Number of propeller governors on Pilatus PC-6 / PT6
 

I have a question, maybe it is funny for you, but I can't find answer on google.

So I received status of one Pilatus PC6 with engine PT6A-27, where there is also "Propeller overspeed governor, PN 8210-002" stated, with overhaul 4.100FH.

And on second, different PC6 with same engine PT6A-27, there are two propeller governors stated on Status List.
One is "Propeller overspeed governor, PN 8210-002", overhaul 4.100FH
and second "Propeller governor, PN 210615", with overhaul 6.500FH.

So is this a mistake in status on second aircraft? Maybe someone forgot to delete one governor after replacement?
Or is it possible to have two governors?

Not overly familiar with pt6 and not at all with the -27 but I'd imagine that you'll find you have on each engine an overspeed governer and also a variable governer, controlled/varied by the pitch lever.

Hope this helps

Try reading system decription on this page.Should answer question.


http://www.aviationpros.com/article/10387616/troubleshooting-taking-a-look-at-the-pt6a-27-engine

As orion stated, they are separate components.

cwetto:

They are separate components as mentioned above.

If I recall correctly, the prop governor provides constant speed, beta, and power turbine speed control. The prop overspeed governor is installed in parallel to the prop gov and is strictly a fail-safe device that bypasses the control oil flow once the overspeed limit is reach.

W1

Hello!

Thank you all for your answers, very helpfull!!!

Now I have a problem, that I am missing one governor on first Pilatus PC6 status.
And it is offcourse overhaul limited.

Hopefully I will find it digging in papers.