After loss of primary navigation data, which navigation guidance should be used?

• A. Use standby navigation modes; revert to raw data if needed; inform ATC/dispatcher
• B. Continue using primary navigation data
• C. Switch off all navigation
• D. Inform passengers of navigation issues

Answer: (A)

When primary navigation data is unavailable, you rely on backup guidance to keep your position and flight path known. Using standby navigation modes gives you a separate, independent source of guidance that isn’t tied to the failed system, so you can maintain a safe course and avoid a loss of situational awareness. If the situation calls for it, revert to raw sensor data to verify your position and track directly from the instruments rather than trusting potentially corrupted processed data. At the same time, inform ATC or your dispatcher about the navigation issue so they can provide vectors, re-clearances, or an alternate routing, helping manage safety, traffic, and fuel planning. Staying on backup guidance and coordinating with ATC is the prudent path; options that abandon navigation entirely or delay informing others risk safety and airspace coordination.