What action should be taken whenever a hung start occurs in an aircraft engine?

In the event of a hung start, which occurs when an aircraft engine does not reach the required RPM during the starting sequence, shutting down the engine and investigating the cause is the appropriate action. This procedure is crucial because a hung start can indicate underlying issues, such as fuel system problems, electrical malfunctions, or other mechanical failures that could lead to more serious complications if left unaddressed.

By turning off the engine, the pilot ensures safety by preventing potential damage to the engine components and allowing for a thorough assessment of the situation. Following the shutdown, a detailed inspection can be performed to identify and rectify any issues, ensuring that the aircraft is safe for future operations.

Actions like notifying air traffic control, checking fuel levels, or allowing the engine to cool down might be part of the overall procedure following safety protocols, but they do not directly address the immediate risk and implications of a hung start. Thus, prioritizing a comprehensive inspection after shutting down the engine is the most effective response.