Kennon plugs were custom fit to the Mooney, including a two-part plug to accomodate the airscoop.

We’re constantly surprised at how few owners bother with protective gear for their airplanes—covers and cowl plugs—which sharply limit damage from the sun’s ultraviolet rays and keep junk and moisture out of the engine compartment. On a recent ramp drive-through, we noted that two in 10 airplanes had covers and only one had cowl plugs.

We think every airplane needs a pair, however. Birds nesting in the engine compartment is a serious safety hazard and has caused fires that have done significant damage. As we discovered recently, even an overnight sit is long enough for some industrious birds to make a mess. In cold country, a pair of cowl plugs is…