What is the maximum altitude loss permitted during an unpressurized aircraft instrument static pressure system integrity check?

The correct answer is based on regulatory standards for unpressurized aircraft during an instrument static pressure system integrity check. A maximum altitude loss of 100 feet in 1 minute is established as an acceptable limit, which is critical for ensuring that the aircraft's altimeter and associated pressure instruments function accurately. This level of altitude loss indicates that the static pressure system is maintaining its integrity while allowing for fluctuations that can occur in various operational contexts.

Overall, when conducting a static pressure check, maintaining these standards ensures both the safety and reliability of the aircraft's instruments, preventing issues that could arise from incorrect altitude readings. This loss threshold is established to verify that the static pressure system is not compromised, thus allowing pilots to rely on their instruments during flight.