Track, heading, drift and the 1-in-60 rule

Navigation · Chapter 7 · DGCA CPL and ATPL

The five words every navigation sum uses, Table, and the 1-in-60 rule that turns "miles off track" into degrees.

Remember

Drift = heading ↔ TMG. Track error = TR ↔ TMG. They are different.
Port drift: heading more than track. Starboard drift: heading less than track.
Starboard TE: TMG = TR + TE. Port TE: TMG = TR − TE.
1 in 60: angle = off ÷ distance × 60.
Turn to destination = TE (distance gone) + closing angle (distance to go) = CA × total ÷ gone.
Regain track: 2 × TE for the same time, then back TE; not past half-way.

Delhi to Dubai on the map

The flight • Delhi to Dubai: about 1 180 NM over Pakistan and the Arabian Sea • ATC clears you on a track of 260°: the gold line • No wind: point the nose along it, heading 260°, and you arrive
A north wind • The wind blows from the north: from your right as you fly west • It would push you left (south), so you point the nose 10° right, into it: heading 270° • If 10° is the right guess, the aircraft crabs along the gold line: nose on 270, path on 260
The wind was stronger • 10° was not enough: with the nose still on 270° you really move over the ground on 240° (pink) • Hold it and you reach the Arabian Sea off Oman, ~400 NM south of Dubai
Three directions, two angles • Track required 260 (gold) · heading 270 (the nose) · track made good 240 (pink) • Next lesson: the two angles between them, drift and track error

Track, heading, track made good

A wind from the north • The pilot turns 10° right into it: heading 270° • That 10° is the pilot's guess at the drift; the real wind may differ
Where it really went • The aircraft ends up on track made good 240°
Drift: heading ↔ TMG • Drift, as in chapter 6: heading ↔ TMG • 270 − 240 = 30° • Left wing ahead: 30° port (port = left)
Track error: TR ↔ TMG • 260 − 240 = 20° • TMG is left of TR: 20° port • Also: expected drift 10° − real drift 30° = 20°