Aviation Guides

Why an airport has both a 3-letter IATA code and a 4-letter ICAO code, what the ICAO letters mean region by region, and which code to use for tickets, flight plans and weather.

Why runway 27 points about 270° magnetic, how reciprocal and parallel runways are named, why airports renumber runways, and how to use the number with the wind.

What a flight level is, why FL350 is not always 35,000 ft above the sea, how the transition level moves with QNH, and which levels to cruise at eastbound or westbound.

Why your altimeter over-reads in cold air, how to apply cold temperature corrections, FAA restricted airports and worked examples.

Every free USFITools aviation calculator and guide organised by ground school subject: meteorology, performance, navigation, instrument flying and logbook time.

ISA values every pilot should know, how to work out ISA deviation, why hot climates hurt performance, and how ISA links to altimeters and density altitude.

Time, speed and distance formulas for flight planning, how to use the E6B calculator side, mental shortcuts, worked examples and fuel calculations.

Avgas and Jet A-1 densities, how to convert litres and gallons to kilograms and pounds, worked examples for trainers and turbines, and common fuel traps.

How the 1 in 60 rule works, track error and closing angle, two ways to correct back to track, drift lines and other uses in descent and radio navigation.

How to choose and fly direct, teardrop and parallel holding entries, with the 70° sector rule, a quick mental method, worked examples and timing.