All turbine engines; other than engines installed in:1. Aircraft administered by an approved sports aviation body; and2. Aircraft issued with a limited category certificate of airworthiness under regulation 21.189 of the CASR; and3. Aircraft issued with an experimental certificate under regulation 21.195A of the CASR.
Requirement:
1. OVERHAUL/INSPECTION PERIODS FOR TURBINE ENGINES1.1 Turbine engines must be overhauled or inspected at periods not exceeding:(a) those detailed in Requirements 1.2, 1.3 and 1.4 of this Directive; or(b) the recommended hours in service published by the engine manufacturer; or(c) those detailed in a system of maintenance approved under regulation 42M of the Civil Aviation Regulations 1988 (an approved system of maintenance).1.2 Honeywell TPE331 series engines must be:(a) overhauled at the periods specified in, and subject to the requirements of, the latest revision of the Honeywell Service Bulletin detailing TPE331 series engine time between overhaul (TBO) intervals and requirements that applies to the engine model (for the purpose of this AD, annual utilisation, or type of operation, are not requisites to establish a TBO period for Honeywell TPE331-1, -2, -3, -5, -6, -8, -10, -11, -12 series engines); or(b) inspected in accordance with, and subject to the requirements of, the latest version of a Honeywell published Continuous Airworthiness Maintenance Operation (CAM) program that applies to the engine model (for the purpose of this AD, annual utilisation, or type of operation, are not requisites to establish a TBO period for Honeywell TPE331-1, -2, -3, -5, -6, -8, -10, -11, -12 series engines); or(c) inspected and overhauled as detailed in an approved system of maintenance.
1.3 Pratt and Whitney Canada PT6A series engines, other than PT6A engines installed in aircraft conducting aerial agricultural operations or fire-fighting operations, must be:(a) overhauled at the periods specified in, and subject to the requirements of, the latest revision of the Pratt and Whitney Canada Service Bulletin detailing Pratt and Whitney Canada PT6A operating time between overhaul and hot section inspection frequency that applies to the engine model; or(b) overhaul at periods not to exceed 5,000 hours time in service, subject to compliance with the maintenance requirements detailed in Appendix A of this AD; or(c) inspected and overhauled as detailed in an approved system of maintenance.1.4 Pratt and Whitney Canada PT6A series engines installed in aircraft conducting aerial agricultural operations or fire-fighting operations must be:(a) overhauled at the periods as specified in, and subject to the requirements of, the latest revision of the Pratt and Whitney Canada Service Bulletin detailing Pratt and Whitney Canada PT6A operating time between overhaul and hot section inspection frequency that applies to the engine model; or(b) inspected in accordance with an engine on-condition program having regard to that detailed in Appendix B of this AD; or(c) inspected, overhauled and “on-condition” monitor as detailed in an approved system of maintenance.Previously issued Alternative Means of Compliances (AMOCs) or Exclusions to AD/ENG/5 Amdt 9 are considered acceptable for compliance with the equivalent requirements of this AD.
Compliance
No later than 30 June 2026This Amendment becomes effective on 31 March 2026
Background:
Amendment 10 of this AD has been issued to remove an obsolete reference to Pratt and Whitney Canada SIL PT6A-122 and replace it with a reference to Revision 10 (Pratt and Whitney Canada SIL No. GEN-055 R10 dated 13 November 2018), the latest version of this Service Information Letter as at the commencement of this AD.The AD is issued to address an unsafe situation relating to turbine engines by requiring turbine engines to be overhauled or inspected at specified intervals. The unsafe condition, if not addressed, could result in loss of power, uncontained release of debris, damage to the engine, and damage to the aircraft.
Background (continued):
This AD does not apply in relation to turbine engines installed in certain, specified aircraft. This AD addresses the engine certification requirement to publish instructions for the continued airworthiness of a type-certificated engine. In addition to listing the manufacturer’s published TBO or inspection periods, this AD also provides unique CASA initiated options for certain turbine engines.
David Punshon's signature.
David Punshon
Delegate of the Civil Aviation Safety Authority
18 March 2026
AD/ENG/5 Amdt 10
PT6A Enhanced Maintenance Program
Appendix A
REQUIREMENTS
The PT6A engine maintenance program must be carried out in accordance with approved maintenance data and detailed in an approved system of maintenance. The system of maintenance must include, but need not be limited to, the following requirements:
PT6A engines not previously maintained in accordance with a maintenance program reflecting the intent of the maintenance requirements detailed in this Appendix and with engine hours in service greater than 75% of the Pratt and Whitney Canada published Time Between Overhaul (TBO) period at the time of introduction, must be subject to a pro-rata TBO period based on the Pratt and Whitney Canada published TBO period.
The engine must be on an Engine Condition Trend Monitoring (ECTM) program, including data collection, analysis and follow up actions. This program must be in accordance with the WebECTM® system or CAMP Systems International (CAMP), as required under revision 10 of Pratt and Whitney Canada SIL No. GEN-055 (PWC SIL No. GEN-055 R10 dated 13 November 2018), as existing at the commencement of this instrument, and include requirements for qualification and training for personnel conducting ECTM.
Hot section inspections must be carried out at intervals not to exceed:
(a) 1250 hours time in service; or
(b) 1760 hours time in service subject to a boroscope inspection of the engine hot section for evidence of cracks, distortion, burning and coating loss at intervals not to exceed 610 hours time in service.
All fuel nozzles must be cleaned and flow checked at intervals not to exceed 460 hours time in service.
The engine oil filter element must be inspected for contamination at intervals not to exceed 220 hours time in service.
The reduction gearbox chip detector must be inspected for contamination, or continuity, at intervals not to exceed 220 hours time in service.
Engines with an annual utilisation of less than 500 hours per annum, an engine oil change must be carried out at intervals not to exceed 12 calendar months time in service.
An inspection of the 1st stage compressor for evidence of Foreign Object damage (FOD), corrosion and contamination must be carried out at intervals not to exceed 220 hours time in service.
A compressor power recovery wash must be carried out in response to trend monitoring parameter deviations, or at intervals not to exceed 220 hours time in service, or 3 calendar months, whichever occurs first.
All life limited components must be replaced at engine manufacturer’s published life limits per AD/ENG/7.
Critical components, as identified in the Pratt and Whitney Service Bulletin that applies to the engine model, must be inspected at intervals specified by the engine manufacturer.
TBO of accessories must be per the recommendations of Pratt and Whitney Canada.
The maintenance program must be reviewed and revised as required at periods not to exceed 2 years taking into consideration all major defects and defects that affect engine durability. Outcome of the review must be reported to CASA via CASA’s online Defect Reporting System (DRS) Portal or via Form 404 referring to AD/ENG/5.
AD/ENG/5 Amdt 10
PT6A Agricultural OperationsOn-Condition Maintenance Program
Appendix B
REQUIREMENTS
The PT6A engine on-condition maintenance program must be carried out in accordance with approved maintenance data and detailed in an approved system of maintenance. The system of maintenance must include, but need not be limited to, the following requirements:
The engine must be on an Engine Condition Trend Monitoring (ECTM) program, including data collection, analysis and follow up actions, qualification and training of personnel. This program must be in accordance with the WebECTM® system or CAMP Systems International (CAMP), as required under revision 10 of Pratt and Whitney Canada SIL No. GEN-055 (PWC SIL No. GEN-055 R10 dated 13 November 2018), and include requirements for qualification and training for personnel conducting ECTM.
Hot section inspections must be carried out at intervals not to exceed 1510 hours time in service.
All fuel nozzles must be cleaned and flow checked at intervals not to exceed 460 hours time in service.
The engine oil filter element must be inspected for contamination at intervals not to exceed 220 hours time in service.
The reduction gearbox chip detector must be inspected for contamination, or continuity, at intervals not to exceed 220 hours time in service.
Engines with an annual utilisation of less than 500 hours per annum, an engine oil change must be carried out at intervals not to exceed 12 calendar months time in service.
Engines not incorporating an engine air intake positive barrier air filter, an inspection of the 1st stage compressor for evidence of Foreign Object Damage (FOD), corrosion and contamination must be carried out at intervals not to exceed 220 hours time in service.
All life limited components must be replaced at the engine manufacturer’s published life limits per AD/ENG/7.
Critical components, as identified in the latest revision of the Pratt and Whitney Service Bulletin that applies to the engine model, must be inspected at intervals specified by Pratt and Whitney Canada.
Engine work-scope during engine shop visits must have regard to the recommendations of Pratt and Whitney Canada, including minimum modification standards for engine durability; and
TBO of accessories must have regard to the recommendations of Pratt and Whitney Canada.
The on-condition program must be reviewed and revised as required at periods not exceeding 2 years taking into consideration all major defects and defects that affect engine durability. Outcome of the review must be reported to CASA via CASA’s online Defect Reporting System (DRS) Portal or via Form 404 referring to AD/ENG/5.
Part Engines - General - AD/ENG/5 Amdt 10 – Turbine Engine Continuing Airworthiness Requirements - Engines - General | Zoe