Overview

The Civil Aviation Safety Authority issued Airworthiness Directive AD/LTS/17 on 3 May 2002 under subregulation 39.1 (1) of the Civil Aviation Regulations 1998. The directive aims to address a safety concern associated with the potential for cracks to develop in the back plate area of certain compressor impellers used in AlliedSignal (Lycoming) LTS 101 Series turboshaft engines. These cracks could potentially lead to engine damage or failure. The directive applies to LTS 101 Series engines that use impellers with specific part numbers, unless these impellers are listed in certain service bulletins that exempt them from the directive. The policy objective is to ensure that the unsafe condition is rectified through specified actions, including visual and fluorescent inspections, removal of non-compliant impellers, and replacement of impellers with acceptable ones before further flight or installation. This Airworthiness Directive was gazetted on 22 May 2002 to ensure compliance across the aviation industry.

Scope and Application

The Airworthiness Directive issued by the Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998 targets the LTS 101 Series turboshaft engines that use specific compressor impellers. The directive applies to all LTS 101 Series turboshaft engines equipped with centrifugal compressor impellers bearing the part numbers 4-101-052-57 or 4-101-052-62, except for those impellers explicitly listed in Honeywell or AlliedSignal service bulletins, which are exempted from the requirements of the directive. This legislation applies across the Commonwealth of Australia, with compliance being mandatory for all aircraft operators and owners of the specified engines. The directive mandates a one-time visual and fluorescent inspection of the impellers within 900 gas generator cycles after the directive's effective date, the removal of any impellers that do not meet the specified criteria, and the replacement of such impellers before further flight. Additionally, spare impellers must be inspected before installation in an aircraft. The directive does not extend or restrict its application through subordinate instruments, and it became effective on 13 June 2002.

Key Provisions

The Airworthiness Directive AD/LTS/17 issued by the Civil Aviation Safety Authority (CASA) specifies requirements for LTS 101 Series turboshaft engines with certain centrifugal compressor impellers. According to section 1 of the AD, the following actions must be taken: first, a visual and fluorescent inspection of the impellers must be conducted within 900 gas generator cycles after the effective date of the AD (section 3(1)); second, any impellers that do not meet the inspection criteria specified in the referenced service bulletins must be removed from service (section 3(2)); and third, any impellers that meet the part numbers listed in the applicability section must not be fitted unless they meet the inspection criteria (section 3(3)). Additionally, spare impellers must be inspected prior to installation (section 3(3)). These requirements are intended to address a potential manufacturing issue that may cause cracks in the impeller back plate area, leading to engine damage or failure. The AD imposes several obligations on the parties governed by it. Firstly, operators of LTS 101 Series turboshaft engines must ensure that the required inspections and actions are performed within the specified timeframes. This includes conducting visual and fluorescent inspections, removing any non-compliant impellers from service, and ensuring that only compliant impellers are installed. Operators must also ensure that spare impellers are inspected prior to installation. These obligations are intended to maintain the airworthiness of the affected aircraft and prevent potential engine failures. Failure to comply with the requirements of the AD may result in various consequences. Firstly, non-compliance with the inspection and removal requirements may lead to the continued operation of unsafe aircraft, which poses a risk to flight safety. Secondly, installing non-compliant impellers may also result in engine damage or failure, further compromising flight safety. The AD does not explicitly state penalties for non-compliance, but it is likely that CASA may take enforcement action against operators who fail to comply with the AD, which could include fines, suspension or revocation of airworthiness certificates, or other regulatory penalties. It is important for operators to adhere to the AD to ensure the continued airworthiness of their aircraft and the safety of passengers and crew.