When must all cabin crew carry out the drill relevant to the NITS briefing?

The correct response is that all cabin crew must carry out the drill relevant to the NITS briefing during boarding and disembarking. This timing is essential because it ensures that the crew is fully prepared and knowledgeable about their responsibilities right before passengers are allowed to enter or exit the aircraft, when the potential for requiring safety measures might be heightened.

Implementing the NITS briefing drill at this stage helps reinforce the safety protocols that must be in place as passengers embark or disembark, ensuring that the cabin crew can effectively manage the situation and respond to any issues that may arise. Conducting the drill during these phases prioritizes passenger safety and reinforces the crew's training and situational awareness in a practical context. This timing is critical for maintaining effective cabin safety and emergency preparedness, as it accounts for various complexities involved during the transitions of passenger flow into and out of the aircraft.