Last reviewed and updated:
ZZZZ is a placeholder in the ICAO flight plan. It means “there is no ICAO designator for this; the details are in Item 18.” It is not the code of any airport. Use it when the departure, destination or alternate aerodrome has no four-letter ICAO location indicator, or when the aircraft type has no ICAO type designator, and then describe the real place or type in Item 18 (Other information).
Where ZZZZ can appear
| Flight plan item | When to use ZZZZ | What to add in Item 18 |
|---|---|---|
| Item 9: Type of aircraft | The type has no ICAO type designator | TYP/ followed by the aircraft type |
| Item 13: Departure aerodrome | The departure aerodrome has no ICAO location indicator | DEP/ followed by the aerodrome name and location |
| Item 16: Destination aerodrome | The destination has no ICAO location indicator | DEST/ followed by the name and location |
| Item 16: Alternate aerodrome(s) | An alternate has no ICAO location indicator | ALTN/ followed by the name and location |
How to describe the location
After DEP/, DEST/ or ALTN/, give the aerodrome name and, where it is not listed in the national AIP, its position. The usual format for a position is latitude in four figures (degrees and minutes) followed by N or S, then longitude in five figures followed by E or W, with no spaces:
2512N05530E means 25°12′ N, 55°30′ E.
If your coordinates are in decimal degrees, convert them first with the Coordinate Converter. 25.2° is 25°12′, not 25°20′. Some States also accept a bearing and distance from a nearby significant point. Check your national AIP or flight planning office for the exact format it expects.
Worked example
A light aircraft departs a private desert strip with no ICAO indicator and flies to an airport that has one. The relevant parts of the flight plan look like this (illustrative only):
Item 13: ZZZZ0600
Item 16: OMAL0130
Item 18: DEP/DESERT STRIP 2425N05530EItem 13 says the departure aerodrome has no indicator and gives the departure time of 0600 UTC. Item 16 names the destination by its ICAO code. Item 18 tells ATC where the flight is actually starting from. Without that DEP/ entry, the plan would leave ATC with no departure point at all.
Related placeholders you may see
- AFIL in Item 13 means the flight plan was filed while airborne, rather than from an aerodrome.
- ZZZZ in Item 9 with TYP/ is common for homebuilt, experimental or very rare aircraft types. A formation flight of several types also uses ZZZZ, with the types listed in
TYP/.
Common mistakes
- Entering ZZZZ but forgetting the Item 18 entry. ATC then has no way to know the real location or type.
- Using ZZZZ for an aerodrome that does have an ICAO indicator. Look it up first with the Airport Code Lookup.
- Writing coordinates in decimal or with spaces when the format expects degrees and minutes run together.
- Swapping N/S or E/W, which can put the aerodrome on the other side of the world.
Related guides
- ICAO vs IATA Airport Codes: How the Letters Work
- Zulu Time (UTC) in Aviation, since flight plan times are in UTC
Educational content only. Follow ICAO PANS-ATM, your national AIP and your flight planning office’s requirements.
Sources and further reading
- ICAO Doc 4444, PANS-ATM, Appendix 2 (flight plan completion, items 9, 13, 16 and 18)
- AIM 5-1, Preflight (flight plans)
- ICAO Doc 7910, Location Indicators, and ICAO Doc 8643, Aircraft Type Designators
Sources checked November 2026. Rules differ between countries and change over time: for real flights, use the current publications of the authority that applies to you, your aircraft flight manual and your operator’s procedures.