Aeronautical Fixed Telecommunication Network and Message Handling
AFTN questions test whether you can build a message that will be delivered, at the right priority, to the right offices, without corrupting its content.
Message structure
- An AFTN message has a heading and a text. The heading carries the priority indicator, addressees, originator and filing time; the text carries the ATS, MET or NOTAM content.
- Addresses are eight characters: a four-letter ICAO location indicator, a three-letter office or function designator and one filler letter, for example DNMMYFYX. A seven-character address is a corrupt address.
- Priorities: SS distress, DD urgent, FF flight safety, GG general, KK routine. They are transmitted in that order.
Handling rules
- Use UTC in the date-time group, YYMMDDHHMM. Local time is a classic and dangerous error.
- Match the priority to the content: a routine administrative note is not FF, and a distress message must not queue behind KK traffic.
- Do not add addressees the originator did not authorise, and do not alter the text. Errors are fixed by a correction message or a cancellation, not by editing in transit.
- Record receipt and onward transmission. AFTN is store-and-forward, so delivery is not proof of reading.
Worked example. You receive a routine landing-slot request with priority KK and address DNMMYFYX. Check the address is eight characters, the originator is correct and the time is UTC. The content is administrative, so KK is right; sending it FF would push it ahead of safety traffic.
Traps. Writing a seven- or nine-character address; using local time; escalating routine traffic to DD or SS; forwarding to offices not addressed; retyping text instead of sending a correction.