Overview

The Civil Aviation Safety Authority Airworthiness Directive AD/TFE 731/32, issued in 2002, pertains specifically to the AlliedSignal (Garrett/AiResearch) Turbine Engines - TFE 731 Series. This directive was enacted to address the unsafe condition of fan rotor discs in certain TFE 731 series turbofan engines, which had a history of cracking in the dovetail area, potentially leading to in-flight shutdowns. The problem was identified through eddy current inspection techniques, but it was found that these techniques were not fully effective in detecting all cracks. The directive requires the replacement of specified fan rotor discs to mitigate the risk of in-flight shutdowns and ensure flight safety. The policy objective is to mandate the removal of potentially unsafe fan rotor discs from service to enhance aviation safety standards. The directive was issued under the authority of the Civil Aviation Safety Authority (CASA) and became effective on 18 April 2002, with compliance required at the next access to the fan rotor disc, next scheduled inspection, or before 31 December 2002, whichever came first.

Scope and Application

The Airworthiness Directive (AD) issued under subregulation 39.1(1) of the Civil Aviation Regulations 1998 applies specifically to TFE731-2, -3, and -4 series turbofan engines that have fan rotor discs with particular part numbers. This legislation mandates that certain fan rotor discs must be replaced to address an identified unsafe condition, namely the potential for cracking in the dovetail area, which could lead to catastrophic engine failure during flight. The replacement must adhere to instructions outlined in Honeywell Service Bulletin TFE731-A72-3668. The directive applies to the mentioned engines at the next access to the fan rotor disc, next scheduled inspection, or before 31 December 2002, whichever is earliest. The AD was made effective from 18 April 2002, and as of 31 December 2002, several other related directives were cancelled due to the obsolescence of the affected fan rotor discs.

Key Provisions

The Airworthiness Directive (AD) AD/TFE 731/32 applies to the TFE731-2, -3, and -4 series turbofan engines with specific fan rotor disc part numbers: 3072162-All, 3072816-All, 3073436-All, 3073539-All, and 3074529-All. These part numbers cover all dash numbers. The directive mandates that the applicable fan rotor discs be replaced in accordance with Honeywell Service Bulletin TFE731-A72-3668. This replacement must occur under specific conditions: at the next access to the fan rotor disc, at the next scheduled inspection of the fan rotor disc, or before 31 December 2002, whichever is earliest. Access to the fan rotor disc is defined as when the fan shaft is unstretched. Serviceable discs, which are not listed in this directive, will remain in service. The AD imposes several obligations on the parties governed by it. Firstly, it requires operators and maintainers of the specified turbofan engines to ensure that the fan rotor discs listed in the applicability section are replaced as per the instructions in the requirement section. This means that during the next maintenance access, next scheduled inspection, or before the specified deadline, the affected fan rotor discs must be removed and replaced with new ones following the procedures outlined in the Honeywell Service Bulletin. Secondly, it mandates that the obsolete discs must be phased out by 31 December 2002, ensuring that no such discs remain in service after this date. Failure to comply with this AD can lead to severe consequences. The primary concern is the risk of in-flight shutdown due to fan rotor disc failure, which poses a significant flight safety hazard. Non-compliance with the directive may result in the aircraft being grounded or denied operation until the required actions are taken. Additionally, the AD references FAA AD 2001-23-09, indicating that similar regulatory frameworks apply in other jurisdictions, potentially leading to cross-border enforcement actions. The Civil Aviation Safety Authority (CASA) has the authority to take regulatory action against non-compliant entities, including fines and other penalties as stipulated in the Civil Aviation Regulations 1998. The directive does not explicitly mention specific penalties or fines within the text itself but refers to the broader regulatory framework under which CASA operates. Under the Civil Aviation Regulations 1998, non-compliance with an AD can result in penalties, including substantial fines and potential criminal charges for serious breaches that endanger safety. The exact penalties depend on the severity of the non-compliance and the specific regulations applied. The AD underscores the importance of adhering to these requirements to maintain the airworthiness of the aircraft and ensure flight safety.