What action could result in a starter failure if the starter valve did NOT close after engine start?

When considering the operation of the starter system in an aircraft, it's critical to understand the role of the starter valve and the management of bleed air during engine start procedures. If the starter valve does not close after the engine has started, allowing the starter to continuously engage, it can lead to overheating and mechanical failure of the starter.

Shutting down the engine before removing the bleed air supply is a situation that can lead to starter failure. In this scenario, if the starter valve remains open after the engine has already been shut down, the starter would still receive bleed air to continue operating even though the engine has stopped. This could cause the starter to over-rev or overheat since it is designed to only operate while starting the engine. The failure to remove the bleed air supply prior to shutting down the engine can exacerbate the excessive operation of the starter, ultimately resulting in a failure of the starter system.

In contrast, the other situations provided do not directly contribute to a starter failure under the described conditions. For instance, selecting another ignition system or pulling out the starter valve pushbutton would not cause the same issues associated with operational bleed air management. Therefore, managing the bleed air in relation to engine shutdown is a critical action that must be handled properly to ensure