AD/AS 355/71 Amdt 1 - Electrical Power System

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Legislation au F2006B02521 In force Legislative Instrument

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AIRWORTHINESS DIRECTIVE


For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/AS 355/71 and issues the following AD under subregulation 39.1 (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.


 

Eurocopter AS 355 (Twin Ecureuil) Series Helicopters

 

AD/AS 355/71

Amdt 1


Electrical Power System 11/2003

 

 

Applicability: AS 355 helicopter versions E, F, F1, F2 and N, equipped for IFR flights, before embodiment of MOD 073019 or before compliance with Eurocopter AS 355 Alert Service Bulletin (ASB) No. 24.00.14, and equipped with the following part number electrical master boxes:

 

48xGC01Yxxx or 49xGC01Yxxx

 

Note 1: x in the part number indicates any digit.

 

Requirement: 1. If not previously accomplished in accordance with AD/AS 355/55 or the original issue of this Directive, revise the Aircraft Flight Manual (AFM) as follows:

 

  1. Insert the following into the Limitations Section, Operating Limitations, Electrical and Hydraulic Power Systems Limitations (Section 2.1.13):

 

Landing Lights

Do not use the landing light outside the landing and take-off phases.

 

b.        Insert the following into the Emergency Procedures Section, Systems Malfunction, Electrical Power Systems Failures (Section 3.2.5):

 

Loss of Electrical Power Generating Systems, Except for the Battery  Direct Battery Power (Indicated to the pilot by the equipment connected to the Bus Bars PP11, PP12, PP13, PP14, PP19 and PP20 - Refer to AFM Section 7.8)

 

-                                                                                                                     Apply the following procedure

 

  • Limit the aircraft speed to 100 knots (reduce this value by 1 knot every 1000 ft) in order to minimise the risk of engine limit exceedence.

 

  • Land as soon as possible

 

  • Estimate the remaining flight time taking into account the last known fuel quantity and average fuel consumption of 200 kg per hour. The remaining flight time, starting from the loss of electrical power generating systems, shall not exceed the minimum value between the previously calculated flight time and the maximum flight duration using battery power, which is 45 minutes during the day and 30 minutes at night.

 

These revisions may be accomplished by inserting a copy of this Directive into the AFM.

 

2.         If not previously accomplished in accordance with AD/AS 355/55 or the original issue of this Directive, install a placard, in clear view of the pilot, with letters of at least 6 mm (¼ inch) high, stating:

 

Do not use the landing light outside the landing and take-off phases

 

3.         Replace the non temperature-compensated contactors with temperature- compensated circuit breakers, in compliance with the instructions described in either ASB No. 24.00.14 or ASB 24.00.14 Revision 1 (corresponds to MOD 073019).

 

Following embodiment of this modification the Requirement 1 AFM revisions and the Requirement 2 placard may be removed.

 

Note 2: DGAC AD 2000-339-060(A) R3 refers.

 

Compliance: For Requirements 1 & 2 - As of the effective date of this Directive.

 

For Requirement 3 - Before 1 December 2003.

 

This Amendment becomes effective on 30 October 2003.

 

Background: AD/AS 355/55 was issued following several reports of complete loss of the electrical power generating systems, except for the direct battery power, on AS 355 helicopters. The failures occurred at a high outside air temperature (above 25°C) during long duration flights (more than one hour with landing light on).

 

AD/AS 355/55 required an AFM revision, which limits the landing light operation to take-off and landing and introduces emergency procedures for loss of the electrical power generating systems. The Directive also required a placard to be fitted advising the pilot of the landing light operational limitation.

 

The original issue of this Directive superseded the earlier AD, limited applicability to helicopters equipped for IFR flights, extended applicability to cover electrical master boxes with all part numbers and introduced a terminating action.

 

This Amendment removes the serial number range for the electrical master boxes from the Applicability Statement, references Revision 1 of the service bulletin and extends the compliance time for Requirement 2.

 

The original issue of this Airworthiness Directive became effective on 20 February 2003.


Jim Coyne

Delegate of the Civil Aviation Safety Authority 18 September 2003

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


The above AD is notified in the Commonwealth of Australia Gazette on 8 October 2003.

Overview

The Civil Aviation Safety Authority (CASA) issued the Airworthiness Directive (AD) AD/AS 355/71 Amendment 1 in 2003 to address safety concerns related to the electrical power system of Eurocopter AS 355 (Twin Ecureuil) Series Helicopters. This AD was enacted to rectify the unsafe condition identified in earlier reports of complete loss of electrical power generating systems, except for the direct battery power, on AS 355 helicopters. The original AD/AS 355/55 was superseded by this amendment, which broadened the applicability to include helicopters equipped for IFR flights and all part numbers of electrical master boxes. The primary policy objective of this AD is to enhance the safety of the aircraft by implementing specific operational limitations and emergency procedures, as well as ensuring the replacement of non-temperature-compensated contactors with temperature-compensated circuit breakers. This legislative instrument was issued under the authority of the Civil Aviation Safety Authority (CASA) to ensure compliance with the Civil Aviation Safety Regulations 1998.

Scope and Application

The Airworthiness Directive (AD) AD/AS 355/71 Amdt 1 issued under the Civil Aviation Regulations 1998 applies specifically to Eurocopter AS 355 (Twin Ecureuil) Series Helicopters, namely versions E, F, F1, F2, and N, which are equipped for IFR flights. The AD targets aircraft that have not yet incorporated modification 073019 or complied with Eurocopter Alert Service Bulletin (ASB) No. 24.00.14, and are fitted with specific electrical master box part numbers: 48xGC01Yxxx or 49xGC01Yxxx, where the 'x' denotes any digit. The directive mandates revisions to the Aircraft Flight Manual (AFM), the installation of a placard to alert pilots about the limitations on the use of landing lights, and the replacement of non temperature-compensated contactors with temperature-compensated circuit breakers. These requirements must be fulfilled by the specified compliance dates, with modifications to the AFM and placard installation required by the effective date of the directive, while the replacement of contactors must be completed before 1 December 2003. This directive applies nationally across the Commonwealth of Australia, enforced by the Civil Aviation Safety Authority (CASA). The AD extends its application through subordinate instruments, ensuring comprehensive oversight and enforcement of airworthiness standards.

Key Provisions

The Airworthiness Directive (AD) AD/AS 355/71 Amendment 1, issued under subregulation 39.1(1) of the Civil Aviation Safety Regulations 1998, is aimed at addressing safety concerns associated with the electrical power system of Eurocopter AS 355 series helicopters. This directive revokes the previous AD/AS 355/71 and introduces specific requirements to mitigate risks associated with the electrical power system, particularly under certain conditions. The directive applies to AS 355 helicopter versions E, F, F1, F2, and N, equipped for IFR flights and possessing specific electrical master boxes, before the embodiment of modification 073019 or compliance with Eurocopter ASB No. 24.00.14 (Section 1). The AD mandates several actions to be taken by the relevant parties. Firstly, operators must revise the Aircraft Flight Manual (AFM) to include specific limitations on the use of landing lights outside of the landing and take-off phases, and emergency procedures for loss of electrical power generating systems, except for the battery (Section 1). Secondly, a placard must be installed to inform the pilot of the landing light operational limitation (Section 2). Lastly, non-temperature-compensated contactors must be replaced with temperature-compensated circuit breakers in accordance with the instructions provided in ASB No. 24.00.14 or its revision (Section 3). The AFM revisions and placard may be removed once the specified modification has been embodied. Failure to comply with the requirements of this AD may result in significant safety risks, including potential loss of electrical power systems during critical phases of flight. The AD specifies compliance timelines, with certain actions required as of the effective date of the directive, and others to be completed before 1 December 2003 (Section 4). Although the AD does not explicitly outline specific penalties for non-compliance, it is likely that failure to adhere to such safety directives could result in enforcement actions under the Civil Aviation Safety Regulations 1998. These could include fines, operational restrictions, or other regulatory actions aimed at ensuring compliance with safety standards.

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