Which of the following statements about the navigation system is incorrect?

The statement that auto tune is available at any phase of flight is incorrect because the functionality of the navigation system often varies depending on certain operational phases. During specific phases of flight, particularly during critical maneuvering operations like takeoff, landing, or when the aircraft is under specific flight conditions, the use of auto-tuning may be restricted or suspended to ensure pilot control and decision-making remains paramount.

The other statements accurately describe the operation of the system. Green needles indeed signify manual tuning, which means the pilot has inputted frequency information directly. White needles are represented during auto-tuning, indicating that the system automatically selects the appropriate navigation frequency. Additionally, standby instruments have limitations and can only function correctly under particular conditions, emphasizing the need for situational awareness regarding instrument usability.