Figure 4.1-4 Stand-by Compass
Discussion of direction will continue in Lesson Topic 4.2 when charts and plotting
techniques are introduced.
Time can be expressed in two ways: as the time of day (0815, 1400, etc.) or elapsed time.
Elapsed time is written as hours and minutes or minutes and seconds. With elapsed time,
the units are separated with a "+" sign (2+30, 3+15, etc.).
Estimated time of departure (ETD) and estimated time of arrival (ETA) will be expressed in
four-digit time of day format, while elapsed time, such as estimated time en route (ETE),
will be expressed in hours and minutes (or for short distances, minutes and seconds). All
aircrew must be able to convert from local time to Greenwich Mean Time (Zulu time) and
vice versa. This will be covered in greater detail in Lesson Topic 4.2.
Speed is the magnitude of the velocity of an aircraft. It is the distance traveled with respect
to time and is stated in nautical miles per hour (knots). Lesson Topics 4.3 and 4.4 will
cover speed in greater detail and explain how atmospheric conditions (altitude,
temperature) affect it.
Speed = Distance