Fatigue Prevalence and comparison study in Portuguese Airline pilots

Fatigue Prevalence and comparison study in Portuguese Airline pilots
Cátia Reis et al [1] carried out a research to investigate the fatigue prevalence in Portuguese and compare level of fatigue between medium short haul and long haul pilots.
This research used survey study approach,giving pilots questionnaires of self-response fatigue severity scale (FSS) to measure the subjective fatigue and the perception of fatigue. The researched discovered that medium short haul pilots showed higher level of total and metal fatigue and this may contribute to further fatigue study.


1. Pretest and baseline characteristics of the validation and study of airline pilot population

Comparison between validation and study shows that the two are comparable and roughly identical regarding sample, sex, professional category, types of flight and working times.The results of the validity and reliability analysis suggested
the FSS is a reliable measure to evaluate fatigue in the study population.

2. Identifying the factor structure of the fatigue severity scale using principal component analysis.

Illustration 1. Assign questions to dimensions
Statements mental symptoms physical symptoms assignment
1. My motivation is lower when I am fatigued. 0.64 mental
2. Exercise brings on my fatigue. 0.82 physical
3. I am easily fatigued. 0.73 physical
4. Fatigue interferes with my physical functioning. 0.79 mental
5. Fatigue causes frequent problems for me. 0.58 0.52 mix of two
6. My fatigue prevents sustained physical functioning. 0.77 mental
7. Fatigue interferes with carrying out certain duties and responsibilities. 0.86 mental
8. Fatigue is among my three most disabling symptoms. 0.86 mental
9. Fatigue interferes with my work,family, or social life. 0.88 mental

3. Comparison between medium/short haul and long haul:(Mann-Whitney U).

Illustration 2. Total fatigue between medium/short haul and long haul
min max 25% 75% median
medium/short haul 2.1 6.8 4.6 5.7 5.3
long haul 1.3 6.3 4.1 5.6 4.9
Comparison U=15,772.50; P=0.001 very significant, medium/short higher
Illustration 3. Mental fatigue between medium/short haul and long haul
min max 25% 75% median
medium/short haul 2.3 7.0 5.3 6.5 6.0
long haul 1.4 7.0 4.6 6.3 5.6
Comparison U=15,882.50; P=0.001 very significant, medium/short higher

4. Concerning fatigue perception, answers to the four questions confirmed the prevalence of fatigue in pilots.


Research approach

The study used survey study approach, with questionnaires collecting data.


456 valid responses were obtained from a total of approximately 1500 commercial airline pilots. They are all on active duty, either being commanders or first Officers, age between 20 and 65 years old and all have flown during the last 6 months


validation questionnaire:a pretest of 9 questions concerning the servility of the fatigues in different situations.
final questionnaire: the final questionnaire also requested socio-demographic data, scales of psychological evaluation, and questions concerning labor conditions.


1. validation variables:
sample(quantity and age)
sex (male or female)
professional category(Commanders or first officers)
types of flight(medium/short haul or long haul or mix)
working times(duty and flight hours and sectors flown)
2. fatigue variables:
fatigue severity score range from 1 to 7


questionnaire answers including the socio-demographic data, scales of psychological evaluation(FSS) and work conditions


1. A pretest to validate the survey,answered by a sample of 104 pilots from mid-January to mid-February
2. Final questionnaire were given to pilots and collected
3. Analysis

Data analysis

1. An exploratory factor analysis was applied to the FSS scale
2. Mann-Whitney test was used to compare the fatigue levels between two groups A significance level of 5% was adopted.

Generalization potential

1. This research concluded that medium short haul pilots showed the highest level of total and metal fatigue.
2. The questionnaire study did not control the timing of the survey (questionnaires are put in the locker of the pilots), this study contains inherent subjectivity and limitations.
3. Prevalence of total and mental fatigue in pilots were observed, recommending relevant airlines or aviation authorities to adopt actions.
4. Baseline data was established and further study regarding fatigue among Portuguese pilots can be done upon this.

1. REIS Catia, MESTRE Catarina & CANHAO Helena (2013). Prevalence of Fatigue in a Group of Airline Pilots. Aviation, Space & Environmental Medicine, 2013, volume 84, number 8, pages 828-833.

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