AD/DHC-8/16 Amdt 1 - Engine Bleed Air

Overview

The Civil Aviation Regulations 1998, specifically Part 39 - 105, includes a legislative instrument aimed at enhancing aviation safety through the implementation of Airworthiness Directives. Enacted by the Australian Government, this instrument addresses potential risks associated with certain aircraft models. The Civil Aviation Safety Authority schedules these directives to ensure compliance with safety standards. One such directive pertains to the Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes, specifically targeting the engine bleed air system. This directive mandates amendments to the aircraft flight manuals to prohibit the use of engine bleed air during take-off and landing for DHC-8-100 series aircraft that have not incorporated specific de Havilland Inc. modifications. The policy objective is to mitigate risks such as engine failure during critical phases of flight, ensuring safer operations in line with international safety standards.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, encompasses a detailed schedule of airworthiness directives designed to ensure the safety and reliability of civil aircraft operating within Australian airspace. This particular directive applies to Bombardier (Boeing Canada/De Havilland) DHC-8 series aeroplanes, specifically the DHC-8-100 series aircraft that do not include the de Havilland Inc. modifications #8/1155 and #8/1820. The directive mandates that the Aircraft Flight Manuals (AFM) for these aircraft must be amended to prohibit the use of engine bleed air during take-off and landing, aligning with Transport Canada's AD CF-91-32R1. Compliance with this directive is required unless the specified modifications have already been incorporated, in which case the bleed air operations may proceed according to Supplement 21, Issue 2 of the AFM. The directive must be complied with before 20 January 1994, with the original issue of the AD satisfying the amendment's requirements. The directive’s application is national, extending across the Commonwealth of Australia and is subject to enforcement by the Civil Aviation Safety Authority.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, outlines the Civil Aviation Safety Authority's Schedule of Airworthiness Directives for the Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes. Within this, AD/DHC-8/16 Amendment 1, issued on 3 September 1994, pertains to engine bleed air, requiring specific amendments to the aircraft's flight manuals. This directive is applicable to DHC-8-100 series aircraft that do not incorporate de Havilland Inc. modifications #8/1155 and #8/1820 (Section 39 - 105 (3)). The main requirement of this directive is that the DHC-8-100 Series Aircraft Flight Manuals must be updated to prohibit the use of engine bleed air during take-off and landing operations, aligning with Transport Canada's AD CF-91-32R1 (Section 39 - 105 (4)(a)). The obligations imposed by this directive mandate that any DHC-8-100 series aircraft not incorporating the specified de Havilland modifications must amend their flight manuals accordingly to ensure safety during critical phases of flight. This includes prohibiting the use of engine bleeds during take-off and landing. The compliance deadline was set for 20 January 1994, and compliance with the original issue of this AD is sufficient to meet the requirements of this amendment (Section 39 - 105 (5)). The directive provides flexibility by noting that any subsequent amendments to the flight manuals that meet the Transport Canada AD CF-91-32R1 criteria will also satisfy the requirements of this AD. Failure to comply with the provisions of this directive can lead to significant safety risks, as highlighted by the background information provided. Specifically, the directive notes that a failure of the left-hand engine during a bleed-on take-off could cause the remaining engine's bleed system to move to the maximum bleed position, reducing the available uptrim power. This situation could compromise the aircraft's safety during critical flight phases. The terminating action for this directive is the incorporation of de Havilland Inc. modifications #8/1155 and #8/1820, which allow for the resumption of bleed-on take-off and landing operations in accordance with Supplement 21, Issue 2 of the AFM. Regarding consequences for non-compliance, the Civil Aviation Regulations do not specify particular offences, penalties, or civil/criminal consequences for breaches of this directive within the provided text. However, non-compliance with airworthiness directives generally can result in serious repercussions, including fines, operational restrictions, or even the grounding of the aircraft until compliance is achieved. The seriousness of such non-compliance underscores the importance of adhering to these safety mandates to ensure the safe operation of the DHC-8-100 series aircraft.