DOT/FAA/AM-16/6

Office of Aerospace Medicine

Washington, DC 20591

Evaluation of Fatigue and 

Responsibilities of Cargo 

Supervisors and Flight 

Mechanic Cargo Supervisors

Michelle R. Bryant

Thomas E. Nesthus

Crystal Rowley

Civil Aerospace Medical Institute 

Federal Aviation Administration 

Oklahoma City, OK 73125

August 2016

Final Report
NOTICE

This document is disseminated under the sponsorship of 

the U.S. Department of Transportation in the interest of 

information exchange. The United States Government 

assumes no liability for the contents thereof.

___________

This publication and all Office of Aerospace Medicine 

technical reports are available in full-text from the 

Civil Aerospace Medical Institute’s publications website: 

http://www.faa.gov/go/oamtechreports
i 

Technical Report Documentation Page 

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.

DOT/FAA/AM-16/6

4. Title and Subtitle 5. Report Date

Evaluation of Fatigue and Responsibilities of Cargo Supervisors and

Flight Mechanic Cargo Supervisors

August 2016

6. Performing Organization Code

7. Author(s) 8. Performing Organization Report No.

Bryant MR, Nesthus TE, Rowley C

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)

FAA Civil Aerospace Medical Institute

P.O. Box 25082

Oklahoma City, OK 73125

11. Contract or Grant No.

12. Sponsoring Agency name and Address 13. Type of Report and Period Covered

Office of Aerospace Medicine

Federal Aviation Administration

800 Independence Ave., S.W.

Washington, DC 20591 14. Sponsoring Agency Code

15. Supplemental Notes

16. Abstract

In response to an open National Transportation Safety Board (NTSB) recommendation (2016; A-15-014) 

and at the request of the Federal Aviation Administration’s (FAA’s) Aircraft Maintenance Division (ASF300), a study was conducted to document the current rest and fatigue status of cargo load supervisors as well 

as collect information regarding the perceived responsibilities of load supervisors while performing regular 

duties. A total of four organizations agreed to have researchers observe daily cargo operations and recruit 

participants for each of the three studies: (a) a general fatigue survey, (b) a 14-day field study, and (c) a twohour interview. Findings supported previous research on fatigue risk in shift workers and indicated that load 

supervisors were at risk of fatigue on all seven primary and contributing factors of fatigue: Time of day, 

Time awake, Time on task, Time asleep, Adequate sleep, Work schedule factors, and Cumulative sleep debt. 

Night shift load supervisors exhibited a greater risk of fatigue than their day shift counterparts. Interviews 

revealed that load supervisors perceived a majority of their responsibilities to be shared with cargo 

personnel, as opposed to holding sole responsibility. Recommendations include fatigue awareness training, 

monitoring of load supervisor duty/rest times inclusive of overtime, the use of Safety Management Systems 

(SMS) and Fatigue Risk Management Systems (FRMS) to reduce risk, and having clearly defined roles and 

responsibilities for load supervisor duties.

17. Key Words 18. Distribution Statement

Fatigue, Cargo, Responsibilities, Risk Mitigation Document is available to the public through

the Internet:

http://www.faa.gov/go/oamtechreports/

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price

Unclassified Unclassified 21

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized 
Contents
 

EVALUATION OF FATIGUE AND RESPONSIBILITIES OF CARGO SUPERVISORS 

AND FLIGHT MECHANIC CARGO SUPERVISORS 

INTRODUCTION....................................................................................................................................................................1
 

Roles and Responsibilities of Load Supervisors................................................................................................................1
 

Research Questions................................................................................................................................................................1
 

METHOD ...................................................................................................................................................................................1
 

General Fatigue Survey..........................................................................................................................................................2
 

14-Day Field Study.................................................................................................................................................................2
 

Daily log ..............................................................................................................................................................................2
 

Psychomotor vigilance test...............................................................................................................................................2
 

Actigraphy device...............................................................................................................................................................3
 

Training procedure ............................................................................................................................................................3
 

Interviews ................................................................................................................................................................................4
 

Interview procedure ..........................................................................................................................................................4
 

Participant Overview .............................................................................................................................................................4
 

General fatigue survey participants.................................................................................................................................4
 

Field study participants .....................................................................................................................................................5
 

Interview participants........................................................................................................................................................5
 

RESULTS.....................................................................................................................................................................................5
 

Sleep Data................................................................................................................................................................................5
 

Time of day.........................................................................................................................................................................5
 

Time awake .........................................................................................................................................................................5
 

Time asleep .........................................................................................................................................................................6
 

Adequate sleep ...................................................................................................................................................................6
 

Work schedule and alertness............................................................................................................................................7
 

Cumulative sleep debt.......................................................................................................................................................8
 

Summary of Sleep Data.........................................................................................................................................................9
 

Interview Data ........................................................................................................................................................................9
 

Perception of responsibility .............................................................................................................................................9
 

DISCUSSION...........................................................................................................................................................................12
 

Current Rest/Duty Schedules ............................................................................................................................................12
 

Shifts ..................................................................................................................................................................................12
 

Flying with cargo..............................................................................................................................................................13
 

Current Fatigue Risks ..........................................................................................................................................................13
 

Current Duty Responsibilities ............................................................................................................................................14
 

Study Limitations..................................................................................................................................................................14
 

SUMMARY ...............................................................................................................................................................................14
 

REFERENCES.........................................................................................................................................................................15
 

APPENDIX A............................................................................................................................................................................1
 

APPENDIX B ............................................................................................................................................................................1
 

APPENDIX C ............................................................................................................................................................................1
 

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EVALUATION OF FATIGUE AND RESPONSIBILITIES OF CARGO
 

SUPERVISORS AND FLIGHT MECHANIC CARGO SUPERVISORS
 

INTRODUCTION 

On April 29, 2013, a Boeing 747-400 cargo jet 

crashed just after takeoff. All crewmembers onboard 

died, and the airplane was destroyed. Improper cargo 

loading was the primary contributing factor to this 

event. As a result of the accident investigation, the National Transportation Safety Board (NTSB) recommended the FAA create a certification for personnel 

responsible for the loading, restraining, and documentation of special cargo loads (2016; A-15-014). Included in 

the NTSB report was a recommendation that the certificating process include information regarding procedures, training, and duty/rest hours consistent with other safety-sensitive, certificated positions. The FAA’s 

Aircraft Maintenance Division (AFS-300) has assigned 

the Cargo Focus Team to support this effort. The team 

requested a preliminary study of the current duty/rest 

times and responsibilities associated with cargo load 

supervisors for cargo-only operations. A small sample 

was recruited to explore possible patterns and trends of 

cargo load supervisors that may mirror patterns and 

trends found in similar studies of shift workers in the 

aviation industry. This report documents: (a) the current 

rest and fatigue status of cargo load supervisors, and (b) 

load supervisor’s perceived job responsibilities. 

Roles and Responsibilities of Load Supervisors 

Cargo loading is managed and/or supervised by 

load supervisors. The load supervisor must be present 

to oversee the sequencing, loading, securing, and distributing of weight of the cargo; calculate the cargo restraint requirements; calculate the weight and balance of 

the aircraft given the cargo, passenger, and fuels 

weights; and prepare the load manifest prior to flight. 

The cargo can range from standard unit load devices to 

unique items called “special cargo,” which may require 

restraining the cargo directly to the aircraft structure. 

Examples of this type of special cargo include munitions, aircraft engines, and large equipment such as tractors, oil rigging equipment, or heavy military vehicles. 

In some instances, the load supervisor and/or 

maintenance personnel (e.g., flight mechanics) accompany the aircraft on long extended missions. The requirements to have personnel on board the aircraft are 

driven by the uncertainty of destinations, ground support, and mission requirements. The load supervisor is 

responsible for the duties previously mentioned and 

other flight and cargo safety issues often specific to a 

particular aircraft. The flight mechanics are present to 

ensure servicing, maintenance, and inspection applicable 

to the aircraft. In some operations, the flight mechanic 

may also perform the duties of the load supervisor. The 

availability of the load supervisor and flight mechanic 

are particularly critical when qualified personnel are 

simply not available at remote locations. 

One of the challenges associated with 24/7 operations, such as cargo loading and maintenance, is fatigue. 

The load supervisors often work in shifts and work long 

hours. The load supervisor and flight mechanics who 

accompany the aircraft often arrive at remote locations 

and proceed immediately to work, while flight crews are 

headed to quarters for appropriate sleep/rest. 

Research Questions 

In response to the research request, a study was 

conducted to gather information concerning work 

schedules and fatigue in load supervisors and flight mechanics. The purpose of this study was to determine: 

1. What are the current rest/duty schedules of load 

supervisors and flight mechanics? 

2. What are the current fatigue risks present for load 

supervisors and flight mechanics? 

3. What are the current duties and responsibilities of 

load supervisors in the field? 

A total of six cargo-only certificate holding organizations were contacted to request participation. Four 

organizations agreed to allow researchers to observe 

daily cargo operations and to recruit participants for 

each of the three studies included in this report: (a) a 

general fatigue survey, (b) a 14-day field study, and (c) a 

two-hour interview. Those personnel who were identified as a load supervisor or flight mechanic had the opportunity to participate in all three studies. 

METHOD 

One principal investigator (researcher) and one research technician (assistant) travelled to two U.S. locations for a one-week period at each location. Throughout these visits, the researchers briefed management on 

the goals and outcomes of the study and recruited, observed, trained, and collected data from participants. 

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Table 1 

Sample Questions from the General Fatigue Survey 

Question categories Example questions 

Shiftwork History • Are you currently working shift work? 

• How many years have you worked shifts? 

Duty/Rest Time • How many hours of overtime do you typically work? 

• How often do you work overtime? 

• What is your average one-way commute time to your cargo loading job? 

Sleep and Fatigue • Do you often have difficulty falling asleep? 

• Do you frequently awaken in the night? 

• Do you drink beverages with caffeine within 5 hours of trying to sleep? 

Health and Wellbeing • Do you exercise on a regular basis? 

• Please describe your typical diet/eating pattern. 

• Have you suffered from (diagnosed by your doctor) any of the following medical conditions? 

Coping • To what extent does working shifts cause you problems with sleep, social life, domestic 

life, or work performance? 

• To what extent do you use the following strategies when you have problems caused by 

working shifts? 

Work Environment • To what extent do you feel your cargo organization facility adjusted scheduling to minimize fatigue? 

• What type of training or information has your airline provided you regarding fatigue? 

• What operational changes would you recommend to reduce your risk of fatigue? 

Circadian Type • Do you tend to need more sleep than other people? 

• If you had to do a certain job in the middle of the night, do you think you could do it 

almost as easily as you could at a more normal time of day? 

• If you have a lot to do, can you stay up late to finish it off without feeling too tired? 

Demographics • Please indicate your primary role/position. 

• What is your age? 

• How long have you worked in your current position? 

General Fatigue Survey 

A general fatigue survey was compiled and modified 

from three previously administered studies regarding 

fatigue and shift workers in the aviation industry (Barton, et al., 1995; Hall, Johnson, & Watson, 2001; 

Nesthus, Schroeder, Connors, Rentmeister-Bryant, & 

De Roshia, 2007). The survey questions focused on 

general information regarding shiftwork history, duty/rest times, health and wellbeing, coping, work environment, circadian type, and demographic data. Table 1 

lists each category and example questions from each. 

The items listed in this table are not exhaustive of all 

questions asked. 

14-Day Field Study

Daily log. In the 14-day field study, participants 

were asked to log their daily activities twice a day for 

each of 14 days using a mini iPad®. This log was similar 

to those used in previous fatigue research (Cruz & Della 

Rocco, 1995; Cruz, Detwiler, Nesthus, & Boquet, 2003). 

Participants were instructed to fill out their log within 40 

minutes of waking and the second log was to be entered 

at least 30 minutes prior to lying down for sleep. Daily 

activities such as type of day, sleep and wake times, 

mood, food and beverages ingested, symptoms, medication taken, as well as any additional comments the participant had were all included. Table 2 provides the categories of questions as well as sample items for each. 

The items listed in this table are not exhaustive of all 

questions asked. 

Psychomotor vigilance test. In addition to the 

daily log, participants were asked to complete a 5­

minute Psychomotor Vigilance Test (PVT) using the 

mini iPad® twice a day: once upon waking, and once just 

before bed. This measure has been used in previous research (e.g., Roma, Hursh, Mead, & Nesthus, 2010), is 

considered the “gold standard” of alertness measurement in fatigue studies (Basner & Dinges, 2011), and 

has been used as a measurement of alertness in a myriad 

of studies including aviation, space, and other industries 

that include 24/7 operations such as the trucking, rail 

road, and coal mining industries. Sleep loss and fatigue 

studies have shown PVT data to accurately reflect alertness associated with sleep loss and circadian 

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Table 2 

Sample Questions from the 14-day Daily Field Log 

Question categories Example questions 

Day Details • Is today a workday, day off, office work, inspection day, etc.? 

Sleep/Wake • What time did you awaken? 

• What time did you arise? 

• What time did you go to bed? 

• What time did you fall asleep? 

• Please indicate how deeply you slept last night. 

• Please indicate how rested you feel right now. 

Mood • How interested do you feel right now? 

• How alert do you feel right now? 

• How attentive do you feel right now? 

Food • List the meals/snacks you had today, please indicate what time and quantity as well. 

Symptoms • Did you experience any of the following symptoms today, headache, backache, nasal 

congestion, light-headedness, etc.? 

Medication • Did you take any prescription or over-the-counter medications today? If so, please indicate the name, time, and dosage. 

Miscellaneous • Is there anything about today which sets it apart from any other day? 

rhythm. Vigilant attention is an important factor in safe 

performance. Thus, measurement of reaction time upon 

waking and prior to sleeping provided an indicator of 

performance at different points in a participant’s circadian rhythm and represented an indicator of effects of 

sleep differences on performance. 

There are three primary measures when PVT data 

are collected. First, simple reaction time to the stimulus 

is measured and response speed is calculated. Reaction 

time is the time it takes for the participant to react when 

the stimulus is presented. Therefore, a lower time measured indicates faster reaction time and thus, better performance. Reaction time is used to calculate response 

speed where the reciprocal of the reaction time (1/RT) 

is examined and represents how quickly the participant 

responded to the stimuli. Response speed is a standard 

measure used to interpret PVT data. Thus, the higher a 

participant’s speed, the better their performance (the 

inverse of reaction time). Second, the number of times 

participants miss the stimulus entirely is represented by 

lapses. This measure is the ultimate measure of alertness 

wherein missing the stimulus or responding slower than 

500 m/s (lapsing) is equivalent to not attending to the 

task (Basner, Mollicone, & Dinges, 2011). Third, to determine those who are at risk of lapsing, the slowest 

10% of responses are reported. This measure represents 

those who may be at risk of fatigue simply due to how 

slowly they responded to the stimulus. 

Actigraphy device. An actigraphy device was worn 

by all participants to measure daily activity with an accurate accelerometer designed for long-term monitoring of 

motor activity. This measure has been used in previous 

research as an objective measure of sleep/wake activity 

(Signal, Gale, & Gander, 2005). Participants wore the 

watch-like device on their non-dominant hand for the 

duration of the 14 days of study. Participants were instructed to remove the device for water/liquid-related 

activities (e.g., showering, washing dishes, the need to 

submerge their hand/arm in liquids for work-related 

activities). Once the water/liquid activity was complete, 

participants were instructed to put the device back on. 

The actigraphy device was used to determine each participant’s hours of sleep, sleep latency, and overall sleep 

quality. For the purposes of this report, only the number 

of hours of actual sleep is reported. 

Training procedure. All participants were provided an informed consent form in which the study purpose, duties, and duration were all explained. Once participants acknowledged and consented to participating, 

they were issued a hand-held electronic device (mini 

iPad®) and the actigraphy watch. The researcher then 

trained participants on the daily procedure of logging 

their information. In addition, participants were trained 

to complete the PVT application on the mini iPad®. The 

PVT was to be completed at the same time participants 

filled in their log each day. Upon completion of training, 

participants were provided multiple avenues (e.g., email, 

phone) to contact the researcher for the duration of the 

study. At the end of the study, participants returned all 

equipment in a pre-paid envelope via overnight mail. 

Data were confirmed and uploaded. Upon final review 

of hours (i.e., verification that logs were entered and 

PVT tests were completed at the specified times), participants were compensated for their time. 

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Figure 1. A sample of responsibilities identified and the percent to which load supervisors may perceive that responsibility as 

their own. For example, “What percentage of the time are you responsible for the job functions of your subordinates and direct 

them accordingly?” 

Interviews 

Data were gathered to support the perceived responsibilities of load supervisors while on duty. These 

data were collected via 2-hour, one-on-one, structured 

interviews. Interviewees were asked a list of 43 questions based on a database search of the most common 

responsibilities for load supervisors (see Table 6 for the 

full list). Participants were asked to estimate the percentage of responsibility the load supervisor has for 

each task listed (Figure 1). For example, participants were 

asked, “About how much of the time are you responsible 

elaboration or further clarification of the answers. All 

interviews lasted between 60 and 90 minutes. 

Participant Overview 

Participants across each of the three studies were all 

male. The age distribution of participants is displayed in 

Figure 2. A majority of respondents reported between 1 

and 5 years of experience in their current position, with 

between 1 and 30 years in the industry overall. 

50 44.4% 

for maintaining a sufficient workforce while on duty?” A 

participant may answer, “About 30% of the time.” 

Additionally, interview participants were asked to 

answer questions regarding their past work experience, 

cargo type experience (e.g., special cargo, live animals, 

etc.), how a cargo loading team divides responsibility, 

and the load supervisor’s duty/rest time. Participants 

were also asked to rate their subjective workload and 

stress experienced on the job using a continuous analog 

scale anchored from 0 to 100. Finally, participants were 

Percent of Participants 40 

30 

20 

10 

11.1% 11.1% 

33.3% 

0 

asked about the use of rest facilities while flying with 

cargo. Each section of the interview was intended to 

understand the daily descriptions of the duties and responsibilities of load supervisors, while also placing 

those descriptions within the context of their workday. 

Interview procedure. All participants were provided an informed consent form in which the study purpose, duration, and conclusion were explained. Once 

participants acknowledged and consented to participat18-25 years 26-30 years 31-35 years 46-50 years 

Figure 2. Percent of participants across age groups for all three 

studies. 

General fatigue survey participants. A total of 15 

participants were recruited to participate in a General 

Fatigue Survey (Table 3). Three participants returned 

study equipment without completing the General Survey. Two participants’ data were incomplete, in that they 

did not fill out the entire survey (i.e., less than half). Of 

ing, their permission was requested to audio record the 

session. All participants agreed to be recorded at which 

the four participating cargo organizations (carriers), one 

(Carrier C) did not employ load supervisors for their 

time the interview began. The items outlined above operations. Rather the ground operations supervisor 

were asked in a semi-structured interview format. This performed the duties associated with load supervisor 

means that while most questions were pre-planned, responsibilities. This participant did not choose to parthere were instances where the researcher asked for ticipate in the general fatigue survey. 

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Table 3 

Demographic Characteristics of General Survey Participants 

General 

Survey Carrier N Day Shift 

Night 

Shift LS FM 

A 4 2 2 3 1 

B 3 1 2 3 0 

C 0 0 0 0 0 

D 3 2 1 3 0 

Total 4 10 5 5 9 1 

*Note: Load Supervisor (LS), Flight Mechanic (FM) 

Day shift and night shift Ns were computed by the 

observed sleep and wake times reported daily. Participants were then assigned the shift that they typically 

worked while participating in the field study. 

Field study participants. A total of 15 participants 

were recruited to participate in the 14-day log study. 

Three participants returned study equipment without 

completing the full 14 days. One participant’s data was 

incomplete in that the data provided were not consistent 

enough to warrant inclusion. Therefore, a total of 11 

participants were included in the final data analysis (Table 4). Of the four carriers, one (Carrier C) did not employ load supervisors for their operations. Rather, the 

Ground Operations Supervisor performed the duties 

that would be associated with load supervisor responsibilities. This participant was included in the interviews 

but did not participate in the 14-day field study. 

Table 4 

Demographic Characteristics of Field Study Participants 

Field Day Night Carrier N LS FM Study Shift Shift 

A 6 4 2 5 1 

B 2 1 1 2 0 

C 0 0 0 0 0 

D 3 0 3 3 0 

Total 4 11 5 6 10 1 

*Note: Load Supervisor (LS), Flight Mechanic (FM) 

Interview participants. The same cargo carriers allowed their load supervisor personnel to participate in a 

two-hour interview regarding the responsibilities of a 

load supervisor. A total of nine participants were interviewed (formally or informally) as to the responsibilities 

and duties associated with the load supervisor position 

(Table 5). Two participants were informally interviewed 

while the researcher observed normal duty time operations. Therefore, the information collected pertained to 

specific scenarios and operations and was constrained to 

the timing and events occurring in real time. In these 

instances, it was not possible to ask these individuals all 

of the formal interview questions. 

Table 5 

Demographic Characteristics of Interview Participants 

Day Night Interview Carrier N Shift Shift 

A 4 3 1 

B 1 1 0 

C 

D 

1 

3 

1 

2 

0 

1 

Total 4 9 7 2 

RESULTS 

Sleep Data 

Night shift load supervisors in this study were 

found to be at risk of fatigue on each of three primary 

contributing factors: Time of day, Time awake, and 

Time asleep. That is, night shift load supervisors’ behaviors appear to follow similar patterns and trends of larger fatigue studies on each of the primary contributing 

factors (See, Della Rocco & Nesthus, 2005 for review). 

Time of day. Alertness and fatigue fluctuate as a 

function of time of day, i.e., in response to changes in 

the circadian rhythm. Fatigue is, when present, most 

severe between 2:00 a.m. and 6:00 a.m. (Folkard, 1996). 

Observations conducted by the principal investigator 

while collecting data found that the average start time 

for the night shift was 10:00 p.m. while day shift workers average start time was 8:00 a.m. Previous research 

has shown that start time prior to 9:00 a.m. resulted in 

decreased overall sleep time and quality, alertness reduction, and vigilance performance decrements in pilots 

(Simons & Valk, 1999, from Della Rocco & Nesthus, 

2005). Based on the field log data, night shift load supervisors primarily worked a “4-on-4-off” schedule (i.e., 

working 4 days at 10 hours each, then having 4 days off) 

while day shift load supervisors averaged working 5 days 

a week for a duration of 8 hours. Though night shift 

workers may be accustomed to the “4-on-4-off” schedule, research shows that these disruptions in schedule 

result in disruptions to the circadian rhythms can result 

in more than just decreased alertness (Monk, Folkard, & 

Wedderburn, 1996, from Della Rocco & Nesthus, 2005) 

but can also have negative long-term health effects as 

well (Costa, 1999, from Della Rocco & Nesthus, 2005). 

Time awake. When people have been continually 

awake for a long period of time, they are more likely to 

be fatigued. Figure 3 shows what the average day and 

night shift workers’ “day” looked like when the reported 

work hours (from Field Study), overtime hours (General 

Fatigue Survey), recorded sleep times (actigraphy device), and commute times (General Fatigue Survey) were 

included. 

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Day Shift Night Shift
 

1 

8.0 

8.3 

6.7 Commute 

Work and OT 

Personal 

Sleep 

1.5 

3.7 12.7* 

6.1 

Figure 3. The average day of load supervisors and flight mechanic by shift. Data were combined across studies. Personal time was 

calculated by summing commute, work and overtime, and sleep times, then subtracting that total from 24 (hours in a day). 

*Note: Given the ”4-on-4–off” schedule of the night load supervisor included in this study, 4 workdays would be at least 40 hours, with the remaining overtime 

allotted to a day off. This would increase the night load supervisor’s work week by one full day as opposed to their day shift counterparts. 

Time asleep. Getting less than 8 hours of sleep in 

the past 24 hours means one is more likely to be fatigued (Carskadon & Roth, 1991). A majority of load 

supervisors in this study reported sleeping less than 6 

hours the night prior to the study date (Figure 4; General Fatigue Survey). This was also found to be the case 

in previous research conducted by Johnson Hall, & 

Watson (2001) where maintenance personnel reported 

an average of 5 hours per night. Compared to the Bureau of Labor Statistics (2014), these personnel reported 

sleeping roughly two hours less than their working 

counterparts. 

37.5% 37.5% 40 

cadian low. Sleep should not be fragmented with interruptions (reducing sleep quality). In addition, environmental conditions, such as temperature, noise, and light, 

impact how beneficial sleep is and how performance is 

restored (Della Rocco & Nesthus, 2005). Sleeping during the daytime has also been found to be shorter in 

duration, more disrupted, and less restorative (Knauth 

& Rutenfranz, 1982). 

Actigraphy data collected from1 load supervisors in 

this study found that night shift workers both slept less 

and awoke consistently more frequently during their 

daytime sleep period than their day shift counterparts 

who sleep during the nighttime (Figure 5 and Figure 6, 

respectively). 

Percent of Participants35 

30 

25 

20 

15 

10 

5 

9:36 

8:24 

25% 

8:07 

7:34 

6:41 

6:05 

Actual 3:36 

Hours and Minutes 7:12 

6:00 

4:48 Reported 

0 

Less than 5 5 hours but 7 hours but 

hours less than 6 less than 8 2:24 hours hours 

Figure 4. Percent of participants and their reported sleep for 

the night prior to taking survey as reported in the General 

Fatigue Survey. No participant responded they had 6 hours 

but less than 7 hours of sleep the previous night. 

Adequate sleep. Research has consistently demonstrated that adequate sleep of around 8 hours sustains 

performance (Dinges, Graeber, Rosekind, Samel, & 

Wegmann, 1996). Sleep during the nighttime is preferable because it provides the most recuperative value due 

to the fact that sleep is occurring during the normal cir1:12 

0:00
 

Day Night
 

Figure 5. Mean hours of sleep duration by shift (Daily Log) 

for reported sleep hours and actigraphy sleep hours (actual). 

1 Given the small sample, descriptive and frequency counts 

were used to observe possible differences between day and 

night shift load supervisors for all actigraphy data. 

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Actigraphy Recorded Awakenings

20 

18 

16 

14 

12 

10 

8 

6 

4 

2 

13.6 

19.1 

Day 

Night 57 58 58 56 

43 

47 

39 44 

0 

10 

20 

30 

40 

50 

60 

70 

80 

90 

100 

Difficult/Poor Easy/Good 

Day 

Night 

0 

Day Night Ease of Slept Ease of Rested 

Falling Deeply Getting 

Figure 6. Actigraphy results of mean number of awakenings 

during sleep by shift.
 

Differences between data shown in Figure 4 and 

Figure 5 may be related to several factors. First, data 

collected regarding the previous night’s sleep (Figure 4) 

was asked at the outset of the study. Therefore, participants may have given a more representative answer of 

their actual sleep length. Second, data collected regarding the average reported sleep (Figure 5) was asked as 

the study progressed through the 14 days. It is possible 

that participants became more aware of their sleep habits and over-estimated their sleep schedules based on 

knowledge gained about the risks of getting too little 

sleep. This bias is not uncommon in research studies 

(see Fisher, 1993 for examples) and is a primary reason 

why collecting objective data (via actigraphy and PVT 

data) are required elements of sleep research. 

According to field log data, when asked on a continuous scale from 1 to 100, night shift load supervisors 

also reported consistently lower quality of sleep when 

compared to day shift load supervisors (Figure 7). These 

awakenings include times in which the participant may 

not have been aware of the awakened state, but that 

according to the accelerometer readings, the individual 

was moving at a frequency consistent with wakefulness. 

It is also important to note that these values were not 

skewed by one or two individuals but are representative 

of the participants overall. 

Work schedule and alertness. The work schedule 

of an individual can also affect sleep and subsequent 

alertness (Knauth, 1993 as cited in Della Rocco & 

Nesthus, 2005). These include early morning start times, 

extended work periods (over 8 hours), insufficient time 

off between work periods (e.g., 8-hour quick turns), insufficient recovery time off between consecutive work 

periods, amount of work time within a shift or duty peAsleep Up 

Figure 7. Mean ratings of sleep quality by shift as reported in 

Daily Logs. Participants were asked to rate on an anchored, 

continuous scale from 0 to 100 for each item. 

riod (e.g., without breaks), number of consecutive work 

periods, night work through one’s window of circadian 

low, daytime sleep periods, and day-to-night or night-today transitions (as cited in Della Rocco & Nesthus, 

2005). The load supervisors in this study reflected what 

would be expected of typical shift workers with regard 

to alertness. 

Response speed. A post-hoc multivariate analysis 

showed a significant effect of shift on response speed 

(F(1)= 34.08, p<.001) where night shift personnel responded faster than day shift overall even when day 

shift reported sleeping longer. Additionally, the post-hoc 

analysis revealed a significant Time by Shift interaction 

for response speed (F(1)=8.25, p=.005; Figure 8). That 

is, day shift response speeds were faster upon waking, 

than before bed, while night shift response speeds were 

faster before bed than upon waking. This finding supports the previous statements regarding the effects of 

the circadian rhythm. For example, it appears that day 

shift workers’ alertness predictably declined over the 

time of their shift, whereas night shift workers’ alertness 

did not. Given that the average time their night shifts 

ended was 8 a.m. (as recorded through researcher observations), participants were outside of the “window” 

for fatigue risk (between 2 a.m. and 6 a.m.) and were 

likely experiencing the normal rise in alertness associated with their body clock (i.e., circadian rhythm). Additionally, there may be more factors such as environmental cues (i.e., shift changes where an increase in interactions between people occurred, etc.), which may have 

contributed to this result. 

7
 
t 

Series1

Series2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

eries1

eries2

Series1

Series2

S 

S 

5 5 

4 4 

3 3

Response Speed (1/RT)

Response Speed (1/RT)

Day 

Night 2 

1 

Day 

2 Night 

1 

0
 

Upon Wake Before Bed
 

Figure 8. Response speed (1/RT) by shift at waking and at 

bedtime. Higher reaction speed (faster) indicated better performance. 

Lapses. A lapse is defined as a response longer than 

500 m/s. In post-hoc testing, there was a significant 

effect of shift in reaction time lapses (F(1)=31.35, p 

<.001) where day shift lapsed significantly more than 

night shift overall. Additionally, a significant Shift by 

Time interaction for lapses was shown (F(1) =6.174, p 

<.05; Figure 9). That is, day shift lapsed less upon waking, than before bed, while night shift lapsed more upon 

waking than before bed. This indicated that day shift 

was more alert upon waking, than before bed, while 

night shift appeared more alert at bedtime. This finding 

supports that the performance of each shift was not 

simply due to one group having a faster time than another, but that each group lapsed predictably when 

compared to their response speed. It also supports sleep 

research (Folkard & Tucker, 2003), which suggests that 

night shift alertness does not decline in a predictable 

pattern when compared to day shift alertness. 

12 

0
 

Upon Wake Before Bed
 

Figure 10. Lowest 10% response speed (1/RT) by shift at waking and at bedtime. Lower response speed (slower) indicated 

poorer performance. 

Slowest response speeds. Finally, post-hoc tests revealed 

a significant shift effect for the slowest 10% of responses (F(1)= 27.30, p <.001) where day shift responses 

were slower than night shift overall. Additionally, a significant Shift by Time interaction was revealed for the 

slowest 10% of responses (F(1) =6.174, p <.05; Figure 

10). That is, of the slowest 10% of responses, the day 

shift responded faster upon waking than before bed. In 

contrast, the night shift’s slowest responses were worse 

upon waking than before bed. This supports the previous two PVT findings reported, which indicate that day 

shift alertness and fatigue risk followed a predictable 

pattern, whereas night shift did not. 

Cumulative sleep debt. Essentially, cumulative 

sleep debt is the difference between the amount of sleep 

a person received over the past several days and the 

amount of sleep one would have received if they had 8 

hours of sleep per night (Van Dongen, Rogers, & Dinges, 2003). At the end of a work-week with an accruing 

sleep debt, you are more likely to be fatigued. This is 

especially true for those personnel who work overtime, 

double shifts, or with inconsistent schedules. When a 

Frequency of Lapse 10 

8 

6 

4 

2 

0 

Upon Wake Before Bed 

Day 

Night 

person has accumulated a sleep debt over the workweek, recovery sleep is necessary to fully restore the 

person’s “sleep reservoir.” Recovery sleep should occur 

during at least one nighttime, that is, one sleep period 

during nighttime hours in the time zone in which the 

individual is acclimated. The average person’s recovery 

sleep (dependent on the amount of cumulated sleep 

debt; Pejovic et al., 2013) should be 9 hours or more to 

recover from a sleep debt (as cited in Della Rocco & 

Nesthus, 2005). The numbers reported in this study are 

well below these minimums. 

The load supervisors in this study reported both 

their work days and days off were different depending 

Figure 9. Number of lapses by shift at waking and at bedtime. 

More lapses (slower than 500 m/s) indicated decreased alerton which shift they worked. For example, day shift 

workers typically worked overtime by adding time to the ness. beginning or end of their shifts. However, night shift 

workers (in this study, a majority worked “4-on-4-off”) 

8 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

often worked on their days off in addition to extending 

their workdays. This pattern of reported work times 

indicated that the work days represented in Figure 3 for 

night shift load supervisors, adds one extra 12-hour day 

to their condensed schedule and may not allow for 

enough restorative sleep to make up for the cumulative 

sleep debt accruing during their work week. In fact, 

these data highlight the heightened risk of those load 

supervisors who work night shifts and consecutive, regular overtime as being at the greatest risk of fatiguerelated mishaps than their day shift counterparts. 

Summary of Sleep Data 

There are seven primary risk factors associated with 

fatigue: Time of day, Time awake, Time asleep, Amount 

of recent sleep, Adequate sleep, Work schedule factors, 

and Cumulative sleep debt (see Folkard, 1996; Monk, 

1990 for reviews). On all seven factors, load supervisors 

were found to be at risk of fatigue. The pattern of alertness found for nightshift load supervisors is supported 

in the scientific literature, however was contrary to how 

load supervisors reported their alertness. That is, in this 

study when load supervisors were asked to report their 

alertness levels at the start and end of their day, both 

day and night shift reported being more alert upon waking. However, PVT measures showed that night shift 

load supervisors were actually less alert at waking. It is 

important to note that people respond to fatigue factors 

a little differently and may become more fatigued at different times and to different levels of severity under the 

same circumstances (Della Rocco & Nesthus, 2005). 

However, the data collected and reported in this report 

indicate that while load supervisors reported feeling fatigued at times while on duty, they reported that it was 

not an issue they felt contributed to their performance. 

This means that based on the data collected, they did 

not know when they were most susceptible to fatigue, 

nor were they taking appropriate steps to reduce their 

risk of experiencing fatigue. By comparison, a study 

conducted by Belenky et. al, (2003) found that long-haul 

truck drivers who got less than 7 hours of sleep a night, 

also experienced decreased performance. In addition, 

they found that those who obtained 6 to 7 hours of 

sleep over consecutive nights cannot recover as quickly 

as someone who has been deprived of sleep for just one 

night. Further, research supports that those who are 

sleeping in the day time are experiencing less quality of 

sleep than those sleeping during traditional night hours 

(Akerstedt, 2003). In a follow up study, Akerstedt and 

Wright (2009) found that night shift workers were experiencing shorter sleep times and higher risk of crashes 

with lower productivity when compared to day and 

swing shifts. These comparisons show that though the 

sample for this particular study of cargo supervisors was 

small, the reported results point toward a high risk segment of the aviation industry that commands attention. 

Interview Data 

Perception of responsibility. Participants were 

asked to report about how much of the time they were 

responsible for a list of commonly listed load supervisor 

duties. Their responses could range from 0 (e.g., “I am 

never responsible for that task,”) to 100 percent (e.g., “I 

am always responsible for that task,”) and any percentage in between. Table 6 shows the collective responses 

for each of the 45 prompts asked of participants and 

presented by percentage of responsibility. 

Load supervisors who were interviewed agreed that, 

with the exception of one task, all of the tasks were the 

responsibility of the load supervisor to some degree. 

The extent to which they were solely responsible for the 

task varied. For example, one participant responded that 

checking each pallet for illegal cargo is primarily the responsibility of the organization’s front desk, where the 

cargo was initially taken from a customer. Another load 

supervisor responded that it would be “really hard” to 

know if there was illegal cargo in a unit load device because of the way it is palletized and responded that it is 

difficult to assign a percentage to that responsibility for 

the load supervisor alone. In another example, a load 

supervisor indicated that it was the responsibility of all 

cargo crew members to ensure locks are in the up and 

locked position for each flight, which led him to assign a 

smaller percentage of responsibility to the load supervisor for that task. For all of these items, the idea of 

“shared responsibility” permeated most if not all interviews. Therefore, percentages where load supervisors 

reported less than 100 percent responsibility were often 

caveated with a statement of this idea that it is the 

shared responsibility of all cargo team members to ensure these responsibilities were completed. In another 

example, in response to the prompt, “Positioning each 

pallet/container correctly in the appropriate position 

and then installing it there by properly locking the pallet 

in place,” cargo supervisors responded that they are responsible for that action about 75% of the time. They 

would go on to explain that the other 25% of the time, 

this action is performed by their loading crew, leaving 

the cargo supervisor to later observe that this action had 

been done. This was the case for all of the responsibilities presented during the interviews where the percentage not accounted for by a supervisors responsibility 

was considered to be the responsibility of a cargo team 

member. Indeed, the degree to which they shared a perception (indicated by a lower standard deviation) was 

most often influenced by the amount a participant indicated they relied on their team. Therefore, cargo supervisors who did not rely on their teams to a great degree 

would report a higher percentage of sole responsibility 

where supervisors who did rely on their teams would 

report a lower percentage of sole responsibility. 

9
 
 

 

 

 

 

 

Table 6 

Perception of Responsibility Load Supervisors Report for Specific Tasks 

Legend Code 

Duty/Responsibility that had high agreement. Lower variance represents 

more similar ratings across load supervisors for a duty/responsibility. 

Low Variance 

Color: Green; B&W: ˅σ2 

Duty/Responsibility that had moderate agreement. Moderate Variance 

Color: Green; B&W: ~σ2 

Duty/Responsibility that had low agreement. High variance represents more 

differences across load supervisors for a duty/responsibility. 

High Variance 

Color: Green; B&W: ˄σ2 

Duty/Responsibility that had high agreement and relatively low percentage 

of responsibility perceived. 

Not a Responsibility

Color: Brown; B&W * 

The percent responsible column represents the amount of time the load 

supervisor felt the duty/responsibility was their sole responsibility. % Responsible (Mean) 

The variance in answers column represents the degree to which answers 

across load supervisors were similar. Variance in Answers (Standard Deviation) 

Position Duties/Responsibilities Mean Std. 

Deviation Code 

1 Calculate load weights for different aircraft compartments. 100.0 0.0 ˅σ2 

2 Certifying that dangerous goods shipments have been loaded correctly. 100.0 0.0 ˅σ2 

3 Certifying that pallet locks are in the up and locked position for each 

cargo laden flight that departs. 

100.0 0.0 ˅σ2 

4 Distribute cargo in such a way that space use is maximized. 100.0 0.0 ˅σ2 

5 Sequencing cargo for a particular flight based on the load plan. 100.0 0.0 ˅σ2 

6 Signing the loading certification form certifying that the aircraft has been 

properly loaded. 100.0 0.0 ˅σ2 

7 Supervise the sequencing, loading, unloading, and securing of cargo. 100.0 0.0 ˅σ2 

8 Affixing the pallet position on the pallet/containers tag as depicted on 

the load plan form (as directed). 96.7 8.2 ˅σ2 

9 Calculate the weight and balance of the aircraft. 96.7 8.2 ˅σ2 

10 Directing the installation of pallets in the aircraft according to proper 

methods and practices. 96.7 8.2 ˅σ2 

11 Ensuring that the loaders safely and correctly install pallets/containers in 

the aircraft in the assigned locations. 94.0 13.4 ˅σ2 

12 Ensuring that all pallet/container locks are in the up and locked position 

for all cargo (loaded). 93.3 11.5 ˅σ2 

13 Certifying aircraft have been loaded properly. 91.7 20.4 ~σ2 

14 Reporting any cargo restraint fittings that are missing or not functioning 

properly. 91.7 20.4 ~σ2 

15 Bring any irregularity to the attention of the immediate supervisor. 90.0 20.0 ~σ2 

16 Checking all pallets containing dangerous goods for leakage prior to loading into the aircraft. 90.0 22.4 ~σ2 

17 Positioning each pallet/container correctly in the appropriate position 

and then installing it there by properly locking the pallet in place. 90.0 22.4 ~σ2 

10
 
 

 

 

18 Preparing cargo load plans and assigning specific positions to the pallets 

for a particular flight. 90.0 20.0 ~σ2 

19 Checking aircraft cargo areas for signs of cargo leakage and debris. 88.3 20.4 ~σ2 

20 Contacting airline management, dispatch or FAA for suspected dangerous good spills or leaks and initiating the emergency response by directing personnel away from the aircraft and area until relieved by superiors. 

86.0 31.3 

~σ2 

21 Checking the aircraft and ramp area for debris and potential hazards. 84.0 35.8 ~σ2 

22 Brief the aircraft commander or designated representative on the aircraft 

load, hazardous cargo and weight distribution. 83.3 40.8 ˄σ2 

23 Maintaining all cargo loading equipment. 82.5 23.6 ~σ2 

24 Checking the cargo loading equipment to ensure proper function and 

operation. 80.0 27.4 ~σ2 

25 Compute aircraft center of gravity. 80.0 44.7 ˄σ2 

26 Determining the quantity and orientation of cargo. 80.0 44.7 ˄σ2 

27 Preparing the weight and balance documents (i.e., load manifest) prior to 

flight. 80.0 27.4 ~σ2 

28 Staging aircraft cargo or baggage. 80.0 27.4 ~σ2 

29 Inspecting aircraft cargo compartment areas prior to loading (e.g., checking for proper number, condition and operation of pallet locks, cargo 

loading system, cargo restraint equipment, and side rails. 

78.3 24.8 

~σ2 

30 Positioning each pallet on the aircraft according to instructions received, 

and pointing out to the immediate supervisor pallets that appear to be 

going into wrong position (such as a very heavy pallet/container going 

toward the tail section instead of over the wing). 

75.0 41.8 

˄σ2 

31 Securing cargo to the aircraft (e.g., Installing cargo restraint or pallet 

locks (”bear traps”)). 75.0 41.8 ˄σ2 

32 Supervising ACMI flights when applicable. 75.0 41.8 ˄σ2 

33 Reporting any unsafe practices to airline management. 70.0 46.9 ˄σ2 

34 Being able to do the job functions of your subordinates and directing 

them accordingly. 63.3 31.4 ~σ2 

35 Accompany aircraft to perform duties related to cargo or maintenance. 62.0 52.2 ˄σ2 

36 Planning, selecting, sequencing, manifesting, and monitoring each aircraft 

cargo/mail load. 60.0 40.5 ˄σ2 

37 Coordinating the removal of trash from within the aircraft prior to the 

installation of cargo. 58.3 34.3 ~σ2 

38 Checking each pallet/container for illegal cargo such as batteries, chemicals, etc. 55.0 52.6 ˄σ2 

39 Maintaining a sufficient workforce. 55.0 32.7 ~σ2 

40 Reporting potential hazards to the appropriate authorities, flight operations, or captain. 55.0 42.0 ˄σ2 

41 Ensuring that subordinates are adequately trained. 44.0 34.4 ~σ2 

42 Assigning loading crews to each flight. 37.5 47.9 ˄σ2 

43 Assist in briefing passengers or couriers on safety and emergency procedures. 10.0 14.1 ˅σ2 

44 Performing record maintenance (e.g., hiring, training, posting revisions). 0.0 0.0 ˅σ2 

*Note: Interviewees were asked, “Performing record maintenance is your responsibility blank percent of the time,” to which interviewees responded with a percentage. Lower variance represents more similar ratings across load supervisors for a duty/responsibility. 

11 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Crew treatment. The Cargo Focus Team requested 

that participants be asked, “When you fly with cargo, 

what role do you play and are you treated as one of the 

crew?” For those participants who flew with cargo, 

there were two different experiences reflected. First, 

when load supervisors travels with cargo, they experienced being treated as a “jumpseater.”2 That is, being 

allowed to ride in an available jumpseat and available if 

help was needed, but not considered a part of the crew. 

The second experience was being treated as one of the 

crew. However, all participants agreed that even when 

they were treated as one of the crew, they were not 

comfortable using available on-board rest facilities 

as it was well-known that those areas were “reserved” 

for pilots. 

Flying versus non-flying load supervisors. The topic of 

scheduling based on the number and duration of flights 

in which a load supervisor accompanied cargo yielded 

unanticipated results. In interviews with load supervisors who flew with cargo, it was pointed out to the researcher that although their organizations considered 

the full duration of the flights as duty time, it was also 

expected that any rest that would be needed would be 

done while flying between destinations. Although participants indicated that they were not comfortable using 

the on-board rest facilities, they were expected to sleep 

when on long-duration flights. In the interviews, it was 

clear that there was a distinction to be drawn not only 

between flying versus non-flying load supervisors, but 

also between short-duration and long-duration cargo 

hauls. 

Short- haul. In a short-haul operation, participants 

indicated they would typically work a normal shift where 

if on day shift, they would arrive around 8:00 a.m. and 

assist with the end of loading a cargo flight for about 

one to two hours (given that this plane has typically 

been loaded by the night shift and will only need one or 

two additional pallets/ULDs added just before departure). Then the load supervisor departs with the plane, 

arriving at a destination within one to two hours of the 

departure time. At this point, the cargo supervisor 

would assist with unloading (and re-loading if necessary) 

for about one to two hours, and then return to the origination airport. This shift would last approximately 8.5 

hours, with approximately 2 to 4 of those hours comprised of flight time. These short-haul flights can be 

delayed by maintenance or related issues in which case 

the cargo supervisor would get overtime. In situations 

where more than 3 to 4 hours of overtime would occur, 

2 A jumpseat, in aviation refers to an auxiliary seat for individuals other than normal passengers, who are not operating 

the aircraft. In a cargo-only aircraft, it is typically located just 

rear of the cockpit. 

the oncoming cargo supervisor would take over the 

shift. An example of a load supervisor short-haul schedule is located in Appendix A. This short- haul flight is 

characterized by two conditions, (a) the cargo supervisors begin and end their duty time in the same location, 

and (b) the cargo supervisors begin and end their duty 

cycle in no more than 12 hours including flight time. 

Long-haul. In a long- haul flight operation, participants indicated they would typically work around the 

shift schedule of the cargo. That is, the load supervisor’s 

shift beginning was directed by the departure time of the 

cargo flight the supervisor will accompany. In addition, 

the shift is not determined by duty hours, rather the 

amount of cargo loaded/unloaded, the length of the 

flight, and the duration of the time at destination locations, the aircraft capabilities (e.g., fuel, specialized landing abilities, weight and balance requirements), and 

flight crew availability. Currently, this so-called longhaul operation has no length of time limitation from 

origin start to origin return, geographic locations, or 

cargo type. Examples of two different load supervisor 

long–haul schedules are located in Appendix B and Appendix C. This long- haul flight operation is characterized by two items, (a) cargo supervisors do not begin 

and end their duty time in the same location (see Appendix B and C for examples) while in Quito, Ecuador 

and in Atlanta, Georgia, the load supervisor would stay 

in lodging over night before continuing the flight) and 

(b) the cargo supervisors duty cycle is more than 24 

hours including flight time, but typically in excess of 48 

hours including flight time, from origin beginning to 

origin return. 

DISCUSSION 

In response to the research request, a study was 

conducted to gather information concerning work 

schedules and fatigue in load supervisors and flight mechanics. The research questions were: 

1. What are the current rest/duty schedules of load 

supervisors and flight mechanics? 

2. What are the current fatigue risks present for load 

supervisors and flight mechanics? 

3. What are the current duties and responsibilities of 

load supervisors in the field? 

Current Rest/Duty Schedules

Shifts. An examination of the reported hours at 

work, actual time asleep, and other activities (such as 

personal time or commute time; Figure 3) revealed that 

night shift load supervisors are working schedules that 

are very different from their day shift counterparts. For 

example, in a ”4-on-4-off” schedule, a shift worker 

would need to get 40 hours of work in four days rather 

than five. In addition, overtime was reported more often 

for night shift load supervisors than day shift. This indi12
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

cates that while a majority of night shifts are scheduled 

with 4 days off each week, many of them are working 

overtime on at least one of those days, reducing their 

overall rest time. 

Flying with cargo. In addition to the typical shift 

patterns reported above, in some cases load supervisors 

are required to fly with the cargo in order to assist with 

unloading/reloading in a location where a load supervisor is not stationed. Reports from interviews in this 

study highlighted distinctions between those who fly 

long-distances (i.e., long-haul), short-distances (i.e., 

short-haul), and those who do not fly with cargo at all. 

Findings from these data highlight that the practicality 

of flying a long-haul cargo flight is likely to increase the 

risk of fatigue for load supervisors (See Appendices B 

and C for examples). Short-haul load supervisors seem at 

less risk. However, a larger study specifically targeted toward differences between long and short-haul cargo 

flights is necessary before attempting to include data specific to these variables and their possible risk of fatigue. 

Current Fatigue Risks 

Fatigue is classified as more than simply sleepiness. 

There are physical, mental, and emotional symptoms 

that are indicators one may be suffering from fatigue. 

Indeed, when asked about such symptoms, cargo loaders reported experiencing between 8 and 25 of them 

including difficulty falling asleep due to worry, difficulty 

sleeping due to shiftwork, awakening while trying to 

sleep, tiredness upon waking, and moodiness. 

Previous research shows that there are three primary contributors to fatigue: time spent asleep, time spent 

awake, and circadian rhythm disruption (Folkard, 1996). 

The human body needs between 7 and 9 hours of sleep 

to get high-quality sleep. In this study, load supervisors 

reported getting consistently less than this recommended amount. Previous studies have also shown that performance declines by hours awake in a similar manner to 

those who have been drinking alcohol. Specifically, after 

approximately 17 hours of continuous wakefulness, one 

performs the same as an individual with a blood alcohol 

concentration of .05% (Dawson & Reid, 1997). 

Results from the present study showed that the 

amount of hours an average load supervisor spent 

awake totaled almost 17.5 hours. Day shift cargo loaders 

reported that 10.5 of those hours were spent at work 

and commuting to work daily while night shift reported 

14.25 of those hours as commute time and work time. 

Only one night shift load supervisor reported napping 

intentionally suggesting that these hours of wakefulness 

are, indeed, continuous. Finally, the internal body clock 

or circadian rhythm plays a role in one’s level of alertness. One element of influence on circadian rhythm is 

environmental cues such as light and darkness (Monk, 

1990). These cues influence when the body is signaled 

to wake up and when to go to sleep. Shift workers are 

especially susceptible to fluctuations such as these if 

they find themselves working variable schedules. Load 

supervisors in this study reported working a variable 

work schedule including “4-on-4-off” (indicating 4 days 

of work with 4 days off), rotating schedules where after 

working several day shifts in a row they rotate to working several night shifts in a row, and frequently picking 

up shifts for coworkers, as well as working night shift 

into a day shift overtime or vice versa. Alertness data in 

the present study also showed that load supervisors who 

were working night shifts were at risk of reduced alertness when they started their shift. While the contributing 

factors alone do not make the case that fatigue is a risk 

for load supervisors, the evidence taken together, did 

suggest that fatigue was a risk for load supervisors. Table 

7 summarizes risk factors indicated by load supervisors. 

Table 7 

Load Supervisor and Flight Mechanic Fatigue Risk Characteristics 

Risk Factors LS/FM Characteristics 

1. Time Asleep 6.4 Hours 

2. Time Awake 17.6 Hours 

3. Circadian Rhythm Frequently Changing Schedules 

Load supervisors reported working overtime between once and twice a week, adding more time to an 

already condensed schedule. Night shift load supervisors 

also slept less, reported lower quality of sleep, and 

awoke more often while attempting to sleep than did 

day shift. Alertness data collected revealed that night 

shift alertness levels may be lower when they begin their 

shift, than at shift end. This finding underscores differences between day shift and night shift load supervisors 

in that day shift workers performed predictably, while 

night shift load supervisors did not. When participants 

were asked to report what operational changes they 

would recommend to reduce load supervisor’s risk of 

fatigue, they chose seven from a list of typical fatigue 

risk reduction actions (Table 8). It is important to note 

that only one respondent reported that there was no 

change needed. 

Table 8 

Self-reported Actions to Reduce Load Supervisor’s Risk of Fatigue 

1. Limit the number of duty times allowed. 

2. Shorten duty days. 

3. Limit the number of flight segments/legs. 

4. Do not mix continuous duty overnights with early morning 

report times. 

5. Maintain consistent scheduling. 

6. Consider flight time as duty time. 

7. Lengthen rest periods. 

13
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Current Duty Responsibilities 

There are currently no defined standards for the duty responsibilities of a load supervisor across cargo operations. A list of 45 duties (see Table 6) were mutually 

agreed upon to be included in this study between the 

cargo focus team and the researchers. Seven of the 45 

duties and responsibilities presented to load supervisors 

were agreed to be 100% the duty of a load supervisor. 

These were: sequencing cargo, signing to certify the aircraft was loaded properly, and calculating the load 

weights for different aircraft compartments. Those responsibilities listed in positions 1 to 12 represented the 

highest agreement that the duties were the primary responsibility of the load supervisor a majority of the 

time. However, at position 13, the variability in agreement increased indicating that the load supervisors in 

this study agreed less than in the previous 12 tasks. The 

increase in variability of agreement suggests that the 

responsibilities listed from position 13 through 42 are 

not the sole responsibility of the load supervisor while 

on duty. In fact, in many cases, interviews indicated that 

these responsibilities were shared among the load crew 

to some degree or another. Finally, in position 43, all 

load supervisors agreed that it was never their responsibility to perform record maintenance while on duty. 

The findings from this study suggest that there are 

differences between cargo organizations with regard to 

what is expected of load supervisors. These differences 

seem to be based on cargo type, whether cargo supervisors fly with the cargo or not, and on the degree of 

shared responsibility cargo teams have over the roles 

and responsibilities of a single cargo supervisor. More to 

the point, there are differences of understanding between load supervisors, even within those organizations, 

as to what the primary responsibilities of a load supervisor are while on duty. This finding underscores a need 

for industry-wide standards for defining load supervisors’ responsibilities, as well as conveying those standards uniformly within cargo organizations as a whole. 

Study Limitations 

The preliminary nature of this study resulted in a 

limited recruitment phase and subsequently a small 

sample size. Therefore, the results and discussion are 

limited to the patterns and trends observed in comparison to findings reported in the literature for comparable 

shift work. Though the sample was small, the demographic characteristics of participants are in line with 

cargo supervisors across the industry. For example, every effort was made to adequately represent personnel 

from each shift, overtime hours, frequency and duration 

of loading responsibilities while on shift, and demographic characteristics such as age and experience. In 

addition to this sample representativeness of the industry over all, given the expansiveness of sleep and fatigue 

research for shift workers, our findings show that cargo 

supervisors are susceptible to the same risks found in 

fatigue shift work studies. 

SUMMARY 

Load supervisors view their role in their organizations to be both important as well as interactive. In fact, 

when asked to choose three terms that best describe the 

load supervisor job duties, the three most highly chosen 

terms were challenging, interesting, and very complex. In reported data as well as observed behaviors, the participants in this study deemed their responsibilities to be 

important to the safety and well-being of everyone involved in their operations. They expressed a desire to do 

their job well and to be treated as the integral team 

member they view themselves to be. The knowledge 

gained from this study highlighted that there are steps 

that need to be taken within the cargo industry to ensure 

load supervisors are receiving such treatment. Those 

recommended steps are: 

1. Institute a Human Factors Awareness Training 

program for all cargo loading personnel to include a 

segment focused on Fatigue Awareness and Countermeasures (available at MxFatigue.com). 

2. Organizations should have a tracking system in 

place that monitors the number of duty times and rest 

times afforded to their load supervisors inclusive of 

overtime. 

3. Organizations should institute a Fatigue Risk 

Management System appropriate to the roles and responsibilities associated with load supervisors and cargo 

personnel. 

4. Organizations should use available information 

sources (from current SMS programs and those outlined 

in these recommendations) to take measurable actions 

that limit the risk of fatigue and fatigue related mishaps/accidents in their operations. 

5. Organizations currently emphasize the team aspects of responsibility. However, organizations should 

further emphasize the absolute responsibility of the load 

supervisor in duties where appropriate. 

Each of these recommendations has a source by 

which cargo organizations may use to begin moving 

toward voluntarily mitigating fatigue risk in their operations today. Further information is available at 

MxFatigue.com, and through the FAA’s CAMI Human 

Factors Research Division (AAM-500) in Oklahoma 

City, OK. 

14
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Akerstedt, T. & Wright, K. P. (2009). Sleep loss and 

fatigue in shift work and shift work disorder. Sleep 

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APPENDIX A 

Short-haul Flying Load Supervisor Schedule Example 

•	 The day begins at 0000 at the origin location. The load supervisor spends 2 to 2.5 hours preparing the outbound 

flight. 

•	 At 0230 the flight departs for a one hour flight. The flight arrives at what feels like 0330. 

•	 The load supervisor spends about an hour offloading and reloading (if necessary) the flight. The departure time is 

at 0430. 

•	 The flight lands approximately an hour later at 0530 where the load supervisor spends time offloading and completing ground duties until shift end at 0830. The load supervisor’s shift is approximately 8 and a half hours. 

•	 The Day shift load supervisor would follow a similar flight schedule for approximate shift duration of 8 and a half 

hours. 

•	 Either flight could be delayed for maintenance (Mx) or weather (Wx) related issues, which would result in overtime for the load supervisor. 

•	 In cases where Mx or Wx delays were extensive (exceeding 3 to 4 hours), the next load supervisor to come on 

shift would take over the flight, releasing the initial load supervisor from duty. 

A-1
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

APPENDIX B
 

Long-haul Flying Load Supervisor Schedule Example 1 

In this example, note that the load supervisor starts and ends the shift in Dubai, United Arab Emirates. 

•	 The day begins at what feels like 10:00 a.m. with the sun shining in Dubai. Approximately 3 hours is spent preparing the outbound flight. 

•	 At what feels like 1:00 p.m., the flight departs for a duration of 9 hours and 15 minutes. The flight lands while daylight still shines at what feels like 10:15 p.m. for this load supervisor. The load supervisor spends approximately 3 

hours on the ground offloading and re-loading the flight as the sun is still shining. 

•	 At what feels like 12:15 a.m., with the sun still up, the flight departs for a duration of 8 hours and 10 minutes. At 

what feels like 8:25 a.m., the flight lands in Quito, Ecuador where the sun is beginning to rise. The load supervisor 

then assists with preparing the load for approximately 3 hours and then has about 7 hours and 35 minutes in daylight to rest without ground duties. 

•	 At what feels like 7:00 p.m. the load supervisor arrives back to the departing flight to finish preparations for departure. At this time the sun is slowly setting. The flight departs at what feels like 10:00 p.m. to the load supervisor on 

a 5 hour night flight to Atlanta, Georgia. 

•	 Landing at what feels like 3:00 a.m. in Georgia, in the dark, the load supervisor assists with offloading and/or loading cargo before leaving at what feels like 6:00 a.m. for a 15 hour rest period with no ground duties. The rest time 

is comprised of partial darkness but at what would feel like approximately noon to the load supervisor, the sun 

would begin to rise in Georgia. From this time until approximately 9:00 p.m. the load supervisor would spend rest 

time exposed to sunlight before arriving back to the cargo ramp to prepare the next flight where the sun would 

again be setting. 

•	 At what feels like 12:00 a.m. the flight departs for a partially dark and partially sunlit 13 hour trip to Kuwait. At 

what feels like 1:00 p.m., the flight lands in Kuwait in sunlight where the load supervisor would spend approximately 3 hours preparing for the last flight. 

•	 At what feels like 4:00 p.m., the flight departs for a 1 hour and 45 minute trip back to Dubai. The load supervisor 

would spend roughly 3 hours on the ground finalizing trip reports before completing this leg of duty time at what 

feels like 8:45 p.m. 

B-1
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

APPENDIX C
 

Long-haul Flying Load Supervisor Schedule Example 2 

In this example, note that the load supervisor starts and ends the shift in Dubai, United Arab Emirates. 

•	 The day begins in darkness at what feels like 10:45 p.m. in Dubai. Approximately 3 hours is spent preparing the 

outbound flight. 

•	 At what feels like 1:45 a.m., the flight departs for a duration of 11 hours and 15 minutes. The flight lands in daylight at what feels like 1:00 p.m. for this load supervisor. The load supervisor spends approximately 3 hours performing ground duties and then has about 8 hours of rest. This 8 hours is comprised primarily of daylight exposure. 

•	 At what feels like 1:00 a.m., in the dark, the load supervisor arrives to load and finalize the flight for departure at 

what feels like 3:00 a.m. The flight departs for a duration of 5 hours and 45 minutes primarily in darkness. 

•	 At what feels like 8:45 a.m. the load supervisor arrives in sunny Okinawa, Japan and assists with unloading/loading 

ground duties for approximately 3 hours. At what feels like 11:45 a.m. the load supervisor now has approximately 

10 hours of rest time comprised of about 4 hours of light and 6 hours of darkness. 

•	 At what feels like 10:30 p.m. the load supervisor arrives back to the cargo ramp in Okinawa, in darkness, to finish 

preparations for departure to Hong Kong, China. The flight departs at what feels like 1:30 a.m. to the load supervisor for a 2 hour and 31 minute night flight. 

•	 Landing at what feels like 4:01 a.m. in Hong Kong, in the dark, the load supervisor assists with offloading and/or 

loading cargo before leaving at what feels like 7:00 a.m. for a 5 hour and 15 minute daylight flight to New Delhi, 

India. 

•	 At what feels like 12:15 p.m. the flight arrives in New Delhi, India where the load supervisor performs loading/offloading duties for approximately 3 hours. At what feels like 3:15 p.m., the flight departs for a 3 hour and 25 

minute flight to Dubai. 

•	 At what feels like 5:40 p.m., the flight arrives in Dubai. The load supervisor assists with finalizing ground duties 

before completing this leg of duty time at what feels like 8:40 p.m. 

C-1