If an aircraft engages a raised barrier/cable, what should be initiated immediately?

Engaging a raised barrier or cable during an aircraft's operation indicates a serious safety risk that requires immediate attention. Initiating a crash alarm is the appropriate response because it alerts all necessary personnel and systems that there is a potential emergency situation developing. This quick response is crucial to ensure that emergency services are prepared and can respond to the incident as swiftly as possible, minimizing risks to passengers and crew.

In contrast, emergency landing procedures, deceleration procedures, and standard operating procedures are responses that may be relevant to different types of emergencies but do not primarily address the immediate recognition of a serious hazard like a raised barrier or cable. The crash alarm serves as a first step in managing the situation, enabling other emergency response protocols to be activated.