During which phases of flight are lap-held and vest-type child restraints not acceptable?

Lap-held and vest-type child restraints are not acceptable during taxi, takeoff, and landing due to safety regulations that prioritize the use of appropriate restraint systems to ensure the security and safety of all passengers, especially young children. During these critical phases of flight, the aircraft is either on the ground preparing for departure or in the process of ascending or descending. Any sudden changes in velocity, pitch, or altitude can pose serious risks, and proper child restraint systems must secure children adequately to prevent injury.

Using approved child safety seats or harnesses is crucial during these times since they provide additional protection. This regulation is grounded in the understanding that typical restraints like lap belts may not provide sufficient protection for children, who are smaller and may not be adequately secured by standard safety equipment designed for adults. Therefore, following this guideline is essential for maintaining passenger safety during the most vulnerable stages of flight operations.

The relevance of the other phases of flight mentioned in the other options does not carry the same level of risk or regulatory requirement regarding child restraints, which is why they are not considered in this context.