RV12is - Fuel System Leak Check

Before installing the tailcone on my RV12is I felt it best to leak check the entire fuel system prior to loosing easy access to the fuel filters/pumps on located aft of the baggage bulkhead. The Rotax 912is engine has been installed but I have not completed the avionics installation so I don't have power to the fuel pumps.

Do any fellow builders have any recommendations to pressure / leak test this system using compressed air or is it standard operating procedure to complete the build and test during my first engine run?

Any best practices are appreciated!

Thanks

Rich

I'd say no to compressed air. You'll blow out the proseal in the fuel tank and cause leaks. Fuel leak checks are included in the PAP (Production Acceptance Procedures). I don't think anything would be easier to fix now than it will be at the end of the build.

I'm hoping everything in my center channel is OK (my hands only recently healed from all the cuts trying to work in that tiny space!

Don't forget about the recent AD from Rotax concerning leaking fuel pumps from a certain S/N range. Van's should have mailed affected builders (they did with me). ASB-912 i-010 and ASB-912i-010iS

Rich-

During the build of my RV-12 without the fuel tank installed, I pressurized fuel lines between the firewall and the tank using an air compressor to 55" of water (approximately 2 psi) using a Schrader valve with a pressure gauge to monitor. As temps dropped overnight, so did the indicated pressure ... and the next day as the temps came back up, so did the indicated pressure on the gauge.

The fuel tank was pressurized with the filling neck attached to about a pound of pressure and and monitored using an inches of water gauge. Even with only slightly less than a pound of pressure, one could see the tank was beginning to bulge a bit ... so absolutely DO NOT put more pressure than that on the tank! Below is a link to the pressure testing setups.
http://www.dogaviation.com/2014/04/rv-12-fuel-line-pressure-testing.html

http://www.dogaviation.com/2016/03/fuel-tank-pressure-tested-t-01219c-vent.html

Hope that helps ... happy building,

Pressure Check

In the factory we perform a pressure check using regulated shop air very early on in the build process, long before the fuel tank or engine is installed.

We install a mechanical pressure gauge in the FLF-00013 common to the Rotax Fuel Filter (874 060) in place of the electronic sensor, a Fuel Air Tank Valve (the bike tire fitting used for pressure testing the fuel tanks) in place of the CAV-110, and cap the fittings that will hook up to the fuel tank later. Temp install a fuel hose connecting the two AN837-6D fittings on the firewall to each other and apply shop air to the Air Tank Valve you installed on the baggage bulkhead. Charge it to 45psi (which is the operating system pressure) and watch the pressure gauge for any drop. Soapy bubbles or hissing will lead you to any leaks.

Thank you as all are excellent recommendations!