Guy swore the radar was haunted, turned out to be a coffee cup in the nose bay
So about 8 months ago I'm doing a ramp check on a King Air at a small field outside Wichita and this pilot walks up dead serious and tells me the weather radar has a mind of its own, paints returns over empty farmland, then quits when he levels off. I pulled the rack and ran it on the bench, clean as a whistle, no faults, so I put it back and figured he was just spooked. Two flights later he radios me from the ramp and says 'come look at your ghost' and points at the MFD showing a fat blob right off the nose. I climb in the nose bay with a flashlight and there sits a ceramic mug from the FBO, left on top of the waveguide, and the thing was full of cold coffee that had sloshed out and pooled right on the connector. Moisture in the waveguide was throwing false returns the whole time. Dude had been using the bay as a cup holder for a month because it was the only flat spot he could reach from the chocks. I made him buy me lunch for the two hours I wasted chasing a fault that smelled like Folgers. Anybody else ever track down a squawk that turned out to be straight up pilot housekeeping?