Human Factors in Aviation: A Brief Historical Overview

Human Factors in Aviation: A Brief Historical Overview

Anthropometry, the science of measuring the human body, plays an important role in modern industrial design, aviation, architecture, and clothing design.

At the beginning of the 1900s, industrial engineers Frank and Lillian Gilbreth developed the concept of “call back” or “repeat-back” communication to reduce human error. This is a confirmation system similar to a nurse repeating “scissors” while handing them to a surgeon after the doctor requests them, in order to prevent potential mistakes. Today, this system is still used in aviation through read-back of instructions.

With the rapid expansion of aviation over the last century, engineers working on aircraft design initially had very limited knowledge about human limitations and human error in operating these systems. By the late 1940s and 1950s, ergonomics became a central area of study.

During World War I, aircraft were very basic, with open cockpits and underdeveloped navigation systems. Pilots relied heavily on maps, often without any navigation aids. Becoming lost and landing to ask for directions was a common situation at the time.

Until the early years of World War I, aircraft were often seen as toys, and it was widely believed that they would not be useful in warfare. However, aviation technology developed rapidly during the war. By 1914, when the war began, the Wright Brothers had already achieved the first powered flight. The foundations of today’s aviation strength largely stem from the significant developments during World War I.

From the very beginning, human factors played a central role in aviation, and during wartime this influence became even stronger. At first, aircraft were used mainly for reconnaissance, but they quickly became weapons used for bombing and aerial combat. Much of today’s aviation progress is owed to the engineers and pilots of that period.

It was also reported that around 90% of aviation-related deaths at the time were not caused by engine or structural failures, but by human error (Royal Flying Corps). These findings showed that efforts needed to focus on reducing human mistakes. Military authorities criticized poor pilot selection and inadequate training. At that time, individuals who could ride horses or drive cars were often considered suitable for becoming pilots.

Pilot selection in the Royal Flying Corps (RFC) was rather informal, especially in the early years of the war. In many cases, pilots received only two to three hours of instruction before attempting solo flight. Efforts to overcome human limitations focused mainly on training pilots more effectively. However, approximately 8,000 young pilots died during training in Britain, indicating that more deaths were caused by accidents and equipment failures than by enemy action.

During this period, engineers began to focus on designing aircraft based on human performance and limitations. By the end of the war, aircraft design had become more refined, and ergonomics gained importance.

As a result, flight errors and accidents were strongly linked to judgment, cognition, and sensory perception—i.e., the human body and brain. Consequently, aviation medicine and aviation psychology emerged as scientific disciplines.

Between the World Wars

The period between World War I and World War II is often considered a “golden era” for aviation. Flight speeds increased dramatically, becoming four times faster than just a few years earlier. Navigation technologies and instruments improved significantly. Commercial aviation expanded, and aircraft were also increasingly used as military weapons. Jet engine development began in both the United Kingdom and Germany.

Due to advances in pilot selection and training, strong interest emerged in aviation medicine and aviation psychology. Studies were conducted to understand the characteristics of successful pilots and the impact of environmental stressors on flight performance. Anthropometric measurements of the human body began to be used in aircraft design.

Pilots were frequently exposed to extreme environmental conditions such as heat, cold, variable weather, poor visibility, and icing, and were expected to continue flying under such stress. Over time, meteorology advanced, and doctors, designers, and pilots worked together to develop equipment to protect against these stressors.

During World War II, two major challenges emerged in aviation human factors and ergonomics. First, large numbers of soldiers were recruited, requiring them to quickly adapt to new aircraft designs. Instead of selecting individuals for specific roles, a more general skills-based model became necessary.

Second, rapid technological advancements made it difficult for pilots to adapt, even experienced ones, leading to increased accident rates. This increased the importance of psychologists and physicians, and laboratory-based research methods were developed to solve these problems.

A major breakthrough was the use of flight simulators for training. Devices such as the Link Trainer (1939–1950) revolutionized pilot training by allowing practice of both basic and advanced procedures.

In March 1945, a flight magazine advertised the Link Trainer stating: “Lives have been saved. Aircraft preserved. Money and time saved. Programs unchanged. Military objectives achieved.”

At the end of World War II, aviation psychology began to take shape in the UK and the USA. In addition to pilot training and machine design, aircraft design problems contributing to pilot error were identified for the first time.

Post–World War II to the 1970s

During the war years, millions of data points were collected on human skills, abilities, and limitations. Human factors research expanded rapidly, using this data to improve medical and psychological standards. New psychometric tools were developed, and flight simulators became widely used. Universities began to take a leading role in research.

Research began focusing on pilots’ ability to perform under fatigue and cognitive overload. Key areas of interest included spatial disorientation, fatigue, and information processing capacity.

In 1951, Lt. Col. Paul Fitts became a leading figure in aviation psychology. His report highlighted major aviation problems of the time and criticized the exclusion of operators from the human–machine system, where design focused only on engineering aspects.

Engineers and scientists worked in isolation from each other, ignoring human perceptual and physiological limitations, cognitive processes, and motor coordination. As a result, poorly integrated systems were created.

Fitts’ report identified key human factors problems such as the human role in traffic systems, tasks exceeding human capacity, measurement of human performance, and communication deficiencies.

After the war, the growing complexity of air traffic created significant safety risks. Radar technology developed during wartime took time to be adapted for civilian use, while aviation systems lagged behind industrial progress.

On June 30, 1956, the first major commercial aviation disaster occurred in the United States when two aircraft collided mid-air, killing over 100 people. This accident led to major changes in air traffic control, including mandatory radar-based position tracking systems.

By the 1960s, aviation faced new challenges due to rapid global economic growth and increased demand for passenger and cargo transport. As automation increased, the pilot’s role shifted from “heroic operator” to “system manager.”

In 1972, a major accident attributed to pilot error occurred due to loss of situational awareness and cockpit distraction. The investigation highlighted the need for improved warning systems and better crew coordination, though the focus remained largely technical rather than human-centered.

In 1977, English language proficiency became a requirement for pilots.

In December 1978, a United Airlines DC-8 crashed due to fuel exhaustion despite having sufficient fuel. The crew became distracted by landing gear issues and failed to monitor fuel status. Investigations concluded that communication breakdown within the cockpit was a key contributing factor.

The Emergence of CRM

Following a 1979 NASA workshop, the concept of Cockpit Resource Management (CRM) was introduced by NASA psychologist John Lauber. The goal was to create a less authoritarian cockpit environment where co-pilots could question decisions and improve communication and teamwork.

In 1981, United Airlines became the first airline to implement CRM training.

By the early 1990s, CRM had become a global standard. Accident investigations increasingly identified causes such as poor crew coordination, weak leadership, communication failures, and lack of situational awareness.

CRM research emphasized situational awareness, assertiveness, leadership, decision-making, adaptability, and communication. It also promoted free flow of information within the cockpit.

Today, CRM is applied not only to pilots but also to cabin crew, maintenance teams, air traffic controllers, and airline management. It is also used in air traffic control and aircraft design.

1980s and Beyond

By the 1980s, non-technical skills were recognized as critical to flight safety. Regulatory authorities placed increasing emphasis on CRM training. Automation improved aircraft performance and reduced workload but required significant adaptation to new “glass cockpit” systems.

A 1996 accident report highlighted contributing factors such as poor flight planning, inadequate use of automation, and confusion caused by navigation systems. It also noted limitations in system design.

Fly-by-wire systems with flight envelope protection were introduced, notably with the Airbus A320 in 1987. These systems prevented pilots from exceeding safe operational limits, significantly reducing accident rates, although mode transitions sometimes caused confusion.

From the 1990s onward, regulations increasingly focused on licensing, operations, maintenance, and design from a human factors perspective. Safety culture, teamwork, and non-technical skill assessment (NOTECHS) became standard in Europe.

Threat and Error Management (TEM), introduced in the 1990s, emphasized the identification and management of operational risks. Line-Oriented Safety Audits (LOSA) were developed to observe real flight operations and identify threats and errors.

Conclusion

Today, human factors research has shifted from focusing on individuals to analyzing group and organizational behavior. Aviation accidents are now understood as resulting from both individual and systemic factors.

Human factors influence every link in aviation safety, including crew performance, aircraft design, organizational culture, and operational procedures. Continuous research continues to improve safety by reducing human error and making aviation increasingly reliable.