Properties:

An item having one or more electrodes arranged to form an air gap across which an electric spark is introduced and discharged to ignite fuel and air mixture in an aircraft heater. In heaters designed for the single electrode type, two plugs or one plug and one electrode are required within the combustion chamber in proper placement to effect the air gap. An igniter plug with two or more electrodes differs from a spark plug by always having cooling facilities in the form of holes or slots in the plug casing to allow entry of air currents around the electrodes. Excludes spark plug; glow plug and electrode.