Which event triggers switching to manual navigation?

Which event triggers switching to manual navigation?

• A. Loss of GPS and power outage
• B. Visual Fix Achievable With LOPs
• C. Interference From Radio Transmissions
• D. Routine Course Change

Answer: (A)

When electronic navigation aids fail, you revert to non-electronic methods to maintain safe navigation. The key trigger here is a complete loss of GPS paired with a power outage that takes down the bridge and nav equipment. With GPS gone and power out, the ship loses its primary position source and the instruments that feed autopilot, ECDIS, radar overlays, and other aids. In that moment you must switch to manual navigation, relying on traditional methods like visual bearings to visible landmarks, lines of position from fix attempts, dead reckoning using known speed and course, and plotting by hand to determine and verify your position. The other scenarios don’t inherently force a switch to manual navigation. Interference from radio transmissions can degrade certain nav aids but isn’t a guaranteed trigger on its own. A routine course change is a normal maneuver that can still be managed with active navigation systems; it’s not about losing the ability to determine your position. The option about a visual fix achievable with lines of position describes a capability you use when navigating manually, not the event that forces you to stop relying on electronic aids.

When electronic navigation aids fail, you revert to non-electronic methods to maintain safe navigation. The key trigger here is a complete loss of GPS paired with a power outage that takes down the bridge and nav equipment. With GPS gone and power out, the ship loses its primary position source and the instruments that feed autopilot, ECDIS, radar overlays, and other aids. In that moment you must switch to manual navigation, relying on traditional methods like visual bearings to visible landmarks, lines of position from fix attempts, dead reckoning using known speed and course, and plotting by hand to determine and verify your position.

The other scenarios don’t inherently force a switch to manual navigation. Interference from radio transmissions can degrade certain nav aids but isn’t a guaranteed trigger on its own. A routine course change is a normal maneuver that can still be managed with active navigation systems; it’s not about losing the ability to determine your position. The option about a visual fix achievable with lines of position describes a capability you use when navigating manually, not the event that forces you to stop relying on electronic aids.