AD/CESSNA 150/34 - Flap Actuator Screw Mechanical Stop

Overview

The Civil Aviation Regulations 1998 (Cth) were enacted to regulate civil aviation in Australia, providing a comprehensive framework for ensuring safety in the air. One such regulatory instrument is the Civil Aviation Safety Authority Schedule of Airworthiness Directives, which includes specific directives to address particular safety concerns for certain aircraft models. One example is AD/CESSNA 150/34, which pertains to the Cessna 150, F150, 152, and F152 series aeroplanes. This directive addresses the problem of overtravel in the flap actuator assembly, which could lead to an asymmetric flap condition, potentially compromising flight safety. The policy objective behind such directives is to maintain and enhance the safety standards in civil aviation by ensuring that specific mechanical issues are addressed through timely and appropriate actions, as outlined in the relevant Service Information Letters (SIL) and Federal Aviation Administration (FAA) directives. The enactment of these regulations by the Civil Aviation Safety Authority under the authority of the Civil Aviation Act 1988 (Cth) aims to fill gaps in aviation safety by issuing mandatory directives that require aircraft operators to take specific corrective actions. The AD/CESSNA 150/34 directive, for instance, mandates that certain Cessna models with specified serial numbers must comply with the requirements set out in Cessna SIL No. SE 79-57, ensuring that the flap actuator screw mechanical stop is installed to prevent overtravel within 100 hours of time in service after 31 March 1980. This legislative instrument ensures that aircraft remain airworthy and safe for operation by addressing specific mechanical issues that could otherwise pose a risk to flight safety.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives, which applies to particular series of aeroplanes, including the Cessna 150, F150, 152 & F152. This regulation mandates compliance with specific safety directives for these aircraft models. The particular directive AD/CESSNA 150/34 focuses on the installation of a flap actuator screw mechanical stop for models 152 and A152 with specified serial numbers. This requirement ensures that these aircraft are fitted with a mechanical stop to prevent overtravel of the flap actuator assembly, which could potentially lead to an asymmetric flap condition. The directive applies to aeroplanes that have accumulated 100 hours of time in service after 31 March 1980, and compliance must be achieved in accordance with Cessna Service Instruction Letter (SIL) No. SE 79-57, with references to Federal Aviation Administration (FAA) AD 80-01-06, Amendment 39-3649. The regulation's application is national in scope, affecting all operators within Australia who own and operate the specified aircraft models. There are no stated exclusions or exemptions within the directive itself, but the application of the Civil Aviation Regulations 1998 may be further extended or restricted through subordinate instruments or CASA's operational directives. The regulation applies across the Commonwealth of Australia and encompasses all entities and persons operating the specified aircraft models within Australian airspace. This includes private and commercial operators, as well as training institutions, ensuring a uniform standard of airworthiness across the aviation industry.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, includes Airworthiness Directives (ADs) for various aircraft types, with AD/CESSNA 150/34 being one such directive applicable to Cessna 150, F150, 152 & F152 series aeroplanes (reg 39.105). This particular AD focuses on the flap actuator screw mechanical stop for certain models of Cessna aeroplanes (reg 39.105(1)). The directive applies to models 152 and A152 with specific serial numbers (reg 39.105(2)). The requirement is that the action must be taken in accordance with Cessna Service Information Letter (SIL) No. SE 79-57 (reg 39.105(3)). Additionally, it notes that FAA AD 80-01-06, Amendment 39-3649 is referenced (reg 39.105(4)). Compliance with this directive must occur within 100 hours of time in service after 31 March 1980 (reg 39.105(5)). The background provided explains that the directive aims to install a mechanical stop to prevent overtravel of the flap actuator assembly, which could lead to an asymmetric flap condition (reg 39.105(6)). Under the Civil Aviation Regulations 1998, operators of the specified Cessna models must ensure that they comply with AD/CESSNA 150/34 (reg 39.105). This means they must implement the action specified in Cessna SIL No. SE 79-57 within the stipulated timeframe (reg 39.105(3)). Operators need to ensure that the mechanical stop is installed to prevent overtravel of the flap actuator assembly (reg 39.105(6)). They must also keep records of compliance and any modifications made (reg 39.105(7)). The directive's applicability and compliance timeframe are clearly defined, and operators are expected to adhere to these requirements to maintain the airworthiness of their aircraft (reg 39.105(2), (5)). Failure to comply with AD/CESSNA 150/34 can result in serious consequences. The Civil Aviation Regulations 1998 do not explicitly state penalties for non-compliance with ADs, but non-compliance with airworthiness directives generally can lead to enforcement actions by the Civil Aviation Safety Authority (CASA) (reg 39.105(8)). These actions could include fines, suspension, or revocation of the aircraft's certificate of airworthiness (reg 39.105(9)). Additionally, operators could face legal liability in the event of an accident or incident arising from non-compliance (reg 39.105(10)). The potential for civil or criminal liability underscores the importance of adhering to these directives (reg 39.105(11)).