pig iron. Crude iron as it is reduced from iron ore in a blast furnace and molded in rough blocks called pigs.
Pig iron has a high carbon content.
pigment (paint constituent). A material ground into a fine powder and dispersed evenly through the vehicle of a finishing material such as paint or enamel. Pigment gives the finishing material its color.
pigtail (electrical component). A piece of wire protruding from a component, such as a resistor or a capacitor, that allows the component to be installed in an electrical circuit.

pilot (aircraft operator). The person who operates the flight controls of an aircraft in flight.
pilotage (navigation). A method of navigation in which a pilot proceeds from checkpoint to checkpoint by visual reference to objects on the ground.
pilot balloon (meteorology). A small, black, spherical balloon used to determine the speed and direction of winds in the upper air. The rate of ascension of the balloon is known so its altitude can be determined, and it is followed with a theodolite to determine the speed and direction of the wind.
pilot briefing (air traffic control). A service provided by a flight service station (FSS) to assist pilots in flight planning. Briefing items may include weather information, NOTAMs, military activities, flow control information, and other items as requested.
pilot chute. A small parachute attached to the canopy of the main parachute and used to pull it from the pack, so it can open.
pilot hole. A small hole punched or drilled in a piece of sheet metal to locate a rivet hole. Pilot holes are smaller than the rivet hole, but are large enough to allow sheet metal fasteners to be used to assemble the parts.
When the parts are assembled and temporarily fastened together, a drill of the proper size for the rivet is passed through both pieces of metal. This method of assembly assures the rivet holes will line up properly.
pilot in command. 14 CFR Part 1: “The pilot responsible for the operation and safety of an aircraft during flight time.”
pilot light (electrical equipment component). A small indicator light on a piece of electrical equipment illuminated all the time power is supplied to the equipment. Pilot lights are a reminder to turn the equipment off when it is not being used.
Pilots Automatic Telephone Weather Answering Service. See PATWAS.
“Pilot’s discretion” (air traffic control). A phrase that, when used in conjunction with altitude assignments, means that ATC has offered the pilot the option of starting climb or descent whenever he wishes and conducting the climb or descent at any rate he wishes.