Definition
An operating mode of an area navigation (RNAV) or flight management system in which the system holds the current active waypoint and does not automatically advance to the next waypoint in the flight plan when the aircraft passes over it. The pilot must manually select the next waypoint to resume normal sequencing.
Plain English
A setting on the navigation computer that stops it from automatically moving on to the next point in the flight plan. The aircraft stays pointed at the current waypoint until the pilot tells the system to move on.
Context Anchor
Seen when using panel-mounted GPS or area-navigation equipment, especially during instrument procedures, holding, or any situation where automatic route advance may be paused.
Derivation
Sequencing comes from the Latin sequi, meaning 'to follow.' In navigation, sequencing is the system following one waypoint after another in order. Nonsequencing simply means that automatic following is suspended.
Why Pilots Care
Gives the pilot deliberate control so the aircraft does not unexpectedly proceed to the next fix during a hold, course reversal, or missed approach.
Intuition Check
Nonsequencing Mode does not mean the navigator has failed. It means automatic movement to the next route point is turned off or paused.
Example Sentence 1
Before entering the hold, the pilot placed the GPS in nonsequencing mode so it would not skip ahead to the next waypoint.
Example Sentence 2
With nonsequencing mode active, the system will not sequence to the next waypoint until the pilot manually resumes sequencing.