AD/HS 748/5 - Engine Subframe Tubular Struts

Overview

The Civil Aviation Regulations 1998, specifically under Part 39 - 105, introduced the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives to ensure the safety of aviation operations in Australia. This legislative instrument aims to address issues related to the maintenance and inspection of aircraft components, with a focus on preventing failures due to internal corrosion and other structural issues. The policy objective of these regulations is to mandate regular and rigorous inspections of critical components, such as engine subframe tubular struts, to maintain airworthiness standards and ensure the safety of all aircraft operations. The regulations are enforced by CASA, which is tasked with overseeing compliance and ensuring that all aircraft meet the required safety standards. One specific Airworthiness Directive, AD/HS 748/5, targets British Aerospace (Hawker Siddeley) HS 748 Series Aeroplanes and mandates actions related to engine subframe tubular struts. The directive applies to all engine subframes that have been in service for over six years or have not been radiographically examined within the last seven years. The requirement includes adhering to the procedures outlined in the Jetstream Aircraft Mandatory Service Bulletin HS748-54/25 and references the UK Civil Aviation Authority AD 0119 for further guidance. Compliance with these directives ensures that appropriate radiographic inspections are conducted at specified intervals, thereby mitigating the risk of structural failure due to corrosion and maintaining the integrity of the aircraft.

Scope and Application

The Civil Aviation Regulations 1998, under Part 39 and specifically within the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, apply to all engine subframes of British Aerospace (Hawker Siddeley) HS 748 Series Aeroplanes that have been installed on aircraft for longer than six years or whose previous radiographic examination was conducted more than seven years ago. This regulatory framework is designed to ensure that such engine subframes are inspected for internal corrosion, which has been identified as a safety concern following recent scheduled radiographic examinations. Compliance with the AD/HS 748/5 directive is mandatory, with specific timeframes outlined for radiographic inspections depending on the age of the subframe from the date of installation or the last scheduled inspection. The directive references UK CAA AD 0119 for further guidance. The geographic reach of this directive is national, applying across the Commonwealth of Australia, as it falls under the overarching authority of the Civil Aviation Regulations 1998. The regulation mandates that operators and owners of HS 748 Series Aeroplanes adhere to the specified inspection periods to ensure compliance with airworthiness standards. Failure to comply with these directives may result in regulatory action, highlighting the importance of timely and thorough inspections. The directive does not explicitly mention any exclusions, exemptions, or thresholds beyond the specified age parameters of the engine subframes, indicating that all applicable aircraft must adhere to the outlined requirements.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, mandate certain actions for the maintenance and inspection of British Aerospace (Hawker Siddeley) HS 748 Series aeroplanes (Section 39-105). One such directive, AD/HS 748/5, focuses on the engine subframe tubular struts. This directive applies to all engine subframes that have been in use for longer than six years or whose previous radiographic examination occurred more than seven years ago (Section 39-105 AD/HS 748/5). To comply with these regulations, the action must be taken in accordance with Jetstream Aircraft Mandatory Service Bulletin HS748-54/25. This directive references UK Civil Aviation Authority AD 0119. The regulations impose specific obligations on the parties responsible for the maintenance of these aircraft. Owners and operators must ensure that the engine subframes are examined as per the specified timeframes. For subframes that have been in use for more than six but not more than ten years, the next radiographic inspection must occur within specific periods: before 8 December 1995 for those exceeding six but not eight years; before 8 September 1995 for those exceeding eight but not nine years; and before 8 June 1995 for those exceeding nine but not ten years (Section 39-105 AD/HS 748/5). These timeframes are calculated from 8 December 1994. Failure to comply with these inspection requirements can result in serious safety concerns, including the potential for internal corrosion in the tubes of the subframe struts, which has been discovered during previous examinations. Failure to comply with the requirements of the Civil Aviation Regulations 1998, particularly those outlined in AD/HS 748/5, can lead to significant consequences. The legislation does not explicitly state the penalties for non-compliance, but it is understood that breaches of aviation safety regulations can result in severe civil or criminal penalties. These may include fines, suspension or revocation of operating licenses, and potential criminal charges for those responsible. The severity of these penalties reflects the critical nature of ensuring the safety of aircraft and their passengers.