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ISO counter weights for hartzell 3 bladed composite prop


Well-Known Member
Lifetime Supporter
Aug 20, 2007
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Benny, I can't help you with the counter weights even though I somehow curiously have three of these props.

However, I will put a PSA out there for anyone who owns one:

There is a Service Bulletin on these props that has been out for a few years that requires an inspection of the secondary windings to ensure conformity to the type design specifications. The SB indicates the inspection must be done while the prop is disassembled for an overhaul or re-seal, but Northwest Propeller was able to do these for me while the prop was assembled after concurrence from Hartzell engineers. If the blades are found to be out of spec, Hartzell will repair them at no cost, but only until January 15th, 2021. After that the SB is silent as to what happens.

I for one did not want to find out and have to pay to repair or replace any blades! The SB is attached for anyone who needs it.


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