Definition
The horizontal track an aircraft is required to fly over the ground along a route or procedure, defined by a sequence of fixes, courses, and turns. It describes where the aircraft goes when viewed from above, separate from the vertical profile of climbs and descents.
Plain English
The side-to-side route the aircraft follows across the ground, ignoring how high it is. It is the line you would draw on a map showing where the airplane is supposed to go.
Context Anchor
Seen when planning and flying a standard instrument departure, where the published procedure shows both the route to follow and the climb requirements to meet.
Derivation
Lateral comes from the Latin lateralis, meaning 'of the side.' In aviation it refers to side-to-side movement across the ground, as opposed to vertical (up and down) movement.
Why Pilots Care
Staying on the published lateral path keeps the aircraft within protected airspace and clear of obstacles.
Intuition Check
Do not read lateral path as the whole flight plan. Here, lateral means the horizontal route across the ground, separate from altitude or climb instructions.
Example Sentence 1
The crew briefed the lateral path of the SID, noting each fix and the courses between them.
Example Sentence 2
The pilot maintained the published lateral path while climbing through the departure sector.