Summary

This document is a learning module on human factors in aviation maintenance. It covers the importance of human factors, learning objectives, and a summary of typical examples of aviation incidents.

Full Transcript

Human Factors - General (9.1) Learning Objectives 9.1.1.1 Describe the need to take human factors into account (Level 2). 9.1.1.2 Compare and contrast HF for maintenance with ight crew CRM (Level 2). 9.1.2 Describe typical examples of aviation incidents attributable to human factors and...

Human Factors - General (9.1) Learning Objectives 9.1.1.1 Describe the need to take human factors into account (Level 2). 9.1.1.2 Compare and contrast HF for maintenance with ight crew CRM (Level 2). 9.1.2 Describe typical examples of aviation incidents attributable to human factors and human error (Level 2). 9.1.3.1 Explain Murphy's Law and give an example of how it applies in an aircraft maintenance environment (Level 2). 9.1.3.2 Describe a simple strategy for 'Murphy-proo ng' (Level 2). Summary This topic introduces the term Human Factors (HF) and explains its importance within the aviation industry. This training course will be the initial introduction to the subject, but employees will be regularly refreshed in their HF knowledge and competence throughout their careers. The subject examines the relationship between humans and incidents or accidents in terms of human error. It also discusses 'Murphy’s Law', which states ‘if something can possibly go wrong, then one day it will go wrong’. 2023-01-12 B-09 Human Factors Page 14 of 340 CASA Part 66 - Training Materials Only The Need to Take Human Factors into Account What Is Meant by the Term Human Factors? In aviation, human error is responsible for operational incidents and accidents. The study of human factors in aircraft maintenance seeks to examine the people, environment, the actions and resources involved in the conduct of aircraft maintenance. It recognises that humans make mistakes and don’t work well under some conditions. Further, it seeks to challenge and, if possible, rectify the chance for poor human performance, including errors, to have aviation safety consequences, including operational incidents and accidents. Image by Marcelino James from Pixabay Aircraft on ramp Human factors in aircraft maintenance are an evolution of the original Cockpit Resource Management (CRM) awareness training that was introduced for commercial pilots in the 1970s. This training later included cabin crew and was referred to as Crew Resource Management. CRM was introduced to reduce incidents and accidents attributable to human error, or to poor human interaction, such as in communication or teamwork. It was determined that other job roles in the aviation system were also susceptible to human error and poor human interaction, with the potential to cause undesirable incidents and accidents. Human factors training was then adapted to these other job roles, including aircraft maintenance. 2023-01-12 B-09 Human Factors Page 15 of 340 CASA Part 66 - Training Materials Only Aircraft maintenance personnel work in a vastly different environment to ight crew and cabin crew. Therefore, HF training for maintenance professionals is very different to CRM. Some of the theory of human physiology and behaviour is common across all groups, but each job role has different tasks, different resources, and different environmental conditions. Image by Eugen Visan from Pixabay Pilot at ight deck window There are many de nitions of HF available. A simple de nition could be: Human factors refers to the study of human capabilities and limitations in the workplace. In aircraft maintenance, this study centres on the interaction among maintenance personnel, the equipment they use, the written and verbal procedures and rules they follow, and the environmental conditions of their system. 2023-01-12 B-09 Human Factors Page 16 of 340 CASA Part 66 - Training Materials Only Image by David Mark from Pixabay Engine maintenance The aim of human factors for aircraft maintenance could be written: "To optimise the relationship between maintenance personnel and systems with a view to improving safety, ef ciency and well-being." 2023-01-12 B-09 Human Factors Page 17 of 340 CASA Part 66 - Training Materials Only Human and Environmental Attributes Included in Human Factors Awareness Human factors include such attributes as: Human physiology Psychology (including perception, cognition, memory, social interaction) Workplace design Environmental conditions Human-machine interface Anthropometrics (the scienti c study of measurements of the human body). Image by delo from Pixabay Propeller maintenance 2023-01-12 B-09 Human Factors Page 18 of 340 CASA Part 66 - Training Materials Only Why Study Human Factors? The aviation regulators insist that we study human factors because the human is the most unreliable piece of the aviation system. Aircraft and other machinery have become more sophisticated and reliable, but humans will always make mistakes. This imperfection is part of being human and can never be entirely eliminated. HF training seeks to make people aware of these limitations, and to examine the organisations where the work is carried out, so that mechanisms may be put in place to capture human error before it can have bad consequences. An understanding of the importance of human factors to aircraft maintenance engineering is essential to anyone considering a career as an, Aircraft Maintenance Engineer (AME) or working in the many support or managerial roles within a Maintenance and Repair Organisation (MRO). This is because human factors will affect everything they do in the course of their job in one way or another. 2023-01-12 B-09 Human Factors Page 19 of 340 CASA Part 66 - Training Materials Only Short History of CRM and HF Training As early aircraft evolved into more complex machines, systems were designed to complement the human abilities of pilots, so the need for consideration of human/machine interface became apparent, as did the need for maintenance personnel to have more and more complex skills and knowledge from maintenance personnel. From the very early days it was obvious, mistakes made when designing, building, controlling or maintaining aircraft could lead to catastrophic results. Over time, it became clear that, no matter how experienced or well-trained, no person is infallible. Expensive and tragic accidents in aviation were consistently attributable to human error. For human factors in aircraft maintenance, signi cant accidents in the 1970s, 1980s and 1990s highlighted the fact that aircraft maintenance is a highly technical job, particularly dependent on knowledge and skill. It became evident that the job of ensuring the safety of the aircraft is extremely sensitive to human error, but the nature of the work and the environment in which the work is conducted makes it almost inevitable that errors will occur. Photo by Austrian National Library on Unsplash Historical aircraft parts manufacturing 2023-01-12 B-09 Human Factors Page 20 of 340 CASA Part 66 - Training Materials Only The SHELL Model When trying to understand the nature of work in aircraft maintenance, and how to develop strategies to make the work safer, it is often useful to consult a model. A common model to explain the interactions in any complex environment is the SHELL model. © Aviation Australia SHELL Model 2023-01-12 B-09 Human Factors Page 21 of 340 CASA Part 66 - Training Materials Only The Interface Between Each SHELL Model Component The study of human factors focuses on the interfaces between the human individual (the 'L' in the centre) and the other elements of the SHELL Model. The SHELL Model provides an overview of human factors by showing how humans interact with all other things in the workplace and life in general: The SHELL elements are: Software - For example, maintenance procedures, maintenance manuals, checklist layout, etc. Hardware - For example, tools, test equipment, the physical structure of aircraft, design issues, warning and lockout devices, equipment maintenance etc. Environment - For example, physical environment such as conditions in the hangar, conditions on the line, etc. and work environment such as work patterns, management structures, public perception of the industry, etc. Liveware - The individuals or groups of people with whom a person has to interact. For example, supervisors, customers, team members. Liveware - The person or people at the centre of the model and their own physical and psychological strengths and limitations. Sometimes the interfaces between elements are shown as blurred or wavy lines to indicate the interface is never perfect. This represents how errors can occur. © Aviation Australia SHELL Model (Imperfect) 2023-01-12 B-09 Human Factors Page 22 of 340 CASA Part 66 - Training Materials Only For example: S - misinterpretation of procedures, badly written manuals, poorly designed checklists, untested or dif cult to use computer software. H - not enough tools, people not trained to use tools, inappropriate equipment, poor aircraft design for maintainability. E - uncomfortable workplace, inadequate hangar space, extreme temperatures, excessive noise, poor lighting. L - relationships with other people, shortage of manpower, lack of supervision, lack of support from managers. Since Liveware is at the centre of the model, all other aspects (Software, Hardware and Environment) must be designed or adapted to assist human performance and respect human limitations. If these two aspects are ignored, the human, in this case the maintenance engineer, will not perform to the best of their abilities and may make errors or jeopardise safety. The goal when studying how humans interact with other aspects of their work environment is to improve these relationships, which will improve ef ciency and safety. Thanks to modern design and manufacturing standards, aircraft are becoming more and more reliable. However, it is not possible to redesign the human being. We can educate, train, mentor and support people in certain ways, but we must accept the fact that the human being is fundamentally unreliable. We can challenge that unreliability by providing procedures and tools, performing Independent Inspections, etc. We can also reduce the potential for error by improving aircraft design such that, for example, it is physically impossible to reconnect something the wrong way around. This is known as 'Murphy-proo ng' and is discussed further in this course. These measures are implemented to support people when doing their job and attempt to minimise errors. But if errors cannot be eliminated, then implementing procedures and other interventions can help capture human errors before they can do any harm. 2023-01-12 B-09 Human Factors Page 23 of 340 CASA Part 66 - Training Materials Only Image by Dirk Wouters from Pixabay Measures can be implemented to support people when doing their job. 2023-01-12 B-09 Human Factors Page 24 of 340 CASA Part 66 - Training Materials Only Incidents Attributable to Human Factors / Human Error Human Failure vs Other Causes Boeing have reported that in the early days of ight, approximately 80% of accidents were caused by the machine and 20% were caused by human error. Today that statistic has reversed. Approximately 80% of airplane accidents are due to human error (pilots, air traf c controllers, mechanics, etc.) and 20% are due to machine (equipment) failures. © Aviation Australia Incidents attributable to human factors/human error. In a further breakdown, according to FAA, approximately 80% of all maintenance failures involve human factors and undetected maintenance failures often lead to accidents. Human-Related Maintenance Causes of Signi cant Accidents A detailed study (noted in UK CAA CAP 718) of 93 major world-wide accidents between 1959 and 1983- found that 12% of the accidents were attributed to maintenance and inspection factors (4th on the list). 2023-01-12 B-09 Human Factors Page 25 of 340 CASA Part 66 - Training Materials Only Causes/major contributory factors % of accidents in which this was a factor Pilot deviated from basic operational procedures 33 Inadequate cross-check by second crew member 26 Design faults 13 Maintenance and inspection de ciencies 12 Absence of approach guidance 10 Captain ignored crew inputs 10 Air traf c control failures or errors 9 Improper crew response during abnormal conditions 9 Insuf cient or incorrect weather information 8 Runway hazards 7 Air traf c control/crew communication de ciencies 6 Improper decision to land 6 The UK CAA carried out a similar exercise in 1998, looking at causes of 621 global fatal accidents between 1980 and 1996. Again, the area 'maintenance or repair oversight/error/inadequate' featured as one of the top 10 primary causal factors. It is clear from such studies that human factors problems, in aviation generally and aircraft maintenance engineering in particular, are a signi cant issue warranting serious consideration. As stated, the human is the most unreliable piece of the aviation system. Aircraft and other machinery have become more sophisticated and reliable, but humans will always tend to make mistakes. This imperfection is part of being human and can never be entirely eliminated. 2023-01-12 B-09 Human Factors Page 26 of 340 CASA Part 66 - Training Materials Only Image by Frederik Schweiger on Unsplash Humans will always tend to make mistakes Case Study Examples of Incidents and Accidents This module describes a number of systematic failures and past incidents and accidents that have been important in highlighting human error in aircraft maintenance or have prompted changes in the way people work or how our industry operates. When referencing past incidents and accidents in these notes, the [CS] denoting 'Case Studies' will be applied to the title. Some of the case studies are listed below. If searching for resources related to these incidents, it is far more common to nd videos, etc., related to the in- ight aspects of the event. You will often need to re ne your search to nd resources that describe the circumstances surrounding the maintenance of the aircraft involved. Aloha Airlines Flight 243, Boeing 737 in 1988 Accident en route to Maui, Hawaii on 28 April 1988; Section of upper fuselage structure ripped off in ight; De ciency in structural inspection methods. 2023-01-12 B-09 Human Factors Page 27 of 340 CASA Part 66 - Training Materials Only British Airways Flight 5390, BAC 1-11 in 1990 Accident near Didcot, UK, on 10 June 1990; Cockpit windscreen blew out in ight; Cockpit windscreen installed with many incorrect fasteners. Excalibur Airways Charter Flight, Airbus A320 in 1993 Incident on take-off from London Gatwick Airport on 26 August 1993; Uncommanded roll after take-off; Spoilers left in disabled mode after maintenance. British Midland Airways Charter Flight, Boeing 737 in 1995 Incident near Daventry, UK, on 23 February 1995; Loss of oil pressure in both engines; Engines not restored to correct condition after maintenance. Aloha Airlines Boeing 737 in 1988 In the accident involving Aloha Flight 243 in April 1988, an explosive cabin decompression occurred as 6 metres of the upper cabin fuselage structure were suddenly ripped away in ight due to structural failure. The Boeing 737 involved in this accident had been examined, as required by US regulations, by two of the engineering inspectors. One inspector had 22 years' experience and the other, the chief inspector, had 33 years' experience. Neither found any cracks in their inspection. Post-accident analysis determined there were over 240 cracks in the skin of this aircraft at the time of the inspection. The ensuing investigation identi ed many human-factors-related problems leading to the failed inspections. As a result of the Aloha accident, the US instigated a research program to examine the problems associated with human factors and aircraft maintenance, with particular emphasis upon inspection techniques and ageing aircraft. The full NTSB (US) accident investigation report can be found at: https://www.ntsb.gov/investigations/AccidentReports/Pages/AAR8903.aspx Relevant Youtube link: The accident on Aloha Airlines Flight 243 For more information, search: ‘Aloha Airlines ight 243’ 2023-01-12 B-09 Human Factors Page 28 of 340 CASA Part 66 - Training Materials Only British Airways BAC 1-11 in 1990 On 10 June 1990 in the UK, a BAC 1-11, British Airways Flight 5390 was climbing through 5300 m on departure from Birmingham International Airport when the left windscreen, which had been replaced prior to the ight, was blown out under the effects of cabin pressure. The windscreen blew out when the cabin pressure overcame the securing bolts, of which 84 of a total of 90 were smaller than the speci ed diameter. The commander was sucked halfway out of the windscreen frame and was restrained by cabin crew while the co-pilot ew the aircraft to a safe landing at Southampton Airport. The Shift Maintenance Manager (SMM), undermanned on a night shift, had decided to carry out the windscreen replacement himself. He consulted the Aircraft Maintenance Manual (AMM) and concluded that it was a straightforward job. He decided to replace the old bolts and, taking one of the bolts with him (a 7D diameter bolt), he looked for replacements. The storeman advised him that the job required 8D diameter bolts, but since there were not enough 8Ds, the SMM decided that 7Ds would do, since these size bolts had been in place previously. However, he used sight and touch to match the bolts and incorrectly selected 8Cs instead, which were longer but thinner. He failed to notice that the countersink was lower than it should be once the bolts were in position. He completed the job himself and certi ed for the task, the procedures not requiring a pressure check or Independent Inspection. Several human factors issues contributed to this incident, including perceptual errors made by the SMM when identifying the replacement bolts, poor lighting in the stores area, failure to wear spectacles, circadian effects, working practices, and possible organisational and design factors. The full AAIB (UK) accident investigation report can be found at: https://www.gov.uk/aaib-reports/1- 1992-bac-one-eleven-g-bjrt-10-june-1990 For more information search: ‘British Airways ight 5390’. 2023-01-12 B-09 Human Factors Page 29 of 340 CASA Part 66 - Training Materials Only Excalibur Airways Airbus A320 in 1993 An incident in the UK in August 1993 involved a charter airline Airbus A320 which, during its rst ight after a ap change, exhibited an uncommanded roll to the right after take-off. The aircraft returned to Gatwick and landed safely. The investigation discovered that during maintenance, in order to replace the right outboard ap, the spoilers had been placed in maintenance mode and moved using an incomplete procedure. Speci cally, locking collars and ags were not tted to the spoilers. The purpose of the collars and the way in which the spoilers functioned was not fully understood by the AMEs. This misunderstanding was due, in part, to familiarity of the engineers with another aircraft type. This contributed to a lack of adequate brie ng on the status of the spoilers during the shift handover. The locked spoiler was not detected during standard pilot functional checks. The full AAIB (UK) accident investigation report can be found at: https://www.gov.uk/aaib-reports/2- 1995-airbus-a320-212-g-kmam-26-august-1993 For more information search: ‘Excalibur Airways Airbus A320’ British Midland Airways Boeing 737 in 1995 In the UK in February 1995, a British Midland Airways Boeing 737-400 suffered a loss of oil pressure in both engines. The aircraft diverted and landed safely at Luton Airport. The investigation discovered that borescope inspections had been carried out on both aircraft engines during the preceding night. The investigation also found the high pressure (HP) rotor drive covers had not been re tted, resulting in the loss of almost all the oil from both engines during ight. A line engineer was originally going to carry out the task, but for various reasons he swapped jobs with the base maintenance controller. The base maintenance controller did not have the appropriate paperwork with him. The base maintenance controller and a tter completed the work despite many interruptions, but failed to re t the rotor drive covers. No ground idle engine runs were carried out. This step would have revealed an oil leak with the drive covers not tted. The job was certi ed as complete. The full AAIB (UK) accident investigation report can be found at: https://www.gov.uk/aaib-reports/3- 1996-boeing-737-400-g-obmm-23-february-1995 For more information search: ‘British Midland engine failure Luton’ 2023-01-12 B-09 Human Factors Page 30 of 340 CASA Part 66 - Training Materials Only Characteristics of the Case Studies In all of these incidents, the engineers involved were considered by their companies to be well quali ed, competent and reliable employees. They were working within the expectations of their employers. All of the incidents were characterised by the following: There were staff shortages; Time pressures existed; Errors occurred at night or under poor inspection conditions; Shift or task handovers were involved; They involved supervisors doing long hands-on tasks; There was an element of a 'can-do' attitude; The inspections and tasks were characterised by interruptions; There was some failure to use approved data or company procedures; Manuals and other maintenance documentation were confusing; and There was inadequate pre-planning, equipment or spares. Incidents and Accidents Should Serve to Improve Standards The errors shown in the four case studies above are very common when studying human factors in aircraft maintenance. They all involve human performance de ciencies and, like many incidents and accidents, have served to improve standards in the industry and initiate changes in procedure. Some additional relevant case studies are given in Module 9.8 of this course. 2023-01-12 B-09 Human Factors Page 31 of 340 CASA Part 66 - Training Materials Only Good People Doing Good Work Most incidents and accidents involve good people trying to do the right thing. In all the examples above, the incident or accident involved good people trying to do the right thing, but falling short in some way. All these incidents were preventable and could have been avoided if any one of a number of things had been done differently. In some cases, several individuals were involved, and the outcome could have been different if any one of them had reacted or queried a particular action. In each situation, the individuals failed to recognise or react to signs of potential hazards, did not react as they would normally be expected to, or allowed themselves to be distracted or diverted from giving their attention to the task in hand. By doing these things, they left themselves open to a greater likelihood of committing an error. Image by Miguel A. Amutio on Unsplash Incidents or accidents can be caused by good people trying to do the right thing, but falling short. 2023-01-12 B-09 Human Factors Page 32 of 340 CASA Part 66 - Training Materials Only The Error Chain The error chain represents a series of events that lead to an incident or accident. As with many incidents and accidents, the examples given above all involve a series of problems which formed an error chain. When complete, the links in the chain allowed errors to progress causing an incident or accident. However, if any of the links in this chain had been broken, these incidents may have been prevented. Additional safety measures built into the organisation and maintenance processes, such as better procedures, enhanced inspection methods or better training, would contribute to breaking the error chain. Image by Clker-Free-Vector-Images from Pixabay Breaking the error chain Accidents result from a chain of events. If the error chain is broken, incidents and accidents are prevented. 2023-01-12 B-09 Human Factors Page 33 of 340 CASA Part 66 - Training Materials Only The 'Swiss Cheese' Model The error chain can also be explained by Professor James Reason's well-known 'Swiss Cheese' Model of accident causation. In this model, the slices or layers of Swiss cheese represent barriers of defence between hazards or errors and the bad consequences possibly arising from those errors, e.g. accidents. Like the error chain, barriers might represent better procedures, enhanced inspection methods, better training or other enhancements. Any of the barriers has the ability to prevent an accident from occurring. But, like Swiss cheese, the barriers are usually not perfect, or complete. They have de ciencies, represented by holes, which allow the hazard situation to move progressively closer to causing undesirable consequences. If circumstances allow all the holes in the layers of defence to line up, then a particular hazard will cause an undesirable event: an incident or accident. Model created by Dante Orlandella and James T. Reason of the University of Manchester Reason's Swiss Cheese Model 2023-01-12 B-09 Human Factors Page 34 of 340 CASA Part 66 - Training Materials Only Murphy’s Law Murphy’s Law and Human Complacency A common way of expressing Murphy’s Law is: “If something can go wrong, it will.” The belief that an accident will never happen to me or to my company can be a major problem when attempting to inform individuals or organisations about human factors issues, to recognise risks and to implement improvements. It is necessary to make human factors issues relevant and important rather than merely paying lip service to them. Complicating Murphy’s Law, there is a tendency among human beings towards complacency. Complacency is sometimes described as a feeling of security while unaware of some potential danger or defect. Complacency in aircraft maintenance may come about because an organisation is very safe and the maintenance workers have never experienced an accident or incident. Thus, they may feel as though because an accident HAS NEVER happened, an accident WILL NEVER happen. The belief that an accident will never happen to me or to my company can be a major problem when attempting to inform individuals or organisations about human factors issues, where the challenge is to recognise risks and to implement improvements. Image by William Daigneault from Unsplash The belief that an accident will never happen to me can be a major problem. 2023-01-12 B-09 Human Factors Page 35 of 340 CASA Part 66 - Training Materials Only Murphy-Proo ng Defences against Murphy’s Law are often known as ‘Murphy-proo ng’ (sometimes called ‘poka- yoke’). For example, the two identical electrical connectors are side by side, and it is physically possible for the connectors to be reversed, i.e. the left-hand connector can be tted to the right-hand receptacle, then from the paragraph above, Murphy's Law says this mistake of mis-connecting the wiring will eventually happen. Murphy-proo ng in this situation may mean replacing one of the connectors with a connector of different size or shape, meaning that reversing the connectors is not physically possible. © Jonathan Trout, Noria Corporation modi ed by Aviation Australia Error elimination by design 2023-01-12 B-09 Human Factors Page 36 of 340 CASA Part 66 - Training Materials Only Promote 'Constructive Worrying' Complacency in aircraft maintenance is dangerous. Keep thinking about ways to improve. If everyone could be persuaded to acknowledge Murphy’s Law, this might help overcome the complacent belief that accidents will never happen. It is certainly not true that accidents happen only to people who are irresponsible or sloppy. Some errors are unavoidable due to poor design, organisational pressure or other underlying factors. Image by Scottslm from Pixabay Keep thinking about ways to improve. The incidents and accidents described show that errors can be made by experienced, well-respected individuals and that accidents can occur in organisations previously thought to be safe. When working in an organisation that hasn't had a workplace incident or accident for a long time, the sense of complacency can be magni ed. To combat this, a conscious effort needs to be made to keep thinking that a bad accident is just around the corner and to keep trying to proactively improve workplace conditions and procedures. 2023-01-12 B-09 Human Factors Page 37 of 340 CASA Part 66 - Training Materials Only Image by skeeze from Pixabay Maintenance environment can contribute to complacency. 2023-01-12 B-09 Human Factors Page 38 of 340 CASA Part 66 - Training Materials Only Human Errors in Aircraft Maintenance Are Not Random Past human factors research has shown that maintenance-related errors are not random events. They fall into recurrent patterns shaped by situation and task factors characteristic of maintenance activities in general. For example, if a task has a complex, multi-step process, then it is well known that people cannot remember too many steps without memory aids. So, it is good practice to provide a detailed checklist for workers to follow. It is also good practice to alert other members of the working group not to interrupt these people when they are concentrating on their complex task. Human limitations are obvious in many aircraft maintenance situations. Once you have worked in the industry for a while, you will recognise the potential for error in the aircraft maintenance system. For example, aircraft maintenance often involves people conducting detailed inspections in the middle of the night. Considering humans are not nocturnal animals, this situation is not ideal. Image by Soumya Ranjan from Pexels Aircraft maintenance often involves people conducting detailed inspections in the middle of the night. Errors are not committed by a few careless or incompetent individuals. One of the basic principles of error management is that the best people can make the worst mistakes. Data shows that different people in different organisations keep on making the same mistakes. Because of this, we can leverage well-de ned business risk processes to focus limited resources for maximum remedial effect. 2023-01-12 B-09 Human Factors Page 39 of 340 CASA Part 66 - Training Materials Only Strategies for Error Management Human performance is part of the aircraft maintenance system, so it must be accounted for. Human limitations may be countered through strategic design of the workplace, work practices and machines. It should be stressed, however, that there is no single best way of limiting and containing human error. Effective error management requires a wide variety of countermeasures directed at different levels of the system: The individual The team The task The workplace The organisation as a whole. © Aviation Australia Strategies for Error Management This training material is one strategy to highlight the causes and effects of human error as well as ways to contain it. Your awareness of human factors is critical to how you perform the important work of aircraft maintenance. 2023-01-12 B-09 Human Factors Page 40 of 340 CASA Part 66 - Training Materials Only

Use Quizgecko on...
Browser
Browser