Definition
A standardized set of single-letter codes used on the ICAO flight plan form to tell air traffic control what navigation, communication, and surveillance equipment is installed and serviceable on the aircraft. The codes are entered in Item 10 of the flight plan (Item 10a for radio communication, navigation, and approach aids; Item 10b for surveillance equipment such as transponder and ADS-B), and they determine which routes, procedures, and clearances ATC can issue to that aircraft.
Plain English
A list of letters you put on your flight plan to tell ATC what gear your aircraft has — what radios, what navigation equipment, and what kind of transponder. ATC uses that list to decide which routes and approaches you're allowed to fly.
Context Anchor
You see these codes when filing a flight plan, especially for instrument flights, area navigation departures, and routes that require specific aircraft capabilities.
Derivation
ICAO stands for the International Civil Aviation Organization, the United Nations body that sets worldwide aviation standards. The codes are 'ICAO' codes because they come from that international standard, used on flight plans worldwide rather than the older U.S.-only domestic format.
Why Pilots Care
Correct codes ensure ATC can clear the aircraft for RNAV departures and provide appropriate separation; incorrect codes may cause routing restrictions or plan rejection.
Intuition Check
Do not read “equipment codes” as a general list of everything installed in the airplane. In this context, they are flight-plan entries for equipment and capabilities that are installed, working, and appropriate to use for that flight.
Example Sentence 1
Before filing, the pilot reviewed the ICAO flight plan equipment codes and entered the letters matching the GPS, transponder, and ADS-B Out installed in the aircraft.
Example Sentence 2
Using the proper equipment codes allowed the aircraft to receive clearance for the RNAV departure procedure.