.  
physical demands it requires (e.g. strength required, etc.);

.  
mental demands it requires (e.g. complexity of decisions to be made, etc.).

.  
The circumstances under which the task is performed, such as the:

.  
standard of performance required (i.e. degree of accuracy);

.  
time available to accomplish the task (and thus the speed at which the task must be carried out);

.  
requirement to carry out the task at the same time as doing something else;

.  
environmental factors existing at time (e.g. extremes of temperature, etc.).

.  
The person and his state, such as:

.  
skills (both physical and mental);

.  
experience (particularly familiarity with the task in question);

.  
current health and fitness levels;

.  
emotional state (e.g. stress level, mood, etc.).

As the workload of the flight crew may vary, they may experience periods of overload and underload. This is a particular feature of some flights and sectors, but overloads are often unpredictable.

2.3 Overload
Overload occurs at very high levels of workload, when the individual's or crew's workload exceeds the ability to cope well. As highlighted previously, performance deteriorates when arousal becomes too high and we are forced to shed tasks and focus on key information. Error rates may also increase. Overload can occur for a wide range of reasons based on the factors highlighted above. It may happen suddenly
(e.g. if asked to remember one further piece of information whilst already trying to remember a large amount of data), or gradually. It is good practice to try to plan tasks such that the flight crew are not left with several things to be done at once, possibly during the final stages of the approach. Task management between flight crew members can reduce the likelihood of one pilot being overloaded. It is particularly important to ensure that in overload situations, it is always clear as to who is carrying out the vital task of flying the aircraft.

2.4 Underload
Underload occurs at low levels of workload (when the pilot becomes under aroused). Underload can result from a task a pilot finds boring, or indeed a lack of tasks. The nature of long-haul flights means that workload tends to come at the start and finish of a flight, with long periods of low workload in the cruise. Hence, unless stimulating ‘housekeeping’ tasks can be found, underload can be difficult to avoid at times.

Stress: Domestic and Work Related
Stress is an inescapable part of life for all of us. Stress can be defined as any force, that when applied to a system, causes some significant modification of its form where forces can be physical, psychological or due to social pressures.
　
中國航空網 www.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：CAP 737 Crew Resource Management (CRM) Training 機組資源管理培訓(44)