If approach lights are not visible upon arrival at the DH during an ILS approach in IFR conditions, what is the pilot required to do?

When the approach lights are not visible upon reaching the Decision Height (DH) during an ILS approach in IFR (Instrument Flight Rules) conditions, the pilot is required to execute the missed approach procedure. This is because the visibility of the approach lights is an important safety criterion indicating that it is safe to proceed to landing. Without seeing the approach lights or having the required visual references, the pilot cannot ensure a safe landing, which necessitates a missed approach.

Executing a missed approach ensures that the aircraft can safely climb away from the runway environment and set up for another approach if desired or proceed to an alternate airport if conditions do not improve. The missed approach procedure outlines the specific actions a pilot must take to maintain safety and is essential in situations where visual references are insufficient to continue safely to the runway.

The other actions listed do not specifically address the requirement to adhere to safety protocols when visual references are not available, which emphasizes the importance of executing the missed approach procedure under such circumstances.