If a turbine engine catches fire internally during the start cycle, what initial action should be taken?

When a turbine engine catches fire internally during the start cycle, the immediate and appropriate initial action is to shut off the fuel and continue motoring the starter. This procedure is critical for effectively managing the situation.

Shutting off the fuel stops additional fuel from feeding the fire, which could otherwise exacerbate the problem and increase the risk of damage or explosion. Continuing to motor the starter helps to clear the engine of any combustibles, essentially aiding in the fire suppression process by creating airflow that can help cool the engine components and potentially extinguish the flames.

This approach allows for a reduction of risks associated with the ongoing fire while attempting to prevent further complications. Igniting the fire suppression system, while ultimately necessary in many cases, may not be the first action taken at this critical moment, especially if the situation can be managed through fuel control.

The procedure prioritizes maintaining safety and stability within the aircraft system during what can be a volatile situation.