AD/CESSNA 170/34 Amdt 1 - Engine Mounting Bracket Bolts

Overview

The Civil Aviation Regulations 1998, under Part 39, incorporates the Airworthiness Directives (AD) issued by the Civil Aviation Safety Authority (CASA) to ensure the safety of civil aviation in Australia. One such directive, AD/CESSNA 170/34 Amendment 1, specifically addresses the issue of engine mounting bracket bolts for certain Cessna 172N aeroplanes. This amendment was introduced to address the problem of potential loosening of engine mounting bracket bolts, which could compromise the integrity of the engine-to-aircraft mounting. The policy objective is to ensure that these bolts maintain the required torque to prevent any failure in service. CASA mandates compliance with this directive to maintain the highest safety standards in Australian civil aviation. Enacted by the Australian Parliament, the Civil Aviation Regulations 1998 were designed to fill gaps in ensuring that civil aviation operations are conducted safely and efficiently. This particular AD was introduced to mitigate risks associated with the loosening of engine mounting bolts, which could lead to catastrophic failures. The directive applies to all Cessna Model 172N aircraft fitted with specific Lycoming engines and requires inspections and re-torqueing of bolts to specified standards. The directive aims to prevent the recurrence of such issues by ensuring regular and stringent maintenance checks.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, addresses the safety directives for certain Cessna aeroplanes, including the 170, 172, F172, FR172, and 175 series. This regulatory framework is administered by the Civil Aviation Safety Authority (CASA) and pertains to all Cessna Model 172N aeroplanes fitted with Lycoming 0-320-H2AD series engines, covering serial numbers from L-101-76 to L-5707-76, as well as any engines remanufactured prior to 4 January 1979. The directive mandates specific actions to prevent the loss of engine integrity due to the loosening of engine mounting bracket bolts, requiring inspection and appropriate torquing of these bolts. The regulation applies to the mentioned aircraft models within the specified serial number range and requires compliance within 10 hours of service after 1 August 1980 and subsequently at intervals not exceeding 100 hours of service. The directive does not specify any exclusions or exemptions, ensuring all affected aircraft adhere to the safety measures outlined.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, provides detailed directives regarding the airworthiness of certain aircraft, with AD/CESSNA 170/34 Amendment 1 focusing on Cessna 172N aircraft fitted with specific Lycoming engines. According to section 39-105(1), the directive mandates that the engine mounting bracket bolts of Cessna Model 172N aeroplanes equipped with Lycoming 0-320-H2AD series engines, with serial numbers ranging from L-101-76 to L-5707-76, or any remanufactured engines before 4 January 1979, must be inspected and tightened. This is to prevent the engine from becoming detached from the aircraft due to the bolts loosening. Under this legislation, the primary requirement is for the inspection of the eight engine mounting bracket bolts (P/N LW 38-2.75) for tightness. If any of these bolts are found to have less than 200 inch-pounds of torque, they must be replaced. The replacement bolts must then be tightened to 360 inch-pounds. If the bolts are found to have more than 200 inch-pounds but less than 360 inch-pounds of torque, they must be re-torqued to 360 inch-pounds. This directive also references Lycoming SI No 1380 and FAA AD 79-10-03 R2 Amendment 39-3628. The obligations imposed by this regulation require compliance within 10 hours of time in service following 1 August 1980, and thereafter, the inspections and necessary actions must be carried out at intervals not exceeding 100 hours of time in service. It is imperative that these checks are performed to maintain the structural integrity of the engine mounting and prevent potential in-flight failures. Failure to comply with these directives can lead to severe safety risks, as the loss of the engine to the aircraft could result in catastrophic outcomes. In terms of enforcement, breaches of the Civil Aviation Regulations 1998 can result in significant consequences. Civil penalties can be imposed for non-compliance, which may include fines and other sanctions as stipulated under the Civil Aviation Act 1988. The maximum penalties for serious breaches can include substantial fines and potential imprisonment, as outlined under the regulatory framework governing civil aviation safety. It is therefore crucial for operators and maintenance personnel to adhere strictly to these directives to ensure the continued airworthiness and safety of the affected aircraft.