The FAA has issued an emergency Advisory Directive (AD). They are following the lead of Transport Canada and EASA (Transport Canada Emergency AD CF-2024-05). Pratt and Whitney Canada have also issued a corresponding category 1 service bulletin (A14574). To highlight what this means regarding importance, Pratt & Whitney Canada has only issued three other category 1 service bulletins, the last being in 2014.
All of this information applies to the following engine models: All PT6A-64, PT6A-66, PT6A-66A, PT6A-66B, PT6A-66D, PT6A-66T, PT6A-67, PT6A-67A, PT6A-67AF, PT6A-67AG, PT6A-67B, PT6A-67D, PT6A-67F, PT6A-67P, PT6A-67R, PT6A-67RM, PT6A-67T engines.
This AD and service bulletin indicate that they must be complied with before the next flight. For most engine owners/operators, this will mean a review of the AD and determining applicability. The inspection/replacement of the affected parts is specifically targeted to a batch of blades made from a specific batch of raw materials.
The parts affected are the second-stage power turbine blades (PT2). These blades all have individual serial numbers on each blade, and for new engines, the blade serial numbers should be listed in the logbook on the serialized component list. Suppose you have had your PT2 blades replaced within the last 50 hours of operation. In that case, the installing maintenance provider should have provided or be able to identify for you the serial numbers of the blades that were installed.
This is the critical information that you are looking for. The serial numbers of the affected blades are listed in the service bulletin (A14574). If you find these blades in your engine, please get in touch with someone within the Pratt & Whitney Canada network. You can contact your field service manager or the Designated Overhaul Facility you work with. Pratt & Whitney Canada has assured me that parts will not be an issue as they know the number of blades affected and have set aside the replacements.
The majority of engines out there won’t be affected by this AD. All that needs to be done is a review of the information and to make a logbook entry stating that the AD does not apply to your engine. This step does need to be done before your next flight. Get with your maintenance provider, and please ensure that you do this. It will keep you out of trouble if an inspector does a review of your logs.
I advise everyone to be aware and review this AD to ensure you are covered.
Robert Craymer has worked on PT6A engines and PT6A-powered aircraft for the past three decades, including the last 25+ years at Covington Aircraft. As a licensed A&P mechanic, Robert has held every job in an engine overhaul shop and has been an instructor of PT6A Maintenance and Familiarization courses for pilots and mechanics. Robert has been elected to the NAAA board as the Allied-Propulsion Board Member. Robert can be reached at robertc@covingtonaircraft.com or 662-910-9899. Visit us at covingtonaircraft.com.
