During a stabilized IMC approach, what configuration should the aircraft be in before descending below 1819?

Before descending below 1819 feet during a stabilized IMC approach, the aircraft should be in the landing configuration. The landing configuration typically involves extending the landing gear and setting the flaps as necessary for approach and landing. This ensures that the aircraft is trimmed and stable for the descent, allowing for better control and a more predictable flight path.

Being in the appropriate configuration is crucial during an instrument approach, especially in low visibility conditions, as it maximizes performance and enhances safety by reducing the workload on the pilot. Transitioning to the landing configuration before descending below a critical altitude helps prepare the aircraft for landing, ensuring that the aircraft can maintain a stable approach speed and descent rate.

Other configurations, such as cruise, climb, or takeoff configurations, do not provide the necessary stability and control for a safe approach and landing, making the landing configuration the correct choice.