Aircraftman

Aircraftman (AC), or Aircraftwoman (ACW), is the lowest rank in the Royal Air Force and the air forces of several other Commonwealth countries.

Aircraftman ranks below Leading Aircraftman and has a NATO rank code of OR-1. It is presently a training rank only and no airmen in productive service hold this rank. Aircraftman do not wear any rank insignia.

History
The rank was introduced on the formation of the RAF in 1918, replacing the Royal Flying Corps rank of Air Mechanic 2nd Class. There were two grades: Aircraftman 1st Class (AC1) and Aircraftman 2nd Class (AC2; also colloquially known as an "AC plonk").

Royal New Zealand Air Force
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.

Royal Air Force
In RAF slang, Aircraftmen are sometimes called "erks". The word "erk" is perhaps a phonetic spelling of an East Londoner's pronunciation of the abbreviation, "airc".

The spelling "Aircraftsman", despite being seen even in official documents, is incorrect in the RAF.