AD/VAT/41 Amdt 1 - Wing Main Spar and Tailplane Fatigue Life Limit

Overview

The Civil Aviation Regulations 1998, as amended by the legislative instrument F2006B07576, aim to ensure the airworthiness of aircraft by issuing specific directives for the Victa and A.E.S.L. Airtourer Series aeroplanes. Enacted by the Australian Government, these regulations address the critical issue of aircraft structural integrity, particularly focusing on fatigue life limits for certain components. The policy objective is to enhance aviation safety by mandating the retirement of specific components that have reached their service life limits, thereby reducing the risk of structural failure due to fatigue. The directive applies to all models within the specified series and requires the retirement of the wing main spar lower cap assembly, wing front attachment spigot fittings, tailplane rear spar assembly, and tailplane to fuselage attachment fittings. For aircraft engaged in competition or display aerobatics, the time spent performing such manoeuvres is multiplied by a factor of twenty when assessing the total time for structural life limitation purposes, ensuring that these high-stress activities are appropriately accounted for in the aircraft's service life assessment. Compliance with these directives is mandatory and must be achieved within a specified timeframe to maintain the safety standards required by the Civil Aviation Safety Authority.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, addresses the airworthiness directives for Victa and A.E.S.L. Airtourer Series Aeroplanes, with a focus on AD/VAT/41 Amendment 1 concerning the wing main spar and tailplane fatigue life limits. This legislation applies to all models of the specified aeroplanes and mandates the retirement of certain components from service, including the wing main spar lower cap assembly, wing front attachment spigot fittings, tailplane rear spar assembly, and tailplane to fuselage attachment fittings. Notably, aircraft equipped with wing main spar reinforcement to Hamilton drawing 90014 are also subject to these requirements, necessitating the retirement of the lower reinforcement strap assembly. Furthermore, aeroplanes engaged in competition or display aerobatics must factor their flight time in such activities by multiplying it by a factor of twenty when assessing the total time for structural life limitation purposes. The regulation's applicability is not limited to any specific geographic or jurisdictional boundary within the Commonwealth of Australia but extends to all relevant aircraft operating within its jurisdiction. Compliance with these directives must be achieved at or before 17,200 hours of time in service.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105 and Schedule of Airworthiness Directives AD/VAT/41 Amendment 1, address the airworthiness of Victa and A.E.S.L. Airtourer Series Aeroplanes, particularly focusing on the wing main spar and tailplane fatigue life limit (sections 6/84). The main requirement of this directive is the mandatory retirement of certain components from service. This includes the wing main spar lower cap assembly and wing front attachment spigot fittings, as well as the tailplane rear spar assembly and tailplane to fuselage attachment fittings (section 6/84). For aircraft fitted with a wing main spar reinforcement to Hamilton drawing 90014, the lower reinforcement strap assembly must also be retired (Note 1). The directive applies to all models of the specified aeroplanes. The Act imposes several obligations on the parties it governs. Aircraft operators must ensure that the specified components are retired at or before the aircraft reaches 17,200 hours of time in service (section 6/84). For aircraft engaged in competition or display aerobatics, additional calculations must be performed to account for the increased structural load. Time spent in such aerobatics must be multiplied by a factor of twenty (20) when assessing the total time for structural life limitation purposes (Note 2). The definition of competition or display aerobatics includes manoeuvres like Lomcevaks, snap rolls, outside loops, square loops, and spins with high exit speeds (Note 3). For aircraft that have not previously recorded competition aerobatic time, this time must be conservatively estimated based on the known history of the aircraft (Note 4). The life limitation specified in the directive is based on measured stress and conservative loads data, and it will be subject to review based on future measurements of a representative flight loads spectrum (Note 5). Failure to comply with the airworthiness directive can result in serious consequences. Civil Aviation Regulations 1998 do not specify particular offences or penalties for non-compliance with the airworthiness directive in this instance. However, non-compliance with airworthiness directives generally can lead to enforcement actions by the Civil Aviation Safety Authority (CASA). These actions can include fines, suspension or revocation of airworthiness certificates, and potential criminal charges for endangering safety if the non-compliance results in an accident or incident. The severity of the penalties will depend on the nature and extent of the non-compliance, as well as any resulting harm or risk.