Commonwealth legislation

AD/CF6/14 - High Pressure Turbine Discs

In ForceCTH

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

5/10 complexity

This directive requires operators of GE CF6-45/50 engines to remove specified first-stage high-pressure turbine discs and replace them on a tiered schedule based on each disc's cycles since new (CSN) and cycles in service (CIS). It targets particular part numbers after an uncontained disc fracture and the discovery of similar cracks. Operators and maintenance providers pay for removals, replacements and shop visits; compliance imposes discrete timing windows, record-keeping and parts-tracking obligations to mitigate fracture risk.

JSON API

Deep dive

Want the full deep dive?

Zoe can write the in-depth analysis on top of the summary above: how it works, who it affects and what each part actually does.

Current sections

Direct links to the current provisions in AD/CF6/14 - High Pressure Turbine Discs.

AD/CF6/14 - High Pressure Turbine Discs

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

View image in the official source
General Electric Turbine Engines - CF6 Series

AD/CF6/14 High Pressure Turbine Discs 1/91

Applicability: CF6-45/50 series engines.

Requirement: Remove from service, first stage high pressure turbine discs P/N 9264M57P01, 9264M57P02, 1322M88P04, 1322M88P05, 1322M88P07, 9283M31P02,

9283M55P04 and 9283M55P05 in accordance with the compliance schedule of this Directive.

Note: FAA AD 90-19-09 refers.

Compliance: Effective 24 January 1991:

Remove within 100 cycles in service (CIS) after the effective date of this AD, discs with greater than or equal to 7,500 CSN.

2. Remove at the next engine shop visit, but no later than 1,000 CIS after the effective date of this AD or prior to accumulating 7,600 CSN, whichever occurs first, discs with greater than or equal to 6,000 CSN, but less than 7,500 CSN.

3. Remove at the next engine shop visit after accumulating 5,500 CSN, but no later than 1,500 CIS after the effective date of this AD or prior to accumulating 7,000 CSN, whichever occurs first, discs with greater than or equal to 4,000 CSN, but less than 6,000 CSN.

4. Remove prior to exceeding 5,500 CSN, discs with less than 4,000 CSN.

5. Thereafter, remove affected discs from service and replace with a serviceable disc prior to exceeding 5,500 CSN.

Note: CF6-50 Series Service Bulletin 72-966, dated September 1, 1989, introduces a new HPT stage one disc, P/N 1473M65P02, which has an FAA approved time limit of 15,000 CSN.

Background: This Directive has been issued to require removal of certain high pressure turbine discs from service. The requirement follows advice of an uncontained stage one high pressure turbine disc fracture event. Investigation of the disc fracture event found six similar discs to be cracked.

Source text

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

1 AD/CF6/14 - High Pressure Turbine Discs