What is the rule of thumb?
One in sixty rule
An angle of 1° will subtend (angle) a distance of 1nm
over a range of 60nm.
Altering heading to parallel track
Regaining Track any distance ahead
Regaining Track an equal distance ahead and
then maintaining Track
Flight plan concepts
Route and Altitude selection is considered
together with:
Safety - terrain, met, Danger areas.
Legality - complying with procedures
Feasibility - alt limit, range with load carried
Costs - Route distance, engine performance