The study of human factors is about understanding human behaviour and performance. In aviation operations, human factors knowledge is used to optimize the fit between people and the systems in which they work in order to improve safety and performance.
Human error has been documented as a primary contributor to more than 70% of commercial airplane hull-loss accidents. While typically associated with flight operations, human error is also a major concern in aircraft maintenance practices and air traffic management.
The term "human factors" has grown increasingly popular as the commercial aviation industry has realized that human error, rather than mechanical failure, underlies most aviation accidents and incidents. In commercial aviation, human factors are often considered synonymous with crew resource management (CRM).
Errors can be broadly distinguished in two categories:
Execution failure can be split into slips (attention troubles) and lapses (memory troubles):
Planning failures can be split into rules based mistakes and knowledge based mistakes:
In the IVAO network, interruptions and distractions are usual threats generated in the operating environment that affect or complicate the performance of a task or a crew's compliance with applicable standards.
Here are the results of a nice study of the effects of distractions and interruptions in approach and landing accidents:
| Factor | % of events |
|---|---|
| Omission of action or inappropriate action | 72 |
| Inadequate crew coordination, cross-check and backup | 63 |
| Insufficient or loss of lateral or vertical situational awareness | 52 |
| Inadequate or insufficient understanding of prevailing conditions | 48 |
| Slow or delayed action | 45 |
| Incorrect or incomplete pilot/controller communications | 33 |
An interruption/distraction often leaves the flight crew with a feeling of being rushed and faced with competing tasks of varying priority. This can result in an increase in workload even when the actual task load is reasonable and steady. As a result, a crew faced with concurrent task demands will typically focus on one or a few tasks while ignoring all others. This response is typical of most people when dealing with excessive workload.
The following are examples of unsafe situations resulting from interruptions and distractions:
Some interruptions and distractions are difficult to detect. The first priority must be to recognize that a disruption has occurred. Once you are aware that the normal flow of activities has been interrupted, the second priority is to re-establish situational awareness. This is accomplished through the following steps:
Pilots sometimes may deviate due to different factors like:
Errors in using automatic flight systems and insufficient knowledge of these systems are contributing factors in landing accidents and approach incidents. The following factors are cited when discussing errors using automatic systems are:
The following factors are cited when discussing the problems of understanding in communication:
The following factors are cited when discussing non-stabilized approaches:
The following factors are cited when discussing runway overruns:
The importance of briefing techniques is often underestimated and sometimes not performed by non-experienced crew.
Routine and formal repetition of the same information on each flight may create a sensation of counterproductive task, but adapting and expanding the briefing should help the pilot flying to know the sequence of events and actions, and the special hazards of the flight phase concerned.