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Guides

Plain-English explanations of the calculations and rules behind the tools.

How to Calculate Crosswind and Headwind ComponentsLearn the crosswind formula, a quick mental method and a worked example, plus why METAR wind needs a magnetic correction.Guide How to Read a METAR: A Plain-English GuideDecode every group in a METAR: wind, visibility, weather, cloud, temperature, pressure and flight category, with a worked example.Guide How to Read a TAF: Airport Forecasts ExplainedUnderstand TAF validity times and the FM, BECMG, TEMPO and PROB change groups, with a decoded example and planning tips.Guide What Is in an ICAO Flight Plan? Every Item ExplainedA line-by-line guide to the ICAO flight plan (FPL): items 7 to 19, with a worked example you can generate yourself.Guide The Wind Triangle Explained: Heading, Ground Speed and DriftHow the wind triangle works: wind correction angle, true heading and ground speed, with formulas and a worked example.Guide FAA Part 117 Explained: Flight Time, Duty Period and RestA plain-English guide to FAA Part 117: flight time limits, flight duty period tables, augmented crews, rest facility classes and rest rules.Guide Flight Fuel Planning Explained: Trip, Contingency, Alternate and ReserveUnderstand the parts of block fuel: taxi, trip, contingency, alternate and final reserve, with a worked example you can check in the calculator.Guide Density Altitude Explained: How Heat and Height Cut PerformanceWhat density altitude is, how to calculate it from pressure altitude and temperature, and why it lengthens takeoffs and reduces climb.Guide How to File a Flight Plan: Steps for Pilots and DispatchersThe steps from planning to filing an ICAO flight plan, what happens after filing, and the delay and cancellation messages.Guide How to Read a NOTAM: ICAO Format ExplainedA guide to the ICAO NOTAM format: the Q-line, the A to G fields, validity times and a decoded example.Guide EASA Flight Time Limitations: The Basics and How They Differ from FAA Part 117An overview of EASA flight and duty time limits (ORO.FTL): daily FDP by sectors, extensions, cumulative limits, and how they compare with FAA Part 117.Guide EDTO Explained: Extended Diversion Time Operations from ScratchWhat EDTO is, why it exists, how diversion time is calculated, what threshold time and maximum diversion time mean, and what an operator must plan.Guide Adequate vs Suitable Aerodrome: What Is the Difference?Adequate and suitable aerodromes explained: how they differ, why the difference matters for alternates and EDTO planning, and what changes with the time of use.Guide How to Calculate an Equal Time Point (ETP)Learn what an equal time point is, the formula, how wind moves it, and a worked example you can check in the calculator.Guide EDTO Approval and Dispatch Requirements ExplainedHow operators get EDTO approval, the approval levels and the dispatch checks before every EDTO flight, based on ICAO guidance and national circulars.Guide The North Atlantic Organised Track System (NAT OTS) ExplainedWhat the NAT OTS is, how the tracks are built and published, the lateral spacing, and where the tracks sit in the high level airspace.Guide The NAT Track Message and TMI Number ExplainedWhat is in a NAT Track Message, what the three-digit TMI number means, how re-issues are labelled, and how the TMI is used in clearances.Guide NAT High Level Airspace (HLA) Requirements ExplainedThe NAT HLA vertical limits, the approvals and equipment needed to enter it, RVSM and datalink requirements, and what non-approved aircraft can do.Guide Oceanic Clearance on the North Atlantic: How It WorksHow to obtain an oceanic clearance for the North Atlantic, what a clearance contains, the abbreviated readback with the TMI, and common errors.Guide NAT Contingency Procedures and SLOP ExplainedWhat to do over the North Atlantic when a clearance cannot be obtained, and how strategic lateral offsets work, based on ICAO bulletins and SKYbrary.Guide Polar Routes Explained: What Is Special About Flying Near the PolesWhat counts as a polar area, why polar routes are used, and the fuel, communication, diversion and radiation issues that make them special.Guide Polar Operations Requirements Checklist (FAA)The items an operator must include to be authorised to fly in the North Polar Area under FAA rules: diversion airports, recovery plan, fuel freeze, communications, MEL, training, radiation plan and cold weather suits.Guide