When are life jackets required on an aircraft?

Life jackets are required on aircraft based on their operation over water and distance from land. The correct condition for requiring life jackets is linked to the understanding that when an aircraft is operating beyond a certain distance from land, specifically 50 nautical miles (nm), the likelihood of encountering an emergency situation where a water landing could occur increases.

The regulation reflects the safety protocols intended to ensure that passengers and crew are adequately prepared in a scenario where a ditching into water becomes necessary. By mandating life jackets when operating 50 nm or more from land, the safety measures in place aim to enhance survivability in such emergencies.

Choosing the 50 nm distance aligns with the operational risk assessments that aircraft face when flying over large bodies of water. Other distances mentioned in the options would not adequately address the increased risks associated with flying further away from potential rescue options. Thus, 50 nm serves as a critical threshold for compliance with safety regulations regarding life jackets on board an aircraft.