Nonstaining leak tracer solution and method employing same

Abstract

Leak tracer solution particularly effective for inspection of aircraft fuel tanks and lines prior to use, without staining painted surfaces of the aircraft consists essentially of an aqueous solution containing not more than about 10%, generally about 0.1 to about 10%, of a nonionic oxyalkylated aliphatic alcohol surfactant, and a small amount, generally about 0.005 to about 1.0%, of a water soluble, e.g. dual visibility, dye such as Uranine, which does not migrate into or penetrate the painted aircraft surface. A small amount of an anti-parasitic agent can be added to prevent algae growth. The solution is used by introducing it into the interior of new fuel tanks and lines, viewing the external surfaces of such tanks and lines under suitable lighting conditions such as daylight or black (fluorescent) light to detect any cracks or leaks, and draining the solution from the tanks and lines. After such draining, preferably a 'depuddling' agent is introduced to chemically blend any water-based leak tracer solution remaining in depressions of the fuel tanks or lines, with the oil-based aircraft's fuel, for removal of such remaining leak tracer solution. A preferred 'depuddling' agent is a 50-50 mixture by volume of a petroleum-based aircraft fuel, and a nonionic oxyalkylated aliphatic alcohol surfactant.