AD/AMD 50/41 - Oxygen - Incompatible Passenger Mask Boxes (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.

AMD Falcon 50 and 900 Series Aeroplanes AD/AMD 50/41 Oxygen - Incompatible 5/2007 Passenger Mask Boxes

Applicability: Falcon 900EX aeroplanes serial numbers (S/N) 120 through 146 inclusive, that have not implemented Dassault Aviation Service Bulletin (SB) F900EX-257 dated 15 March 2006 or SB F900EX-257 Revision 1 dated 22 March 2007. Requirement: Replace the passenger oxygen mask boxes in accordance with SB F900EX-257 or later revision approved by the European Aviation Safety Agency (EASA). Note: EASA AD 2007-0073 refers. Compliance: No later than 30 June 2008. This Airworthiness Directive becomes effective on 10 May 2007. Background: On early Falcon aeroplanes featuring the EASy cockpit, a new electropneumatic oxygen (O2) controller was installed. An internal review by Dassault Aviation has determined that the passenger oxygen mask boxes are not compatible with this new controller. In OVERRIDE mode, when the internal pressure reducer is by-passed, O2 flow is nominal, while in NORMAL mode, O2 flow is reduced by half compared to what it should be.

Consequently, in NORMAL mode, the minimum mass flow of supplemental O2 for each passenger, as required by Certification Specifications, is no longer met. This could lead to passengers' incapacitation due to insufficient body oxygenation.