A carrier becomes amphibious through its assigned role

When is a carrier considered an amphibious vessel?

When it carries troops and operates as a helicopter landing platform; providing air defence alone makes it a supporting carrier, not amphibious lift.

Operational assignment determines whether a carrier is part of the amphibious lift system. A ship transporting troops and acting as a landing platform helicopter performs an amphibious role. A carrier providing fighter cover remains a sea-control or air-defence element supporting the landing. The distinction keeps the focus on function rather than assuming every flat deck performs the same job.