COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Percival Vega Gull Series Aeroplanes
AD/GULL/4 Airframe Structure - Inspection 1/73
Applicability: All models.
Requirement: 1. Preparation: Prepare the aeroplane for inspection by removing all removable equipment, cabin linings, seats, inspection access panels, fairings, fabric patches, tape sealing and sufficient fabric and secondary structure to enable an inspection of the airframe in accordance with these requirements.
2. Inspection Procedure:
2.1 Inspect all fabricated structural components such as box spars, wooden ribs, bulkheads and braces, and all glued connections between these components for the following defects:
(a) Cracks, cuts, splits, bruises, compression shakes, warping contamination by foreign matter such as oil, attach by fungus in the wood, shrinkage of the timer at bolt holes.
(b) Separation or sponginess in the glued joints and plywood. A 0.005 in. feeler gauge should be used to determine separation of glued joints and the depth of glue failure.
2.2 Inspect all plywood skin for the following defects:
(a) Cracks, splits, cuts, bruises and shakes in the surface of the wood, deterioration and contamination by foreign matter.
(b) Separation of the glue where skin connects to the skeletal structure beneath. Particular attention should be paid to the flaps since they are exposed to moisture, and also subject to contamination by oil.
Note: Load carrying wooden skin becomes inefficient and the complete structure loses strength when adhesion to the structure beneath has failed. Consequently, all structural connections and joints must be thoroughly inspected for deterioration and defects. When carrying out an inspection the following may prove helpful in detecting defects.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Separation from the structure is often detectable from the exterior in several ways. It is likely to appear as a local discontinuity in the skin contour which can be pressed down without the immediate firm resistance anticipated. When the structure is flexed the skin will tend to take up waves. If these waves do not pass across the lines of gluing to the structure beneath, adhesion may be taken as sound. Oblique lighting of the surface will be found helpful in studying surface waves and contour discontinuities. Timber shakes appear as thin lines across the timber on the varnish layer. By sponging ink on the varnish and subsequently wiping off, a line where the shake exists should be apparent. Where there are signs of failure in the protective coating it should be removed to inspect the wood beneath. Special attention is to be paid to points in the structure where liquids can collect or oil contamination can occur. Casein glue deteriorates if repeatedly exposed to moisture or oil. Where possible, the inspection should be made from the interior. However, for wings, initial inspection may be made from the exterior. When inspecting the interior structure of the wings it may be necessary to cut holes in load carrying covering. In these instances reference should be made to the Secretary for an approved scheme for the incorporation of inspection holes.
Compliance: 1. Within 12 months of last inspection in accordance with AD/GENERAL/29 and thereafter at intervals not exceeding 12 months.
2. For aircraft which have not been inspected in accordance with AD/GENERAL/29 in the 12 months prior to 31 January 1973 - inspect within three months after 31 January 1973 and there- after at intervals not exceeding 12 months.
Overview
The Civil Aviation Regulations 1998, enacted by the Parliament of Australia, establish a comprehensive framework to ensure the safety of civil aviation within the country. One of the key components of these regulations is the Schedule of Airworthiness Directives, which includes AD/GULL/4 for the Percival Vega Gull Series Aeroplanes. This directive was introduced to address specific maintenance and inspection requirements to ensure the ongoing airworthiness of these aircraft, particularly focusing on the airframe structure. The policy objective behind these directives is to maintain high safety standards by mandating regular inspections and maintenance procedures to detect and rectify potential structural issues that could compromise the safety of the aircraft.
The AD/GULL/4 directive provides detailed requirements for the preparation and inspection of the airframe structure of the Percival Vega Gull Series Aeroplanes, including specific procedures for inspecting fabricated structural components and plywood skin for various defects. Compliance with these directives is mandatory, with specified intervals for inspections to ensure the continued airworthiness and safety of these aircraft.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105 concerning Airworthiness Directives for Percival Vega Gull Series Aeroplanes, mandates rigorous inspection procedures for the airframe structure. This regulation applies to all models of the Percival Vega Gull series, demanding that the aeroplane be prepared for inspection by removing various components and structures to ensure thorough examination. The inspection must include all fabricated structural components and glued connections, as well as the plywood skin, for specific defects such as cracks, splits, contamination, and separation. The regulation further specifies the need for detailed visual and physical examination, including the use of tools like feeler gauges and oblique lighting to detect issues. The directive applies nationwide within Australia, governed by the Civil Aviation Safety Authority, and outlines compliance requirements, including inspection intervals of up to 12 months, with specific timelines for aircraft that have not been inspected previously. The regulation extends its application through subordinate instruments, which may provide further guidance or specifications on the inspection procedures and compliance measures.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, include detailed provisions for the maintenance and inspection of Percival Vega Gull Series aeroplanes. Section 1 of the AD/GULL/4 mandates the preparation of the aeroplane for inspection, requiring the removal of all removable equipment, cabin linings, seats, inspection access panels, fairings, fabric patches, and sufficient fabric and secondary structure to allow a thorough inspection of the airframe (s. 1). This section also specifies that the inspection should focus on all fabricated structural components such as box spars, wooden ribs, bulkheads, and braces, as well as all glued connections between these components (s. 2.1). Furthermore, the plywood skin must be inspected for defects such as cracks, splits, cuts, bruises, shakes, and any deterioration or contamination by foreign matter (s. 2.2). The inspection process should also evaluate the separation of the glue where the skin connects to the skeletal structure beneath, with particular attention to areas like flaps that are more susceptible to moisture and oil contamination.
The obligations imposed by these regulations require aircraft owners, operators, and maintenance personnel to ensure that the aeroplanes are prepared and inspected according to the detailed procedures outlined. This includes the timely removal of necessary components to facilitate a comprehensive inspection, and the identification and documentation of any defects or separations in structural components and joints. For aircraft that have not been inspected within the last 12 months in accordance with AD/GENERAL/29, inspections must be conducted within three months after 31 January 1973, and then at intervals not exceeding 12 months thereafter (s. Compliance 1 and 2). Moreover, the regulations stipulate that inspections should be carried out meticulously, with special attention to areas prone to moisture and oil contamination, and any signs of failure in the protective coating should be addressed.
Failure to comply with the inspection requirements and standards set forth in these regulations can lead to serious consequences. Non-compliance may result in civil or criminal penalties, depending on the severity of the breach. For instance, if an aeroplane is operated without the required inspections, it may be deemed unsafe to fly, leading to potential enforcement actions by the Civil Aviation Safety Authority (CASA). The specific penalties for breaches can vary, but they may include fines, enforcement notices, and in severe cases, prosecution. The maximum penalties for non-compliance can include substantial financial penalties and potential imprisonment for individuals found guilty of serious safety violations.