First sightings: aircraft types and countries new to these records

A first sighting is the first time something appears in this site's own records: an aircraft type designator never seen before, or an aircraft whose ICAO address comes from a block assigned to a country that has not shown up here. The claim is local and dated. It says the records had not contained the type or the country before that day, and how often the type flies elsewhere is a question these records cannot answer.

The check waits for at least 90 days with an hour or more of recorded traffic before it trusts a first. Group designators such as ZZZZ, used when a type has no code of its own, never count, and neither do addresses that begin with a tilde, which mark tracks without a real ICAO address. An address that appeared under a different type on more than two earlier days points to a database change, so it does not count as a new type. Country firsts start only after a 30-day warm-up.

A type can pass overhead during a gap in coverage and leave no record, so a first sighting dates the first record, which may come after the first visit. The country comes from the ICAO address allocation table. It tells you which state assigned the address and nothing about who operates the aircraft today or where it is based.