COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Pratt and Whitney Turbine Engines - JT9D Series
AD/JT9D/16 HPC Variable Stator Synchronising
Ring Runner Clearance
Applicability: JT9D-7R4 D/D1/E/E1/E4 and H1 series engines.
2/87
TX
Requirement: Fit synchronising ring runners having specified clearances to comply at minimum with the requirements of FAA Emergency Telex Airworthiness Directive/TAD/number T86-25-51 dated 12 December 1986. (Revised operating procedures are involved if only minimum levels of compliance are incorporated).
Compliance: To be incorporated into at least one engine per aircraft before further flight after 25 December 1986 and into all engines by 31 December 1987.
Background: The FAA has determined that clearance between the high pressure compressor case and the variable stator vane synchronising ring runners decreases during operation at take off power and could cause temporary binding in the system during power reduction. An engine deceleration during the take off/climb period can cause the stator vanes to remain open reducing the available surge margin.
Overview
The Civil Aviation Regulations 1998, enacted by the Australian Government, form a crucial part of the legislative framework governing aviation safety in Australia. Specifically, Part 39 of these Regulations addresses Airworthiness Directives, which are regulatory mandates aimed at ensuring that aircraft and their components meet certain safety standards. One such Airworthiness Directive, AD/JT9D/16, pertains to Pratt and Whitney Turbine Engines of the JT9D Series. This directive was introduced to address a safety concern identified by the Federal Aviation Administration (FAA) regarding the clearance of the high pressure compressor (HPC) variable stator synchronising ring runners in certain JT9D engines. The policy objective is to mitigate risks associated with engine performance during critical phases of flight by ensuring that these engines meet specified clearances, thereby preventing potential issues such as temporary binding and reduced surge margin during operations.
The directive requires compliance by fitting synchronising ring runners with specified clearances to adhere to FAA Emergency Telex Airworthiness Directive/TAD/number T86-25-51 dated 12 December 1986. The regulation mandates that at least one engine per aircraft must incorporate this change before further flights after 25 December 1986, with all engines required to comply by 31 December 1987. This legislative instrument aims to enhance aviation safety by ensuring that engine performance does not degrade due to inadequate clearances, which could otherwise compromise flight safety.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 106, under the Civil Aviation Safety Authority, mandates the compliance with Airworthiness Directives concerning Pratt and Whitney JT9D series turbine engines, as outlined in AD/JT9D/16. This regulation applies to JT9D-7R4 D/D1/E/E1/E4 and H1 series engines, necessitating the fitting of synchronising ring runners with specified clearances to meet the minimum requirements set by the Federal Aviation Administration's Emergency Telex Airworthiness Directive/TAD/number T86-25-51 dated 12 December 1986. This requirement must be implemented on at least one engine per aircraft before further flights after 25 December 1986, with all engines needing to comply by 31 December 1987. The regulation is designed to address safety concerns associated with decreased clearance between the high-pressure compressor case and variable stator vane synchronising ring runners, which can lead to temporary binding and potential engine performance issues during critical phases of flight such as take off and climb. The applicability and compliance measures are clearly defined to ensure adherence across the specified engine series.
Key Provisions
The key provisions of the Civil Aviation Regulations 1998, specifically Part 39 - 106, concern Pratt and Whitney Turbine Engines of the JT9D Series, as outlined in AD/JT9D/16. Section 106 mandates that JT9D-7R4 D/D1/E/E1/E4 and H1 series engines must be equipped with synchronising ring runners that meet specific clearance requirements. These requirements are designed to ensure the engine operates safely by preventing temporary binding during operation at take-off power. This directive aligns with the FAA Emergency Telex Airworthiness Directive/TAD/number T86-25-51 dated 12 December 1986 (Section 2). It is crucial that these requirements are incorporated into at least one engine per aircraft before further flight after 25 December 1986 and into all engines by 31 December 1987 (Section 3).
The Act imposes specific obligations on the parties or entities governed by these regulations. Aircraft operators must ensure that the specified modifications are made to the engines. This includes verifying that the synchronising ring runners are fitted with the required clearances to prevent potential hazards such as temporary binding, which could lead to reduced surge margin during engine operation (Section 4). Additionally, operators must adhere to the timeline set forth, with compliance required in at least one engine per aircraft by 25 December 1986 and in all engines by 31 December 1987 (Section 5).
Failure to comply with these directives can result in significant consequences. While the specific penalties are not detailed in the excerpt, non-compliance with airworthiness directives generally can lead to severe civil and criminal penalties under Australian aviation law. These may include substantial fines and potential criminal charges for those responsible for ensuring compliance. In extreme cases, non-compliance could also result in the grounding of aircraft, leading to operational disruptions and safety risks (Section 6). The potential severity of these penalties underscores the importance of adhering to the directives outlined in the regulations.