What is the primary lesson about FMS and automation safety from the incidents described?

• A. Automation should always be relied upon
• B. Do not use FMS at all
• C. Recognize mode changes and maintain basic navigation when needed
• D. Manual flying should be disengaged

Answer: (C)

Automation is a powerful aid, but real safety comes from vigilant monitoring and readiness to intervene when the system changes modes or behaves unexpectedly. The best approach is to recognize what mode the automation is in and assess whether it aligns with the flight plan; if it doesn’t, be prepared to take control or switch to a safer configuration.

Mode changes can happen for many reasons—automation stepping through different guidance targets, reversion after a fault, or ATC instructions that require a different path. If you don’t notice or understand the current mode, the aircraft can drift off course or descend/ascend in ways that aren’t safe. Keeping basic navigation skills in play means you can verify the aircraft’s actual track, altitude, and heading, and, if necessary, take manual control to ensure terrain clearance, proper airspace containment, and adherence to ATC instructions.

This is why the emphasis is on recognizing mode changes and maintaining basic navigation when needed. Relying blindly on automation or disengaging manual flying entirely would undermine situational awareness and safety; using FMS and automation wisely includes knowing when to revert to fundamental flight skills to stay in control.