Plain English Meaning

Small caps or sleeves that go over the little metal tube on the outside of the airplane to keep bugs and dirt out while the airplane is parked. They have a red flag or streamer hanging off them so you can't miss them on your walk-around.

Full Definition

Protective covers fitted over the open end of the pitot tube when the airplane is parked, used to prevent insects, dirt, water, or other debris from entering and blocking the tube. They typically include a brightly colored fabric streamer or 'Remove Before Flight' flag so the cover is visible and removed before flight.

Context Anchor

Seen during postflight securing, preflight inspection, and ramp parking, especially when checking that all covers are installed after flight and removed before flight.

Derivation

Pitot is named after Henri Pitot, an 18th-century French engineer who invented the tube used to measure . The 'cover' is simply the protective cap placed over it on the .