Emergency AD Issued For PT6 Turbine Blade Failures

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Transport Canada issued an emergency Airworthiness Directive (AD) on Feb. 15 mandating the grounding of aircraft equipped with certain Pratt & Whitney Canada (P&WC) PT6 turboprop engines until turbine blade replacements are conducted. 

The move comes as there have been reports of three PT2 blade failures, which were all contained. P&WC says it is investigating the root cause of the failures but in its preliminary investigation, the power turbine modules in all event engines contained newly manufactured part number blades from the same raw material. All had also accumulated less than 25 hours air time since new. 

According to the AD, “Failure of PT2 blades could lead to engine power loss or in-flight shut down, potentially resulting in reduced control of the aeroplane.” 

P&WC parent company RTX said the order affects some 160-180 PT6A and PT6E turboprops. Affected PT2 blades are listed in the AD and “have accumulated less than 50 hours air time since new, or since shop visit, or since second-stage power turbine repair.” 

Operators are required to replace the affected blades “prior to the next flight,” according to the AD.

Amelia Walsh
Amelia Walsh is a private pilot who enjoys flying her family’s Columbia 350. She is based in Colorado and loves all things outdoors including skiing, hiking, and camping.

12 COMMENTS

  1. I hope this isn’t an indication of Pratt following the Boeing model of finding the cheapest possible supplier for every part. I mean what could possibly go wrong….

  2. Sounds like the metallurgy of the blade material was substandard from the start. It would be interesting to see the manufacturing documents from the supplier and how P&W tested the batch to verify its alloy content. For power turbine blades I would expect testing 100% of the metal in each blade. Not sure if those are single crystal blades, but either way it could also be a crystal grain issue. Power turbine blades operate at both high temperature and high rpm, so pretty demanding service. I had one fail on me many years ago in an engine that had about 40 hours on it. Fortunately it happened shortly before rotation, so it just involved a short trip through the grass next to the runway as the engine went to zero thrust very quickly. Five or six seconds later and it would have been REALLY interesting!

  3. It sounds to me as though PW has a major problem all across their engine line. This is likely the very same issue they have with the GTF engines. In the case of the A320 NEOs, one has to wonder just how sure they are these aircraft are safe to operate with those engines? Is the new material any better than what they’re replacing? They are now producing those blades at a breakneck speed to keep the flow of new engines to Airbus flowing along with replacements for grounded engines. Is our FAA/EASA on top of this? They certainly were not when those blades were produced. And I might add, Airbus seems to be perfectly comfortable with all of this. After all, they do need to keep those deliveries on schedule. Sounds very familiar to me.

  4. According to P & W:

    “[P&WC] has recently identified a limited subpopulation of high power PT6A and PT6E engines that require part replacement before returning to service. The population is limited to engine parts […] manufactured from a single batch of sourced product.”

    They also stated that the issue “is not powder-metal-related.”

    One failure resulted in an aborted takeoff, the other two occurred during testing at the supplier.

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