aircraftman n : a noncommissioned officer in the British Royal Air Force [syn: aircraftsman]
Aircraftman (AC), or Aircraftwoman (ACW), is the lowest rank in the Royal Air Force (however this is a training rank only) and the air forces of several other Commonwealth countries, ranking below Leading Aircraftman and having a NATO rank code of OR-1. The rank was introduced on the formation of the RAF in 1918, replacing the Royal Flying Corps rank of Air Mechanic 2nd Class. There used to be two grades: Aircraftman 1st Class (AC1) and Aircraftman 2nd Class (AC2; also colloquially known as an "AC plonk"). There is no rank insignia associated with this rank.
In the Royal New Zealand Air Force, the rank is known as "Aircraftsman", regardless of the person's sex, in line with Seaman in the Royal New Zealand Navy. The spelling "Aircraftsman", despite being seen even in official documents, is incorrect in the RAF.
In RAF slang, Aircraftmen are sometimes called "erks". The word "erk" is likely a phonetic spelling of an east-Londoner's pronunciation of the abbreviation, "airc".