Crew record
Licences, medicals, authorisations, qualifications and documents, each with its date.
Licences are in one file, medicals in another, instructor authorisations in a third, and the recurrent check dates sit in the training records. Somebody reconciles them once a month, and a lapse is found when a session is already booked.
Every licence, medical, authorisation, qualification and document sits on the crew record with its expiry date. The credentials tracker reads them all across the whole crew, soonest first. Recurrent check due dates come from the completed checks themselves, so they are never typed.
Licences, medicals, authorisations, qualifications and documents, each with its date.
The next due date set by the completed check, never by hand. A failed check does not move it.
Who is told, how early, and by which channel. People choose how they are reached.
Sessions and programme items check the instructor against the authorisation catalogue as they are assigned.