Black Maria (IFF)

Black Maria was the rainbow code name for an identification friend or foe (IFF) interrogator carried by interceptor aircraft in the Royal Air Force[1] and US Navy.[2] When initially developed, beginning in 1951, it was based on the World War II-era IFF Mark III[3] IFF system because the newer IFF Mark X units were not available from US at the time. Marconi received interim Mark X equipment in mid-1953 and quickly added support, but it was not until mid-1955 that the first production units became available.[4] During development in the UK, it was also referred to as the Fighter Identity System, or FIS.[1] In the US it was known as TN-103/APX.[5]