Definition
The position, track, and guidance information that an aircraft's navigation system continuously calculates by combining inputs from sensors such as GPS, DME, VOR, or inertial reference units. The navigation solution is what the avionics use to display where the aircraft is, where it is going, and how to fly the programmed route or procedure.
Plain English
It is the answer the aircraft's navigation system produces about where the aircraft is and how to get to the next point. The system blends signals from satellites and ground stations to figure this out, and that combined answer is the navigation solution.
Context Anchor
Seen in instrument departure planning and equipment discussions, especially when a departure procedure depends on onboard navigation equipment to keep the aircraft on the correct path.
Derivation
In math and engineering, a 'solution' is the answer a system produces from its inputs. The navigation system takes in sensor data and outputs a 'solution' — the calculated position and guidance. It does not mean a fix to a problem in the everyday sense.
Why Pilots Care
A valid navigation solution confirms the aircraft can safely follow the departure path while staying clear of terrain and traffic.
Intuition Check
Do not read solution here as a suggested route or a general answer to a problem. A navigation solution is the computed position-and-guidance result the navigation equipment is using right now.
Example Sentence 1
The crew confirmed a valid GPS navigation solution before accepting the RNAV departure.
Example Sentence 2
Loss of the navigation solution during departure requires the crew to revert to conventional navigation.