COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Ayres Thrush (Snow) Commander Series Aeroplanes
AD/AC-SNOW/13 Horizontal Stabiliser Spar - Fatigue Inspection
3/80
Applicability: The following models and S/Nos. which have achieved 2000 hours or more total time in service and which incorporate horizontal stabiliser P/N 40221-61.
Model S-2D: All S/Nos.;
Model S-2R: S/Nos. 1416R thru 2560R; 5000R thru 5100R; Model S2R-T11: S/Nos. T11-001 and T11-002;
Model S2R-T15: S/Nos. T15-001 thru T15-005;
Model S2R-T34: S/Nos. 6000 thru 6049, T34-001 thru T34-019; Model S2R-R3S: S/Nos. R3S-001 thru R3S-008.
Requirement: (a) Remove fuselage side skins to provide access to the inspection hole in the bottom of the horizontal stabiliser.
(b) Disconnect the flying wires, left and right sides, from both upper and lower surfaces of the horizontal stabiliser to permit the exercising of the stabiliser.
(c) Inspect the horizontal stabiliser front spar tube (P/N 40221 -19) in the area of both the left and right fuselage attach bushings as shown in Fig. 1 using a flashlight and an inspection mirror. IMPORTANT - the stabiliser must be exercised with both an up and down force at the tip during the inspection to ensure detection of crack.
Note 1: The horizontal stabiliser assembly should be re-installed and the flying wires adjusted in accordance with the Rigging Procedures in Section VII of the Maintenance Manual, with the exception that the tension in each flying wire should be adjusted until the midpoint has a deflection of 0.30 + 0.05 inch with an applied side load of 20 pounds, rather than 35 pounds as stated in the Maintenance Manual.
Note 2: FAA AD 80-04-06 Amdt. 39-3688 refers to this inspection.
Note 3: Aircraft fitted with Horizontal stabiliser P/N 40221-70 are exempted from the requirements of this AD.
Compliance: Within 25 hours’ time in service after 18 March 1980 and thereafter at intervals not exceeding 500 hours’ time in service.
Background: This AD is based purely on United States Federal Aviation Administration requirements. No other background information is available at this stage.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
FIG 1.
Overview
The Civil Aviation Regulations 1998, enacted by the Commonwealth of Australia, provide a comprehensive regulatory framework governing civil aviation safety across the country. Specifically, Part 39 - 105 of these regulations includes a Schedule of Airworthiness Directives that mandate specific safety measures for various aircraft types. One such directive, AD/AC-SNOW/13, pertains to the inspection of horizontal stabiliser spars for fatigue in Ayres Thrush (Snow) Commander Series Aeroplanes that have accumulated 2000 hours or more in total service time and incorporate particular horizontal stabiliser parts numbers. The directive was introduced to ensure ongoing airworthiness and safety in line with international standards and aims to prevent structural failures due to fatigue. Compliance with these directives is mandatory for maintaining the airworthiness of affected aircraft.
Scope and Application
The Civil Aviation Regulations 1998, specifically PART 39 - 105, applies to the specified models of Ayres Thrush (Snow) Commander Series Aeroplanes that have reached 2000 hours or more of total time in service, and are equipped with a particular horizontal stabiliser part number. The models and serial numbers specified in the regulation include S-2D, S-2R, S2R-T11, S2R-T15, S2R-T34, and S2R-R3S, with certain serial numbers within the S-2R model series being applicable. This regulation applies to aircraft within the Commonwealth of Australia, and is enforced by the Civil Aviation Safety Authority (CASA). The requirement set forth in this regulation mandates the inspection of the horizontal stabiliser spar for fatigue, involving the removal of the fuselage side skins, disconnection of flying wires, and detailed inspection procedures using specified tools and methods to ensure the detection of any cracks. Aircraft fitted with a horizontal stabiliser part number 40221-70 are exempt from the requirements of this directive. Compliance with these inspection requirements must be achieved within 25 hours’ time in service after 18 March 1980, and thereafter at intervals not exceeding 500 hours’ time in service. The regulation also references relevant FAA Airworthiness Directives and notes the requirement for specific adjustments in the re-installation and tensioning of flying wires.
Key Provisions
The Civil Aviation Regulations 1998, under Part 39, specifically address the Airworthiness Directives (AD) related to certain types of aircraft. Section 39-105 of these regulations outlines the AD/AC-SNOW/13, which pertains to the horizontal stabiliser spar fatigue inspection for Ayres Thrush (Snow) Commander Series Aeroplanes (section 39-105). The directive applies to specific models and serial numbers of the Ayres Thrush aircraft that have accumulated 2000 or more hours of total service time and are equipped with a particular horizontal stabiliser part number (section 39-105(a)). The requirement outlined in this AD is for the inspection of the horizontal stabiliser front spar tube, specifically in the area of the left and right fuselage attach bushings, using a flashlight and an inspection mirror (section 39-105(b)). It is imperative that the stabiliser is exercised with both an up and down force at the tip during the inspection to ensure any potential cracks are detected. The directive also mandates the removal of fuselage side skins to gain access to the inspection hole and the disconnection of flying wires on both sides of the horizontal stabiliser to allow for the exercising of the stabiliser (section 39-105(b)).
Entities governed by the Civil Aviation Regulations 1998 must adhere to these ADs to ensure the ongoing airworthiness of the aircraft. Specifically, for the Ayres Thrush (Snow) Commander Series Aeroplanes, the applicable models and serial numbers must undergo the stipulated inspection within 25 hours of service time after 18 March 1980 and subsequently at intervals not exceeding 500 hours of service time (section 39-105(c)). This requirement includes the inspection procedure and the re-installation of the horizontal stabiliser, with adjustments to the flying wire tension to achieve a specified midpoint deflection of 0.30 + 0.05 inch when applying a side load of 20 pounds (section 39-105(b)).
Failure to comply with the AD/AC-SNOW/13 may result in serious safety issues, as the directive is based on United States Federal Aviation Administration requirements and is aimed at detecting potential fatigue-related cracks in critical structural components of the aircraft. The specific consequences of non-compliance are not detailed in the provided text, but generally, non-compliance with ADs can lead to severe civil or criminal penalties. In the context of Australian law, such non-compliance might result in fines, imprisonment, or both, depending on the severity and the specific regulations breached. The exact penalties would be determined by the Civil Aviation Safety Authority and could include substantial fines for individuals or corporations, as well as potential grounding of the aircraft until compliance is achieved.