CPL Navigation cheat sheet

1 nautical mile = 6,076.1 ft (1,852 m); 1 nm = 1 minute of latitude. Earth circumference ≈ 21,600 nm; 1 minute of longitude = cos(latitude) × 1 nm.

Conversion factors: 1 nm = 1.15078 statute miles; 1 kt = 1.852 km/h; 1 ft = 0.3048 m; 1 US gallon = 3.785 L; 1 imperial gallon = 4.546 L.

Great circle distance (nm) = 60 × angular distance in degrees; use haversine or spherical law of cosines for legs where the track changes materially.

Track error (deg) = (distance off track ÷ distance flown) × 60. Closing angle (deg) = (distance off track ÷ distance remaining) × 60. Heading change to destination = track error + closing angle.

1-in-60 rule: 1° subtends 1 nm at 60 nm. Lateral offset = distance × (angle ÷ 60).

Wind triangle: heading = track ± drift; drift (deg) = (crosswind component ÷ TAS) × 60 approximately. Groundspeed ≈ TAS ± headwind/tailwind component.

Crosswind component = wind speed × sin(angle between wind and runway/track); headwind component = wind speed × cos(angle).

Magnetic variation east is least (subtract from true to get magnetic); west is best (add). Deviation is aircraft-specific and applied after variation: T → V → M → C (add east variation/deviation when going from magnetic/compass to true).

ISA: sea-level temperature 15 °C, pressure 1013.25 hPa, lapse rate 1.98 °C per 1,000 ft. Pressure altitude = elevation + 30 × (1013 − QNH hPa); true altitude differs from indicated by temperature error.

Fuel plan components: taxi, trip (climb/cruise/descent), contingency (commonly 5% of trip), alternate, final reserve (typically 30 min holding at 1,500 ft), plus extra fuel. Total = sum of all components.

Endurance (h) = usable fuel ÷ hourly fuel flow; safe endurance subtracts reserves. Range (nm) = groundspeed × safe endurance.

POH cruise tables are usually based on ISA; correct fuel flow and TAS for temperature deviation and for aircraft mass above/below tabulated values.

Density altitude (ft) = pressure altitude + 120 × (OAT − ISA temperature at that pressure altitude). High density altitude increases takeoff/landing distances and reduces climb performance.

Weight and balance: moment = weight × arm; CG = total moment ÷ total weight. CG must remain within the forward and aft limits for takeoff, in-flight, and landing.

Navigation log fields: waypoint, true track, wind (dir/speed), variation, magnetic track, drift, heading, TAS, groundspeed, distance, ETA/ETD, fuel remaining.

VFR fuel planning commonly requires enough fuel to reach destination plus 30 minutes (day) or 45 minutes (night) at normal cruise - verify against the applicable regulation.

NOTAMs, AIP supplements, and chart currency dates must be checked before flight; expired charts or unread NOTAMs invalidate the plan.

Alternate aerodrome is required when destination weather is at or near minima or when the destination has no instrument approach; the alternate must meet published weather criteria.