HUMAN FACTORS IN AVIATION

1 UK 147 0072 FAA/EASA PART 147 AIRCRAFT TYPE TRAINING COMPANY HUMAN FACTORS IN HUMAN FACTORS REVIEWCOURSEUK 147 0072 PART 147 AIRCRAFT TYPE TRAINING COMPANY This booklet is the copyright material of and may not be copied or HUMAN FACTORS REVIEWCOURSEHUMAN FACTORS - A COMPLETE COURSEC hapter 1 IntroductionThe Need To Take HUMAN FACTORS Into Account 2 Incidents and Accidents Attributable To HUMAN FACTORS / HUMAN Error 4 Murphy's Law 9 Summary9 Chapter 2 HUMAN Performance and LimitationsHuman Performance as Part of the Maintenance Engineering System 12 Vision 12 Hearing 20 Information Processing 21 Claustrophobia, Physical Access and Fear of Heights 29 Summary31 Chapter 3 Social PsychologyThe Social Environment 34 Responsibility: Individual and Group 35 Motivation and De-motivation 39 Peer Pressure 40 Culture Issues 42Te a m Wo r k i n g 4 4 Management, Supervision and Leadership 47 Maintenance Resource Management (MRM) 49 Summary52 Table of 4/1/2004 11:24 AM Page 1 HUMAN FACTORS REVIEWCOURSEC hapter 4 FACTORS Affecting PerformanceFitness and Health 54 Stress.

2 Domestic and Work Related 56 Time Pressure and Deadlines 58 Workload - Overload and Underload 60 Sleep, Fatigue and Shift Work 63 Alcohol, Medication and Drug Abuse 67 Summary70 Chapter 5 Physical EnvironmentNoise 72 Fumes 72 Illumination 73 Climate and Temperature 75 Motion and Vibration 76 Confined Spaces 77 Working Environment 77 Summary78 Chapter 6 TasksPhysical Work 80 Repetitive Tasks 81 Visual Inspection 82 Complex Systems 84 Summary85 Chapter 7 CommunicationWithin and Between Teams 88 Work Logging and Recording 91 Keeping Up-to-Date, Currency 92 Dissemination of Information 93 Summary94 Chapter 8 HUMAN ErrorUnderstanding HUMAN Error 96 Error Models and Theories 96 Types of Error in Maintenance Tasks 102 Implications of Errors ( Accidents) 105 Avoiding and Managing Errors 106 Summary108 Chapter 9 Hazards In The WorkplaceRecognizing and Avoiding Hazards 110 Summary113 HUMAN FACTORS in AVIATION 4/1/2004 11:24 AM Page 2 HUMAN FACTORS REVIEWCOURSEThis chapter introduces HUMAN FACTORS and explains its importance to the AVIATION industry.

3 It examines the relationship between HUMAN FACTORS andincidents largely in terms of HUMAN error and "Murphy's Law" ( , ifsomething cango wrong, it will).Introduction1 Chapter 4/1/2004 11:24 AM Page 3 HUMAN FACTORS REVIEWCOURSEThe Need To Take HUMAN FACTORS Into AccountIn the early days of powered flight, the design, construction, and control of aircraft wasthe predominated focus. The main attributes of the first pilots were courage and themastery of a whole new set of skills in the struggle to control the new flying the technical aspects of flight were overcome, the role of the people associated withaircraft became more important. Pilots were supported initially with mechanisms tohelp them stabilize the aircraft, and later with automated systems to assist the crewwith tasks such as navigation and communication. With the introduction of thesehighly complex systems the interface between the pilot and technician and the effectsof one on the other became very important.

4 The study of HUMAN /machine interface isergonomics and the application of this science is HUMAN importance of HUMAN FACTORS to the aircraft maintenance technician, supervisorsand managers is essential. This is because HUMAN FACTORS will affect everything they doin the course of their job in one way or is " HUMAN FACTORS "?The term " HUMAN FACTORS " is used in many differentways in the AVIATION industry. Most people known itin the context of aircraft cockpit design and CrewResource Management (CRM). However, thoseactivities are only a small part of AVIATION -related HUMAN FACTORS , as broadly speaking it coversall aspects of HUMAN involvement in use of the term " HUMAN FACTORS " in AVIATION maintenance engineering is new. Aircraft accidentssuch as that of the Aloha aircraft in the USA in 19881and the BAC 1-11 windscreen accident in the UK inJune 19902focused attention on HUMAN FACTORS . Thisdoes not mean that HUMAN FACTORS issues were notpresent before these dates or that HUMAN error didnot contribute to other incidents only that it took anaccident to draw attention to HUMAN FACTORS problems and potential summary HUMAN FACTORS covers three areas of influence on people at work.

5 The organization The job Personal factorsThese are affected by the systems of communication within the organization and thetraining system and procedures in operation all of which are directed at preventinghuman error and FACTORS in AVIATION Maintenance2A Definition ofHuman FactorsHuman FACTORS covers a range of issues including perceptual, physical andmental capabilities,the interaction and effects onindividuals of their job andworking environments, theinfluence of equipment andsystem design on humanperformance and finally theorganizational characteristicswhich influence safetyrelated behavior at 4/1/2004 11:24 AM Page 4 HUMAN FACTORS REVIEWCOURSEH uman FACTORS includes: HUMAN physiology Psychology(including perception, cognition, memory, socialinteraction, error, etc.) Work place design Environmental conditions HUMAN -machine interface Anthropometrics (the scientific study of measurements of the HUMAN body)The SHEL ModelIt can be helpful to use a model to aid in the understanding of HUMAN FACTORS , oras a framework around which HUMAN FACTORS issues can be structured.

6 A modelwhich is often used is the SHEL model, a name derived from the initial letters ofits components: Software ( , maintenance procedures, maintenance manuals,checklist layout, etc.) Hardware ( , tools, test equipment , the physical structure ofaircraft, design of flight decks, positioning and operating sense ofcontrols and instruments, etc.) Environment ( , physical environment such as conditions in the hangar,conditions on the line, work environment such as work patterns, management structures, public perception of the industry, etc.) Liveware ( , the person or people at the center of the model,including maintenance technicians, supervisors, planners,managers, etc.)The ____ offers the following in regards to HUMAN FACTORS :"As stated before, HUMAN FACTORS refers to the study of HUMAN capabilities and limitations in the FACTORS researchers study system performance, the interaction of maintenancepersonnel with the equipment they use, the written and verbal procedures andrules they follow, and the environmental conditions of any aim of HUMAN FACTORS is to optimize the relationship between maintenancepersonnel and systems with a view to improving safety, efficiency, and well-being.

7 " 4/1/2004 11:24 AM Page 5 HUMAN FACTORS REVIEWCOURSEH uman FACTORS concentrateson the interfaces betweenthe HUMAN (the "L" in the center box) and the otherelements ofthe SHEL model1(see Figure 1). Froma safety standpoint, it exam-ines where these elements can be in SafetySoftware: misinterpretation of procedures, badly written manuals, poorly designed checklists, untested or difficult to use computer softwareHardware: not enough tools, inappropriate equipment , poor aircraft design for maintainabilityEnvironment: uncomfortable workplace, inadequate hangar space,extreme temperatures, excessive noise, poor lightingLiveware: relationships with other people, shortage of manpower,lack of supervision, lack of support from managersHumans, the "Liveware," can perform a wide range of activities. Despite the fact thatmodern aircraft are now designed to use the latest Built-In Test equipment (BITE)that modern computers can provide, one aspect of AVIATION maintenance has notchanged: maintenance tasks are still done by HUMAN beings.

8 However, humans have limitations. Since Liveware is at the center of the model, all other aspects (Software,Hardware, and Environment) must be designed or adapted to assist HUMAN performanceand respect HUMAN limitations. If these two aspects are ignored, the HUMAN - in thiscase the maintenance technician - will not perform to the best of his abilities, maymake errors, and may compromise of modern design and manufacturing, aircraft are becoming even more , it is not possible to re-design the HUMAN being: we have to accept the factthat the HUMAN being is intrinsically unreliable. We can work around that unreliabilityby providing good training, procedures, tools, duplicate inspections, etc. We can alsoHuman FACTORS in AVIATION Maintenance4 HSLLEF igure 1 SHEL Model. Source: Edwards, 1972 (as referenced in ICAO HUMAN FACTORS Digest No 1, Circular 216 (1989)) 4/1/2004 11:24 AM Page 6 HUMAN FACTORS REVIEWCOURSE reduce the potential for error by improving aircraft design so that it is physicallyimpossible to reconnect something the wrong and AccidentsAttributable To HUMAN FACTORS / HUMAN ErrorIn 1940, it was calculated thatapproximately 70% of all aircraftaccidents were attributable to man's performance, that is to say HUMAN the InternationalAir Transport Association (IATA) reviewed the situation 35 years later, they foundthat there had been no reduction in the HUMAN error component of accident statistics (Figure 2).

9 Astudywascar-riedout in the USA in 1986 looking at significant accident causes in 93 aircraft results of this study are highlighted in Table FAILUREF light Crew, ATC,Maintenance, AircraftDesign, 2 The dominant role played by HUMAN performanceSource: IATA, 1975 Causes/ major contributory factor% of accidents in whichthis was a factorPilot deviated from basic operational procedures33 Inadequate cross-check by second crew member26 Design faults 13 Maintenance and inspection deficiencies 12 Absence of approach guidance10 Captain ignored crew inputs 10 Air traffic control failures or errors 9 Improper crew response during abnormal conditions9 Insufficient or incorrect weather information8 Runway hazards7 Air traffic control/crew communication defeciencies6 Improper decision to 4/1/2004 11:24 AM Page 7 HUMAN FACTORS REVIEWCOURSEOne of the main aims of this book is to help all personnel in the maintenance engineering environment (technicians, planners, managers, etc.)

10 To recognize humanperformance limitations in themselves and others, and to be able to avoid, detect andrectify errors or error prone behavior and can be seen from Table 1, the maintenance errors and omissions have a disproportionately high risk level that results in serious failures on the aircraft. Moreimportant is the Fatal and Serious Accident Rating FAR/SAR, details of which can beobtained from the Air Accident Investigation Board (AAIB) or the National AviationSafety Data Analysis Center (NASDAC) or the National Transportation Safety Board(NTSB). Records from 1972 to the present confirm that maintenance errors related tohuman FACTORS scores over FAR/SAR, well above other accident types. This indicates that in these instances there is a greater loss of life. The following accidentreports will demonstrate the significant impact of HUMAN FACTORS in Civil AVIATION Authority (CAA), carried out a similar exercise1in 1998 lookingat causes of 621 global fatal accidents between 1980 and 1996.