第4部分规定了对有经验的空中潜水员进行进一步培训和认证所需的培训活动和能力，以确保其作为行李员和锁定潜水员安全、胜任地操作。此类资质是负责控制海上深海潜水（如石油和天然气勘探）的监管机构的最低要求。

Part 4 specifies the training activities and competencies required for the further training and accreditation of experienced air divers to operate safely and competently as bellmen and lockout divers. Such qualification is the minimum required by regulatory authorities who are responsible for the control of deep diving off-shore, e.g. oil and gas exploration.