1、CIRCULAR 24 - to outline a methodology for investigating Human Factors in aircraft accidents and incidents; and - to describe how the information gathered should be reported. 3. The digest is intended to complement the ICAO Manual of Aircraft Accident Investigation (Doc 6920). The philosophical appr
2、oach outlined in this digest should be understood when applying the practical guidance provided in the investigation and prevention manuals. The field of Human Factors also encompasses medical issues; however, the thrust of this digest is on the non-medical aspects. 4. The primary focus of the diges
3、t is on the events which led up to the occurrence and not on post-accident events, such as search and rescue or survivability issues. It will not include guidance for handling post-mortems, toxicological examinations and injury pattern analysis. These special areas are discussed in the Manual of Air
4、craft Accident Investigation and the Manual of Civil Aviation Medicine (Doc 8984). Nevertheless, the investigator is expected to be familiar with the physiological as well as the psychological aspects of human performance. 5. Through the international Standards and Recommended Practices (SARPs) set
5、forth in Annex 13 to the Chicago Convention and related guidance material, ICAO has assisted States in the accident investigation and prevention field. There is a continued emphasis on objectivity in investigation and prevention. Improvements in the investigation of Human Factors in accidents and in
6、cidents will add significantly to this effort. 6. This digest includes the following: Chapter I discusses the need for and the purpose of Human Factors investigation: addresses some of the obstacles to Human Factors investigation; discusses the nature of human error and accidents; and provides a sys
7、tems approach model by which the scope of the Human Factors investigation can be determined. Chapter 2 addresses the conduct of the Human Factors investigation; discusses the organization and management of the investigation; details who should conduct the COPYRIGHT International Civil Aviation Organ
8、izationLicensed by Information Handling Services- ICAO CIRCULAR*240 * I 48414Lb 0027995 b5T E 2 ICAO Circular 24O-ANA44 investigation, what information should be collected, where it can be found, and presents a discussion on how to analyze the information collected. Chapter 3 discusses the reporting
9、 of accidents and incidents with the emphasis on the treatment of Human Factors information, the identification of hazards and the development of safety action to prevent recurrence. Appendix 1 provides examples of Human Factors Checklists. Appendix 2 provides guidance in Witness Interviewing Techni
10、ques. Appendix 3 presents a sample listing of Explanatory Factors - a proposed expansion of the ADREP Manual. Appendix 4 provides a listing of available accidenthcident data bases. Appendix 5 presents a list of recommended readings. 7. This digest was prepared with the assistance of the ICAO Flight
11、Safety and Human Factors Study Group. Particular recognition goes to the Transportation Safety Board of Canada for its support and diligent work in producing the initial draft. 8. Six other Human Factors digests have been published including: Digest No. 1 - Fundamental Human Factors Concepts (Circul
12、ar 216); Digest No. 2 - Flight Crew Training: Cockpit Resource Management (CM) and Line- Oriented Flight Training (LOFT) (Circular 21 7); Digest No. 3 - Training of Operational Personnel in Human Factors (Circular 227); Digest No. 4 - Proceedings of fhe ICA0 Human Factors Seminar (Circular 229); Dig
13、est No. 5 - Operational Implications of Automation in Advanced Technology Flight Decks (Circular 234); and Digest No. 6 - Ergonomics (Circular 238). COPYRIGHT International Civil Aviation OrganizationLicensed by Information Handling ServicesICA0 CIRCULAR*240 * = 48414Lb 0027996 S9b = Chapter 1 NEEDF
14、ORANDPURPOSEOF HUMAN FACTORS INVESTIGATION BACKGROUND 1 .I As evidenced by investigation records dating back to the 1940s, Human Factors are involved in the majority of aviation accidents and incidents. Regardless of the actual percentage, there is little disagreement among government and industry e
15、xperts over the importance of Human Factors as a primary element in the causes of accidents and incidents. In spite of this knowledge. and the notion that “to err is human”, progress has been slow in adopting a uniform approach to the investigation of Human Factors in aviation occurrences. When no t
16、angible technical evidence was found to explain the occurrence, investigators and their authorities sometimes found it difficult to deal with Human Factors issues. The unfortunate result has been described by George B. Parker, Associate Professor of Safety at the University of Southern California, a
17、s the Law of Exception: If we have ruled out everything except the pilof, the cause must be pilot factor. 1.2 Accident investigation reports usually depict clearly what happened and when, but in too many instances they stop short of fully explaining how and why the accidents occurred. Attempts to id
18、entify, analyse, and understand the underlying problems that led to the breakdowns in human performance and thus to the accidents are sometimes inconsistent. By stating that a pilot did not follow the rules implies that the rules are well-founded, safe, and appropriate. Hence, the investigation repo
19、rts often limit conclusions to phrases such as “pilot error”, “failed to see and avoid”, “improper use of controls”, or “failed to observe and adhere to established standard operating procedures (SOPS).” This narrow focus is but one of many obstacles to the effective investigation of Human Factors.
20、1.3 Below are listed other common obstacles, along with solutions which can eliminate them. OBSTACLES AND SOLUTIONS Obstacle: The need to investigate Human Factors issues has not been readily accepted. One may hear comments, such as “Human Factors is an area that is too soff, human nature cannot be
21、changed”, or “it is too difficult to prove conclusively that these factors contributed to the accident”. Solution: More education, describing how experimental research has managed to eliminate many speculative elements in the field of Human Factors, with scientifically supported documentation. For e
22、xample, research has shown empirically the advantages of effective cockpit communication, a recognition that has translated directly into courses in crew resource management and pilot decision- making. Obstacle: The reluctance to investigate Human Factors may stem from a lack of understanding of wha
23、t the term “Human Factors” encompasses. Unfortunately, some investigators believe themselves ill-equipped because they are not medical doctors or psychologists. The field of Human Factors extends well beyond the 3 COPYRIGHT International Civil Aviation OrganizationLicensed by Information Handling Se
24、rvicesICAO CIRCULAR*240 * 484141b 0027997 422 9 4 ICAO Circular 240-ANh44 physiological and the psychological; ironically, most investigators, unbeknownst to themselves, have a broad awareness of the subject which they apply in an informal manner. Solution: Better Human Factors training for investig
25、ators will develop a more thorough understanding of what the investigation of Human Factors entails. Obstacle: Investigators may mishandle questions related to the petformance of crew members, air traffic controllers, maintenance personnel, and others. This can happen when the investigator has not e
26、stablished an atmosphere of objectivity and trust, and those whose performance is being questioned feel threatened by or antagonistic towards the investigator. In the worst case, crew members or other interested parties may withhold valuable information and assistance from the investigation authorit
27、y. Solution: Investigators should ensure that people understand the objective of the process - to prevent recurrence - and the method by which the investigator intends to achieve this objective. If there is a possibility of misunderstanding, this information should be discussed openly at the beginni
28、ng of the investigation. Obstacle: There is often a natural reluctance on the part of witnesses (for the purposes of this digest these include peers, supervisors, management and spouses) to speak candidly about the deceased. Also, investigators may be somewhat reluctant to ask questions which may be
29、 interpreted as unfavourable by a relative, friend or colleague. Solution: Well planned interviews are required. By comparing the information obtained through these interviews to information gathered by other means in the investigation process, a more complete explanation can be achieved. Obstacle:
30、Balancing an individuals right to privacy with the need to uncover and report on the factors involved in the accident is another difficulty. On the one hand, information from the cockpit voice recorder (CVR), air traffic control (ATC) recordings, and witness statements may be essential in determinin
31、g how and why the accident occurred. On the other hand, these same sources often contain sensitive personal information about involved individuals who would naturally want such information protected. Solution: Accident investigation authorities should provide a degree of protection to such sources (
32、see Annex 13, Chapter 5). Depending on an individual States laws, this protection may need to be legislated. Investigation authorities will have to be discriminating, publishing only that information which is essential to the understanding of the accident and which promotes prevention. Obstacle: The
33、 investigation philosophy adopted by the management of the investigation authorities is very important. Investigators will be hampered in their efforts to conduct a full systematic investigation if the management for whom they work do not believe in the importance of investigating Human Factors in a
34、ccidents and incidents. Without management support, there is little doubt this field will continue to be neglected. Solution: Knowledge of Human Factors and an understanding of how to apply this knowledge in an investigation offers the investigation authority a greater opportunity to identify root c
35、auses which may not have been recognized previously. Furthermore, it ofers States administrations a constructive means for handling controversial human performance issues. Some of the key methods by which investigators and their managers can promote the investigation of Human Factors lie in keeping
36、abreast of current literature, attending Human Factors courses and seminars, and applying concepts such as those outlined in this digest. COPYRIGHT International Civil Aviation OrganizationLicensed by Information Handling ServicesICAO CIRCULAR*240 * W 484L4Lb 0027998 369 W ICAO Circular 24O-AM144 5
37、Obstacle: In many States, the regulatory authority also has the responsibility for investigating accidents and incidents. The absence of an independent investigation authority has the potential for creating a conflict of interest within the organization. There could be an unwillingness on the part o
38、f the regulators to investigate those issues that are related to their role as regulators. This situation could also cause the travelling public to view the regulators investigative findings with scepticism. Solution: Some States have created an independent investigative body whose sole mission is t
39、o determine the causes of accidents and make safety recommendations to prevent their recurrence. Such a body is free to make findings and recommendations without encumbrance. Obstacle: The rush of media and litigants to find someone fo blame to suit their own objectives may result in premature concl
40、usions. For example, the pilot is sometimes made the scapegoat to reassure the public that an individual has been found responsible. Solution: Investigators must be diligent in promoting the philosophy that only after a full, systematic investigation has been completed can all the causes be determin
41、ed. Obstacle: The determination of conclusions and causes by the investigation authority can inadvertently apportion blame, fault or liability, To the extent that this happens, the potential for preventing future accidents and incidents may be diminished. How States publish their findings thus becom
42、es a crucial part of the process of preventing accidents. Solution: Accident investigation reports which concentrate on identifying underlying problems instead of laying blame will contribute far more to the prevention of accidents. However, while every effort should be made to avoid assigning fault
43、 or liability, the reports must not refrain from reporting objectively and fully on the causes merely because fault or liability might be inferred from the report. Obstacle: There is a general lack of accepted international guidance material in this field. Solution: With the publication of this dige
44、st, it is anticipated that the most significant obstacles to the investigation of Human Factors will be eliminated. By applying the approach outlined in this digest, investigators and their authorities should feel more confident in conducting these investigations. 1.4 Despite these obstacles, atitud
45、es are changing. Government and industry experts are emphasizing the value of investigating Human Factors in aviation accidents and incidents as part of the over- all aim of accident prevention and improved safety. ICAO recognizes this change in emphasis as a positive step taken by States to improve
46、 investigation procedures, techniques and prevention. THE NATURE OF ACCIDENTS AND INCIDENTS 1.5 The investigation of Human Factors in aircraft accidents and incidents should be an integral part of the entire investigafion and its resulting report. Humans do not act alone; they are but one element of
47、 a complex system. Often, the human is the last barrier that stops the sequence of events from causing an accident. However, when events combine and interact together to cause a catastrophe, the investigation authority must ensure that all elements of the complex system are investigated to understan
48、d why the accident happened. A systematic search for the “Why” is not intended to pinpoint a single cause, nor is it intended to assign blame or liability, nor even to excuse human error. Searching for the “Why” helps identify the underlying deficiencies that mighf cause other incidents or another a
49、ccident to happen. COPYRIGHT International Civil Aviation OrganizationLicensed by Information Handling ServicesICAO CIRCULAR*240 * 4B4L4Lb 0027977 2T5 6 ICAO Circular 240-AN/144 I .6 The formal definition of an accident is useful in determining the criteria for reporting the occurrence ta the investigation authority and in identifying when an investigation should be conducted. The extent of an investigation will be governed by the investigation authoritys legislative mandate. The investigation authority may not be able to investigate every occurrence in depth. DEFINITION OF AN
