AD/A330/52 Electronic Instrument System Display Units (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.
Airbus Industrie A330 Series Aeroplanes
| AD/A330/52 | Electronic Instrument System Display Units | 10/2005 TX |
Applicability: | Airbus A330 aeroplanes, all certified models, all serial numbers, equipped with Electronic Instrument System EIS 2 software L4-1 installed through modification 51153 during production or Airbus Service Bulletin (SB) A330-31-3057 or |
Requirement: | 1. Perform the ‘switching on/switching off’ procedure of Electronic Instrument System (EIS) Display Units (DU) in accordance with Airbus All Operators Telex (AOT) A330-31A3092 dated 1 August 2005 or later revision approved by the French Direction Générale de l’Aviation Civile (DGAC). 2. Repeat the Requirement 1 procedure. |
| A complete electrical shut down of the aircraft is also acceptable to reset the DUs and is an alternative means to the above procedure. | |
| Note: DGAC AD UF-2005-150 (EASA Approval 2005-6144) refers. | |
Compliance: | 1. No later than two days after the effective date of this Directive and without exceeding four days from the last DU reset or aircraft complete power off. 2. At intervals not to exceed four calendar days. |
| This Airworthiness Directive becomes effective on 12 August 2005. | |
Background: | The DGAC has advised that an operator reported the simultaneous blanking of three EIS DUs on an A330 aircraft during flight. These DUs went blank and displayed the message “INVALID DISPLAY UNIT”. The DU’s were recovered automatically after approximately 40 seconds and the flight was continued normally. The analysis of Display Management Computer (DMC) data confirmed the three DUs had undergone a simultaneous automatic reset followed by a power on self-test. The investigation shows that after a continuous power on of a DU for more than six days, an internal timer reaches a limit that provokes an automatic reset. |
| A situation where both the EIS DUs and standby instruments are simultaneously unavailable may have unsafe consequences in certain phases of flight. Actions required by this Directive are designed to prevent automatic reset of several DUs in flight by performing a periodic ‘switching off/switching on’ procedure whilst the aircraft is on the ground. This procedure will reinitialise the internal timer of all the DUs. |
James Coyne
Delegate of the Civil Aviation Safety Authority
11 August 2005
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