AD/CFM56/10 Amdt 1 - Stage 1-2 Spool HPC and No.3 Bearing Aft Stationary Air/Oil Seal

Overview

The Civil Aviation Regulations 1998, enacted by the Commonwealth of Australia, aim to ensure the safety of civil aviation operations within the country. This legislation, overseen by the Civil Aviation Safety Authority (CASA), establishes various requirements and directives to maintain airworthiness standards, prevent accidents, and protect public safety. One such directive is AD/CFM56/10, which addresses specific issues related to CFM International Turbine Engines - CFM56 Series. The directive was introduced to address the problem of seal separations and subsequent rubbing on the high-pressure compressor spool stage 1-2, which had resulted in service incidents. The policy objective of this airworthiness directive is to enhance aviation safety by mandating the timely removal and replacement of affected engine components to mitigate the risk of further incidents.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 106, encompass the Civil Aviation Safety Authority’s Schedule of Airworthiness Directives. The Airworthiness Directive AD/CFM56/10Amdt 1 applies to specific CFM International (CFMI) turbofan engines, namely the CFM56-2 and CFM56-3, -3B, and -3C model engines. The directive mandates the removal and replacement of certain components within these engines to mitigate risks identified through service bulletins and observed operational issues. The directive applies to these engines irrespective of the aircraft they are installed on, and it extends to all operators within the Commonwealth of Australia, thereby having a national jurisdictional reach. The directive does not specify any exclusions or exemptions, meaning it applies universally to the identified engines within the scope of its provisions. The compliance requirements must be met within specified timeframes and cycle counts, ensuring that the identified safety concerns are addressed promptly. This legislative instrument underscores the importance of maintaining stringent safety standards in civil aviation, ensuring that engine components are regularly inspected and maintained to prevent operational hazards.

Key Provisions

The Civil Aviation Regulations 1998, specifically under Part 39 - 106, establish the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives for CFM International Turbine Engines of the CFM56 Series (AD/CFM56/10 Amendment 1). This directive applies to the CFM56-2 and CFM56-3, -3B, and -3C model turbofan engines. The main requirements (Sections 1-3) are that certain High Pressure Compressor (HPC) stage 1-2 spools and No. 3 bearing aft stationary air/oil seals must be removed and replaced. For CFM56-2 engines, if the HPC stage 1-2 spool part number 9992M60G07 shows rubbing marks, it must be removed and replaced with a serviceable part, as per Service Bulletin CFM56-2 No. 72-825 dated 23 January 1998. Similarly, for CFM56-3, -3B, and -3C engines, the HPC stage 1-2 spool part number 1589M66G02 must be removed and replaced if it matches the serial numbers listed in Service Bulletin CFM56-3/-3B/-3C 72-856 dated 23 January 1998. Additionally, engines with specified serial numbers must have their No. 3 bearing aft stationary oil seal part number 1663M91G03 removed and replaced, and a No. 3 bearing aft air/oil seal retention bushing installed according to Service Bulletin CFM56-3/3B/3C No. 72-855 dated 23 June 1997. The directive imposes specific obligations on the entities governed by it. They must ensure that the identified parts are removed and replaced as per the detailed instructions in the relevant service bulletins. The compliance requirements necessitate actions to be taken at the next exposure of the spools after the effective date of this directive, but prior to accumulating 2000 cycles since the last shop visit associated with the rub event (Section 1). For the specific actions related to the No. 3 bearing aft stationary air/oil seals, these must be completed before 1 May 1998 (Section 3). Failure to comply with these directives could lead to serious safety issues, as the directive is aimed at preventing rubbing and other issues caused by seal separations. Failure to comply with the provisions of this Airworthiness Directive may result in significant safety risks. The Civil Aviation Regulations 1998 do not explicitly state penalties for non-compliance in this context; however, non-compliance with airworthiness directives generally can lead to severe consequences. These may include civil penalties, such as fines, and criminal charges, including imprisonment, as the directives are designed to ensure the safety of air travel. The exact penalties would depend on the specific circumstances of the non-compliance and the jurisdiction under which the offence is prosecuted.