AD/EC 135/8 - FADEC Fail Warning Light (Cth)

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES

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 39.1 (1) of CAR 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.

Eurocopter EC 135 Series Helicopters

AD/EC 135/8 FADEC Fail Warning Light 12/2002 TX

Applicability: All Model EC 135 T1 helicopters.

Requirement: Amend the Aircraft Flight Manual (AFM) by inserting the appropriate pages enclosed as Appendices 1 through 4 to Eurocopter Alert Service Bulletin EC135-71A-024 dated 6 August 2002.

Note: LBA AD 2002-333 refers.

Compliance: Before further flight after the effective date of this Directive.

This Airworthiness Directive becomes effective on 27 September 2002.

Background: The German Luftfahrt-Bundesamt has received reports of a FADEC FAIL caution indicatio n being displayed on EC 135 T1 helicopters. This was caused by a discrepancy in the parameters which were generated within the fuel main metering unit and transmitted to the FADEC. This discrepancy can lead, on appearance of the FADEC FAIL caution indication, to 'freezing' of the fuel main metering valve at its momentary position, resulting in loss of the automatic engine control in the affected system. Despite measures undertaken by Turbomeca for elimination of the problem (software improvements TU19C, TU23C and TU45C), a few further FADEC FAIL cases have occurred on EC 135 T1 helicopters, for which no explanation has yet been found and by which a discrepancy in parameters at the cause cannot be ruled out.