Caution - Aeroquip 601 Hose Leaks
July 1987
We have yet another report of one of these rubber, reinforced-with-stainless-steel, outer, braid hoses that has suddenly sprung a massive leak. Again, it happened after the airplane had not been flown for a while. Our own experience with the Grizzly was that the airplane was not used for almost one year, then when we turned on the fuel valve and the boost pump, fuel ran out of the cowling just as though a line had been removed.
A fuel line, an Aeroquip 601, was leaking at one of the fittings. This hose had never leaked before and no one had touched it between flights. We have now heard from at least four builders with this problem. Here at RAF, we have gone over to Stratoflex Teflon hoses and we order them made up to the length we want. We have them pressure checked and have fire sleeves installed on each fuel line. These fuel lines are more expensive but we believe they are a much safer way to go. We have been getting our hoses from Aircraft Spruce and they are available from dash-3 to dash-8.
Check all your hoses aft of the firewall, both oil lines and fuel lines, frequently, especially if you have Aeroquip 601 hoses and even more frequently if you made be considered one of the most hazardous situations that these up yourself. A fuel leak aft of the firewall must can occur and must be taken care of before it happens while airborne. Replace any suspect fuel/oil lines. Have them pressure tested and have fire sleeves installed on each line.