Number of propeller governors on Pilatus PC-6 / PT6

[cwetto]

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?

[orion1210]

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

[Cessna Master Beta]

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

[Corrosion]

As orion stated, they are separate components.

[wrench1]

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

[cwetto]

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.