COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
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.
Overview
The Civil Aviation Regulations 1998, specifically under Part 39, introduces a legislative instrument to address safety concerns regarding certain high-pressure turbine discs in General Electric CF6 Series engines, particularly those used in the CF6-45/50 series. The directive was enacted to ensure the removal of potentially faulty turbine discs to prevent incidents like the uncontained high-pressure turbine disc fracture that had previously occurred. This legislation was introduced by the Commonwealth of Australia, with the Civil Aviation Safety Authority (CASA) as the enforcing body, aiming to enhance aviation safety by mitigating risks associated with the specified turbine discs. The policy objective is to maintain the highest safety standards in civil aviation by mandating timely inspections and replacements of the identified turbine discs based on their cycles in service or accumulated cycles.
Scope and Application
The Civil Aviation Safety Authority (CASA) issues Airworthiness Directives (ADs) under the Civil Aviation Regulations 1998, which govern the safety standards for aircraft and aviation activities within Australia. The specified AD/CF6/14 pertains to General Electric CF6 series turbine engines, specifically the CF6-45/50 series, and mandates the removal of certain high pressure turbine discs to prevent potential uncontained failures that could compromise flight safety. The directive applies to all operators of aircraft equipped with the affected engines, irrespective of whether the operation is commercial or private. The geographic reach of this regulation is national, as it is enforced by CASA, the Commonwealth authority. There are no stated exclusions or exemptions within the directive itself, though operators may seek clarification or special considerations through CASA. The directive may be extended or further specified through subordinate instruments issued by CASA.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 106, under the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, mandate the removal of certain high pressure turbine discs from service for CF6-45/50 series engines. These directives are encapsulated in AD/CF6/14, which pertains to high pressure turbine discs (Section 1/91). The directive applies to specific parts numbers of high pressure turbine discs and outlines a detailed compliance schedule (Section 1/91).
The main requirement is the removal of first stage high pressure turbine discs with particular part numbers (P/N 9264M57P01, 9264M57P02, 1322M88P04, 1322M88P05, 1322M88P07, 9283M31P02, 9283M55P04 and 9283M55P05) from service (Section 1/91). The removal must follow a phased schedule based on the number of cycles in service (CIS) or the cycles since new (CSN) the engine has accumulated. For instance, discs with more than or equal to 7,500 CSN must be removed within 100 CIS after the effective date of this directive (Section 1/91). Discs with lesser CSN must be removed at subsequent intervals and shop visits, following a stringent timeline to ensure safety (Section 1/91).
The obligations imposed by this directive are clear and specific. Operators of CF6-45/50 series engines must adhere to the compliance schedule to remove and replace the specified turbine discs. Failure to comply with these directives can lead to serious safety risks, including potential uncontained engine failures (Section 1/91). The directive also references FAA AD 90-19-09 and the CF6-50 Series Service Bulletin 72-966, which provide additional context and specifications for the replacement discs (Section 1/91).
The consequences for non-compliance with these directives are significant. The Civil Aviation Safety Authority may take enforcement action against operators who fail to adhere to these airworthiness directives, including potential fines, sanctions, or other regulatory measures (Section 1/91). Additionally, failure to comply can result in the grounding of aircraft, which can lead to substantial operational disruptions and financial losses (Section 1/91). The directive ensures that the specified turbine discs are removed and replaced in a timely manner to prevent potential safety hazards, underscoring the importance of strict adherence to the compliance schedule (Section 1/91).