What must be done before attempting to open the canopy?

Before attempting to open the canopy, the engine must be shut down. This is crucial for safety reasons. If the engine is running, there is a risk of sudden movement or malfunction that could lead to injury or damage when the canopy is opened. Shutting down the engine ensures that all systems are stable and that the pilot or crew can safely operate the canopy without the threat of unexpected engine activity.

While performing pre-flight checks and conducting a canopy inspection are also important procedures, they are generally done prior to engine startup or when the aircraft is in a controlled state. Ensuring that the engine is off creates a controlled environment for these subsequent actions and protects individuals from potential hazards associated with a running engine.