COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Cessna 310 Series Aeroplanes
AD/CESSNA 310/53 Wing Front Spar Lower Attachment Fittings 6/89
Applicability: All models.
Requirement: 1. Remove the fairing between the wing and carry-thru and gain access to the wing front spar lower attachment fittings P/N 0822550.
2. Visually inspect the upper and lower edges of the lug of each wing fitting, looking for cracks as shown in the figure below.
3. From inside the wheel well, visually inspect each visible wing fitting for cracks and surface pitting in the area shown in the figure.
Note: It is not necessary to remove the primer for any of the above inspections.
Wing Fitting Showing Typical Cracking
Note: Fitting Shown removed from aircraft for clarity
Compliance: Before exceeding 5000 hours component time in service or before the issue of the next Maintenance Release after 15 June 1989, whichever is the later. Thereafter, reinspect at each scheduled inspection for issue of a new Maintenance Release.
Background: Fatigue cracking has been discovered in the wing fitting from an Australian-registered Cessna 310R with 6500 hours time in service. No abnormality could be found in the fitting or the aircraft’s history. Since then stress corrosion cracking has been found in a similar wing fitting in a Cessna 402C with 6400 hours time in service.
There is insufficient evidence to regard either of these as isolated occurrences: either or both may be expected to occur at a later time elsewhere in the fleet of Cessna twins which use the same generic wing fitting. A simple repetitive visual inspection has therefore been introduced.
Overview
The Civil Aviation Regulations 1998 (Cth), amended under the authority of the Civil Aviation Act 1988, were enacted to regulate the safety and operational standards of civil aviation within Australia. A specific amendment, F2006B08180, introduced Airworthiness Directive AD/CESSNA 310/53 to address fatigue and stress corrosion cracking issues identified in the wing front spar lower attachment fittings of Cessna 310 Series aeroplanes. The problem arose from the discovery of cracking in the wing fittings of two Australian-registered aircraft, a Cessna 310R and a Cessna 402C, both of which exhibited significant flight hours without any apparent contributing factors. This directive was issued to ensure that these potential safety risks are proactively managed through regular visual inspections. The objective is to enhance flight safety by mitigating the risk of structural failure due to these identified defects. Compliance with this directive is mandatory before a specified component time in service and at subsequent scheduled inspections.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105, includes a schedule of airworthiness directives that apply to all Cessna 310 series aeroplanes. This directive, AD/CESSNA 310/53, pertains to the wing front spar lower attachment fittings P/N 0822550 and requires these fittings to be inspected for fatigue and stress corrosion cracking. The directive applies to all models within the specified aircraft series and mandates inspections before the aircraft component reaches 5000 hours of service time or before the next Maintenance Release following 15 June 1989, whichever is later. Subsequent inspections are required at each scheduled maintenance check for a new Maintenance Release. The directive does not necessitate the removal of primer during inspections. Its aim is to ensure the ongoing airworthiness of the fleet by identifying and addressing potential structural weaknesses that could compromise safety.
Key Provisions
The main sections of the Civil Aviation Regulations 1998, specifically AD/CESSNA 310/53, provide detailed instructions for the inspection and maintenance of wing front spar lower attachment fittings on Cessna 310 Series aeroplanes. Section (1) identifies the requirement to remove the fairing between the wing and carry-thru to access the fittings, while section (2) mandates a visual inspection of the upper and lower edges of the lug of each wing fitting for any cracks. Section (3) requires an additional inspection from inside the wheel well for visible cracks and surface pitting in the specified area. Importantly, section (4) clarifies that the primer need not be removed for these inspections.
The obligations imposed on parties by these provisions are clear and direct. Aircraft owners and operators must ensure that these inspections are conducted before the component reaches 5000 hours of service or before the next Maintenance Release after 15 June 1989, whichever occurs later. Once these initial inspections are completed, the regulations require that the fittings be reinspected at each scheduled inspection for any new Maintenance Release. These inspections are crucial to ensure the ongoing airworthiness and safety of the aircraft, given the documented instances of fatigue and stress corrosion cracking in similar fittings.
Failure to comply with these requirements can lead to serious consequences. While the specific regulatory framework does not detail civil or criminal penalties, non-compliance with airworthiness directives generally results in enforcement actions by the Civil Aviation Safety Authority (CASA). Such actions can include the grounding of the aircraft until compliance is achieved, which can significantly disrupt operations and incur substantial costs. In severe cases, repeated non-compliance or significant safety breaches may lead to the revocation of an operator's licence, resulting in the cessation of all operations until corrective actions are taken and regulatory approval is re-obtained.
Additionally, the potential for fatigue and stress corrosion cracking poses not only a compliance risk but also a significant safety hazard. If such cracks are not detected and addressed, they can lead to catastrophic failure during flight, putting the lives of passengers and crew at risk. The regulatory framework aims to mitigate this risk through regular, mandatory inspections. Therefore, adhering to these requirements is not just a legal obligation but also a critical safety imperative.