SAR aircraft MMSI (111MIDxxx)

What it identifies

A 111 prefix identifies a search-and-rescue aircraft — a helicopter or fixed-wing aircraft fitted with AIS so it can be seen by ships and coordination centres during an operation.

How to read it

These positions move at aircraft speeds and in patterns no ship would make. AIS reports from SAR aircraft use their own message type, so a well-built plot shows them differently; a sudden fast-moving "vessel" with a 111 identity is an aircraft.

Does it give a flag?

Not a flag — the MID in digits 4 to 6 identifies the administration operating the aircraft.

Every vessel page on this site works this out before printing a flag. Where the MMSI is not a ship station, the page names the kind of station instead — a wrong flag is worse than an honest “this is a coast station”.

All MMSI formats

Have a number to check? The MMSI decoder applies these rules to any nine digits. For the background, read Reading an MMSI.