Can anyone please provide me with an official source describing the grammar/syntax of flight plans like:K0875S0960 BEKRO3F BEKRO A106 PABRI A113 AKB G3 QL B365 TOBLO/K0894F340 UP140...

i don't know a site off the top of my head without doing a google search for one, but I can give you a brief description of what it means.K0875S0960 BEKRO3F BEKRO A106 PABRI A113 AKB G3 QL B365 TOBLO/K0894F340 UP140BEKRO3F appears to be the name of the departure,SID, or DP as it often called.BEKRO is the first waypoint/fix of the departure, then you would fly to PABRI via airway A107, then PABRI to AKB via airway A113, etc, etc, with TOBLO being the last waypoint in your flight plan you listed. Some times they are flown DIRECT between waypoints and dont use a victor airways, jet airways, or in the case of RNAV a "T" or "Q" airway, "T" being a low altitude airway and "Q" being a high altitude airway.An fake example would be something like BEKRO FOXY DUMAR A106 PABRI A113 AKB JUMPY RABIT, in which case you would fly direct to the waypoints BEKRO FOXY DUMAR, then from DUMAR to PABRI would be via airway A106.Assuming you are entering these into an FMC/FMS the airways are usually input on the LSK under the VIA tab, while the waypoint are input on the right side RSK.Sorry I dont have a link or site to direct you to for more info, but i'm sure someone here can offer something up. In the meantime try a google search for reading IFR flight plans and you might find more info. You can also get some additional info on the different types of airways via a google search.Regards

Can anyone please provide me with an official source describing the grammar/syntax of flight plans like:K0875S0960 BEKRO3F BEKRO A106 PABRI A113 AKB G3 QL B365 TOBLO/K0894F340 UP140...

Try reading this guide on how to fill in a flight plan and then you should be able to read this flight plan: UK flight plan guide/Kim.....