On American Airlines Flight 965, what action did the crew fail to take when FMS navigation became confusing?

• A. Revert to basic navigation and discontinue the approach
• B. Continue the approach
• C. Increase speed
• D. Contact ATC more often

Answer: (A)

When automated navigation becomes unclear or unreliable, the safest course is to fall back to basic, non-augmented navigation and discontinue the approach to regain situational awareness and prevent a loss of control or a wrong path over terrain. In this scenario, the crew faced confusing FMS guidance, and the proper action would have been to switch to conventional navigation methods (using raw VOR/DME, cross-checking with the flight instruments, and re-orienting) and initiate a go-around or discontinue the approach until confidence in the course was restored.

Continuing the approach while navigation is uncertain keeps you locked into potentially incorrect waypoints and autopilot/fms guidance, increasing the risk of terrain error or other navigation mistakes. While contacting ATC more often can help with vectors or clearance issues, it doesn’t directly resolve the confusion in the navigation data. Increasing speed is unrelated to resolving navigation ambiguity and can reduce the time available to detect and correct errors.