AD/CESSNA 208/8 - Engine Mount Ring

Overview

The Civil Aviation Regulations 1998, specifically Part 39 - 105, encompasses various airworthiness directives designed to ensure the safety and operational integrity of aircraft in Australia. One such directive, AD/CESSNA 208/8, pertains to the inspection and maintenance of the engine mount ring in Cessna 208 Series aeroplanes. This directive was enacted to address the problem of engine mount cracking, particularly in models 208 and 208A, and the potential for such cracking to lead to catastrophic failures, including the separation of the engine from the airframe. The directive was issued by the Civil Aviation Safety Authority, with the aim of ensuring that these aircraft maintain their airworthiness and comply with safety standards. Compliance with this directive is mandatory and must be achieved within specific timeframes to mitigate risks associated with engine mount failure.

Scope and Application

The Civil Aviation Regulations 1998, as amended, apply to all aircraft registered in Australia and cover a broad range of aviation safety standards, including the specific Airworthiness Directives. The AD/CESSNA 208/8 pertains to the inspection and maintenance of the engine mount ring on specific models of the Cessna 208 series, namely Models 208 and 208A with serial numbers between 20800001 and 20800130, and Model 208B with serial numbers between 208B0001 and 208B0086. This directive requires operators of these aircraft to visually inspect the lower portion of the engine mount ring for any cracks or misalignment and mandates the replacement of any visibly misaligned rings or those with cracks larger than 43 mm (1.7"). For cracks shorter than 43 mm (1.7"), the repair must be conducted in accordance with the Model 208 Maintenance Manual P/N 02076-2-13. Additionally, the directive requires the replacement of the nose wheel shimmy damper with a specific part number in accordance with Cessna Service Bulletin CAB88-14. Compliance with this directive must be achieved within 100 hours of time in service after 12 July 1990 or at the next inspection for Maintenance Release issue after 12 July 1990, whichever is later. This directive aims to prevent the risk of engine separation due to engine mount cracking and subsequent whirl mode flutter of the propeller/powerplant system.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, mandates the compliance with Airworthiness Directives for certain Cessna 208 Series Aeroplanes. The directive AD/CESSNA 208/8 pertains to the engine mount ring of models 208 and 208A, serial numbers ranging from 20800001 to 20800130, and 208B from 208B0001 to 208B0086. Section 1 of the directive requires a thorough visual inspection of the lower portion of the engine mount ring to identify any cracks or misalignments (AD/CESSNA 208/8, Section 1). If any ring is found to be visibly misaligned or has a crack larger than 43 mm (1.7 inches), it must be replaced. For cracks shorter than 43 mm, the directive specifies that repairs must be carried out according to the Model 208 Maintenance Manual P/N 02076-2-13 (AD/CESSNA 208/8, Section 1(b)). Additionally, the nose wheel shimmy damper must be replaced with a new one, specifically P/N 2643090-1, in accordance with Cessna Service Bulletin CAB88-14 (AD/CESSNA 208/8, Section 2). The directive imposes clear obligations on the operators and maintainers of the affected aircraft. It mandates that the specified inspections and repairs must be conducted within 100 hours of time in service after 12 July 1990, or at the next inspection for Maintenance Release issue after that date, whichever is later (AD/CESSNA 208/8, Compliance). This ensures that the potential risks associated with engine mount cracking and misalignment are mitigated in a timely manner. Compliance with this directive is essential for maintaining the airworthiness of the aircraft and ensuring the safety of all occupants. Failure to comply with the requirements of the Airworthiness Directive can lead to serious consequences. While specific penalties are not detailed within the directive itself, non-compliance with airworthiness directives is generally treated as a serious offence under the Civil Aviation Act 1988. The potential penalties for non-compliance can include substantial fines and other regulatory actions that could impact the operator's ability to continue flying the aircraft until compliance is achieved. The seriousness of the potential safety risks highlighted by the directive underscores the importance of adhering to these regulatory requirements.