ICAO Filing String Decoder

Normal Procedures

Eddie sez:

The first time I ever filed an ICAO flight plan was in 1982 for a Boeing 707 (Air Force EC-135J) flying from Hawaii to Japan. As I recall, Block 10 of the filing string was five characters long, including an "S" for standard equipment, and four extra characters for our HF, VLF, INS, and TACAN. Our Block 18 only contained our Estimated Enroute Times (EETs) and a note about our diplomatic status. I had the Block 10 codes, all five of them, memorized. Fast forward to today and here is the Block 10 for a fully equipped Gulfstream GVII-G500:


Besides the EETs and company specific notes, our Block 18 is:


Even after going through the pain of getting our LOAs for all this stuff, I still don't recognize most of these codes. Fortunately, Ed Lemelin has done the work for us. You can reach him by clicking on the top right link in the following spreadsheet.

The spreadsheet comes directly from him. You can check the source material given in the References given below.

Start by double-clicking the orange cell, then paste in your filing string.

Last revision:


ICAO Filing String Decoder


This tool is designed to help find errors in your ICAO filing strip and to show OPSPEC/LOA requirements as we understand them as of July 2020. It is your responsibility to verify the accuracy of any information presented here. Always double check your filing strip to ensure you're actually filed for what you think you're filed for.

— Ed Lemelin

Click here for instructions: Decoder Instructions.

See Also:

FAA ICAO FPL Quick Guide, 2019-06-14

ICAO Doc 4444 - Air Traffic Management, 16th Edition, Procedures for Air Navigation Services, International Civil Aviation Organization, October 2016