Dash-8 100 PW120 Prop Overspeed Governor Relief Valve Life.

[B208]

Quick question to all you guys working on Dash 8s. I'm told that the Prop Overspeed Governor Relief Valves have to be replaced between 9000-10000 hrs. Could anyone confirm this? All comments welcome.

[Dibbley]

I can't give you overhaul times for these, but I remember there was an AD or SB requiring replacement of them immediately back around 2000. I did our whole fleet over a few weeks back then. Best to give P & W a call and give them your situation details.

[B208]

Thanks Dibbley! Another quick question for anyone out there. When you replace these valves, do you record the serial number of the valve in the log somewhere?

[Dibbley]

The reason for the replacement of the relief valve, was the danger of internal 'coking' of the oil - from what I remember. My guess is that the valve would stick and prop control issues might develop. I have a whole collection of overspeed governor p/n tags in my junk drawer. The mod involved the complete replacement of the overspeed governor part number plate. We were using a work card system at my company during this time and I entered that the mod had been complied with on the document. The records girls might have entered that information in the engine log books - they should have. We never see the books.

[B208]

One last stupid question

Are the valves lifed items, or is the pump a lifed item and the valves just get replaced at overhaul?

[Dibbley]

My guess is that the valve (the post mod variety) would be handled as part of the complete overspeed governor/pump assembly and the overhaul times would be set the same as that unit. When our engines go out for O/H, the overspeed governor/pump goes out as part of the basic engine. What they do with it at the overhaul shop is unknown to me.