Which EFCS mode uses a snapshot of the last valid air data information?

The mode that utilizes a snapshot of the last valid air data information is the FCC FROZEN GAINS mode. This mode is specifically designed to maintain control inputs based on the most recent stable air data parameters. When operating in this mode, the flight control computers use air data information that was valid before a certain event or condition, essentially "freezing" the gains to prevent fluctuations in aircraft performance that could arise from unreliable or rapidly changing data.

This capability is crucial during various flight scenarios where real-time air data may become unreliable or lost, ensuring that the aircraft maintains a necessary level of control and stability even in less-than-ideal conditions. The use of frozen gains can provide a safety margin, allowing the pilot to retain control while they address any issues with current air data sources.

Understanding the functionality of the FCC FROZEN GAINS mode is essential for C-17 pilots, as it highlights the importance of backup systems and stability in flight operations under varying conditions.