Commonwealth legislation

AD/JT9D/16 - HPC Variable Stator Synchronising Ring Runner Clearance

In ForceCTH

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

3/10 complexity

This directive requires operators of aircraft with Pratt & Whitney JT9D-7R4 and H1 series engines to fit synchronising ring runners with specified clearances so the high-pressure compressor variable stator system cannot bind (Requirement; Applicability). The measure responds to an FAA finding that reduced clearances during takeoff can cause temporary binding and lower surge margin; operators must retrofit at least one engine before further flight after 25 Dec 1986 and all engines by 31 Dec 1987 (Background; Compliance).

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Current sections

Direct links to the current provisions in AD/JT9D/16 - HPC Variable Stator Synchronising Ring Runner Clearance.

AD/JT9D/16 - HPC Variable Stator Synchronising Ring Runner Clearance

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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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

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.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/JT9D/16 - HPC Variable Stator Synchronising Ring Runner Clearance