Power Turbine Governors (PTGs) installed on Rolls-Royce 250 series engines, which have been overhauled, and/or supplied by Accurate Accessories in California, USA.
Affected parts may have been supplied by a New Zealand parts supplier, or a New Zealand maintenance organization, or may be installed on an aircraft engine imported into New Zealand.
Power turbine governors that are known to possibly be affected, include, but are not limited to, P/N 2524528-14, 2524769-14, 2524667-15, 2524692-11, 2524769-12 and 2549170-2.
The purpose of this Continuing Airworthiness Notice (CAN) is to advise aircraft owners, operators and maintainers of a possible defective bearing installed in PTGs, which could result in RPM oscillations, or drooping.
This CAN is prompted by a report received by a New Zealand maintenance organization from Accurate Accessories of suspect bearings installed in certain PTGs, which may not reach their TBO.
To date, there have not been any engines failures, loss of engine power, or forced landings due to PTG failures fitted with suspect bearings. Certain overseas operators have experienced engine RPM oscillations, or drooping, which prompted the removal of the PTG.
Anecdotal information suggests that these incidents are due to accelerated wear in the spool bearing. Accurate Accessories has subsequently identified a batch of suspect bearings installed in certain PTGs.
The CAA recommend that operators and maintainers review the aircraft engine records to determine if the PTG was supplied by, and/or overhauled by Accurate Accessories in California, USA.
If an affected PTG is found installed on an engine, contact your maintenance provider, and/or Accurate Accessories, as applicable, and accomplish corrective actions as soon as is practically possible.
If any additional information becomes available, then the CAA will revise this CAN.
If you are affected by this CAN, or have any enquires please contact:
Owen Olls
Airworthiness Specialist
Email: owen.olls@caa.govt.nz
Phone: 04 560 9539
