COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Cessna 170, 172, F172, FR172 and 175 Series Aeroplanes
AD/CESSNA 170/40 Mixture Control Connection 10/80
Applicability: Model 172RG with S/Nos 172RG-0001 to 172RG-0573.
Requirement: (a) Inspect the mixture control connection at the carburettor mixture arm to ensure that the control cable inner wire is secured to the clamp at the arm with an AN960-10 (approx 063ins. thick) washer installed between wire and retaining nut and an AN960-10L (approx .032ins. thick) washer installed between wire and arm.
(b) If the parts are assembled correctly, check that the minimum torque on the MS20365-1032C retaining nut is 15 inch-pounds and that the P/N S2323-11 clamp will swivel in the mixture control arm.
(c) If the parts are assembled incorrectly, remove and discard the MS20365-1032C nut. Install washers in correct sequence and fit new MS20365-1032C nut. Torque nut to 15 inch-pounds minimum and ensure that P/N S2323-11 clamp will swivel in the mixture control arm.
Compliance: Within 25 hours time in service after 7 October 1980.
Background: Incorrect assembly of the mixture control connection during manufacture may cause slippage of the control wire and result in engine power loss due to lean mixture.
Overview
The Civil Aviation Regulations 1998, enacted by the Australian Parliament, constitute a comprehensive regulatory framework governing civil aviation within Australia. Among these regulations, Part 39, specifically addressing airworthiness directives, ensures that aircraft maintain the highest safety standards. One such directive, AD/CESSNA 170/40, pertains to the Cessna 170, 172, F172, FR172, and 175 series aeroplanes, addressing a critical issue identified in model 172RG with serial numbers ranging from 172RG-0001 to 172RG-0573. The directive was introduced to rectify the potential for engine power loss due to incorrect assembly of the mixture control connection during manufacture, which can lead to a lean mixture. The policy objective of this regulation is to enhance flight safety by ensuring proper assembly and operational integrity of the mixture control system. Compliance with this directive is mandatory within 25 hours of time in service following its issuance on 7 October 1980.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105, which governs the Civil Aviation Safety Authority’s (CASA) Schedule of Airworthiness Directives, applies to a specific subset of aircraft. This particular legislative instrument, AD/CESSNA 170/40, mandates that Cessna 170, 172, F172, FR172, and 175 series aeroplanes, particularly Model 172RG with serial numbers ranging from 172RG-0001 to 172RG-0573, must adhere to the outlined requirements concerning the mixture control connection. This directive is designed to ensure airworthiness by preventing engine power loss due to potential slippage of the control wire caused by incorrect assembly. The requirement involves a thorough inspection and, if necessary, the reassembly of the mixture control connection to meet specified tolerances and torque values. Compliance must be achieved within 25 hours of time in service after the specified date of 7 October 1980, ensuring that the safety directive is implemented promptly across the affected aircraft.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, mandates certain safety directives for specific models of Cessna aeroplanes, notably the Cessna 170, 172, F172, FR172, and 175 series. Among these directives, AD/CESSNA 170/40 focuses on the mixture control connection for Model 172RG with serial numbers 172RG-0001 to 172RG-0573. This directive requires thorough inspection and potentially corrective actions on the mixture control connection at the carburettor mixture arm to ensure safety and operational integrity.
The directive requires the inspection of the mixture control connection to verify that the control cable inner wire is correctly secured to the clamp at the arm with specified washers installed (section 10/80(a)). If the components are assembled correctly, the inspection must confirm that the minimum torque on the MS20365-1032C retaining nut is at least 15 inch-pounds and that the P/N S2323-11 clamp can swivel within the mixture control arm (section 10/80(b)). If the assembly is incorrect, the directive mandates the removal and discarding of the existing MS20365-1032C nut, followed by the installation of washers in the correct sequence and fitting of a new nut, ensuring the clamp can swivel and the nut is torqued to a minimum of 15 inch-pounds (section 10/80(c)). Compliance with these requirements must be achieved within 25 hours of the aeroplane being in service after 7 October 1980.
The obligations imposed by this directive on the relevant parties, such as aircraft owners, operators, and maintenance personnel, include conducting the required inspections and taking corrective actions as necessary. These obligations ensure that the mixture control connection is correctly assembled and operational, thereby preventing potential engine power loss due to a lean mixture, which could be a significant safety risk.
Failure to comply with the directive may result in violations of the Civil Aviation Regulations 1998. Such non-compliance could lead to civil or criminal consequences depending on the severity of the breach. While specific penalties are not detailed in the text provided, breaches of aviation safety regulations generally carry significant penalties, including fines and potential imprisonment, reflecting the high stakes involved in maintaining the safety and airworthiness of aircraft.