service Bulletin 747-21A2414, Revision 3:

(a) Do the replacement specified in Requirement 1(b) or 1(c) of this AD. For flight deck humidifiers with a blanking plate: If the blanking plate is removed and a new or supplier-tested cell stack is installed, the replacement must be done in accordance with the Accomplishment Instructions of Hamilton Sundstrand Service Bulletins 821486-21-01, dated 15 March 2000; and after the replacement, the flight deck humidifier may be activated in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-21-2405, Revision 4, dated 29 July 1999.

Note 1: Boeing Service Bulletin 747-21A2414, Revision 3, specifies Group 1 as "all 747-400 aeroplanes with Hamilton Sundstrand flight deck humidifier 821486-01." The correct part number (P/N) for the humidifier is 821486-1.