AD/DHC-8/66 - In-Flight Selection of Ground Beta

Overview

The Civil Aviation Regulations 1998, enacted by the Commonwealth of Australia, are the primary regulations governing civil aviation safety. Within this framework, Part 39 - 105 Civil Aviation Safety Authority Schedule of Airworthiness Directives includes AD/DHC-8/66, which was introduced to address the problem of in-flight selection of ground Beta on Bombardier (Boeing Canada/De Havilland) DHC-8 Series aeroplanes. This issue has been identified as potentially leading to engine failure and propeller overspeed. The policy objective of this directive is to enhance flight safety by requiring specific modifications and updates to the aircraft’s systems and equipment. The modifications include the installation of warning horns and logic disarmers, as well as amendments to the Minimum Equipment List (MEL) to allow limited operation without certain systems, provided that safety thresholds are met. The Civil Aviation Safety Authority (CASA) has set compliance deadlines to ensure that these safety measures are implemented promptly across the affected fleet.

Scope and Application

The Civil Aviation Safety Authority's Airworthiness Directive (AD) DHC-8/66 specifically pertains to Bombardier (Boeing Canada/De Havilland) DHC-8 Series aeroplanes, namely the 100, 200, and 300 variants, with the exception of those that have already integrated the CAA(UK) flight idle configuration per Bombardier (de Havilland) Customer Requests CR873SOO8112, CR873CH00003, and CH873CH00005. This directive applies to aeroplanes with specific serial numbers and mandates various modifications to address safety concerns related to in-flight selection of ground Beta, which can lead to engine failure or propeller overspeed. The directive applies to aircraft operators within the Commonwealth of Australia, enforcing compliance with the prescribed modifications to maintain airworthiness standards. Compliance with the AD must be achieved before 31 October 2001, and certain amendments to the Minimum Equipment List (MEL) must be approved by the local CASA District Office. This AD complements Transport Canada AD CF-99-18 and incorporates subsequent revisions to the Transport Canada Master Minimum Equipment List.

Key Provisions

The Civil Aviation Safety Authority's Schedule of Airworthiness Directives (AD) specifies modifications and requirements for Bombardier (Boeing Canada/De Havilland) DHC-8 Series aeroplanes. Specifically, AD/DHC-8/66 mandates modifications to address the issue of in-flight selection of ground Beta, which has been linked to engine failures and propeller overspeed. Section (1) of the AD requires the installation of Bombardier Modification 8/3083 (Modification of Honeywell AA-300 Radio Altimeter) for aeroplanes with serial numbers (S/Ns) ranging from 003 to 509, excluding S/N 130, in accordance with Bombardier Regional Aircraft Division Service Bulletin (SB) 8-34-126 dated 1 May 1998. Section (2) mandates the installation of Bombardier Modification 8/2852 (Addition of Warning Horn to Flight Idle Gate) for aeroplanes with S/Ns ranging from 003 to 509, excluding S/N 130, in accordance with Bombardier Regional Aircraft Division SB 8-76-15 dated 22 January 1999. Section (3) requires the installation of Bombardier ModSum 8Q100795 (Installation of weight on Wheels Disarming Logic in Aircraft with Ground Spoilers) for Series 100 aeroplanes with S/Ns ranging from 003 to 390, which are equipped with ground spoilers, in accordance with Bombardier Regional Aircraft Division SB 8-76-18 dated 7 January 1999. Section (4) mandates the installation of Bombardier ModSum 8Q100794 for Series 100 and 200 aeroplanes with S/Ns ranging from 391 to 524 (excluding S/N 511) without ground spoilers (Post Mod 8/1860) and Series 300 aeroplanes with S/Ns ranging from 100 to 523 (excluding S/N 521), in accordance with Bombardier Regional Aircraft Division SB 8-76-17 dated 25 January 1999 or Revision A dated 14 May 1999. Finally, Section (5) requires the amendment of the DHC-8 Minimum Equipment List (MEL) to provide three flight days of operation without the system, as long as the trigger system is still functional, in accordance with Temporary Revisions No 40 and 41 of the Transport Canada Master Minimum Equipment List (MMEL). The modifications must be completed before 31 October 2001. The AD imposes specific obligations and requirements on the entities it governs. Operators of DHC-8 Series aeroplanes must ensure that the required modifications are completed before the specified deadline. The modifications include the installation of various Bombardier modifications, which are detailed in the AD. Additionally, operators must amend the DHC-8 MEL to provide three flight days of operation without the system, as long as the trigger system is still functional. The MEL amendments must be approved by the local CASA District Office. Failure to comply with the AD may result in civil or criminal consequences. Under the Civil Aviation Act 1988 (Cth), non-compliance with an AD may be considered an offence, which could result in fines and/or imprisonment. The maximum penalty for an individual is a fine of up to $100,000 and/or imprisonment for up to two years. The maximum penalty for a body corporate is a fine of up to $500,000. Additionally, non-compliance with the AD may result in the suspension or revocation of the aeroplane's Certificate of Airworthiness, which could prevent the aeroplane from operating in Australian airspace.