ICAO 24 Bit Aircraft Address - Mode S Coding

The ICAO 24 bit aircraft address is assigned by the IOMAR to the specific airframe whilst the aircraft remains on the Isle of Man Aircraft Register and a change to another ‘M’ registration mark will not require the issue of a new 24 bit aircraft address.

It is good practice to periodically carry out verification checks using a mode S external receiver to ensure the aircraft is transmitting the correct hexadecimal code and especially when the aircraft undergoes a major maintenance check.

The flight ID will usually be the Registration mark of the aircraft.

Where the operator, as recorded on the aircraft Ops Spec, has been issued with a three-letter ICAO designator, it is acceptable to use the designator followed by numbers (e.g. XXX 123). 

NOTE: In all cases the ATC flight plan MUST reflect the ‘Type of Flight’ as ‘G’ for General Aviation.

The Flight ID must be inserted in to the Mode S Aircraft Identification input device in the cockpit by the flight crew prior to each flight. The Flight ID must correspond to the aircraft identification that is recorded in item 7 of the ICAO flight plan.