The earliest origins of human factors can be traced back to 1487, when Leonardo DiVinci began his research in the area of anthropometrics – ‘the scientific study of the measurements and proportions of the human body’. In studying the flight of birds, DiVinci understood that humans are too heavy and not strong enough to fly using wings simply attached to the arms. Therefore, he sketched a device in which an individual lies down on a plank and works two large membranous wings using hand levers, foot pedals, and a system of pulleys, as shown below.
Today, anthropometry plays a considerable role in the fields of computer design, access design and maintainability of plant/facilities, simplicity of instructions, and the study of people’s efficiency in the workplace (ergonomics).
In the early 1900s, industrial engineers Frank and Lillian Gilbreth were trying to reduce human error in medicine. They discovered that the traditional procedure of a surgeon selecting his own instruments from a tray led to the surgeon spending too much time searching for instruments and not enough time monitoring the patient. The concept of using call backs when communicating in the operating room was developed. For example, the doctor says “scalpel” and the nurse repeats “scalpel” and then hands it to the doctor. This is called the challenge-response system, which is the same verbal protocol used in the control rooms, cockpits and operating theatres of today.
However, it is the aviation industry that is credited with pioneering much of the early work in applied human factors. The earliest example of aviation human factors can be traced to Orville and Wilbur Wright’s attempts to be the first to fly a powered aircraft. On December 17, 1903, they made four controlled powered flights over the dunes at Kitty Hawk, North Carolina with their Wright Flyer as shown below.
In preparing for their flights, the Wright brothers though about how to protect themselves from the hostile outside elements. They used goggles, a warm coat, thick gloves and even a seatbelt to protect themselves. While human factors was not even identified as a discipline in the early 1900’s, the Wright brothers use of human factors countermeasures in maintaining see and avoid principles, keeping warm and ensuring functional hands and fingers, was the beginning of the equivalent modern day fitness to fly!
However, the birth of human factors as we know it today, is generally considered to have been motivated by two major drivers: conflict and tragedy.
Prior to the First World War, the only test of human to machine compatibility was that of trial and error. If the human functioned with the machine, they were accepted, if not they were rejected. The experience of WW I and the following statistics offered by the British Royal Flying Corps at the time, perhaps best sum up the situation. The British found that during WW I, for every 100 aviators killed, 2 met their fate at the hand of the enemy, 8 died as a result of mechanical or structural failures of the aircraft, and an astounding 90 died as a result of what the Flying Corps described in 1941 as ‘their own individual deficiencies’. In hindsight it was clear that the systems were not supporting the human and the required task.
Concerns over how to better manage the individual deficiencies prompted the first real efforts in aircrew selection and training, which at the time had been cursory. For example, imagine only 2 to 3 hours of flying instruction before being expected to fly solo in today’s aviation environment! But the good news is; by the end of WW I progress had been made in better aircraft design to overcome human limitations. This can be considered to be the early origins of the now well established field of ergonomics – ‘the design of products (equipment) to optimise them for human use’. Also there was better recognition that pilot error and accidents in aviation were closely related to human brain limitations such as judgement and cognition and human body issues such as sensory perception. This was the start of two scientific fields known today as Aviation Psychology and Aviation Medicine.
Conflict again in the form of World War II provided another leap forward in human factors as a result of two specific challenges. Rapid changes in aircraft technology meant that airplanes were capable of reaching airspeeds four times faster than those of WW I, and altitude capabilities that exceeded 30,000 ft. While equipment advanced, humans who were selected and trained to operate them did not significantly change leading to a rise in the number of aircraft accidents as pilots struggled to adapt to controls and displays far more complex than anything they had experienced before. The human factors response to these problems was a more scientific approach to pilot selection; the forerunner of psychometric testing; pilot cognitive skills and personality testing within many organisations today.
From the end of World War II and during the 1950’s and 1960’s human factors expanded rapidly in the areas of pilot selection, medical standards, fatigue, spatial disorientation, and pilot information processing. While automation and intelligent systems continued to advance, the human factors focus primarily remained narrow; that is the focus remained on individual human performance limitations; social, situational and broader organisational influences were not really considered as they are today.
The period from World War II until the start of the 1970’s is often referred to as the Technical Era with the focus of safety on the investigation and improvement of technical factors, with comparatively less focus on human factors. Between the 1970’s and 1980’s the Human Factors era emerged with significant efforts devoted to error mitigation and the evolution of early versions of human factors training, known then within the aviation industry as cockpit (and later crew) resource management (CRM) programs. Despite such efforts, human performance contributions continued to dominate accident statistics partly because they tended to focus on the individual, with little attention to how both organisational and operational influences impacted performance. It was not until the early 1990s that it was first acknowledged that human error does not occur in isolation, but is shaped by individual, social, operational and organisational factors. By the mid 1990’s the Organizational Era evolved in which safety was seen from a systems perspective and in particular the notion of the organisational accident was embraced.
More recently from 2010 onwards, the Total System Era has been increasingly embraced; based upon the understanding there can be a failure across all industry service providers, regulator(s) and wider Government influence.
These stages are shown below.
Figure 5. Timeline of human factors evolution
While the theme of conflict and military motivations had historically driven human factors development, it was the civilian sector that invested heavily from the 1970’s and into the 1980’s as a result of tragedy; in the form of a number of passenger transport accidents on both sides of the world.
In the United States, on 29 December 1972, an Eastern Airlines Lockheed L-1011 TriStar crashed into the Florida Everglades resulting in 101 fatalities. The entire flight crew had become preoccupied with a burnt-out landing gear indicator light, and failed to notice that the autopilot had been disconnected. The aircraft gradually lost altitude and crashed.
On the other side of the globe, on 27 March 1977, a KLM Boeing 747 collided with a Pan Am B747, on a foggy runway at Tenerife in the Canary Islands. A total of 583 people lost their lives in the accident, which was the result of a series of communication failures between the two flight crews, air traffic control and a KLM Captain who believed he was cleared for takeoff, despite the Pan Am aircraft not having vacated the runway.
As a consequence of the above tragedies, human factors training was adopted by most airlines around the globe in the 1980’s and 1990’s and eventually expanded outside the cockpit to cabin crew, maintenance and air traffic control.
Throughout the 1990’s human factors regulations for flight crew licensing, flight operations, cabin crew, maintenance and air traffic controllers were introduced internationally by the International Civil Aviation Organisation (ICAO) and have now evolved from a historical focus on soft attitudinal concepts to the assessment of specifically defined behavioural markers or Non Technical Skills (NTS).
Non technical skills are the decision making and social skills that complement technical skills. For example, properly flaring the aircraft on landing is a technical skill, but maintaining situational awareness (attention to the surrounding environment) for a potential runway incursion is a non-technical skill.
Although the aviation industry introduced the concept of the first human factors programs, they have now been widely adopted by many other industries and in some cases, there are legislative requirements enforced by the relevant industry regulator as indicated below:
From the early 2000’s to today, the focus of human factors is now based on a recognition that human failure can occur at any stage of a systems’ lifecycle. From initial design, manufacturing and construction phases, through to operational management, maintenance and even regulatory oversight; human inputs mean that the possibility of errors always exists.
Improving organisational resilience by the adoption of error tolerant systems that defends against human error and removing weaknesses will continue to be a focus beyond 2020.
The success of human factors programs at minimising error
So what’s the evidence that aviation human factors and Non Technical Skills programs have been effective at improving overall air safety and minimising the ever present threat of human error?
Data from the University of Texas’ Line Operations Safety Audit (LOSA) program indicates that 98% of all flights face one or more threats, with an average of four threats per flight. Also errors have also been observed on 82% of all flights with an average of 2.8 errors per flight.
These figures suggest that despite the constant nature of threats and errors, the vast majority of errors are well-managed due to well defended operational controls, of which include the effective application of human factors skills by aircrew, engineers, dispatchers and air traffic control personnel.
Scope of Human Factors Today
The scope and application of human factors today can be divided into four main goals:
- Reducing error;
- Increasing productivity;
- Enhancing safety; and
- Enhancing comfort.
Each of these goals can be broken down further into a number of sub-goals:
- Reducing Error
- Removing ambiguity in the interface to avoid errors
- Including “forcing functions” to prevent erroneous input
- Ensuring all essential information is provided to the user
- Ensuring any error is visible to the user
- Ensuring any error can be recovered from or “reversed”
- Increasing Productivity
- Mapping task sequences and measuring performance
- Removing unnecessary steps from a task
- Creating a more efficient work-space layout
- Building better tools and equipment
- Selecting personnel with greater aptitude for the task
- Enhancing Safety
- Building defences against frequent forms of error
- Reducing the occurrence of error through training
- Removing environmental stressors
- Managing task design to reduce workload
- Increasing/reducing the information provided to operators
- Enhancing Comfort
- Redesigning the workspace to meet changing anthropometric characteristics
- Building a more intuitive interface
- Maintaining comfortable temperature and noise levels
- Increasing/reducing light levels
- Redesigning the roster to reduce fatigue
While workplace safety continues to improve, new threats, complex in nature and often not neatly labelled or transparent, will test whether the field of human factors will continue to make valuable contributions to the global workplace. Current and emerging issues include:
- Security: The ever present threat of terrorism, and the security of our significant infrastructure from extremist groups.
- Advanced Technology: Workplace accidents are continuing to cause concern from an over reliance on technology and automation. For example, we have come to the realisation that humans are notoriously unreliable monitors of systems. However, unfortunately this is exactly what automated systems and advanced technology often increasingly require of human operators; to be less of an active controller of the system and more of a passive monitor of automated systems and technology.There are three main issues emerging with advanced technology:
- Over-reliance – As the level of automation increases, the need for manual control of certain processes reduces. We may be hesitant to take over manual control if we are not confident in our ability to do so
- Automation-induced complacency – operators may be hesitant to intervene at the first signs of trouble as we have a high level of trust in the system to correct itself, and often leave it until it is too late to intervene
- Startle and surprise – this involves unexpected situations that disrupts our cognitive processing and can have a negative impact on our decision-making and problem-solving abilities
The ‘race to automate’ self-drive vehicles has brought about a number of promises and problems. In May 2016, the driver of a Tesla Model S was killed while operating the car in ‘autopilot’ mode. The accident raised questions about the safety of autopilot systems that can perform driving tasks for long periods with little or no human intervention.
The Tesla collided with a semi-trailer that had crossed the highway in front of the vehicle. The driver and the Tesla’s automated driving control system failed to detect the vehicle. An investigation found that the Tesla’s autopilot operated within its limitations, but the driver was using it in way that it was not designed for. The probable cause of the accident, cited by the NTSB (2017), read:
‘Contributing to the car driver’s overreliance on the vehicle automation was its operational design, which permitted his prolonged disengagement from the driving task and his use of automation in ways inconsistent with guidance and warnings from the manufacturer’.
The driver engaged with the steering wheel only seven times for a total of 25 seconds in the 40 minutes prior to the accident. The autopilot sensed that the driver was not engaging with the steering wheel for long periods, and issued visual and auditory warnings each time. The vehicle is designed to issue three such warnings before it automatically slows to a stop with the hazard lights on. However, on each occasion the driver engaged with the steering wheel to cancel the warning and ‘reset’ the system.
Figure 8. Rescue workers attend the scene of a Tesla electric SUV crashed in California
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