民航意外調查機構是香港特別行政區政府運輸及房屋局(運房局)轄下由總意外及安全調查員領導的調查機構，專責調查所有在香港發生，或涉及在香港註冊的民用飛機在外地的意外和嚴重事故，以及加強推廣民航安全。具體而言，總意外及安全調查員職責如下—

(a) 領導和管理民航意外調查機構，包括統籌員工調配、員工培訓、採購和保養調查設備、設施保養和檔案管理等工作，以及制訂優化意外和事故調查及安全管理程序的策略和措施，以確保香港能隨時根據《香港民航(意外調查)規例》(第448B章)及《國際民用航空公約》(《附件13》)進行飛機意外和事故調查；
(b) 履行第448B章下的法定職能和行使第448B章賦予的法定權力，特別是調查所有在香港發生或涉及在香港註冊的民用飛機在外地發生的航空意外及嚴重事故；
(c) 撰寫調查報告，說明意外／嚴重事故的情況和成因，以及提出安全建議以防範意外再次發生，並向行政長官提交該報告；
(d) 監督有關航空安全的資訊和數據的收集、保護和分析，找出安全隱患，向業界發放保障航空安全的訊息作教育用途；
(e) 定期檢視和更新與飛機意外和事故調查相關的法例、安排及程序，以確保香港能隨時根據第448B章及《附件13》進行意外和事故調查；
(f) 代表香港特別行政區政府參與有關航空意外和事故調查及航空安全的國際組織及活動，並與國際組織在相關議題上保持密切聯繫；
(g) 在有需要時為海外的航空意外調查機構提供支援及專業意見(例如在海外發生的意外或事故涉及在香港註冊的飛機)；以及
(h) 監督向航空意外的生還者及遇難者／傷者家屬匯報的工作(如調查進度、有關意外調查的資訊等)。

The CASI is the head of Air Accident Investigation Authority (AAIA), an independent authority under the Transport and Housing Bureau (THB) of the Government of the HKSAR responsible for the investigation of accidents and serious incidents which occur in Hong Kong or which involve Hong Kong-registered civil aircraft outside Hong Kong, and the enhancement and promotion of civil aviation safety. In particular, the responsibilities of the CASI include –
(a) To lead and manage AAIA, including staff deployment, staff training, procurement and maintenance of investigation equipment, facility maintenance and record management, etc, as well as to formulate strategies and measures to enhance accident and incident investigation and safety management procedures, thereby ensuring Hong Kong’s capability and readiness in conducting aircraft accident and incident investigations in compliance with the Hong Kong Civil Aviation (Investigation of Accidents) Regulations (Cap. 448B) and Annex 13 to the Convention on International Civil Aviation (Annex 13);
(b) To carry out the statutory functions and exercise the statutory powers granted under Cap. 448B, in particular to conduct investigations into all air accidents and serious incidents in Hong Kong, and those that occur outside Hong Kong but involve aircraft under its registry;
(c) To prepare and submit investigation reports to the Chief Executive, stating the circumstances and causes of accidents/serious incidents and making safety recommendations to prevent recurrence of accidents;
(d) To oversee the collection, protection and analysis of relevant aviation safety information and data with a view to identifying potential safety hazards and disseminating aviation safety messages to the industry for education purposes;
(e) To regularly review and update the legal provisions, arrangements and procedures for aircraft accidents and incident investigations, in order to ensure Hong Kong’s capability and readiness in accident and incident investigations in compliance with Cap. 448B and Annex 13;
(f) On behalf of the Government of the HKSAR, to participate in international organizations and activities in relation to air accidents and incident investigations and aviation safety; and to maintain close liaison with international organizations on relevant issues;
(g) To provide support and professional advice to overseas air accident investigation authorities when necessary (e.g. when aircraft registered in Hong Kong are involved in accidents or incidents occurred overseas); and
(h) To supervise the reporting (e.g. progress of investigation, information relating to the accident investigation) to be made to survivors and families of victims of air accidents.