What immediate action should be taken if a cabin crew witnesses vandalism?

When cabin crew witnesses vandalism, the immediate action they should take is to advise the flight crew or ground personnel. This is crucial because the flight crew needs to be aware of any security or safety issues within the cabin, which includes vandalism that could escalate into more serious situations. By informing the flight crew, they can take appropriate measures to ensure the safety of all passengers and crew on board. This may involve notifying ground security teams or preparing for an appropriate response upon landing.

Documenting the event in the logbook, informing passengers, or contacting the onboard security team are important steps, but they follow the immediate necessity of alerting the flight crew. The flight crew is trained to handle such situations and can implement the necessary protocols to manage any potential risks effectively.