Which situations require immediate deviation from standard operating procedures?

Immediate deviation from standard operating procedures (SOP) is typically required in situations that pose an urgent threat to the safety of the flight. One such critical situation is engine failure and rapid cabin decompression. This scenario demands immediate and decisive action by the flight crew to ensure the safety of passengers and crew.

In the event of an engine failure, the aircraft may lose thrust and require prompt handling to maintain control, manage airspeed, and potentially execute an emergency landing. Rapid cabin decompression can lead to a loss of cabin pressure, which may deprive passengers of oxygen and necessitate quick use of oxygen masks. These events directly impact the aircraft's ability to fly safely and the immediate health of everyone on board, warranting a swift response that may involve deviations from established procedures.

While weather warnings may require adjustments to the flight plan or route, scheduled maintenance checks are planned operations that don’t usually necessitate immediate deviation. Normal turbulence is also a common occurrence in aviation and does not require a change in standard operating procedures unless it escalates to extreme conditions.