三級航空交通事務員主要接受訓練，以執行航空交通事務員的以下職務： (a) 向航空交通管制中心及指揮塔提供支援服務； (b) 提供航空資料服務； (c) 協助進行技術研究； (d) 協助處理各項航空事務申請、解答查詢、處理投訴及編製投訴統計數字；以及 (e) 協助審核和視察航空活動。 航空交通事務員須二十四小時輪班工作。

An Air Traffic Flight Services Officer III is mainly deployed to undergo training for performing Air Traffic Flight Services Officer’s duties in the following areas : (a) provision of supporting service in the Air Traffic Control Centre and the Control Tower; (b) provision of aeronautical information service; (c) assisting in the conduct of technical research and studies; (d) assisting in the processing of various air services applications, answering enquiries, handling complaints and compiling statistics; and (e) assisting in the conduct of audits and inspections to aviation-related activities. An Air Traffic Flight Services Officer is required to work shifts on a 24-hour basis.