NASA/TMm2000-209611

Crew Factors in Flight Operations XII: A Survey

of Sleep Quantity and Quality in On-Board Crew

Rest Facilities

Mark R. Rosekind, Kevin B. Gregory, Elizabeth L. Co, Donna L. Miller, and David F. Dinges

Alertness Solutions, Inc., Cupertino, California

September 2000
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NASA/TM--2000-209611

Crew Factors in Flight Operations XII: A Survey

of Sleep Quantity and Quality in On-Board Crew

Rest Facilities

Mark R. Rosekind

Alertness Solutions lnc., Cupertino, California

Kevin B. Gregory

Alertness Solutions Inc., Cupertino, California

Elizabeth L. Co

Alertness Solutions Inc., Cupertino, California

Donna L. Miller

David F. Dinges

University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania

National Aeronautics and

Space Administration

Ames Research Center

Moffett Field, California 94035

September 2000
Acknowledgments

This research, conducted by NASA Ames Research Center, was requested and sponsored by the Federal Aviation

Administration's Office of Aviation Research, Human Factors Division.

NASA Center for AeroSpace Information

7121 Standard Drive

Hanover, MD 21076-1320

301-621-0390

Av_lable _om:

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5285 Port Royal Road

Springfield, VA 22161

703-605-6000

This report is also available in electronic form at http://human-fact°rs'arc'nasa'g°v/zteam/
1.0 Operational Summary

This report is the twelfth in a series on

physiological and psychological effects of

flight operations on flight crews, and the

operational significance of these effects.

Long-haul flight operations often involve

rapid multiple time zone changes, long and

irregular work schedules, sleep disturbances,

and circadian disruption. These factors can

result in fatigue, cumulative sleep loss,

decreased alertness, and degraded

performance. Thus, operational effectiveness

and the safety margin may be reduced by pilot

fatigue. Federal Aviation Regulations (FARs)

require that flights longer than 12 h. carry

augmented crews so that crewmembers can

rotate off of the flight deck for rest periods

during cruise. Many aircraft operated on such

flights are equipped with on-board crew rest

facilities, or bunks, to allow crewmembers to

lie down and sleep during rest periods. Sleep

during long-haul flights is an operational

countermeasure to fatigue that has been shown

to improve subsequent alertness and

performance (ref. 1).

Although many anecdotal reports about bunk

use exist, there have been no empirical data

about the effectiveness of crew rest facilities as

an alertness management strategy. The

National Aeronautics and Space

Administration (NASA) was requested by the

Federal Aviation Administration (FAA) to

conduct a study examining the effects of noise

in on-board crew rest facilities during longhaul transport operations. The general lack of

data on bunk usage suggested to investigators

that the study should examine broader issues

as well, including how crewmembers use the

bunks, the quantity and quality of sleep they

obtain, the factors that promote or interfere

with bunk sleep, and the effects of bunk use

on subsequent alertness and performance.

The study was designed to be conducted in

two phases. The first phase of the study was a

survey study to collect data on flight crews,

home sleep habits, bunk usage during

operations, flight crew perceptions of factors

that promote or interfere with bunk sleep, and

flight crew attitudes about the facility and its

efficacy. This report describes the survey

findings, which informed the focus of the

second phase of investigation. The second

phase was an in-flight field study to collect

physiological and subjective data on the

effectiveness of bunk facilities as an alertness

management tool. The results of the second

phase study are reported in a separate

document.

The survey study examined long-haul

crewmembers from three participating U.S.

airlines operating long-haul aircraft with bunk

facilities. In each case, both the airline and the

pilot union endorsed pilot participation in the

study. The three carriers operated three types

of aircraft with different bunk facilities. Two

carriers operated mixed fleets of B747-

100/200s and B747-400s (the latter of which

has a more technologically advanced "glass"

cockpit), and the other carrier operated MDlls.

The retrospective paper-and-pencil survey

consisted of 54 questions' of varied format

and focused on demographics, home sleep,

and bunk sleep (see Appendix 1 for the

complete survey). Surveys were sent to a

contact at each carrier, who distributed them to

appropriate crewmembers. Participation was

voluntary, anonymous, and confidential.

Crewmembers were instructed to return

completed surveys in the provided envelopes,

which were postage-paid and addressed

directly to NASA investigators.

Carrier 1 pilots completed and returned 737

surveys of 2125 sent (35% return rate); 107

were returned of the 220 sent to Carrier 2

(49%); and 560 were returned of 1500 sent to

Cartier 3 (37%), for a total of 1404 completed

surveys (36.5% return rate).

Demographically, the three carriers were

comparable, though Carrier 3 had older, more

experienced crewmembers. Most respondents

(99%) were male, with average ages for the

three carriers being 45 yr., 48 yr., and 5t yr.,

respectively. On average, about 90% of the

' Six questions were added to the survey sent to Carriers 2

and 3. making the total number of questions 60.
subjectsfromeachcarrierratedthemselvesas

"good" or "very good" sleepersat home.

Comparisonsbetweenaircrafttypesrevealed

somesignificantlydifferentresponses

concerningthebunkandbunksleep. The

olderB747-100/200seriesreceivednotably

poorerassessmentsthaneachof thenewer

aircraft. The '100/200groupreportedmore

frequentdifficultiessleepingin thebunk,gave

thebunkapooreroverallratingthaneachof

theothergroups,andcomparedto theMD-1I

group,ratedturbulenceasmoreinterfering

withbunksleep.TheMD-11groupreturned

themostpositiveratings.MD-11

crewmembersreportedthefewestproblems

sleepingin thebunk,gavethebunkthebest

overallrating,andreportedthemost

improvementin alertnessandperformanceas

aresultof bunksleep.

Overthree-quarters(81%)of thesubjectswho

ratedthemselvesasbeinggoodhomesleepers

reporteddifficultiessleepingin thebunk. On

theotherhand,thosewhoratedthemselvesas

poorsleepersat homeneverthelessreportedan

averagebunksleepdurationof nearly2 hours

(1h.52min.),whichsuggeststhatdespiteany

perceivedshortcomingsof thefacilities,

crewmemberswereableto sleep.

Thelist of factors-identifiedaspromoting

sleepathomewasalmostidenticalto thelist of

factorspromotingsleepin thebunk,and

includedpillows,blankets,andreadinessfor

sleep.Likewise,thefactorsreportedto

interferewith sleepat homeandwith sleepin

thebunkwereverysimilarandincluded

randomnoise,thoughts,heat,andtripsto the

bathroom.Interestingly,randomnoisewas

identifiedasaninterferingfactorwithmuch

morefrequencythanconstantbackground

noise,whichindicatesthatthecharacterof a

noise,andnotjust its volume,maybean

importantconsideration.

Thefindingssuggestthatbunksleepmaybe

improvedby maximizingphysicalcomfort

andby minimizingrandomnoise. Some

potentiallyhelpfulchangesmaybe

straightforward,suchasprovidingcomfort

itemsin thebunk(e.g.,pillowsandblankets)

orrequestingthatflight andcabincrews

minimizerandomnoiseevents(e.g.,service

2

carts hitting the bulkhead or cockpit door

closings). The data also suggest the possibility

for more involved approaches, such as locating

rest facilities farther from busy passageways;

training crewmembers in relaxation techniques

to minimize racing thoughts; providing better

environmental controls in the bunk; and

locating a crew lavatory nearby. Additionally,

educating crewmembers in basic sleep

physiology and alertness management

strategies would enable them to plan their

sleep efficiently, and to use other strategies

effectively to enhance their sleep at home and

in the bunk. The education of schedulers,

management, and other industry members

concerning fatigue issues and strategies may

also provide important support for

maximizing crewmember rest and alertness.

2.0 Introduction

2.1 Fatigue in Long-Haul Operations

Commercial long-haul crewmembers routinely

face rapid multiple time zone changes, long

and irregular duty schedules, sleep

disturbances, and circadian disruption. These

events can result in fatigue, cumulative sleep

loss, decreased alertness, and degraded

performance which, in turn, have the potential

to reduce operational effectiveness and the

safety margin. Thus, crewmember fatigue in

commercial long-haul operations presents a

substantial safety concern.

Many sources validate this concern.

Numerous studies have shown fatigue-effects

in long-haul commercial crews, including

alertness and performance decrements and

unintended napping (e.g., refs. 1-3). The

NTSB identified fatigue as a probable cause in

an aircraft accident involving a DC-8 in

Guantanamo Bay, Cuba in 1993, and as a

contributing factor in the 1997 Korean Air

accident in Guam (refs. 4-5). Incidents

reported to the NASA Aviation Safety

Reporting System (ASRS), a confidential

reporting system for flight crews and others

who operate in the National Airspace System,

have identified fatigue as a significant safety

issue (ref. 6). As global travel becomes
increasinglycommon,andastheNAS

becomesmorecrowded,thesafetymargin

mayleavelessroomfor humanerror.

Analystsprojectthatcommerciallong-haul

travelwill continueto growinthecoming

decades,withsomeof thehighestannual

growthratesfor U.S.flagcarriersoccurring

onroutesbetweentheU.S.andLatinAmerica

(averagegrowth6.3%annuallybetween

1999-2010)andthePacific(6.1%)(ref.7).

Theincreaseddemandonequipmentandon

theairspacesystemmayserveto magnifythe

importanceof alert,highlyperformingflight

crews.

FARPart121requiresthatflightslongerthan

12h. carryaugmentedcrews.Whencrewsare

augmented, a crewmembercanrotateoff of

theflight deckfor a restperiodduringcruise,

whileanothercrewmemberfills theposition.

Manyaircraftoperatedon suchflightsare

equippedwith on-boardcrewrestfacilities,or

bunks,to allowcrewmembersto lie downand

sleepduringrestperiods.A bunkfacility may

consistof:twosleepsurfaces,eitherin

upper/lower"bunk-bed"configurationor

onehorizontalbunkandonefold-downseat;

beddingitems;anareafor storage;curtains

separatingbunksleepsurfaces;andadoor

separatingthebunkfromtherestof thecabin.

If thecrewis augmentedby morethanone

crewmember, thentwocrewmembersmayuse

thebunkfacility atthesametime(i.e.,be

"bunk partners"). The schedulingof bunk

periodsis generallyat thecaptain'sdiscretion.

Sleepis criticalbecauseit is theonly

physiologicalmechanismthatcanreverse,

ratherthansimplymask,sleepiness.When

availableto crewmembers, asonaugmented

flights,it isaninvaluablealertness

management tool. As anoperational

countermeasureto pilot fatigue,sleephasbeen

shownto improvesubsequent alertnessand

performance,andto prevent"dozingoff"

(ref.1). Yet whileanecdotalevidencesuggests

thatcrewmembersusetherestfacilityto sleep,

therehavebeenno empiricaldata

documentingits effectiveness.

Theprimaryobjectiveof thisstudywasto

determinehowcrewmembersusedthebunk,to

documentthequantityandqualityof sleep

theyobtainedin thebunk,andto identifythe

factorsthataffectedbunksleep.

2.2 Physiological Background

Augmentation and the use of on-board crew

rest facilities are presumably intended to

maximize the safety of flight by maintaining

an alert, high-performing crew on the flight

deck. Fatigue, alertness, and performance are

physiologically determined. A basic

understanding of two physiological

factors--sleep and the internal body clock "

(called the circadian clock)--are necessary

background information. Together, sleep and

circadian rhythms play a fundamental role in

determining fatigue and alertness at a given

time. Therefore, factors that affect sleep or the

circadian system have the potential to affect

fatigue, alertness, and performance as well.

Sleep is a vital physiological need. Most

individuals require about 8 hours of sieep each

day. When a person loses sleep, essentially all

aspects of functioning can suffer, including

alertness, performance, and mood. Sleep loss

can degrade cognitive processes, vigilance,

physical coordination, judgment and decision

making, communication, outlook, and

countless other parameters (refs. 8-9). In fact,

research has demonstrated that 1 hour of sleep

loss can affect waking alertness, and that 2

hours of sleep loss can significantly affect

both alertness and performance (ref. 10).

Sleep loss, over time, accumulates into a sleep

debt, which can exacerbate the effects of acute

sleep loss.

Sleep is a complex process, influenced by

many factors. The quantity and quality of

sleep

an individual obtains at a given time depend

on prior sleep and wakefulness, time of day,

age, and environment. Further complicating

the matter, these factors interact with one

another.

The basic concept behind the influence of prior

sleep/wake patterns is the following: when

individuals don't sleep, they become sleepy.

That is, a homeostatic drive to sleep builds from

3
the time of awakening until the next sleep, just

as the drive to eat (hunger) builds between one

meal and the next. The longer the period of

time since sleep, the stronger the drive to sleep.

Conversely, the homeostatic drive is weaker

shortly after sleep. A very long period of

continuous wakefulness can create an intense

sleep drive and associated sleepiness. When the

drive for sleep becomes strong enough, it can

send the brain and body into spontaneous

sleep, regardless of whether sleep is appropriate

or safe under the circumstances.

Almost every aspect of sleep changes with age.

In general, the quantity and quality of sleep

decrease with age. While older people do not

necessarily need less sleep, they tend to obtain

less sleep at night, have more nocturnal

awakenings, truncate sleep in the morning, and

nap more during the day. Therefore, the age

of crewmembers may affect their experience

of sleep, fatigue, and alertness.

The sleep environment also plays a large role

in the quantity and quality of sleep. Dark,

quiet surroundings and a comfortable

temperature and sleep surface are key

elements for a sleep-conducive environment

(ref. 11). Because individual preferences

differ widely, the ability to adjust the

environment for comfort is an important

consideration. However, even with an ideal

sleep environment, sleep may be difficult due

to stress, thoughts, or worries.

The ability to sleep also varies with the

circadian rhythm of sleepiness. The term

"circadian rhythm" (from Latin circa

"about" and dies "day") refers to the cycle

of a physiological function that repeats

approximately every 24 hours. Virtually all

functions of the body (e.g., sleep/wake,

digestion, immune function) are controlled by

circadian rhythms, which are regulated by the

circadian clock in the brain. Generally, the

body is programmed to sleep at night and to

be awake during the day. Additionally,

humans have two times of maximal sleepiness

and two times of peak alertness each day. At

approximately 3-5 a.m. and 3-5 p.m.,

sleepiness peaks, and sleep may come more

easily. These times correspond to lower levels

of alertness and performance. Conversely, at

4

about 9-11 a.m. and 9-11 p.m., alertness and

performance peak, and it may be difficult to

obtain sleep, even if sleep-deprived. Time-ofday fluctuations in performance have been

observed in several unrelated operational

settings (ref. 12).

The circadian system cannot adjust

immediately to changes in the work/rest

schedule or time zone. When such changes

occur, the circadian system is desynchronized

from the environment for a period of time,

and individual rhythms are out of sync with

one another. Circadian disruption caused by

irregular schedules or time zone changes can

lead to sleep loss, performance decrements,

worsened mood, digestive upset, and other

symptoms. It can take from days to weeks for

the circadian clock to resychronize

completely.

Clearly, a range of physiological factors can

influence sleep in the bunk, and consequently,

affect fatigue, alertness, and performance.

Understanding how rest facilities affect

crewmembers' sleep provides a means to

maximizing its benefit. Well-rested, alert flight

crews, in turn, can enhance operational

effectiveness and flight safety. There is no

simple solution to fatigue in commercial air

transport. However, by augmenting crews and

utHfzing on-board crew rest facilities to help

manage fatigue and alertness in long-haul

flight operations, the industry takes an

important step in maintaining or improving

the safety margin.

3.0 Methods

The initial survey comprised 54 questions of

varied format, including multiple-choice, short

written responses, and fill-in-the-blank

answers. The survey was divided into three

sections: "General" (basic demographics--14

questions), "Sleeping at home" (20

questions), and "Sleeping in aircraft bunks"

(20 questions). Six questions were added to

the version administered to Carders 2 and 3 to

gather additional information regarding bunk

sleep. See Appendix A for the complete

survey. Survey results can be found in
appendixB for Carrier1,in appendixC for

Carder2, andin appendixD for Carrier3.

Threeairlineswereinvitedto participatein the

study. In eachcase,theairlinemanagement

andthepilot unionmanagementsigneda

letterof agreementendorsingpilot

participation.Eachairlinereportedthe

numberof pilots flying long-haulaircraft

equippedwith bunks,andthecorresponding

numberof surveyswassentto acontactat

eachairlinefor distributionto the

crewmembers.Accompanyingeachsurvey

wereacoverletter,acopyof theletterof

agreement,anda stampedreturnenvelope.

Thecoverletterexplainedthestudyand

emphasizedthat all informationprovidedby

subjectswasanonymousandconfidential.

Theletterof agreementwasincludedto

communicatethe supportandcommitmentof

bothmanagementandunion. Theenvelope,

addressedto NASA, was included so that

completed surveys were returned directly to

the investigators, helping to ensure anonymity

and confidentiality for both the respondent

and the airline.

The carriers operated three types of aircraft,

each with different bunk facilities. Carders 1

and 3 operated mixed fleets of B747-100/200

and B747-400 ("glass" cockpit), while

Carrier 2 operated MD-1 l's. Therefore,

comparisons were possible among different

aircraft as well as among different carriers.

The survey posed questions that addressed

general demographics, sleep habits at home,

and experience with sleeping in on-board

bunks. Targeting this broad spectrum was

intended to identify factors that relate to an

individual's ability to sleep in the bunk, and to

provide a mechanism by which to compare

bunk sleep with normal home sleep.

Additionally, some questions were designed to

assess the effects of bunk sleep on flight crew

alertness and performance.

The "General" section on basic

demographics requested personal information

such as age, gender, height, weight, and family

at home, as well as professional information

such as flight experience and total flight

hours.

Questions on "sleeping at home" addressed

the subject's average night of sleep, including

sleep timing, nocturnal awakenings, sleep

problems, and the use of sleep aids. A key

component of this section was a question that

provided the subject with a list of 18 factors

and asked how each affected sleep at home.

The factors were rated on a 5-point scale from

1-"interferes" to 5-"promotes," with a

middle rating of 3-"no effect."

The questions concerning "sleeping in aircraft

bunks" requested information based on

personal experience in the aircraft bunks.

Questions targeted such data as sleep duration,

difficulty sleeping, factors determining bunk

usage, factors affecting bunk sleep, and how

bunk sleep affected subsequent alertness and

performance. A key component of this

section was a question asking subjects to rate a

series of 25 factors on how each affected sleep

in the bunk. The question was designed for

ready comparison with ratings of factors

affecting home sleep, and listed the 18 factors

from the home sleep questions plus 7 factors

specific to bunk sleep.

Most questions were multiple-choice, which

allowed for basic quantitative statistical

analysis. Open-ended questions that required

fill-in responses were analyzed by categorizing

the comments from each question and then

tallying them. Categories were developed

according to the responses given.

All data then were entered into a modified

Relation Information Management (RIM)

database on a VAX 11/750 computer. Data

manipulation and generation of graphics were

performed using the S-Plus package

(Statistical Sciences Inc, Seattle, WA). Analysis

of variance, t-tests, principal components

analysis, and equality-of-proportion tests were

conducted using S-Plus and BMDP statistical

software (University of California, Los

Angeles).

To facilitate analysis of variance, multiplechoice responses with word-based scales were

converted into a numerical code. Answers

5
were coded from 1 to 5, in order of the

responses as they appeared in the survey (see

Appendix 1). Lower values indicated

"negative" or "less frequent" responses, and

higher values corresponded to "positive" or

"more frequent" responses.

4.0 Results

Crewmembers from all three carriers

combined returned a total of 1,404 completed

surveys of the 3,845 that were distributed

(36.5% response rate).

4.1 Carrier 1

Crewmembers from Carrier 1 completed and

returned 737 surveys of 2,125 sent (35%

response rate).

4.1.1 Demographics

Carrier 1 responses (see Appendix 2) were

received from 303 captains (41%), 276 first

officers (38%), 147 second officers (20%),

and 5 international relief pilots (< 1%). About

two thirds of the group (69%) were flying the

B747-1001200 series, while almost a third

(31%) was flying the B747-400. Total flight

hours averaged 12,522 h., ranging from 400

to 30,000 h. Crewmembers' experience flying

long-haul operations averaged 8.8 years and

ranged from one month to 40 years.

The sample consisted of 727 males (99%) and

10 females. The average age was 44.5 yr., and

ranged from 27 to 63 yr. (only one subject, a

flight engineer, was over age 60). The average

weight was about 184 lb., ranging from 117 to

300 lb. The average height was 71.3 in.

(range = 63-79 in.).

The Pacific time zone was the most frequently

reported home time zone (42%), and the

Central time zone the second most common

(32%). A majority of crewmembers (89%)

reported having a regular sleeping partner, and

about half (48%) had children under the age

of 18 living at home.

4.1.2 Sleep at Home

Data on home sleep habits were analyzed for

the 737 subjects. The average bedtime was

2258 h. (10:58 p.m.), and the average get-up

time was 0719 h (7:19 a.m.). Crewmembers

reported that it took almost 20 minutes to fall

6

asleep (mean = 19.4 min.) and that they

usually awakened 1 or 2 times during the

night. The 671 responses to an open-ended

question on the causes of awakenings were

grouped into 6 categories. The most

frequently reported causes were physiological

needs (420 reports), which included

awakening to use the bathroom, and

disturbances from family members or pets

(103). After awakening, it took subjects an

average of 12.8 minutes to go back to sleep.

The average total sleep duration was 7 hours

47 minutes. More than half of the group

(55%) reported "never" or "seldom" taking

a nap during the daytime. Nearly two-thirds

(64%) reported "never" or "seldom" having

problems getting to sleep.

Respondents rated 18 factors on how each

affected home sleep, using a scale from

1-"interferes" to 5-"promotes" (with a

middle rating of 3-"no effect"). These

ratings were examined in two ways: (1) the

frequency with which each factor was rated at

the extreme ends of the scale and (2) the mean

rating.

The factors most often identified as promoting

sleep (i.e., rated 5) were comfort aids: sleep

surfaces (15% of all "promote" responses),

pillows (15%), sheets (10%), and blankets

(10%). Readiness to sleep, representing the

physiological component of the ability to fall

asleep, was the third most frequently cited

factor and accounted for 13% of all

"promote" responses.

The factors most often rated as interfering with

sleep (i.e., rated 1) were thoughts (19% of all

"interfere" responses), heat (15%), random

noise (11%), and trips to the bathroom (10%).

Responses for all factors were converted onto a

scale from -2 to 2 (i.e., 3 was subtracted from

each response value on the 5-point scale), so

that factors identified as interfering (originally

rated as I or 2) were expressed as negative

scores, factors described as having no effect

were expressed as zero, and factors identified

as promoting (originally rated as 4 or 5) as

positive scores. The mean scaled ratings are

shown in Figure 1. These findings were

reinforced by the 82 responses to an "other
(specify)"commentquestionendingthelist

of factors.Theresponsesweregroupedinto4

categories,all of whichwerecitedby subjects

aspromotingsleep:environment(35

responses), comfort(20),goodmentalattitude

(16),andphysicalactivity(11).

Respondentswereaskedto ratefouradditional

factorsfor thedegreeto which they interfere

with sleep at home, using a scale of

1-"strongly interferes" to 5-"no effect."

"Personal worries" was cited most as

interfering with sleep, with 60% of subjects

rating this as 1 or 2 on the scale, followed by

thirst (42%), and hunger (28%). More than

half (51%) rated respiratory factors as having

"no effect." An open-ended question asked

for additional interfering factors. The 81

responses were grouped into 5 categories, with

the most common responses being jet lag (29

responses) and noise (14).

An open-ended question asking subjects to list

factors that promote home sleep yielded 1105

responses, which were grouped into 8

categories. Crewmembers most often

identified the following factors as promoting

sleep: comfortable environment (336

responses--nearly a third of all responses),

good mental attitude (180), pre-sleep activities

(156), exercise and physical activities (137),

and personal comfort (129).

A great majority of the group (94%) reported

"never" or "seldom" using medication as a

sleep aid. Of the 92 respondents who reported

using medication to help them sleep, 50 used

cold remedies or aspirin (the mostly

commonly reported medications), and 39 used

sleeping pills. A majority (88%) reported

"never" or "seldom" using alcohol to help

them sleep.

More than 91% rated themselves as "good"

or "very good" sleepers. Most of the group

(89%) reported that they had no sleep

problem. The 73 pilots who reported having

sleep problems cited circadian disruption (32

responses), being a restless sleeper (19), and

snoring and sleep apnea (10) as problems.

Only 6 pilots reported having had their sleep

problem diagnosed by a physician, and only 6

reported that the sleep problem had prevented

them from flying a scheduled trip.

4.1.3 Bunk Sleep (B747-100/200 and B747-

400 aircraft)

In the year preceding the study, each subject

used the crew rest facility on his or her current

aircraft an average of 21 times and used the

1.5

0.5

O

tel

Promote

/-

-0.5

-1

-1.5

Figure 1. How various factors affected sleep at home (Carrier 1).

7
facilities in other aircraft an average of 1.59

times. When asked which bunk they usually

used, respondents were about evenly split, with

36% reporting use of the upper bunk, 31% the

lower bunk, and 33% reporting either bunk.

Most (88%) reported having the opportunity

to undress for a more comfortable sleep, and

about the same percentage (81%) reported that

it was important for them to undress for a

comfortable sleep in the bunk. Crewmembers

reported that it took them an average of 44

minutes to fall asleep (range = 2-180 min.).

More than half (54%) reported difficulty

falling asleep in the bunk "often" or a

"majority of time."

Ninety-three percent of the subjects reported

that there were no requirements for them to

use the bunk. An open-ended question on the

factors determining bunk use and rostering

received 593 responses, which were grouped

into 7 categories. Seniority and crew decision

were cited in 229 responses (38%), identifying

it as a principal determinant. Ninety-nine

(17%) cited that crewmembers alternated

choice, 82 (15%) identified the schedule or

direction from the flight operations

department as a factor, 75 (13%) cited sleep

and circadian factors, and 70 (12%) listed

augmentation. Crewmembers reported, on

average, that 33% of cruise time was allocated

for each individual to use the bunk.

When asked about their overall attitude about

the bunk, nearly half of the group (49%)

indicated a "positive" or "very positive"

attitude, another 20% gave it a neutral rating,

while slightly under a third (31%) gave a

"negative" or "very negative" rating. Most

of the group (86%) reported that alertness was

"improved" or "very improved" by using

the bunk. A similar percentage (83%)

reported that performance was "improved" or

"'very improved" by bunk use. When asked

to rate their ability to sleep on the airplane in

areas other than the bunk, 27% reported that

they were able to sleep "often" or "almost

always" in a first class seat, 10% in a cockpit

seat, and 6 % in a passenger seat. Conversely,

74% reported ....never" or "seldom"

8

obtaining sleep in passenger seats, 63% in a

cockpit seat, and 31% in a first class seat.

Subjects rated 25 factors on how each factor

affected sleep in the bunk, using a scale from

1-"interferes" to 5-"promotes" (with a

middle rating of 3-"no effect"). The factors

most often identified as promoting sleep (i.e.,

rated 5) were pillows (13% of all "promote"

responses), and readiness for sleep (13%),

followed by blankets (11%), sheets (10%), and

sleep surface (9%). Factors most often rated

as interfering with sleep (i.e., rated 1) were

random noise (11% of all "interfere"

responses), trips to the bathroom (8%), and

thoughts (7%). Figure 2 shows mean ratings

scaled as described in section 4.1.2 (i.e.,

interfering factors as negative values and

promoting factors as positive). The 112

additional comments from an open-ended

"factor" at the end of the list were grouped

into 4 categories. Noise was cited as an

interfering factor in 51 responses. Sixty-one

other comments identified promoting factors:

physical comfort (42 responses), wearing ear

plugs (10), and a positive mental attitude (9).

Several of these were factors identified earlier

as promoting home sleep.

Crewmembers rated four additional factors on

the extent to which they interfered with bunk

sleep, using a scale from 1-"strongly

interferes" to 5-"no effect." Thirst (41%

rated it as 1 or 2) was the factor most often

rated as interfering, followed by personal

worries (33%) and hunger (28%). About twothirds (67%) rated respiratory factors as

having little or no effect (i.e., rated it 4 or 5).

When asked to specify other interfering

factors, subjects provided 230 general

comments, which were grouped into 7

categories, reinforcing that noise (75

responses), bunk discomfort (63), environment

(35), and physiological needs (33) interfered

with bunk sleep.
0.8

Promote

0

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

-1.0

-1.2

=.

-1.4

Figure 2. How various factors affected sleep in the bunk (Carrier 1).

An open-ended question on additional factors

that promoted bunk sleep yielded 950

responses, which were grouped into 8

categories. Comfort (292 responses or 34%),

environment (270, 20%), and fatigue (132,

16%), were most often cited.

Over half of the group (56%) reported using

ear plugs to minimize disturbances in the

bunk, while a quarter (25%) cited using

relaxation techniques. Fewer reported using

eye shades (11%) or listening to music (11%).

In a comment section, 123 subjects specified

reading or changing into comfortable clothes

as activities that helped them sleep.

Pre-trip strategies to promote bunk sleep (i.e.,

actions taken before boarding the aircraft)

were described by 553 subjects. Strategies

were grouped into 8 categories. The most

frequently reported pre-trip strategy (246

responses or 45%) was scheduling sleep at

home with regard to the predicted time of the

bunk period, thereby maximizing the ability to

sleep in the bunk. The next most frequently

cited strategy (137 responses or 26%) was to

bring comfort aids, such as cotton sheets and

pillow cases and soft, loose clothing (e.g., a

jogging suit) to enhance physical comfort.

when asked for suggestions on how to make

the crew rest facility more conducive to sleep,

crewmembers gave 1510 recommendations,

which were grouped into 7 categories.

Comfort was emphasized by 509 respondents

(34%). This category included larger and

thicker mattresses, cloth sheets and pillow

cases, and bigger pillows and blankets. More

soundproofing from random noises was

suggested by 409 respondents (27%). Other

suggestions included a larger bunk area (135

responses or 10%), more privacy (134, 9%),

and better environmental controls (124, 8%).

4.1.4 Comparisons within Carrier I

Aircraft Type

Data were analyzed for an aircraft-type effect.

Tests were conducted to compare responses

from crewmembers of B747-100/200 aircraft

(n = 498, 69%) with those from crewmembers

of B747-400 (n = 229, 31%).

T-tests were used to compare responses from

the two groups concerning demographics and

home sleep, with only one significant finding.

The '400 group rated themselves better as

9
home sleepers (t(717) = 2.35, p < .05) than did

the ' 100/200 group.

When bunk sleep data were compared, several

significant differences were found. The

percentage of cruise time '400 crews reported

spending in the bunk (46%) was almost twice

that of the '100/200 crews (26%) (t(364) =

28.43, p < .001). The two aircraft have

different crew requirements (2-person vs. 3-

person crew stations on the flight deck), which

may result in different rostering, and they may

be operated for different flight durations (see

sec. 5.1). The ' 100/200 group reported

greater difficulty sleeping in the bunk (t(708) =

5.21, p < .001) than did the '400 group.

Consistent with this finding, the '400 group

rated the bunk significantly better overall

(t(7o7) = 7.58, p < .00I). The improvements

to alertness and performance reported by '400

crewmembers were significantly greater than

those reported by the '100/200 group

(alertness t(708) = 6.12, p < .001; performance

t(706) = 5.29, p < .001). On the other hand,

the '100/200 group reported being able to

sleep in both cockpit seats (t(498) = 3.55, p <

.001) and first class seats (t(415) = 4.28, p <

.001) more often than the '400 group.

The influence of specified factors on bunk

sleep also were compared for an aircraft-type

effect. Factors reported to affect bunk sleep

were compared using a two-sample test for

equality of proportions. A proportion was

calculated by comparing the number of

"promote" (or "interfere") responses for a

given factor to the total number of "promote"

(or "interfere") responses for all 25 factors. In

this analysis, a "promote" response refers only

to a rating of "5-promotes"; likewise, an

"interfere" response refers to a rating of

"l-interferes."

Two promoting factors, "readiness for sleep"

and "curtains," were found to differ

significantly between the groups. A

significantly higher proportion of ' 100/200

pilots (15%) than '400 pilots (10%) identified

readiness for sleep to be a sleep-promoting

factor (X2(I) = 6.33, p < .05). A significantly

higher proportion of '400 pilots (15%) than

'100/200 pilots (5%) reported that curtains

10

promoted sleep (X2(1) = 46.47, p < .001).

Similarly, factors identified as interfering with

bunk sleep were compared. Two factors,

"trips to bathroom" and "turbulence,"

differed significantly between the two groups.

A higher proportion of '400 pilots (11%) than

'100/200 pilots (7%) rated trips to the

bathroom as interfering (X2(1) = 11.79, p <

.001). Additionally, a higher proportion of

'400 pilots (9%) than '100/200 pilots (6%)

rated turbulence as interfering (X2(I) = 9.10, p

< .01).

Age

Older crewmembers were compared to their

younger counterparts to reveal any age effects.

The group was divided into two age brackets,

based on an approximate mean split (mean =

44.5): 45 yr. or younger (N = 384), and older

than 45 yr (N = 346). The older group

reported greater use of medications to help

them sleep at home (t(701) = 2.19, p < .05).

The factors reported to promote sleep in the

bunk were compared using a two-sample test

for equality of proportions. No significant

differences were found. Likewise, factors

identified as interfering with sleep were

compared. A significantly higher proportion

of the older crewmembers (8%) than younger

(6%) indicated that heat interfered with bunk

sleep (X2(1) = 5.06, p < .05).

Examination of other bunk sleep variables

revealed one significant difference.

Improvements in overall alertness were

reported to a greater degree by the younger

group (t(708) = 2.69, p < .01) than by the

older group.

Good vs. Poor Sleepers

Subjects were classified as "good" or "poor"

sleepers based on how they rated themselves as

home sleepers (ratings of "good" and "very

good" were combined, as were "poor" and

"very poor"). A series of t-tests were

conducted to compare differences between the

two groups.

The groups exhibited several significant

differences regarding home sleep. Good

sleepers reported a higher average total sleep

time (7.9 h.) than poorer sleepers (7.3 h.)
(t(72)= 4.60,p < .001)andfewerdaytime

naps(t(916) = 2.15, p < .05). Predictably,

good sleepers reported having less trouble

getting to sleep (t(714) = 8.54, p < .001) and

using medication less often (t(72) = 3.56, p <

.001) to help them sleep.

Concerning bunk sleep, the good sleepers

reported a significantly shorter time to fall

asleep (17.8 min.) than did the poor sleepers

(34.7 rain.) (t(68) = 4.16, p < .001). Not

surprisingly, good sleepers also reported

having less difficulty sleeping in the bunk

(t(86) = 6.49, p < .001). They rated their

overall attitude toward the bunk significantly

higher (t(709) = 3.39, p < .01) than did the

poor sleepers, and they reported greater

improvement to both alertness (t(72) - 2.86, p

< .01) and performance (t(74) = 2.45, p < .05)

as a result of bunk sleep.

No significant differences were found between

the groups when factors affecting bunk sleep

were compared.

4.2 Carrier 2

Crewmembers from Carrier 2 completed and

returned 107 surveys of 220 sent (a 49%

response rate). Carrier 2 provided a much

smaller sample than either of the other carriers

because it operated fewer long-haul aircraft

equipped with bunks.

4.2.1 Demographics

Carrier 2 responses (see Appendix C) were

received from 62 Captains (58%) and 45 First

Officers (42%). All of the pilots in this group

were flying the MD-11 aircraft. Total flight

hours averaged 13,804 h. (range = 400 to

30,000 h.). Their experience flying long-haul

operations averaged 7.1 yr., ranging from

several months to 32 yr.

All of the subjects in this sample were male.

The group averaged 48.2 yr. of age and

ranged from 30 to 59 yr. The average weight

was about 182 lb. (range = 131-230 lb.), and

the average height was 70.8 in. (range =

66-75 in.).

The Central time zone was the most frequently

reported home time zone (55%) and the

Pacific time zone second most common

(34%). A majority (87%) reported having a

regular sleeping partner, and about a third

(34%) had one or more children younger than

18 living at home.

4.2.2 Sleep at Home

Data on home sleep habits were analyzed for

the 107 subjects. The average bedtime was

2258 h. (10:58 p.m.), and the average get-up

time was 0715 h. (7:15 a.m.). Subjects

reported that it took almost 18 min. to fall

asleep (mean = 17.6), and that they usually

awakened 1 or 2 times during the night. The

107 responses to an open-ended question on

the causes of awakenings were grouped into 5

categories. The main causes reported were

physiological needs (72 reports, or 68%) and

disturbances from family members or pets

(13). After awakening, it took subjects about

12 minutes (mean = 12.2 min.) to go back to

sleep. The average total sleep duration was

almost 8 hours (mean = 7 h. 50 min.). More

than half of the group (51%) reported

"never" or "seldom" taking a nap during

the daytime. Nearly two-thirds (64%)

reported "never" or "seldom" having

problems getting to sleep.

Subjects rated 18 factors on how each affected

home sleep, using the scale from 1-

"interferes" to 5-"promotes" (with the

middle rating 3-"no effect"). The factors

most often identified as promoting sleep (i.e.,

rated 5) were comfort aids, such as pillows

(15% of all "promote" responses), sleep

surface (11%), sheets (9%), and blankets (7%).

Proper ventilation (12%) was the second most

frequently selected promoting factor,

emphasizing the importance of environmental

factors. Readiness to sleep, representing the

physiological component of the ability to fall

asleep, was the third most frequently cited

factor and accounted for 11% of "promote"

responses. The factors most often cited as

interfering with sleep (i.e., rated 1) were heat

(20% of all "interfere" responses), thoughts

(15%), high humidity (13%), random noise

(13%), and trips to the bathroom (11%).

Figure 3 shows mean ratings scaled as

described in section 4.1.2 (i.e., with interfering

11
factors as negative values and promoting

factors as positive). These findings were

supported by the 10 responses to an "other

(specify)" comment question ending the list

of factors. The comments were grouped into

4 categories, all of which were cited as

promoting sleep: environment (5 responses),

good mental attitude (3), physical activity (1),

and comfort (1).

Respondents rated four specific factors for the

degree to which they interfered with sleep at

home, using a scale of 1-"strongly interferes"

to 5-"no effect." "Personal worries" was

cited most as interfering with sleep (with 55%

of the pilots rating it 1 or 2 on the scale),

followed by thirst (38% rated it 1 or 2), and

hunger (23%). Well over half of the subjects

(61%) rated respiratory factors as having iittig

or no effect. An open-ended question asked

for additional interfering factors. The 14

responses were grouped into 3 categories, with

the most common responses being noise (11

responses), pain (2), and mental attitude (1).

An open-ended question asking respondents

to list factors that promote home sleep yielded

137 responses, which were grouped into 8

categories. The following factors were most

often identified as promoting sleep: physical

environment (48 responsesm37% of the

responses), exercise and physical activities (23,

18%), comfortable sleep area (17, 13%), presleep activities (16, 13%), and good mental

attitude (15, 12%).

A majority of the group (87%) reported

"never" or "seldom" using medication as a

sleep aid. Of the 9 subjects who reported

using medication to help them sleep, 7 used

cold remedies or aspirin, and 2 used sleeping

pills. Most of the group (92%) reported

"never" or "seldom" using alcohol to help

them sleep.

Ninety-two percent rated themselves as

"good" or "very good" sleepers. Most of

the group (94%) reported that they had no

sleep problem. Those few (7) who reported

sleep problems cited being a restless sleeper, or

being disturbed by thoughts and worries.

Only 2 pilots reported having had their sleep

problem diagnosed by a physician, and none

reported that the sleep problem had ever

prevented them from flying a scheduled trip.

4.2.3 Bunk Sleep (MD-11 aircraft)

In the year preceding the study, each pilot

used the crew rest facility in his current aircraft

an average of 34 times and used the facilities

in other aircraft about 1 or 2 times.

Concerning which bunk they usually used,

68% of the subjects reported using the upper

bunk, 17% the lower bunk, and 15% reported

either bunk.

1.5

0.5 |-

Promote

,i-i-l -

-0.5

-1

-1.5

Figure 3. How various factors affected sleep at home (Carrier 2).

12
A large percentage (85%) reported having the

opportunity to undress for a more comfortable

sleep, and 60% reported that it was important

for them to undress for a comfortable sleep in

the bunk. It took crewmembers an average of

27 min. to fall asleep (range = 1 to 120 min.).

They typically slept an average of 1 h. 39 min.

in the bunk, and typical sleep durations ranged

from 20 min. to 3 h. 14 min. Subjects also

reported the longest and shortest bunk sleep

periods they had experienced. The longest

bunk sleeps reported averaged 2 h. 48 min.,

and the average shortest bunk sleep was 1 h. 4

min. More than a third of the group (35%)

reported "never" or "seldom" having

difficulty sleeping in the bunk. On the other

hand, nearly a third of the group (31%)

reported having difficulty sleeping in the bunk

"often" or a "majority of time." A quarter

(25%) of the group reported using the bunk

only for rest and not for sleep "often" or a

"majority of time."

Ninety-five percent of the subjects reported

that there was no requirement for them to use

the bunk. An open-ended question on the

factors determining bunk use and rostering

received 65 responses, which were grouped

into 6 categories. Seniority/crew decision was

reported by 35 (54% of responses),

identifying it as the principal determinant.

Pilots reported, on average, that 38% of cruise

time was allocated for each individual to use

the bunk.

Asked about their overall attitude toward the

bunk, a majority (87%) indicated a "positive"

or "very positive" attitude. Almost all of the

group (98%) reported that alertness was

"improved" or "very improved" by using

the bunk. Most (97%) also reported that

performance was "improved" or "very

improved" by bunk use. When asked to rate

their ability to sleep in various locations on the

airplane, 83% reported being able to sleep in

the bunk "often" or "almost always," 25%

in a first class seat, 8% in a cockpit seat, and

only 4% in a passenger seat.

Conversely, over three-quarters reported

"never" or "seldom" obtaining sleep in a

passenger seat (79%) or a cockpit seat (79%),

and 39% in a first class seat.

Subjects rated 25 factors on how each affected

bunk sleep, using a scale from 1-"interferes"

to 5-"promotes" (with a middle rating of

3-"no effect"). The factors most often

identified as promoting sleep (i.e., rated 5)

were pillows (14% of all "promote" responses),

readiness for sleep (10%), blankets (9%), and

comfortable clothing (7%). Factors most

often rated as interfering with sleep were

random noise (20% of all "interfere"

responses), bathroom trips (15%), heat (13%),

and random thoughts (9%). Figure 4 shows

mean ratings scaled as previously described

(i.e., with interfering factors as negative values

and promoting factors as positive). The 18

additional comments from an open-ended

question at the end of the list were grouped

into 2 "interfering" categories and the

remainder were "promoting" factors. Noise

was cited by 11 subjects as an interfering

factor, and the downward tilt of the head in the

bunk was cited by 4 subjects as interfering.

Promoting factors included fast cockpit access,

clean linens, and using an alarm.

Pilots rated five additional factors on the

extent to which they interfered with bunk

sleep, using a scale from 1-"strongly

interferes" to 5-"no effect." Thirst (36%

rated it as 1 or 2) was the factor most often

rated as interfering, followed by personal

worries (28%), hunger (22%), and

claustrophobia (10%). Almost three-quarters

(73%) rated respiratory factors as having little

or no effect. Asked to specify other

interfering factors, subjects provided 33

general comments grouped into 6 categories,

reinforcing that noise (17 responses) and

environment (4) interfered with bunk sleep.

Five subjects identified smoke from the flight

attendants as interfering as well.

13
1.5

1.0

0.5

-0.5

-1.0

-1.5

Promote

Figure 4. How various factors affected sleep in the bunk (Carrier2).

_An open-ended question on additional

factors that promoted bunk sleep yielded 104

comments, which were grouped into 8

categories. Quiet (25 responses), comfort

(15), and environment (14) were most

frequently cited.

A quarter of the group (24%) reported using

relaxation techniques to facilitate sleep in the

bunk, and only 20% of the group cited using

ear plugs. Very few reported listening to

music (6%) or using eye shades (3%).

Additionally, six identified reading as an

activity that helped them sleep.

Pre-trip strategies to promote bunk sleep (i.e.,

actions taken before boarding the aircraft)

were described by 46 subjects and were

grouped into 7 categories. The most

frequently reported pre-trip strategy (10

responses) was scheduling sleep at home with

regard t_o the predicted ti_me of_the bunk

period, thereby maximizing the ability to sleep

during the bunk period, The next most

frequently cited strategies were to limit food

intake (7), to avoid caffeine (5), to exercise (5)

and to limit food (4) and fluid (4) intake.

When asked for suggestions on how to make

the crew rest facility more conducive to sleep,

crewmembers gave 142 recommendations,

which were grouped into 7 categories.

Locating the bunk away from the galley was

the most common, cited by 36 respondents.

Another 25 proposed enhancing personal

comfort by providing larger and thicker

mattresses, cloth sheets and pillow cases, and

larger pillows and blankets. Improving

environmental controls (i.e., for ventilation,

humidity, and temperature) was suggested by

21 others. Soundproofing from random

noises was suggested in 15 responses.

4.2.4 Comparisons within Carrier 2

Aircraft Type

All subjects from Carrier 2 operated MD-11

aircraft, which precluded aircraft-type

comparisons for this data set.

Age

The data set was divided into 2 groups

according to age using the same criterion as

for Carder 1, that is, 45 yr. and younger (N =

44) vs. older than 45 (N = 63). When the

home sleep data from the two age groups were

14
compared, only one significant difference was

found. With regard to the usage of alcohol as

a sleep aid at home, the younger group

reported a slightly higher (F(I, 105) = 4.03, p <

.05) degree of usage than did the older group.

However, the average response from each

group corresponded to "never" or "seldom"

using alcohol as a sleep aid (i.e., 0-4

times/yr.).

When bunk sleep factors were compared for

age effect, only one significant difference was

found. The older group identified turbulence

as a factor that interfered with sleep

significantly more frequently (t(101) = 2.88, p

< .05) than the younger group (none of the

younger group rated it as an interfering

factor). Comparison of promoting factors

revealed no significant differences between the

groups.

Good vs. Poor Sleepers

Carrier 2 subjects were categorized as "'good"

sleepers or "poor" sleepers based on the

criteria used for Carrier 1 (see sec. 4.1.4).

However, because only 8 subjects (7%) in this

group rated themselves as poor sleepers,

statistical comparison was deemed

inappropriate.

4.3 Carrier 3

Crewmembers from Carrier 3 completed and

returned 560 surveys of 1500 sent (a 37%

response rate).

4.3.1 Demographics

Carrier 3 responses (see Appendix D) were

received from 171 Captains (32%), 295 First

Officers (55%), 68 Second Officers (13%),

and 4 International Relief Pilots (< 1%).

Slightly under half of this group (47%) were

flying the B747-100/200 series, while slightly

over half (53%) were flying the B747-400.

Total flight hours averaged 15,012 h., ranging

from 400 to 38,000 h. Crewmembers'

experience flying long-haul operations

averaged 8.6 years, and ranged from ten

months to 40 years.

The sample consisted of 541 males (98%) and

9 females. The average age was 51.2 yr., and

ranged from 26 to 73 yr. Sixty-two

crewmembers (11%) between the ages of 60

and 73 responded to the survey. The average

weight was 184 lb. (range = 105 to 280 lb.).

The average height was 70.7 in. (range = 62 to

81 in.).

The Pacific time zone was the most frequently

reported home time zone (44%), the Eastern

time zone second most common (22%), and

the Mountain time zone third (21%). A

majority of subjects (88%) reported having a

regular sleeping partner, and over a third

(36%) had children under the age of 18 living

at home.

4.3.2 Sleep at Home

Data on home sleep habits were analyzed for

the 560 subjects. The average bedtime was

2301 h. (11:01 p.m.), and the average get-up

time was 0721 h. (7:21 a.m.). Crewmembers

reported that it took about 20 minutes to fall

asleep (mean = 20.5 min.) and that they

usually awakened 1 to 2 times during the

night. The 522 responses to an open-ended

question on the causes of awakenings were

grouped into 6 categories. The most

frequently reported causes were physiological

needs (312 responses, or 59%), inability to

sleep (87, 17%), noise (51, 10%), and

disturbances from family members or pets (48,

9%). After awakening, it took subjects about

15 minutes (mean = 15.2 min.) to go back to

sleep. The average total sleep duration was

almost 8 hours (mean = 7 h. 50 min.). Half of

the group (50%) reported "never" or

"seldom" taking a nap in the daytime. Over

half (59%) reported "never" or "seldom"

having problems getting to sleep.

Respondents rated 18 factors on how each

affected home sleep, using a scale from

1-"interferes" to 5-"promotes" (with a

middle rating of 3-"no effect"). The factors

most often identified as promoting sleep (i.e.,

rated 5) were comfort aids such as pillows

(14% of all "promote" responses) and sleep

surface (14%). Readiness for sleep,

representing the physiological component of

the ability to fall asleep, was the third most

frequently cited factor and accounted for 13%

of "promote" responses. Proper ventilation

15
was also emphasized (11%). The factors most

often cited as interfering with sleep were

random thoughts (18% of all "interfere"

responses), heat (14%) and random noise

(12%). Figure 5 shows mean ratings scaled as

described in section 4.1.2 (i.e., with interfering

factors as negative values and promoting

factors as positive). These findings were

supported by responses to an "other

(specify)" comment question ending the ]ist.

All 60 of the responses were cited as

promoting sleep. The comments were

grouped into 4 categories: environment (26

responses), good mental attitude (15), physical

activity (12), and comfort (7).

Respondents rated four additional factors for

the degree to which they interfered with sleep

at home, using a scale of 1-"strongly

interferes" to 5-"no effect." "Personal

worries" was cited most as interfering with

sleep (63% of the crewmembers rated it 1 or

2), followed by thirst (49%), and hunger

(33%). More than half (53%) rated

respiratory factors as having little or no effect.

An open-ended question asked for additional

interfering factors. The 41 responses were

grouped into 5 categories, the most common

being noise (23 responses) and poor mental

attitude (9).

An open-ended question asking respondents

to list factors that promote their home sleep

yielded 872 responses, which were grouped

into 9 categories. The following factors were

most often identified as promoting sleep: good

physical environment (379 responses, or 43%),

comfort (144, 17%), and good mental attitude

(128, 15%).

Most of the group (99%) reported "never" or

"seIdom" using medications as a sleep aid.

Of the 92 subjects who reported using

medication to help them sleep, 62 used cold

remedies or aspirin, and 25 used sleeping pills.

A majority of the group (86%) reported

"never" or "seldom" using alcohol to help

them sleep.

About 90% rated themselves as "good" or

"very good" sleepers. A majority of the

group (86%) reported that they had no sleep

problem. The 84 subjects who reported sleep

problems cited being a restless sleeper (26

responses) or circadian disruption (17). Only

12 respondents reported having had the

problem diagnosed by a physician, and 15

reported that the problem had prevented them

from flying a scheduled trip.

1.5

Promote ]

3.5 -

-0.5

-1

-1.5

Figure 5. How various factors affected sleep at home (Carrier 3).

16
4.3.3 Bunk Sleep (B747-100/200 and B747-

4OO)

In the year preceding the study, each subject

used the crew rest facility in his or her current

aircraft an average of 26 times and used the

facilities in other aircraft about 2 times.

Concerning which bunk they usually used,

17% of the subjects reported using the upper

bunk, 49% the lower bunk, and 34% reported

either bunk.

A large percentage (71%) reported having the

opportunity to undress for a more comfortable

sleep, and 74% reported that it was important

for them to undress for a comfortable sleep in

the bunk. It took crewmembers an average of

42 min. to fall asleep (range = 1-300 min.).

They typically slept an average of 2 h. 22 min.

in the bunk, and typical sleep durations ranged

from 10 min. to 7 h. Subjects also reported

the longest and shortest bunk sleep periods

they had experienced. The longest bunk

sleeps reported averaged 3 h. 39 min., and the

shortest bunk sleeps averaged 1 h. 15 min.

Nearly half of the group (49%) reported

having difficulty sleeping in the bunk

"often" or a "majority of time," while a fifth

(20%) reporting having difficulty "never" or

"seldom." Additionally, more than a quarter

of the group (27%) reported using the bunk

for rest only (i.e., not sleep) "often" or a

"majority of time."

Ninety-three percent of the crewmembers

reported that there were no requirements for

them to use the bunk. An open-ended

question on the factors determining bunk use

and rostering received 384 responses, which

were grouped into 6 categories. Seniority/crew

decision was reported by 162 (43%),

identifying it as the principal determinant.

Length of flight was cited by 87 subjects

(23%) and augmentation by 70 (18%).

Subjects reported, on average, that 34% of

cruise time was allocated for each individual to

use the bunk.

When asked about their overall attitude about

the bunk, nearly three quarters of the group

(73%) indicated a "positive" or "very

positive" attitude. Most (91%) reported that

alertness was "improved" or "very

improved" by using the bunk. A similar

percentage (90%) reported that performance

was "improved" or "very improved" by

bunk use. When asked to rate their ability to

sleep in various locations on the airplane, 72%

reported being able to sleep in the bunk

"often" or a "majority of time," 32% in a

first class seat, 10% in a passenger seat, and 8%

in a cockpit seat. Conversely, high

percentages of respondents reported "never"

or "seldom" obtaining sleep in cockpit seats

(71%) and in passenger seats (67%).

Subjects rated 25 factors on how each affected

bunk sleep, using a scale from l-"interferes"

to 5-"promotes" (with a middle rating of

3-"no effect"). The factors most often

identified as promoting sleep (i.e., rated 5)

were comfort aids, such as pillows (13% of all

"promote" responses), curtains (11%), and

blankets (10%). Readiness for sleep,

representing the physiological component of

the ability to fall asleep, was third most

frequently cited and accounted for 11% of

"promote" responses. Factors most often rated

as interfering with sleep were random noise

(13 % of all "interfere" responses), turbulence

(10%), and trips to the bathroom (9%). Figure

6 shows mean ratings scaled as described in

section 4.1.2 (i.e., with interfering factors as

negative values and promoting factors as

positive). The 59 additional comments from

an open-ended question at the end of the list

were grouped into 4 categories. Noise was

cited by 24 subjects as an interfering factor.

Other comments identified promoting factors,

including physical comfort (25 responses) and

good mental attitude (4).

Crewmembers rated five additional factors on

the extent to which they interfered with bunk

sleep, using a scale from 1-"strongly

interferes" to 5-"no effect." Thirst (43%

rated it as 1 or 2) was the factor most often

rated as interfering, followed by personal

worries (41%), hunger (33%), and

claustrophobia (8%). More than half (61%)

rated respiratory factors as having little or no

effect. Asked to specify other interfering

factors, subjects gave 119 comments, which

17
1.5 "-

1.0

0.5

0

-0.5

-1.0

-1.5

Promote

Figure 6. How various factors affected sleep in the bunk (Carrier 3).

were grouped into 6 categories, reinforcing

that noise (40) and physiological needs (21

responses) interfered with bunk sleep.

An open-ended question on additional factors

that promoted bunk sleep yielded 671

responses, which were grouped into 8

categories. Environment (342 responses, or

46%) and comfort (206 or 27%) were most

frequently cited.

Nearly a third of the group (32%) reported

wearing ear plugs to minimize disturbances in

the bunk, and 31% reported using relaxation

techniques. Some listened to music (18%) or

wore eye shades (12%). In a comment section,

subjects identified reading (61 responses) or

changing into comfortable clothes (23) as

activities that helped them sleep.

Pre-trip strategies to promote bunk sleep (i.e.,

actions taken before boarding the aircraft)

were descn'bed by 433 subjects and were

grouped into 8 categories. The most

frequently reported pre-trip strategy (219

responses, or 50%) was scheduling sleep at

home with regard to the predicted time of the

bunk period, thereby maximizing the ability to

sleep during the bunk period. The next most

frequently cited strategy was to avoid caffeine

(56 responses, or 13%).

When asked for suggestions on how to make

the crew rest facility more conducive to sleep,

subjects gave 896 recommendations, which

were grouped into 7 categories. Comfort was

emphasized by 312 respondents (35%),

including larger and thicker mattresses, cloth

sheets and pillow cases, and bigger pillows and

blankets. Soundproofing from random noises

was suggested by 187 respondents (21%).

Other suggestions included a larger bunk area

(93 responses, or 11%), more privacy (87,

10%), and better environmental controls (78,

9%).

4.3.4 Comparisons within Carrier 3

Aircraft Type

Data from Carrier 3 were analyzed for an

aircraft-type effect in the same manner as for

Cartier 1. Tests were run to compare

responses from crewmembers of B747-

100/200 aircraft (N= 257 or 47%) with those

from crewmembers of B747-400's (N= 291

or 53%).

18
When demographic and home sleep data were

compared for significant differences, the

'100/200 group was found to be significantly

older and more experienced. On average, the

'100/200 group (mean age = 53.0 yr.) was 3.4

years older than the '400 group (49.6 yr.)

(F(1,546) = 23.35, p < .001), reported nearly

3,000 more total flight hours (F(I, 535) =

23.85, p < .001), and had 4 yr. more

experience flying long-haul operations (F(1,

443) = 23.19, p < .001).

Comparison of bunk sleep data also revealed

several differences. The '100/200 group

reported an average sleep latency of

approximately 38 rain., which was about seven

minutes less than the average reported by the

'400 group (Fo, 474) = 5.52, p < .05). The

average duration of bunk sleep periods

differed dramatically between the two groups

(F(1,483) = 321.63, p < .001), with the '400

group reporting nearly twice as much sleep

(3.1 h.) on average than the '100/200 group

(1.4 h.). The two aircraft have different crew

requirements (2-person vs, 3-person crews),

which may result in different rostering, and

they may be operated for different flight

durations.

The groups' overall ratings of the bunk

facility differed significantly (F(l, 405) =

112.07, p < .001), with the '400 receiving

superior ratings. The ratings by '400

crewmembers corresponded to an assessment

between "positive" and "very positive,"

while the assessment by ' 100/200 crews was

closer to "'neutral." Further, when rating how

bunk sleep affected alertness (F(1,533) =

31.66, p < .001) and performance (F(I, 531) =

36.31, p < .001), '400 crewmembers indicated

more improvement than did the '100/200

crews.

The influence of specified factors on bunk

sleep also were compared for an aircraft-type

effect. The degree to which factors interfered

with bunk sleep were compared using a 2-

sample test for equality of proportions.

Responses from the two aircraft groups

differed concerning several factors. A higher

proportion of the '400 group identified heat

(X2(l) = 5.20, p < .05), random thoughts (Z2(1)

= 3.96, p < .05), bathroom trips (Z2(1) = 40.08,

p < .001), and turbulence (p < .001) as

interfering factors than the ' 100/200 group.

The proportion of the ' 100/200 group (14%)

citing random noise as an interfering factor

was higher (X2(1) = 4.04, p < .05) than that of

the '400 group (11%). The two aircraft

groups showed more consistency in

identifying factors that promoted bunk sleep,

though a higher proportion of '400 group

(10%) reported sheets as promoting sleep

(X2(D = 4.99, p < .05) than that of the

'100/200 group (7%).

Age

The data set was divided into 2 groups

according to age using the same criterion as

for Carrier 1 (i.e., 45 yr. and younger vs. older

than 45). Because this group was slightly

older than the others, the age 45 break led to

unequal group sizes (N= 138 for the younger

group, and N= 405 for the older).

The two age groups reported different get-up

times at home (F(I, 541) = 5.99, p < .05), with

the younger group waking up about 15

minutes later than the older group. Consistent

with this finding, the younger group's typical

sleep duration was about 14 minutes longer

than that of the older group (F(I, 542) = 9.08,

p < .01). The groups reported falling asleep at

similar times.

The other significant difference in the home

sleep data concerns the use of alcohol as a

sleep aid. The younger group reported using

alcohol as a sleep aid slightly more frequently

(F(I, 206) = 5.61, p < .05) than the older

group. However, the average response from

each group corresponded to "never" or

"'seldom" using alcohol as a sleep aid (i.e., 0

to 4 times/yr.).

When bunk sleep factors were compared for

age effect, only one significant difference was

found. The younger group identified

"comfort of clothing" as a promoting factor

more frequently (Z2(1) = 11.59, p < .001) than

did the older group. No significant

differences were found in factors that

interfered with sleep.

19
Good vs. Poor Sleepers

Carder 3 subjects were categorized as "good"

sleepers or "poor" sleepers by the criteria

used for Carder 1. About 90% of the subjects

were classified as good sleepers, and the poor

sleep group comprised only 10%.

Demographically, no significant differences

were found between the two groups. When

home sleep data were compared, sleep latency

and total sleep duration were found to differ

significantly. The poor sleep group reported

an average sleep latency of about 34 min.,

which is more than 15 min. longer than

average latency reported by the good sleep

group (F(1, 61) = 5.61, p < .01). Consistent

with this finding, the poor sleepers reported

sleep durations that averaged 36 min. shorter

than those of the good sleepers (Fo, 62) =

19.30, p < .001). Not surprisingly, the poor

sleepers also reported having more difficulty

getting to sleep than the good sleepers (F(1,

543) = 65.48, p < .001). The poor sleep

group's average rating corresponded to

"sometimes" (1-3 times/mo.) having

problems getting to sleep, while the good sleep

group's average rating corresponded to

"seldom" (1-4 times/yr.) having problems.

The poor sleepers also reported using

medication more often (F(I, 59) = 19.41, p <

.001) to help them sleep.

Consistent with the home sleep differences, the

poor sleep group reported an average bunk

sleep latency of 52.5 min., which was 12 min.

longer than that of the good sleep group (F(1,

505) = 6.65, p < .01). Further, the typical

duration of bunk sleep reported by the poor

sleepers (mean = 1.9 h.) was about 30 min.

less (F(I, 517) = 5.82, p < .05) than that of the

good sleepers (mean = 2.4 h.).

No differences were found between the two

groups concerning overall attitude toward the

bunk or the effects of bunk sleep on alertness

and performance.

4.4 Comparisons Across All Three

Carriers

4.4.1 Demographics

Demographic data were compared among the

three carriers using one-way analysis of

variance (see table 1). A significant difference

was found in the number of flight hours (F2,

1360 = 24.17, p < .001), with Carder 3

reporting the most (mean = 15,012 h.) and

Carder 1 the least (mean = 12,436 h.). A

Tukey post hoc comparison test revealed that

the difference between Carders 1 and 3 was

significant (p < .01).

The three groups differed significantly in age

as well (F2, 1384 = 104.03, p < .001).

Consistent with the differences in flight hours,

Carrier 3 was the oldest group (average age

51.2 yr.), and Carrier 1 the youngest (average

44.5 yr.). Post hoc Tukey tests showed

significant age differences (p < .01) among all

three carders.

Table 1. Demographic differences among the three carriers.

Flight Hours

Carrier 1

(n= 737)

mean (SD)

Height (in)

12436 (6219)

Carrier 2

(n= 107)

mean (SD)

13282 (7017)

Carrier 3

(n= 560)

mean (SD)

15012 (6796)

71.3 (2.5)

24.17 (2,1360)

P

<.001

Years Exper. 8.8 (7.2) 7.1 (7.6) 8.6 (9.4) 2.36 (2,1384) .09

Age 44.5 (8.2) 48.0 (9.8) 51.2 (8.3) 104.03 (2,1384) <.001 ***

<.001 ***

Weight (Ib)

70.8 (2.1)

181.7 (21.4)

25.5 (2.6)

0.4 (0.8)

Body Mass Index

183.6 (23.5)

70.7 (2.7)

184.1 (24.5)

25.9 (2.8)

0.4 (0.7)

25.4 (2.9)

8.77 (2,1381)

0.47 (2,1381)

4.44 (2,1334)

0.7 22.80 (2,302) Kids at Home (0.9)

.63

<.05 *

<.001

20
The groups differed significantly in height

(F2,1381 = 8.77, p < .001) and in body mass

index 2 (BMI) (F2,1334 = 4.44, p < .05).

Carrier 1, the youngest group, was also the

tallest and had the lowest average BMI, while

Carrier 3, the oldest group, had the lowest

average height and the highest average BMI.

Post hoc Tukey tests for height (p < .01) and

BMI (p < .05) showed that the differences

between Carriers 1 and 3 were significant.

Body mass index was computed for the 1337

subjects who provided the necessary data. The

average BMI was 25.6 kg/m 2. An acceptable

BMI falls between 20 and 25 kg/m 2. The

BMI's for 41% of the sample were in this

range. A small number (2%) were on the

"light" end of the scale (i.e., below 20), while

about half (50%) were in the "overweight"

range, with BMI's between 25 and 30. A BMI

of 30 or greater indicates "obesity", and 7%

of the subjects fell into this range.

These data were analyzed to examine any

correlation between body mass index and a

subject's ability to sleep at home (e.g.,

"good," "poor,"). BMI and type of sleeper

did not correlate significantly. A one-way

analysis of variance compared the BMI for

each of the sleeper categories (i.e., "poor,"

"fair," "good," "very good"). While the

BMI was highest in the small group of

"poor" sleepers, the difference was not

statistically significant. Further, each BMI

range had a high percentage of "good" and

"very good" sleepers. About 90% of subjects

within the acceptable BMI range (i.e., 20-25)

rated themselves as "good" or "very good"

sleepers. A similar proportion (91%) of

subjects in the "overweight" BMI range of

25-30 rated themselves as "good" or "very

good" sleepers. Even in the "obese" group

(i.e., BMI over 30), most (86%) rated

themselves as "good" or "very good"

sleepers.

Carrier 1 also reported a significantly higher

number of children under the age of 18 living

at home (1=2,302 = 22.80, p < .001). While the

group averages were all quite low (each group

averages less than one child), the average for

Carrier 1 was nearly twice that for either of the

other two. A post hoc Tukey (p < .01) showed

this difference to be significant. The average

age of Carrier 1 (44.5 yr.) most likely

accounts for the higher number of children at

home.

4.4.2 Sleep at Home

Home sleep data from the three carders were

compared using one-way analysis of variance

(see table 2). There were no significant

differences among the carrier groups for these

questions.

The data regarding factors that affected home

sleep were analyzed as well. Because the three

groups did not differ significantly in their

responses to questions on home sleep, the data

were combined into one set, which was

subjected toa principal components analysis.

The ten factors that were found to promote

home sleep were analyzed together. The

following three principal components

accounted for nearly 59% of the total

variance:

1 ) Sleep microenvironment (e.g., sheets,

blankets, pillows; 37.5% of variance)

2) Sleep preparedness (e.g., comfort of

clothing, ready for sleep; 11.2%)

3) Sleep macroenvironment (e.g., cold,

sleep surface; 10.0%)

Likewise, the seven factors that were found to

interfere with home sleep were analyzed.

Again, three principal components accounted

for about 57% of the total variance, which

were"

: BMI = weight / height 2 (kg/m 2)

21
Table 2. Differences in home sleep among the three carriers.

Carrier 1 Carrier 2 Carrier 3 F p

(n= 737) (n= 107) (n= 560)

mean (SD) mean (SD) mean (SD) -i

Asleep (local time) 2256 (0:49) ] 2256 (0:58) 2301 (0:56) ......... 0.60 (2,1379) .55

Get Up(Iocattime) 0719 (1:01) 0709 (1:15) 0718 (1:05) 1.08 (2,1384) .34

Latency (min) 19.4 (27.5) 17.6 (13.9) 20.5 (17.7) 1.09 (2,1382) .34

Sleep Duration (hr) 7:52 (0:50) 7:50 (0:47) 7:49 (0:53) 0.35 (2,1376) .70

1) Environmental disturbances (e.g.,

background noise, lighting, random

noise; 26.0%)

2) Personal disturbances (e.g., trips to the

bathroom, thoughts; 16.0%)

3) Environmental discomfort (e.g., high

humidity, heat; 15.0%)

4.4.3 Bunk Sleep

The ratings for factors that affect bunk sleep

by all groups together are shown in figure 7.

Figure 8 shows the ratings grouped by type of

aircraft flown.

Bunk sleep factors were analyzed for principal

components as well. Analysis of the 11 factors

found to promote bunk sleep revealed that the

following three principal components

accounted for about 71% of the total variance:

1) Sleep microenvironment (e.g.,

blankets, pillow, sheets; 49.0%)

2) Sleep macroenvironment (e.g., facility

size, bunk size, ventilation; 11.5%)

3) Sleep preparedness (e.g., ready for

sleep, comfort of clothing; 10.0%)

Likewise, the 12 factors identified as

interfering with sleep were analyzed, and the

following five principal components

accounted for about 56% of the total variance:

Promote

0.5

i - -=-

-0.5

-1.0

-1.5

Figure 7. Ratings of bunk factors by all subjects as a group.

22
2.0

Promote

Figure 8. Ratings of factors that affect bunk sleep grouped by type of aircraft flown.

1) Luminosity (e.g., lighting, illuminated

seat belt sign; 17.4%)

2) Environmental disturbances (e.g.,

background noise, turbulence, random

noise; 11.2%)

3) Personal disturbances (e.g., trips to the

bathroom, thoughts; 9.8%)

4) Environmental discomfort (e.g., low

humidity, cold; 8.7%)

5) Sleep macroenvironment (e.g., bunk

partner, heat; 8.5%)

The remaining data regarding bunk sleep

issues were compared across carriers using

one-way analysis of variance (see table 3).

Reports of bunk sleep latency were found to

differ significantly (F2,299 = 21.32, p < .001)

among the three carriersL The average

latency reported by Carrier 2 (26.6 min.) was

shorter than each of the other two, Carder 1

(41.4 min.) and Carrier 3 (39.2 min.). Post

hoc Tukey tests showed these differences to be

significant (p < .01). Different carders may

30utliers were removed from this data set according to

the following criteria: if a subject reported a sleep

latency of over 2 hours without reporting any total sleep

time, the latency value was not included in the analysis.

Such a subject was identified as one who does not sleep

in the bunk, and the sleep latency measure was

considered inapplicable.

operate different trip patterns, resulting in

bunk periods at different times of day.

Circadian factors make it easier to fall asleep at

certain times of the day and more difficult at

others.

Bunk sleep durations reported by Carriers 2

and 3 were compared (the survey of Cartier 1

did not include this question). The duration

reported by Carrier 3 (mean = 2.4 h.) was

significantly longer (F1,250 = 53.37, p < .001)

than that of Carrier 2 (mean = 1.7 h.). Carder

3 may have operated longer flights, and the

two carriers may have had different rostering

practices.

To facilitate analysis of variance, multiplechoice responses with word-based scales were

converted into a numerical code. Answers

were coded from 1 to 5, in order of the

responses as they appeared in the survey (see

Appendix 1). Lower values indicated

"negative" or "less frequent" responses, and

higher values corresponded to "positive" or

"more frequent" responses.

Reports of difficulty sleeping in the bunk

differed-significantly among the groups

(F2,1359 = 16.32, p < .001). Post hoc Tukey

comparisons revealed that Cartier 2 reported

significantly fewer problems (p < .01) than

either of the other two carriers. The average

• 23
Table 3. Comparison of crewmember bunk sleep by carrier.

Carrier 1

(n= 737)

mean (SD)

Carrier 2

(n= 107)

mean (SD)

26.6 (19.5)

Carrier 3

(n: 560)

mean (SD)

P

Latency (rain) 41.4 (28.6) 39.2 (28.6) 21.32 (2,299) <.001 ***

Sleep Duration (hr) no data 1:39 (0:43) 2:22 (1:23) 53.4 (1,1250) <.001 ***

group response for Carrier 2 (3.0) signified

that the group "sometimes" had difficulty

sleeping, while the higher averages for carriers

1 (3.6) and 3 (3.5) indicated a frequency

between "sometimes" and "often."

There was a significant group effect (F2,322 =

107.63, p < .001) regarding overall attitude

about the bunk. Post hoc Tukey tests showed

that each of the carders differed significantly

(p < .01) from the other two. On a 5-point

scale from "very negative" through

"neutral" to "very positive," Carrier 2 gave

the most favorable rating, with an average

response (4.5) in the "positive" to "very

positive" range; Carder 3 reported an

intermediate rating, with an average response

(3.9) just below the "positive" rating; and

Carrier 1 gave the lowest rating of the three,

with an average response (3.3) near the

"neutral" rating point.

Reports of how bunk sleep affected overall

alertness also displayed a significant group

effect (F2,311 = 35.35, p < .001). Post hoc

Tukey tests showed that all three carriers

differed significantly (p < .01) from one

another. Carder 2 reported the highest rating

(mean = 4.5) indicating an effect midway

between "improved" and "very improved";

the average rating from Cartier 3 (4.2) was

intermediate; and the rating from Carder 1

(4.0) indicated "improved".

Finally, there was a significant group effect

(F2,1359 = 27.46, p < .001) regarding how

bunk sleep affected overall performance. Post

hoc Tukey tests revealed that all three carriers

differed significantly (p < .01) from one

another. Carrier 2 reported the highest rating

(mean = 4.4), signifying an effect between

"improved" and "very improved," while the

average responses for Carders 3 (3.9) and 1

(4.1), were near the "improved" rating.

4.4.4 Aircraft Type Comparisons

Combined data from all surveys were analyzed

with respect to aircraft type. Each subject

operated one of three aircraft types: B747-

100/200, B747-400, or MD-11. The sample

represented 756 B747-100/200 crewmembers

(55%), 519 pilots of the B747-400 (38%), and

108 MD-I 1 crewmembers (8%). All of the

MD-11 crews were from Carder 2, and all

crews of the B747 series ('100/200 and '400)

were from either Cartier 1 or 3.

One-way analyses of variance were conducted

to reveal differences between the aircraft

bunks (see table 4). There was a significant

difference (F2,344 = 29.16, p < .001)

regarding bunk sleep latency. Post hoc Tukey

comparisons showed that the average bunk

latency reported by the MD-11 group (25.8

min.) was significantly shorter (p < .01) than

the latencies for both the '100/200 group

(42.2 min.) and the '400 group (44.2 min.).

Maximum values of 4 and 5 h., respectively,

were reported by the '100/200 and '400

groups, while the maximum latency reported

by the MD-11 group was only 2 h. Even with

these extreme values removed from the

analysis set, the statistical result was significant.

24
Table 4. Comparison of crewmember bunk sleep by aircraft.

B747-100/200 B747-400 MD-11 F p

mean (SD) mean (SD) mean (SD)

Latency (rain) 42.2 (33.4) 44.2 (39.0) 25.9 (20.0) 29.2 (2,344) <.001 ***

Sleep Duration (hr) 1:26 (0:50) 3:07 (1:16) 1:39 (0:43) 167.04 (2,301) <.001 ***

Total bunk sleep duration was analyzed for

Carriers 2 and 3 (the survey of Carder 1 did

not include this question). The subjects in this

analysis were 225 crewmembers of B747-

100/200's, 270 of B747-400"s, and 96 of

MD-1 l's. A significant between-groups effect

(F2,301 = 167.04, p < .001) was revealed. Post

hoc Tukey tests showed that the '400 group

reported a significantly longer (p < .01) bunk

sleep duration of 3.1 h., more than 1.5 h.

longer than the durations reported by the

other two aircraft groups. It is possible that

the '400 aircraft is operated on longer flights,

therefore more cruise time, than the other

aircraft, or that '400 crews are augmented by

only one crewmember (total of 3) instead of

two (total of 4), allowing each crewmember

more time in the bunk.

The groups also displayed significant

differences concerning their reports of

difficulties sleeping in the bunk (F2,1340 =

39.23, p < .001). The '100/200 group

reported the most frequent difficulties, with an

average response (3.7) approaching "often."

The '400 group's average rating (3.3) was

closer to "sometimes," and the MD-11 group

reported the lowest frequency, with its average

response (3.0) corresponding exactly to

"sometimes" (see fig. 9). Post hoc Tukey

tests showed significant differences (p < .01)

among all three aircraft groups.

Overall attitude about the bunk (F2,320 =

161.46, p < .001) also differed significantly

among the groups. MD-11 pilots gave the

most positive rating, with an average response

(4.5) midway between "positive" and "very

positive"; the '400 group gave an average

response (4.1)just above the "positive" level;

and '100/200 crewmembers gave the most

negative rating, with an average response (3.2)

close to a rating of "neutral" (see fig. 10).

Post hoc Tukey tests revealed significant

differences (p < .01) among the ratings of the

three aircraft types.

Consistent with these findings, ratings of how

bunk sleep affected alertness also displayed a

significant group difference (F2,1345 = 59.29,

p < .001) (see fig. 11). Again, the MD-11

group returned the highest rating, an average

response (4.5) midway between "improved"

and "very improved." The '400 group also

gave a positive rating, with an average response

(4.3) better than "improved." The ' 100/200

maj of time_5

often--4

¢7)

,- sometimes--3

¢U

n- seldom--2

never'i

100/200 400 MD-11

Figure 9. Ratings of difficulty sleeping in the bunk grouped by type of aircraft.

25
C7)

¢..

.I

very pos--5

neutral--3 _

r j--2

very hegel

100/200 400 MD-11

Figure 10. Overall ratings of the bunk grouped by type of aircraft.

no change--3 '

tel

rr decreased---2 '

very decr--1

:= :.. ±

..... . ,............:

100/200 400 MD-11

Figure 1 I. Ratings of how bunk sleep affected alertness grouped by type of aircraft.

group again gave the lowest rating, yet its

average response (3.9) was just under the

rating that corresponds to "improved'"

alertness. While post hoc Tukey tests showed

the differences among the three aircraft

groups to be significant (p < .01), each group

nevertheless indicated that bunk sleep

improved alertness. Also noteworthy is that

the lowest individual rating from the MD-11

group was "no change"; no subjects from this

group rated the bunk as having a negative

effect on alertness. Very small percentages of

the '400 group (2%) and the '100/200 group

(6%) reported negative effects.

Similarly, ratings of bunk sleep's effect on

performance displayed a significant group

difference (F2,1340 = 55.86, p < .001) (see fig.

12). Again, the MD-11 group gave the

highest rating, an average response (4.4)

almost halfway between "improved" and

"very improved." The '400 group also gave

a high rating, with an average response (4.2)

also better than "improved." As with the

t--

.i

¢t"

very incr--5

increased_4

no change--3

decreased---2

very decr--1

100/200 400 MD-11

Figure 12. Ratings of how bunk sleep affected performance grouped by type of aircraft.

26
alertness effect, the '100/200 group gave the

lowest rating, an average response (3.9)

slightly below the value that corresponds to

"improved" performance. Post hoc Tukey

tests showed that the rating of the '100/200

was significantly lower (p < .01) than the

ratings of the other two aircraft.

The 25 factors evaluated for their effects on

bunk sleep were compared across aircraft type

as well. The factors were assessed using the

scale from -2 to 2, so that "interfere"

responses were expressed as negative values

and "promote" responses as positive values

(see sec. 4.1.2). The scaled totals were

analyzed across aircraft types using a KruskalWallis rank test. While the '1001200 and MD11 showed a tendency towards difference, it

was not statistically significant.

Figure 13 shows the average scaled ratings of

some factors that appear to display differences

among aircraft types. Several facility

parameters exhibited differences, including

facility size, bunk size, head space, storage

space, and privacy. While the '100/200 group

rated each of these factors as interfering

overall, both the '400 and MD-11 groups

rated each as promoting overall. One-way

analysis of variance revealed significant

differences for each of these factors (p < .01),

with the ratings from the "100/200 group

identifying these factors as significantly more

interfering than ratings from either of the

other groups.

Also, the ratings for turbulence were

significantly worse (i.e., rated as more

interfering) for both the '100/200 and the

'400 than for the MD-11. One-way analysis

of variance indicated that turbulence ratings

were significantly different (F2,1346 = 25.72, p

< .001) across the three aircraft types. Post

hoc Tukey tests showed significant differences

(p < .01) among all three. Thus, turbulence

was rated as being notably least interfering to

sleep in the MD-11, and as most interfering in

the '400.

4.4.5 Bunk Sleep Difficulties, Special Analysis

Overall, the percentage of crewmembers

reporting difficulty failing asleep in the bunk

"often" or a "majority of time" (51%)

differed significantly from that of

crewmembers reporting difficulties at home

with those frequencies (6%).

To explore any negative effect of the bunk

facility on sleep, a special set of analyses was

conducted. Subjects who rated themselves as

0.7

06

O5

04

03

02

01

0

-0.2

-0.3

-0.4

[] 100/200

• 400

[] MD-11

Figure 13. Rest facility parameters that exhibited significant differences among aircraft.

27
good sleepers at home were analyzed for

difficulties sleeping in the bunk. This analysis

was designed to expose the most extreme

difference between good ability to sleep at

home versus poor ability to sleep in the bunk.

The bunk facility itself presumably would be

one of the main variables that would account

for the observed differences.

Combining data from the three carders, 1254

subjects (91%) rated themselves as good home

sleepers (i.e., "good" or "'very good"). Of

these, 1227 responded to a question on how

frequently they experienced difficulty

sleeping in the bunk (on a five-point scale

from "never" to "majority of time").

Nearly half (47%) reported having difficulty

sleeping in the bunk "often" or the

"majority of time." If those who reported

"sometimes" having difficulty are included,

over three quarters (81%) of the good home

sleepers reported having difficulty sleeping in

the bunk.

The set of good home sleepers who reported

having difficulties sleeping in the bunk

"'often" or the "majority of time" was

compared to the set of good home sleepers

who reported "never" or "seldom" having

difficulties sleeping in the bunk. When the

ages of these two groups were compared using

a one-way analysis of variance, a significant

difference (F1,798 = 13.28, p < .001) was

found. The group that reported fewer

difficulties sleeping in the bunk was 2.5 yr.

older on average (49.3 yr.) than the group that

reported regular difficulties (46.8 yr.). This

result is in contrast with the general finding

that, under normal sleep conditions, older

groups tend to experience more, rather than

fewer, sleep difficulties than younger groups.

Of the subjects who reported being good

home sleepers, 648 flew the '100/200 series

aircraft. Of these, 58% reported having

difficulty sleeping in the bunk "often" or the

"majority of time." Crews of the '400

included 467 good home sleepers, with 37%

reporting regular difficulties sleeping in the

bunk. Good home sleepers from the MD-11

group numbered 96, with 28% reporting

regular difficulties in the bunk.

When the good home sleepers who reported

regular difficulties sleeping in the bunk were

compared by aircraft type, a test for equality

of proportions showed a significant difference

(Z2(2) = 62.87, p < .001). Post hoc pairwise

comparisons revealed that the frequency of

difficulties reported in the '100/200 was

significantly greater than that in either the

'400 (Z2(]) = 46.27, p < .001) or the MD-11

(Z2(1) ---- 28.60, p < .001). Thus, a

significantly greater proportion of good home

sleepers reported regular difficulties sleeping

in the bunk of the '100/200 aircraft.

Comparing the sets of good home sleepers

70%

60%

....... 2._o.:._ ,-7 ..-_

50% 40%

20°/o

5 2 Ui::12

10°1o -=......

0%

100/200 400 MD-11

Figure 14. Good sleepers who reported regular difficulty sleeping in bunk, grouped by aircraft.

28
who reported "never" or "seldom" having

difficulties sleeping in the bunk also revealed

significant differences among aircraft types

(Z2(2) = 28.77, p < .001). Post hoc pairwise

comparisons showed that each of the three

groups differed from the other two. The MD11 group reported the highest proportion

(36%) of infrequent difficulties, which was

significantly greater than the 22% of the '400

group who reported infrequent problems

(Z2(1) = 8.17, p < .01), and than the 15% of

the '100/200 group (X2(1) = 25.53, p < .001).

Additionally, the proportion of subjects who

reported infrequent problems in the '400 was

significantly greater (_2(1) = 9.22, p < .01)

than in the '100/200.

The converse situation also was considered by

examining poor home sleepers. Of the 128

subjects from all three carriers who reported

being poor home sleepers, over 6% reported

"seldom" having difficulty sleeping in the

bunk. Further, while this group reported an

average bunk sleep latency of nearly an hour

(57.3 min.), it also reported a mean bunk sleep

duration of 1.86 h., demonstrating that even

poor home sleepers reported being able to

sleep in the bunk once they

fell asleep.

5.0 Discussion

5.1 Caveats

As in any operational study, certain factors are

beyond the control of investigators.

Therefore, limitations of the data should be

kept in mind when drawing conclusions or

making recommendations.

A survey study has the inherent limitation that

the data gathered are subjective, and are

therefore defined by the subject's perception,

memo_, and interpretation of the question.

Additionally, subjectivity plays a welldocumented role in people's perception of

their sleep (ref. 13). Individuals are known to

make inaccurate estimates of their sleep

latency times, sleep durations, awakenings, and

other parameters. In many of the survey

questions, response choices included

quantitative definitions (e.g., "often--I--4

times/wk") to avoid broad interpretation of

descriptors. In other cases, subjects'

perceptions were the targeted data (e.g., "Rate

your overall attitude about the bunk.").

Nevertheless, the subjective nature of survey

data limits the generalizability of these results.

The data were statistically limited in that

Carrier 2 was a much smaller data set than the

other two carders. While Cartier 2 had the

highest return rate (49% return vs. 35% and

37% from Carriers 1 and 3, respectively), the

number of surveys from Carrier 2 was much

smaller (107 surveys compared with 737

surveys from Carder 1 and 560 from Carrier

3). This discrepancy in sample size may have

affected the ability to reach statistical

significance in some of the analyses

comparing the three carriers. Likewise, the set

of MD-11 crewmembers was a much smaller

set than those of the other two aircraft types.

Confounding the matter, all of the MD-11

crewmembers were from Carrier 2, and all

Carrier 2 crewmembers flew the MD-11.

Therefore, it was impossible to isolate the

factor (i.e., the aircraft vs. the carder) that

contributed to the MD-I 1 specific responses.

Independent of any aircraft-type effect, the

culture of a specific carrier, its hub location, or

other characteristics may have affected

responses from that carder's crewmembers.

The same type of limitation arises from the

fact that age and flight experience differed

among carriers. Subjects from Carder 3 were

significantly older than those from Carder 2,

who were significantly older than Carder 1

subjects. Consistent with the age difference,

Carrier 3 crews had significantly more flight

hours than did Carder 1 crews. Therefore, the

difference in age or flight hours may have

contributed to any differences exhibited by

carriers.

Similarly, findings may have been affected by

the fact that rostering practices and bunk

configurations most likely differed among

aircraft types and across carders. Company

rostering practices can vary according to flight

length, routes flown, aircraft performance

29
capability, company policy, contractual

agreements, and other factors. These

differences have several potential effects on

bunk use, including the time of day of bunk

periods, the duration of bunk periods, and

previous sleep patterns of crewmembers. In

addition to rostering variations, bunk

configuration can differ among aircraft types

and even among individual aircraft of the

same type. Variations may have affected the

comfort of the bunk, noise levels, or other

aspects of a crewmember's experience of the

facility.

Finally, the study results may not be

generalized to situations that are beyond the

scope of the scientific issues specifically

addressed in this report

5.2 Findings

5.2.1 Sleep at Home

The subjects studied in all three carders

represent, on average, an average sleep

population. This is evidenced by an average

sleep duration of about 8 h., an average sleep

latency of less than 20 min., few reports of

regular difficulty sleeping, and few reports of

specific sleep problems. Additionally, the vast

majority rated themselves as "good" or "very

good" sleepers at home.

5.2.2 Sleep in Bunk

Clearly, subjects were able to sleep in the bunk,

as evidenced by the average bunk sleep

duration of more than 1.5 h. Overall, subjects

rated both alertness and performance as

improved by bunk use, indicating that bunk

sleep was perceived to have had a restorative

effect. Even those subjects who rated

themselves as poor sleepers at home reported

being able to sleep in the bunk. While this

subset of the surveyed group reported a long

average sleep latency in the bunk (nearly an

hour), they also reported an average sleep

duration of 1.9 h., which was greater than the

average sleep duration of the complete sample.

On the other hand, the time to fall asleep in the

bunk was longer than at home, and a

30

significantly greater percentage of

crewmembers reported difficulty sleeping in

the bunk than reported difficulty at home.

Nearly half (47%) of those that rate themselves

as good home sleepers reported having regular

difficulties sleeping in the bunk.

5.2.3 Factors Affecting Sleep

The main factors identified by subjects as

interfering with home sleep were essentially

the same as those reported as interfering with

bunk sleep. "Random noise," "thoughts

running through your head," "trips to

bathroom," and "heat," were the factors most

commonly cited. Environmental disturbances

(including noise) and personal disturbances

(including trips to the bathroom) were two

categories identified as contributing

significantly to interference with both home

sleep and bunk sleep. Concerning home sleep,

environmental discomfort, including heat, also

contributed, in the bunk, turbulence and light,

including background lighting and the

illuminated seat belt sign, were reported to

interfere.

Random noise was identified with much

greater frequency than was background noise

(see fig. 7). This outcome suggests that the

character of a noise may contribute to its

disturbing effect. Some level of continuous

background noise, in fact, may disguise

random noises that might otherwise disturb a

crewmember in the bunk.

"Thoughts running through your head" was

identified as another factor that strongly

interfered with both home sleep and bunk

sleep. Anecdotal reports suggest that

crewmembers remain concerned with the

safety of operations even when they leave the

flight deck for the bunk. Additional worries,

personal or professional, may contribute to

continuous thoughts that interfere with bunk

sleep.

The main factors identified as promoting sleep

at-home were Similar-t0-th0se identified as

promoting sleep in the aircraft bunk. Most

commonly cited were pillows, readiness for

sleep, blankets, sheets, and curtains. Three

categories of factors found to promote sleep
bothat homeandin thebunkweresleep

microenvironment, sleeppreparedness, and

sleepmacroenvironment.Themostfrequently

identifiedpromotingfactorswerecomfort

items,includingpillows,sheets,andblankets.

Suggestionsfromcrewmembersonhowto

improvethefacility alsofocusedonthe

microenvironment, andincludedlargerand

thickermattresses, clothsheetsandpillow

cases,andbiggerpillowsandblankets.The

secondcategory,preparedness, comprised

readinessfor sleepandcomfortof clothing.

An individual'sreadinessfor sleepis a crucial

andwell documentedcomponentin theability

to sleepat agiventime,anddependsmainly

onprior sleep/wakepatternsandthetimeof

day(i.e.,placein thecircadiancycle). In the

macroenvironment category,a frequently

identifiedfactoraffectingsleepwas

ventilation.

Interestingly,facilityparameterssuchasthe

sizeof thecrewrestfacility,thesizeof the

actualbunk,andheadspacewererated,on

average,ashavinglittle effectin either

direction.However,subjects'

recommendationsincludedsignificant

mentionof facilityparameters, whichindicates

thatthefactorsmaybeimportanto some

crewmembers.Subjects'reactionsto facility'

size,bunksize,andheadspacemaydepend

greatlyonheightandbodymass,resultingin a

broadrangeof responses.Theresponsescale

in this questionrangedfrom "interferes"to

"promotes,";therefore,if manycrewmembers

consideredafactor(e.g.,facility size)

promotingwhilemanyothersconsideredit

interfering,whenresponseswereaveraged,

theymightappearto bea collectiveresponse

of "no effect."

5.2.4 Aircraft Comparisons

Comparisons among the three aircraft types

revealed consistently higher ratings for quality

of sleep promotion in the MD-11 than in

either of the B747 series. MD-11

crewmembers reported a better attitude about

the bunk, shorter sleep latency, and fewer

difficulties sleeping. Further, MD-11 crews

rated subsequent alertness and performance as

more improved by bunk sleep than did their

'1001200 and '400 counterparts. Further, a

significantly greater proportion of good home

sleepers reported regular difficulties sleeping

in the bunk of the '100/200 aircraft.

The longest sleep durations were reported by

subjects from the '400. However, the '400

may have had longer flights or different

rostering that allowed for longer bunk periods

(see sec. 5.1). That is, there is no way to be

certain to what extent the flight schedules and

crew rostering in bunks within those schedules

may have contributed to some of the reported

difference between bunk sleep in the MD-1 l

versus the B747.

Factors affecting bunk sleep also were

compared across aircraft type. The "100/200

aircraft, an older series, received the lowest

ratings overall. Specifically, facility

parameters including facility size, bunk size,

head space, and privacy were rated as slightly

interfering in the '100/200, whereas those

factors were rated as somewhat promoting in

each of the other aircraft (see sec. 5.2.3). For

example, while the '100/200 group rated bunk

size as an interfering factor (i.e., the bunk was

presumably too small), the other two groups

rated bunk size as a promoting factor (i.e., it

was presumably a comfortable size). In

addition, turbulence was rated as least

interfering on the MD-11, and, surprisingly,

most interfering on the '400, which is a newer

series than the '100/200. The frequency of

encountering turbulence may be affected by

common weather patterns across routes, or by

sheer length of the flights.

5.3 Recommendations

Several recommendations can be made based

on the findings. Many are straightforward,

and relatively simple to implement. The main

factors identified as promoting sleep in the

bunk were comfort items: pillows, sheets,

blankets. Following suggestions from

crewmembers by providing larger pillows and

blankets, cloth sheets and pillow cases, and

larger, thicker mattresses would be an easy,

relatively inexpensive way to improve the

benefits of the bunk facilities. Since comfort

of clothing was another highly rated

31
promoting factor, providing time and space

for crewmembers to change would be another

simple improvement.

Factors identified as interfering with bunk

sleep also suggest certain changes.

Crewmembers indicated that random noise was

a main interfering factor, and suggested that

soundproofing might improve the bunk sleep

environment. Additionally, other flight and

cabin crewmembers can be made aware of the

disturbing effects of random noise. Locating

bunk facilities away from galleys and main

passageways also may help minimize random

noise events. The use of ear plugs represents

another straightforward and cost effective

strategy.

Another frequently identified interfering

factor was thoughts. Thoughts and worries

can be reduced through the use of mental

focusing techniques and validated relaxation

skills. These approaches are widely available

through a variety of outlets and may help to

minimize racing thoughts long enough to fall

asleep. By providing access to training in such

techniques, carriers can help crewmembers

further optimize bunk sleep opportunities.

Subjects identified several environmental

factors as affecting bunk sleep, including heat

(interfered), cold (interfered), and ventilation

(promoted). These findings suggest that better

environmental controls in the facilities would

promote bunk sleep. Also, based on the fact

that "trips to bathroom" was rated as

interfering, locating a crew lavatory near the

bunk may also minimize disturbance.

Finally, and perhaps most importantly,

education can play a valuable role in

maximizing the benefits of crew rest facilities.

The fact that readiness for sleep was identified

as one of the main factors that promoted sleep

suggests that this physiological component

should be addressed. Educating crewmembers

in basic sleep physiology may help them to

plan their sleep more efficiently, to use

caffeine strategically, and to practice other

alertness management strategies that would

enhance their ability to sleep during bunk

periods. Education in sleep physiology has

the added benefit of being applicable to

general sleep health as well as to the challenges

of jet lag and other long-haul issues.

Educating cabin crewmembers, schedulers,

dispatchers, managers, and other industry

personnel also may have significant benefits

that come from people in various parts of the

system having the same understanding of

fatigue issues and alertness management

approaches.

Many of these recommendations are

straightforward and inexpensive. These

measures have the potential to benefit

crewmembers by enabling them to obtairi

improved sleep quantity and quality during

inflight bunk periods, and to benefit carriers

by supporting alert, well-rested flight crews

during long-haul operations. By optimizing

existing crew rest facilities and addressing

fatigue and alertness issues through other

efforts, the long-haul industry can widen the

safety margin and improve operational

effectiveness.

32
References

I.

.

.

.

.

.

Rosekind, M.R., Graeber, R.C., Dinges,

D.F., Connell, L.J., Rountree, M.S.,

Spinweber, C.L., & Gillen, K.A. (1994).

Crew Factors in Flight Operations IX:

Effects of Planned Cockpit Rest on Crew

Performance and Alertness in Long-Haul

Operations. NASA Technical

Memorandum 108839. Moffett Field, CA:

NASA Ames Research Center.

Gander, P. H., Graeber, R. C., Connell, L.

J., and Gregory, K. B. (1991). Crew

factors in flight operations: VIII. Factors

Influencing Sleep Timing and Subjective

Sleep Quality in Commercial Long-Haul

Flight Crews. (Technical Memorandum

103852). Moffett Field, CA: National

Aeronautics and Space Administration.

Graeber, R.C. (1986). Crew factors in

flight operations: IV. Sleep and

Wakefulness in International Aircrews.

(Technical Memorandum 88231).

Moffett Field, CA: National Aeronautics

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Rosekind, M. R., Gregory, K. B., Miller, D.

L., Co, E. L., and Lebacqz, J. V. Aircraft

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Nimitz Hill, Guam, August 6, 1997. (No.

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(1992). Sleep, Arousal, and Performance.

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Dinges, D.F. & Kribbs, N.B. (1991).

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experimentally-induced sleepiness. In

T.H. Monk (Ed.), Sleep, Sleepiness and

Performance, (pp. 97-128). Chichester:

Wiley.

Carskadon, M.A. & Roth, T. (1991).

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Sleep, Sleepiness, and Performance (pp.

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M.H. Kryger, T. Roth, and W.C. Dement

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33

Appendix A

General Survey

35

A. GENERAL

1. What is your flightdeck position?

2. What aircraft are you currently operating?

° How many total flight hours have you

logged?

B747 series

r---n

A300 series

r---q

F/O

r--1

MD-11

I--1

B767 series

other (please specify)

4. How much experience do you have

flying long-haul?

5. Gender?

6. Age?

yrs

r---1

male

mos

r---1

female

7. What is your weight? lbs. .OR kg.

8. What is your height?

9. In what time-zone do you live?

ft. i.s. O_.__KR cm.

10. In what time-zone relative to GMT

do you live?

11. Do you have a regular bed partner? yes

[]

no

r-i

I hrs (specify + or-)

12. Number of children at home under

18 years of age?.

13. Number of others living with you?

(e.g., older children, In Laws, relatives)

14. Specify:

37
B. SLEEPING AT HOME

Please give one best answer to each of the following questions based on an average night

of sleep at home. (About 3-4 days after your return home following a long-haul trip).

15. On your days off, what time do you

usually go to sleep? (Use 24 hr. clock) hrs mins

16. On your days off, what time do you

usually get up? (Use 24 hr. clock) hrs mins

17. On your days off, how long after going

to bed do you usually take to fall

asleep?

hrs mins

18. When sleeping at home, how many

times on average do you wake up?

] times

19. If you wake during the night, what is

it that usually causes you to awaken?

20. If you wake during the night, on

average, how long does it take you to

go back to sleep?

hrs mins

21. When sleeping at home, what is the usual

amount of total sleep you get? hrs mins

22.

23.

How often do you take a daytime nap

at home?

never seldom sometimes

1-4 times/yr 1-3 times/mo

[] [] r--1

When sleeping at home, do you have never

problems getting to sleep?

[]

often majority of time

1-4 times/wk 5-7times/wk

r--q r--q

seldom sometimes often majority of time

1-4 times/yr 1-3 times/mo 1-4 times/wk 5-7 times/wk

_ [] r--q r---1

38
REMEMBER: give one best answer based on an average night of sleep at home (about 3-4 days after you

return from a long-haul trip).

24. Please rate the following factors and

indicate how much they interfere with interferes

or promote your sleep at home? 1

no effect promotes

2 3 4 5

1) quality of sleep surface []

2) heat []

3) cold []

4) thoughts running through your head []

5) random noise events []

6) constant background noise []

7) background lighting []

8) readiness for sleep []

9) comfort of clothing []

10) low humidity/dry air []

11) high humidity []

12) trips to bathroom []

13) bed partner []

14) privacy []

15) ventilation []

16) sheets []

17) blankets []

18) pillows []

19) other (specify) []

r--1 r-q [] r--1

r--q r-q [] r--n

[] [] [] r--I

[] [] [] []

r--q r---i [] []

[] [] [] []

[] [] [] []

123 r--1 [] []

[] r--1 [] []

!--1 [] [] r--1

[] [] [] []

_ [] [] _

[] _ [] r-I

_ [] [] []

[] [] [] []

123 [] [] []

r-I I--I [] []

[] [] [] []

[] [] [] []

25. Please rate the following on the extent to

which they .interfere with your sleep at

home?

strongly interferes no effect

1 2 3 4 5

1) hunger []

2) thirst []

3) personal worries []

4) respiratory factors (i.e.asthma, []

allergies, etc.)

5) other (specify) []

[] r-1 [] []

I--I [] [] []

r-I 123 [] I--I

[] [] [] []

[] r-I [] []

26. Please list any other factors that promote your sleep at home.

1.

2.

3.

4.

5.

39
REMEMBER: give one best answer based on an average night of sleep at home (about 3-4 days after you

return from a long-haul trip).

27. Do you take medication to help you sleep? never seldom sometimes often majority of time

1-4 times/yr 1-3 timeslmo 1-4 times/wk 5-7 times/wk

[] [] [] 1"7 r--1

28. If yes, please specify.

29. Do you ever use alcohol to help you sleep? never

[]

seldom

1-4 ti_[_/yr

sometimes

1-3 times/m•

rl

often

1-4 times/wk

rl

majority of time

5-7 times/wk

r-l

30. Overall, what kind of sleeper are you? very poor

[]

poor good

r--q

very good

D

31. Do you have a sleep problem? yes

[]

no

r--l

32. If yes, what is your sleep problem.

33. If yes, has it been diagnosed by a

physician?

yes

[]

no

D

34. Has it ever prevented you from flying

a scheduled trip?

yes

[]

no

[z]

40
Fill out this section ONLY if you are currently flying an aircraft equipped with a bunk

C. SLEEPING IN AIRCRAFT B_KS

Please give one best answer to each of the following questions based on experiences in your aircraft.

35. How often have you used a bunk in the 1) current aircraft ['-"q times

past 12 months? 2) other types of aircraft r] times

36. Based on your current aircraft, which

bunk do you usually sleep in?

upper lower either

[] r--1 r--1

37. Are you able to undress for a yes no

comfortable sleep? [] I"-1

38. Is it important for you to undress

for a comfortable sleep?

yes no

[] D

39. How long after getting into the bunk

does it take you to fall asleep? hrs mins

a) What is the typical amount of sleep you

get in the bunk? hrs mins

b) What is the longest sle..e.p period you

have experienced in the bunk? hrs mins

c) What is the shortest perioqi of time that

you would use the bunk for sleep?

40. When you have an opportunity to use

the bunk how often do you experience

difficulty sleeping?

a) How often do you use the bunk only

for rest and not sleep?

41. Are you required to spend som...._.._e time in

the bunk when not flying?

42. If yes, who or what mandates use?

43. What other factors determine bunk

use and rostering?

hrs mins

never seldom sometimes often

[] rl I--1 FI

never seldom sometimes often

[] F"I r--1 r--l

yes no

[] r-1

Co. policy Sr. Capt. Capt fit. length

[] r--I r-l r-l

°

,

.

majority of time

r--n

majority of time

r--q

other(specify)

41
4. In general, what percentage of cruise

time is made available to you for

using the bunk?

.

%

45. Rate your overall attitude about the bunk. very neg neg neutral pos very pos

[] r] [] r---I 17

46. How does bunk sleep affect your

overall alermess?

very decreased decreased no change improved very improved

alertness alertness alertness alertness

[] [] I-I r--1 D

47. How does bunk sleep affect your

performance?

very decreased decreased no change improved very improved

performance performance performance performance

[] r-7 r-I 17 17

48. How often can you sleep when you

use any of the following.

1) cockpit seat

2) 1st class seat

3) passenger seat

4) bunk

5) at home in bed

never seldom sometimes often almost always

[] [] [] r-7 r7

[] [] _ r7 r-]

[] [] [] D r7

[] r--! [] r-l r-q

[] r-1 r-l F'-I 17

This is one of the most important questions in this survey.

Please take your time and answer thoroughly.

49. Please rate the following factors and

indicate how much they interfere with interferes

or promote your sleep in the bunk? 1

no effect

2 3 4

promotes

5

1) quality of sleep surface [] [] I"'1 [] []

2) heat [] 1"7 I"'1 [] 1"'1

3) cold [] r'-I r--1 [] []

4) thoughts running through your head [] r-I [] [] I-I

5) random noise events [] 17 [] [] []

6) constant background noise [] 17 I"-I [] !"7

7) background lighting [] I--I I--I [] []

8) readiness for sleep . [] I"'1 ["7 [] I'--I

9) comfort of clothing [] [] I-7 [] []

10) low humidity/dry air [] I'-1 [] [] I"1

11) trips to bathroom [] [] _ [] I--I

12) someone in the other bunk [] l"'l [] [] []

13) seat belt sign [] [] [] [] []

I4) turbulence [] ["'! [] [] []

15) privacy [] 1"7 [] [] I--I

16) bunk size [] r'1 I--I [] []

17) facility size [] r"! [] [] []

18) headspace [] I-7 [] [] I"7

19) lighting [] [] [] [] I-'7

20) ventilation [] [] [] [] E]

21) storage space [] [] [] [] []

22) curtains [] I---1 ['-'] [] []

23) sheets [] I"1 [] [] 1"7

24) blankets [] [] [] [] 1"7

42
25) pillows

26) other (specify)

[] [] I--I [] D

[] [] D [] []

50. Please rate the following on the extent to

which they interfere with your sleep in

the bunk?

strongly interferes

1 2 3 4

no effect

5

1) hunger [] [] _ [] []

2) thirst [] _ [] [] []

3) claustrophopia [] !--1 [] [] []

4) personal worries [] [] [] [] []

5) respiratory factors (i.e. asthma, [] V"I _ [] _

allergies, etc.)

6) other (specify) [] !"'1 [] [] []

51. Please list any other factors that promote good sleep in the bunk.

1.

2.

3.

4.

5.

52. When using the bunk, do you do anything

to help you get to sleep or to minimize

disturbance of your sleep, such as:

1) Wear earplugs?

2) Wear eyeshades?

3) Listen to music?

4) Relaxation techniques?

5) Other (specify)

V--1

53. Describe any pre-trip strategies you

use to help you sleep in the bunk.

(things you do befor.._...._e you are on

the aircraft!)

54. Please suggest how the crew rest facility

can be improved to be more conducive to

sleep?

1)

2)

3)

4)

1)

43
2)

3)

4)

Thank you very much for completing this survey. Please return it to NASA by

sending it in the enclosed, stamped envelope.

COMMENTS"

44
Appendix B

Survey Results: Carrier 1

45

lo

o

.

Surveys sent out: 2125

What is your flightdeck position?

(there were also 5 IRP entries)

What aircraft are you currently

operating?

How many total flight hours have

you logged?

4. How much experience do you have

flying long-haul?

5. Gender?

6. Age?

7. What is your weight?

8. What is your height?

9. In what time-zone do you live?

10. In what time-zone relative to GMT

do you live?

Appendix B

Survey Results: Carrier 1

Surveys received: 737 (35% return)

Capt. F/O S/O or F/E

41% 38% 20%

B747 series B747-400

-_ 68% 31%

A300 series

B767 series

x = 12,522

S.D. = 6,156

MD-11 other (please specify)

I-r--1 I i

min max

400 < _ 30,000

i !

x = 8.76 min max

S.D. = 7.24 1 mo. ( > 40 yrs.

yrs

99%@

1%

male female

I I

x = 44.5

S.D. = 8.2

lbs. I w

x = 183.6

S.D. = 23.6

rain max

27 < > 63

I I

x = 71.3

S.D. = 2.3 ins.

Pacific (PT) = 306

Central (CT) = 232

Eastern (ET) = 117

Mountain (MT) - 50

Hawaii (HI) = 15

Alaska (AK) = 6

min max

117_ > 300

rain max

63 < > 79

HI/AK ET

PT 3% 16%

MT

7%

Result_ were inconclusive.

47
11. Do youhave a regular bed partner?

12. Number of children at home under

18yearsof age?

13. Number of others living with you?

(e.g., older children, In Laws, relatives)

14. Specify:

yes no

89%o [::-q !o1%

No 1 or children more children = = 353 379

Results were inconclusive.

Results were inconclusive.

B. SLEEPING AT HOME

15.

16.

17.

18.

19.

20.

On your days off, what time do you

usually go to sleep? CtJse 24 hr. clock)

On your days off, what time do you

usually get up? (Use 24 hr. clock)

On your days off, how long after

going to bed do you usually take

to fall asleep?

I

x = 22:58

S.D. = 0:29

hrs

min

2000

I

x = 07:19 min max

S.D.= 0:35 0311<--'"_ 1400

hr$

I I

x = 19.4

S.D. = 27.5

mins

I m

x = 1.4

When sleeping at home, how many S.D. = 1.1

times on average do you wake up? times

max

0300

If you wake during the night, what is

it that usually causes you to awaken?

If you wake during the night, on

average, how long does it take

you to go back to sleep?

rain max

1 < > 180

rrfin max

0< > 10

Physiological (B) 420

(bathroom)

Children/spouse/pets (F) 103

Can't sleep (S) 65

Noise (N) 57

Pain (P) 15

Thirst (T) 11

P T

N 2% 2%

9%_qf_

16% 61%

x = 12.8

S.D. = 14.1 I min

mins

max

> 90

48
21.

22.

23.

4.

When sleeping at home, what is the

usual amount of total sleep you get?

- I

x = 7:47 min

S.D. = 2:45 4:11<

hrs

max

11:00

How often do you take a

daytime nap at home?

never seldom sometimes often majority

of time

_8 _8

When sleeping at home, do you

have problems getting to sleep?

never seldom sometimes o f t e n majority

of time

__ D8

1) quality of sleep surface

2) heat

3) cold

4) thoughts running through head

5) random noise events

6) constant background noise

7) background lighting

8) readiness for sleep

9) comfort of clothing

10) low humidity/dry air

11) high humidity

12) trips to bathroom

13) bed partner

14) privacy

15) ventilation

16) sheets

Please rate the following factors and indicate how much

they interfere with or promote your sleep at home?

interfere no effect promotes

1 2 3 4 5

_; __ D8 m8 ra8

49
4o

interfere promotes

19) other (specify) [ No substantial findings[

Environment

Comfort

Mental attitude

Physical activity

Please rate the following factors and indicate how much

they interfere with ,or promote your sleep at home?

(results are shown as %'s of total responses in each column)

interfere no effect promotes

1 2 3 4 5

1) quality of sleep surface _ _ _] ['_

2) heat _ _ _ _

3) cold _ _ _ _

4) thoughts running through head _ _'_ _ ['_

5) random noise events _ [_ _ ['_

6) constant background noise ['_ _ _ _

7) background lighting _ _ ['_ _ ['_

8) readiness for sleep _ _ _ _ [_

9) comfort of clothing ['_ _ _ _

10) low humidity/dry air _ _ _ _

11) high humidity _ _ ['_ ['_ ['_

12) trips to bathroom [_ [_ _ _

13) bed partner ['_ _ _] _ [-_

14) privacy _ _'] ['_ _ ['_

15) ventilation ['_ [_]'] _ [_ [_

16) sheets ['_ _ _ [_

17) blankets ['_ _ ['_ _

18) pillows ['_ ['_ [_ _ [_

25. Please rate the following on the extent to which they interfere with your sleep at home?

strongly interferes no effect

! 2 3 4 5

1) hunger

2) thirst ['_--]8 _-_-]5 _ [_ [_']_ []-_8 °

3) personalworries [_° _'_-]_ [_']_ _'%"]8 _ [-_-']8

35

20

16

11

50
4) respiratory factors

5) other (specify)

Jetlag 29

Noise 14

Mental attitude 13

Environment 12

Family/pets 12

26. Please list any other factors that promqte your sleep at home.

27.

30.

Physical environment (PE) 336

Mental attitude (MA) 180

Pre-sleep activities (PSA) 156

Exercise/physical activity (EX) 137

Comfort (C) 129

Schedule (S) 92

Meals/food (M) 40

Alcohol/medication (A) 35

Do you take medication to

help you sleep?

If yes, please specify.

S M A

8% 4_ 3% c_ .'_h_ PE

12%.._._31%

14%

Do you ever use alcohol to

help you sleep?

never seldom sometimes often majority

of time

0%

Do

Overall, what kind of sleeper

are you?

I Cold remedies/aspirin 50

Sleeping pills 39

Allergy medication 3

31. Do you have a sleep problem?

never seldom sometimes often

D8

majority

of time

1%

Do

very poor poor

0% 9%

VTqo l-if1@

good

53% B*

very good

38%

Frl 

34.

yes

11%

Do

no

If yes, what is your sleep problem.

Circadian disruption

Restless sleeper

Talk/Snore/Apnea

Thoughts/worries

Pain

32

19

10

8

5

If yes, has it been diagnosed by a yes

I%

physician? _ O

no

28%

De

no answer

Has it ever prevented you from

flying a scheduled trip?

yes

I% Fq©

no

48%

no answer

51%

51
C. SLEEPING IN AIRCRAFT BUNKS

35. How often have you used a bunk in the past 12 months?

[ x = 21.08 I rain

1) current aircraft [ S.D. = 20.41 I times 0

i

x = 1.59 rain

2) other types of aircraft S.D. = 7.09 times 0 <

max

> 99

max

> 99

36. Based on your current aircraft, which

bunk do you usually sleep in?

upper lower either

33%

37. Are you able to undress for a

comfortable sleep?

yes no

88% 12%

gmo r Tq©

38. Is it important for you to undress

for a comfortable sleep?

yes no

8I% 19%

39. How long after getting into the bunk

does it take you to fall asleep?

1

x = 44.12 rain max

S.D. = 31.70 2 < _ 180

rains

40. When you have an opportunity

to use the bunk how often do you

experience difficulty sleeping?

never

D8

seldom sometimes often majority

of time

41. Are you required to spend some time

in the bunk when not flying?

yes no

7% 93%

F 7-1© 7aqo

42. If yes, who or what mandates use? Result_ were inconclusive.

43. What other factors determine bunk

use and rostering?

Seniority/crew decision (S) 229

Prefer alternate choice (P) 99

Schedule/flight operations (F) 82

Sleep/circadian factors (C) 75

Augmentation (A) 70

Random selection (R) 30

Concern with flight/operations (F) 8

4o In general, what percentage of cruise

time is made available to you for

using the bunk?

I I

x = 32.61 min max

S.D.= 12.69 % 4< >99

R

A 5%

12_ _' s

C 38%

15% P

17%

52
45.

46.

47.

48.

49.

Rate your overall attitude about

the bunk.

very neg neg neutral pus very pus

How does bunksleep affect

your overall alertness?

very decreased decreased no change improved very improved

alertness alertness alertness alertness

How does bunk sleep affect

your overall performance?

very decreased

performance

1%

Do

decreased no change improved

performance performance

D8 r_8 ° __

very improved

performance

16%

rrmo

How often can you sleep when you

use any of the following, never seldom

1) cockpit seat _ _o _ _o

2) 1st class seat [-_ 8 _

3) passenger seat [_ _'] _°

sometimes often almost always

__° D 8 D8

D_ r_aD8

Please rate the following factors and indicate how much

they interfere with or promote your sleep in the bunk?

interfere

1 2

1) quality of sleep surface _ _° _ _°

2) heat [_'_ _°8"] _°

3) cold [_ 8 ° _

4) thoughts running through head _ _° _ _°

5) random noise events _ _ _

6) constant background noise _ 8 ° _

7) background lighting _ 8 ° _

8) readiness for sleep [_8 ['_-] _

9) comfort of clothing Eli 8 [_ 8 °

10) low humidity/dry air _ _° _

11) trips to bathroom E1 _° _

no effect promotes

3 4 5

D$ o__o _8 o

D_ ° _8 ° D8

__ r_am8

_8 ° mar_8

__° Darn8

__ Dar_8

__m8 D8

53
49.

12) someone in the other bunk

13) seat belt sign

14) turbulence

15) privacy

16) bunk size

17) facility size

18) headspace

19) lighting

20) ventilation

21) storage space

22) curtains

23) sheets

24) blankets

25) pillows

_8 _; D_ D 8 D8

__ __ _8 D 8 m8

10%

©

7%

(9

6%

(9

2%

©

interfere promotes

26) other (specify) No,so (wear earplugs) 5111 10 Positive mental attitude 429 I

Please rate the following factors and indicate how much

they interfere with or promote your sleep in the bunk?

(results are shown as %'s of total responses in each column)

interfere no effect promotes

1 2 3 4 5

1) quality of sleep surface [-_ _ _ _ ['_

2) heat _ [_ _ ['_

3) cold _ [_] [_ _

4) thoughts running through head ['_ [_] [_']_ ['_

5) random noise events _ _ [_] ['_

6) constant background noise _ [_] [_] _

7) background lighting _ _ [_ r_]

8) readiness for sleep [_ _ ['_ ['_

9) comfort of clothing _ _'_ _ _ [-_

54
10) low humidity/dry air

11) trips to bathroom

12) bunk partner

13) seat belt sign

14) turbulence

15) privacy

16) bunk size

17) facility size

18) headspace

19) lighting

20) ventilation

21) storage space

22) curtains

23) sheets

24) blankets

25) pillows

50. Please rate the following on the extent

to which they interfere with

your sleep in the bunk?

1) hunger

2) thirst

3) claustrophopia

4) personal worries

5) respiratory factors

6) other (specify)

r_ _ _ Bsq _-a

r_q F_ f_q f_q D

_q D _q r_q r_

strongly interferes

1 2 3

D8 o o

D8 8

no effect

4 5

Noise 75

Bunk comfort 63

Environment 35

Bathroom 33

Scheduling 16

Turbulence 4

Mental attitude 4

55
51. Please list any other factors that promote good sleep in the bunk.

52.

53.

54.

Comfort (C) .. 292

Environment (E) 270

Fatigue (FATG) 132

Length of break (B) 60

Ease of mind (M) 56

Lack of turbulence (T) 55

Privacy (P) 51

Food (FD) 34

When using the bunk, do you do anything to help you get

to sleep or to minimize disturbance of your sleep, such as:

yes no

1) Wear earplugs?

2) Wear eyeshades?

3) Listen to music?

4) Relaxation techniques?

5) Other (specify) Read Comfort aids 9330

Describe any _ strategies you use to help you sleep in the bunk.

Schedule sleep (S) 246

Bring comfort aids (A) 137

Avoid caffeine (C) 44

Limit food intake 8) 40

Limit liquids (L) 30

Exercise (E) 18

Rest (R) 14

Settle problems (P) 4

Please suggest how the crew rest facility can be improved to

be more conducive to sleep?

Comfort (C)

(mattress ,pillows,sheets ,blankets)

Sound proofing (S)

Larger bunk area (A)

Privacy (P)

Humidifier/temperature control if)

Crew lavatory (L)

Darker (D)

509

409

145

134

124

111

78

P FD T

6% 4%

M 6%"a_ _ C

7%"'_4_'l_34%

7% _E

FATG 20%

16%

E R P

L 3% 3%1%

6% _,_,_1

s

8% C.,jI_._45%

8% 26%

L D

T 7% 5%

8%,,A_IL c

10% S

27%

56
Appendix C

Survey Results: Carrier 2

57

Appendix C

Survey Results: Carrier 2

lo

Surveys sent out: 220 Surveys received: I07 (49% return)

1

What is your flightdeck position?

(there were also 5 IRP entries)

What aircraft are you currently

operating?

3. How many total flight hours have

you logged?

4. How much experience do you have

flying long-haul?

5. Gender?

6. Age?

7. What is your weight?

8. What is your height?

9. In what time-zone do you live?

10. In what time-zone relative to GMT

do you live?

11. Do you have a regular bed partner?

Capt. F/O

58% 42%

MD-11

100%

i m

x = 13,804

S.D. = 6,637

man

400 <

max

> 30,000

x = 7.06

S.D. = 7.59

yrs

rain

4 mo.<

max

> 32 yrs

'_ 100%

male

i I

x = 48.2

S.D. = 9.4

min max

30,6-------_ 59

x = 181.8

S.D.= 21.4 lbs.

rain

13I-<

max

> 230

x = 70.8

S.D. = 2.1 ills.

mill

66_

max

>-75

Central (CT) = 59

Pacific (PT) = 36

Eastern (ET) = 8

Mountain (MT) = 3

Hawaii (HI) = 1

MT

H

ET 3%

7%_K_ 1%

34% 55%

Results were inconclusive.

yes no

o

59
12. Number of children at home under

18 years of age?

13. Number of others living with you?

(e.g., older children, In Laws, relatives)

14. Specify:

No 1 or children more children = = 3671 [

Results were inconclusive.

Results were inconclusive.

B. SLEEPING AT HOME

15.

16.

17.

18.

19.

20.

21.

On your days off, what time do you

usually go to sleep? fUse 24 hr. clock)

l

On your days off, what time do you [

usually get up? fUse 24 hr. clock)

On your days off, how long after

going to bed do you usually take

to fall asleep?

__

x = 22:58

S.D. = 0:55

When sleeping at home, how many

times on average do you wake up?

hrs

If you wake during the night, what is

it that usually causes you to awaken?

If you wake during the night, on

average, how long does it take

you to go back to sleep?

I

When sleeping at home, what is the I

usual amount of total sleep you get?

x = 07:15

S.D. = 0:57

hrs

i I

x = 17.6

S.D. = 13.9

mins

min

21:00<

]- ]

x = 1.4

S.D.= 1.1

times

max

• 10:00

min max

1 < >60

rain max

O< )6

Physiological-bathroom (B) 72

Children/spouse/pets (F) 13

Can't sleep (S) I3

Noise (N) 8

Pain (P) 1

i

x = 12.2

S.D. = 15.4

rains

fflin max

>90

- I

x = 7:50

S.D. = 0:47

hrs

min

6:00<

max

) 10:00

max

) 3:00

N P

S 7% 1%

12%_

F B

12%_68%

6O
22.

23.

4o

How often do you take a

daytime nap at home?

never seldom sometimes often majority

of time

33% 1% De I-_18_ Do

When sleeping at home, do you

have problems getting to sleep?

never seldom sometimes often majority

of time

33% 1% De D8 Do

Please rate the following factors and indicate how much

they interfere with or promote your sleep at home?

interfere

1 2

1) quality of sleep surface _ 8 _ 8

2) heat ['_"] _ ['_'] _

3) cold _ 8 __°

4) thoughts running through head [_ _% _ _°

5) random noise events ['_ 8 ° _ _°

6) constant background noise _ 8 _

7) background lighting _ 8 ° [_ _°

8) readiness for sleep _ 8 [1_8°

9) comfort of clothing _ 8 ['_ 8

10) low humidity/dry air [_ 8 _ _°

11) high humidity _-] _° _

12) trips to bathroom _ 8 ° [-_ _°

13) bed partner _ 8 _ _°

14) privacy [-_ 8 _ 8

15) ventilation [-_ 8 _ 8

16) sheets

17) blankets

18) pillows

no effect promotes

3 4 5

rm_ _8 D8

__ D_ ° __o

D_ D8 D8

__° m8 D8

Fa_ ° ra8 r_8

r_ r_ 8 D8

D_ D 8 m8

61
19) other (specify)

interfere

I Kids wake up 1 [

promotes

Environment 5 ]

Mental attitude 3

Comfort 1

Ph_csical activity 1

4m Please rate the following factors and indicate how much

they interfere with or promote your sleep at home?

(results are shown as %'s of total responses in each column)

interfere no effect promotes

1 2 3 4 5

1) quality of sleep surface _ _ _ _']

2) heat _ _ _ _'] ['_

3) cold _ _ ['_ _']

4) thoughts running through head _ [_ _ _

5) random noise events [_ [_ _ _

6) constant background noise _ [_ ['_ _ [_

7) background lighting _ _ _ _

8) readiness for sleep [TS'] _ _ [_ [_

9) comfort of clothing _ _ _ _

10) low humidity/dry air _ [_] _ [-_ ['_

11) high humidity _ _ _ _ _-]

12) trips to bathroom _ _ _ [-_ ['_

13) bed partner ['_ _ _ _

14) privacy _ ['_ _ _

15) ventilation _ ['_ _ [_

16) sheets ['_ ['_ _ _

17) blankets ['_ _ _ _ ['_

18) pillows _ _ [_ _ []_']

25. Please rate the following on the extent to which they

1) hunger

2) thirst

3) personal worries

interfere with your sleep at home?

strongly interferes no effect

1 2 3 4 5

ra 8 D8 D$ _ _$_ Fa_ °

m 8 D_ ° D_ ° __ D8 °

D 8 D8 _g° D_ D_ °

4) respiratory factors

62
5) other (specify)

Noise 11

Pain 2

Mental attitude 1

26. Please list any other factors that promote your sleep at home.

Physical environment (PE) 48

Exercise/physical activity (EX) 23

Comfort (C) 17

Pre-sleep activities (PSA) 16

Mental attitude (MA) 15

Schedule (S) 5

Meals/food (M) 4

27. Do you take medication to

help you sleep?

never seldom sometimes

m8 D8

28. If yes, please specify. Cold remedies/aspirin 7 ] Sleeping pills 2

29. Do you ever use alcohol to

help you sleep?

never seldom sometimes

m8

30. Overall, what kind of sleeper

are you?

very poor poor

0% 7%

Do 77q©

31. Do you have a sleep problem? yes no

32. If yes, what is your sleep problem.

Restless sleeper 3

Thoughts/worries 2

Talk/Snore/Apnea 1

Bathroom 1

33. If yes, has it been diagnosed by a

physician?

yes no

2% 21%

FTlo rT_e

4. Has it ever prevented you from

flying a scheduled trip?

yes no

0% 45%

good

55% r;rl,

S M

MA 4% 3%

13% C_'EX

13% 18%

often

m8

no answer

no answer

55% r;71_

majority

of time

4%

[Zle

majority

of time

0%

Do

very good

38% Fcl_

63
C. SLEEPING IN AIRCRAFT BUNKS

35.

36.

How often have you used a bunk in the past 12 months?

1) current aircraft I _.D.- _45° 44.67 Itimes

I-x - 1.29

2) other types of aircraft S.D. = 9.98 times

min max

1 _----_ 99

rain max

3< >99

Based on your current aircraft, which

bunk do you usually sleep in?

upper lower either

37. Are you able to undress for a

comfortable sleep?

yes no

85% 15% l_lo Do

38. Is it important for you to undress

for a comfortable sleep?

yes no

60% 40%

rm_ D_

39. How long after getting into the bunk

does it take you to fall asleep?

x = 26.52

S.D. = 19.40

mira

rain max

1 < > 120

a) What is the typical amount of sleep

you get in the bunk?

I I

x = 1:39

S.D. = 0:43

hrs

min max

0:20< ._ 3:14

b) What is the longest sleep period you

have experienced in the bunk?

! I

x = 2:48

S.D. = 1:21

hrs

min max

0:30_----_ 6:00

c) I

x = 1:04

What is the shortest sieep_riod of S.D. = 0:41

time that you would use the bunk hrs

for sleep?

min max

0:05 _----_ 3:00

40. When you have an opportunity

to use the bunk how often do you

experience difficulty sleeping?

never seldom sometimes often majority

of time

o oD8 o

a) How often do you use the bunk

only for rest and not sleep?

never seldom sometimes often majority

of time

41. Are you required to spend some time

in the bunk when not flying?

yes no

5% 95%

Do fimo

64
42. If yes, who or what mandates use? Result_ were incpnclu_ive.

43. What other factors determine bunk

use and rostering?

4o

45.

46.

47.

48.

Seniority/crew decision (S)

Sleep/circadian factors (C)

Length of flight (L)

Concern with flight/operations (F)

Augmentation (A)

35 F A

8% 6%

14% 54,%

5 c

4 18%

49.

In general, what percentage of cruise

time is made available to you for

using the bunk?

x = 37.85

S.D. - 19.83 %

rain [l'laX

14 < > 99

Rate your overall attitude about

the bunk.

very neg neg neutral pos very pos

ra8 D8 r_8 7a_; __

How does bunk sleep affect

your overall alertness?

How does bunk sleep affect

your overall performance?

very decreased decreased no change improved very improved

alertness alertness alertness alertness

very decreased decreased no change improved very improved

performance performance performance performance

D8 _8 D8 Fa5° __

How often can you sleep when you

use any of the following, never

1) cockpit seat

2) 1st class seat

3) passenger seat _']

4) bunk

5) at home in bed

seldom sometimes often almost always

_8 D8

_8 D8 _8 _8 __

Please rate the following factors and indicate how much

they interfere with or promote your sleep in the bunk?

1) quality of sleep surface

2) heat

3) cold

interfere no effect promotes

1 2 3 4 5

r_ ° D_ ° __° D 8 D8

65
4) thoughts running through head

5) random noise events

6) constant background noise

7) background lighting

8) readiness for sleep

9) comfort of clothing

10) low humidity/dry air

11) trips to bathroom

12) someone in the other bunk

13) seat belt sign

14) turbulence

15) privacy

16) bunk size

17) facility size

18) headspace

19) lighting

20) ventilation

21) storage space

22) curtains

23) sheets

24) blankets

25) pillows

26) other (specify)

__ ra_ __ D 8 m8

_; D_ ra_ D 8 D8

D 8 Fa_; Fa_ ra8 _8

DS D_; _a_ D 8 D8

D 8 __ __ D_ D8

_a_ Fa_ __ D 8 D8

D8 D8 _a_; _8 _8

....... 16%

D 8 D$" D_ _8 ° D_

_8 m8 D_ ° _8 _8

interfere promotes

I Fast cockpit access [Noise Head tilts down 114 I Cleanlinens Use alarm

66
49. Please rate the following factors and indicate how much

they interfere with or promote your sleep in the bunk?

(results are shown as %'s of total responses in each column)

interfere no effect promotes

1 2 3 4 5

1) quality of sleep surface _ _ [-_ _ ['_

2) heat [_ ['_ [_] [_ ['_

3) cold _ _ _ _

4) thoughts running through head _ _ _ ['_

5) random noise events [_ _ _ ['_

6) constant background noise _ _ _] _

7) background lighting ['_ [7] _ ['_

8) readiness for sleep _ _ ['_ _

9) comfort of clothing _ _ _ [-_ ['_

10) low humidity/dry air _ _ [_ _

11) trips to bathroom [_ _ _ _'] ['_

12) bunk partner ['_'] _ ['_ [-_ [-_

13) seat belt sign _ _ _ [-_

14) turbulence _ _ _ _

15) privacy [_ _ _ _

16) bunk size _ [_] ['_ _']

17) facility size ['_ _ [-_ _

18) headspace ['_ _ _ _ ['_

19) lighting ['_ _ _ _

20) ventilation _ _ _ _

21) storage space _ _ ['_ ['_

22) curtains ['_ _ _ _

23) sheets _ [-_ [_ [_

24) blankets _ _ _ _ ['_

25) pillows _ _ _-] _ [_

67
50. Please rate the following on the extent

to which they interfere with

your sleep in the bunk?

1) hunger

2) thirst

strongly interferes no effect

1 2 3 4 5

3) claustrophopia

4) personal worries

5) respiratory factors

6) other (specify)

738

D8 D8

Noise 17

F/As smoking 5

Environment 4

Ready for duty 2

51. Please list any other factors that promote good sleep in the bunk.

Environment (E)

Comfort (C)

Ease of mind (M)

Lack of turbulence (T)

Fatigue (FATG)

Length of break (B)

Food (FD)

34

15

6

6

5

4

4

B FD FATG

7% 5% 5%

M.,_C_._47% 8%

20%

52. When using the bunk, do you do anything to help you get

to sleep or to minimize disturbance of your sleep, such as:

yes no

1) Wear earplugs?

2) Wear eyeshades?

3) Listen to music?

4) Relaxation techniques?

5) Other (specify)

D8 DS_ t_97_

Read 6 , Make dark 2

53. Describe any _ strategies you use to help you sleep in the bunk.

Schedule sleep (S) 10

Avoid caffeine (C) 5

Exercise (E) 5

Limit food intake (F) 4

Limit liquids (L) 4

Rest (R) 4

Brin_ comfort aids (A) 2

A

R 6%

12% 4,

12% E 15%

15%

68
54. Please suggest how the crew rest facility can be improved to

be more conducive to sleep?

Location/away from galley (LC)

Comfort (C)

(mattress, pillows, sheets, blankets)

Humidifier/temperature control (T)

Sound proofing (S)

F/As quieter (F)

Crew lavatory (LV)

Head forward (H)

Music access (M)

Lar_er bunk area (A)

34

27

20

17

10

7

6

3

2

HM A

LV5% 2% 2%Lc

8%'_27%

s _'_F'c

13% T 21%

16%

69

Appendix D

Survey Results: Carrier 3

71

lo

o

e

*

Surveys sent out: 1500

What is your flightdeck position?

What aircraft are you currently

operating?

How many total flight hours have

you logged?

How much experience do you have

flying long-haul?

5. Gender?

6. Age?

7. What is your weight?

8. What is your height?

9. In what time-zone do you live?

10. In what time-zone relative to GMT

do you live?

11. Do you have a regular bed partner?

Appendix D

Survey Results: Carrier 3

Surveys received: 560 (37% return)

Capt. F/O S/O or F/E IRP

B747 series B747-400

_1 47% 53%

w

x = 15,012

S.D. = 6,796

I-• x = 8.60

S.D. - 9.39

yrs

rain

100 <

max

_- 38000

m]n

1 mo.<

98%ode 2%

male female

I

x = 51.2

S.D. 8.3

I I

x = 184.1 min

S.D. = 24.5 lbs. 105 <

I

x = 70.7

S.D. = 2.7 ins.

Pacific (PT) = 237

Eastern (ET) = 117

Mountain (MT) = 115

Central (CT) = 54

Hawaii/Alaska (HI/AK) = 17

Results were inconclusivel

max

> 40 yrs.

min max

27 _ > 73

max

> 280

min max

62 -_ > 81

HI/AK

MT 3%

10%

21 144%

CT

22%

yes no

88%• Do 12%

73
12. Number of children at homeunder

18yearsof age?

13. Number of others living with you?

(e.g., older children, In Laws, relatives)

T

14. Specify:

No1 or children more children = = 353 196 [

Results were inconclusive.

Results were inconclusive.

B. SLEEPING AT HOME

15.

16.

17.

18.

19.

20.

21.

On your days off, what time do you

usually go to sleep? (Use 24 hr. clock)

I I

x = 23:01 rain max

S.D. = 0:56 2000"¢-----_ 0330

hrs

I I

x = 07:21

On your days off, what time do you S.D. = 0:58

usually get up? (Use 24 hr. clock) hrs

On your days off, how long after

going to bed do you usually take

to fall asleep?

I i

x = 20.5

S.D. = 17.7

mins

I- [

x = 1.5

When sleeping at home, how many S.D. = 1.1

times on average do you wake up? times

If you wake during the night, what is

it that usually causes you to awaken?

_n max

0418_ > 1030

If you wake during the night, on

average, how long does it take

you to go back to sleep?

I

When sleeping at home, what is the [

usual amount of total sleep you get?

min max

1 _ 180

min max

0< >6

Physiological (B) 312

(bathroom)

Can't sleep (S) 87

Noise (N) 51

Children/spouse/pets 0:3 48

Thirst (T) 14

Pain (P) 10

F T P

9% 3% 2%

59%

17%

m

X

S.D. =

15.2

19.3

i

mlns

rain

1<

max

> 180

- 1

x = 7:50

S.D. = 0:49

hrs

rnin

4.00-,

max

> 10:00

74
22.

23.

4o

How often do you take a

daytime nap at home?

never seldom sometimes often majority

of time

When sleeping at home, do you

have problems getting to sleep?

never seldom sometimes often majority

of time

1) quality of sleep surface

2) heat

3) cold

4) thoughts running through head

5) random noise events

6) constant background noise

7) background lighting

8) readiness for sleep

9) comfort of clothing

10) low humidity/dry air

11) high humidity

12) trips to bathroom

13) bed partner

14) privacy

15) ventilation

16) sheets

17) blankets

18) pillows

Please rate the following factors and indicate how much

they interfere with or promote your sleep at home?

interfere no effect promotes

1 2 3 4 5

_8 D8 D8 Fa_ Fa_

D 8 __ D_ _a_ D8

__ __ D_ D 8 m8

75
interfere

_B

19) other (specify) [ No substantial findings [

Please rate the following factors and indicate how much

they interfere with or promote your sleep at home?

(results are shown as %'s of total responses in

promotes

Environment 26

Mental attitude 15

Physical activity 12

Comfort 7

each column)

interfere no effect promotes

1 2 3 4 5

1) quality of sleep surface _ _ [_ [_

2) heat [_ [_ ['_ _

3) cold _ ['_ _ _

4) thoughts running through head [_ _ _ ['_

5) random noise events _ _ _ ['_

6) constant background noise ['_ ['_ _ [_] [_

7) background lighting _ ['_ _ [-_ ['_

8) readiness for sleep _'] _ _ _

9) comfort of clothing _ _ _ [-_

10) low humidity/dry air _ _ _ _

11) high humidity _ _ _ _ _-]

12) trips to bathroom _ [_ [_] _ [-_

13) bed partner _-] _ [_ ['_

14) privacy _ _] ['_ ['_

15) ventilation _ _ _ [_

16) sheets _ ['_ _ [_

17) blankets _ ['_ ['_ [_

18) pillows _'] ['_ _ [-_

25. Please rate the following on the extent to which they interfere with your sleep at home?

strongly interferes no effect

1 2 3 4 5

1) hunger ['_ _ [_']_ [__ _-]_ _-]_°

2) thirst _-]_° _4"]_° _ _ __° _7"]_°

3) personalworries [_']_° _-]_° _']_° [-_]_° [_']_

4)respiratory factors _ _ [-_ _ _ _° ['_ _° _-]_°

76
26.

27.

5) other (specify)

Noise 23

Mental attitude 9

Family/pets 5

Environment 3

Please list any other factors that promote your sleep at home.

Physical environment (PE) 379

Comfort (C) 144

Mental attitude (MA) 128

Exercise/physical activity (EX) 80

Pre-sleep activities (PSA) 62

Schedule (S) 36

Meals/food (M) 25

Alcohol/medication (A) 17

Do you take medication to

help you sleep?

28. If yes, please specify.

29. Do you ever use alcohol to

help you sleep?

30.

S M

4% 3% A

PSA \| 2%

7% "_ _

9% MAI_,] 43%

15% C

17%

Overall, what kind of sleeper

are you?

never seldom sometimes often majority

of time

0%

Do

31. Do you have a sleep problem?

Cold remedies/aspirin 62

Sleeping pills 25

Aller[7 medication 4

never seldom sometimes often

D8

majority

of time

I%

Do

very poor poor

1% 9%

Do Fie

good

55%

very good

35%

34.

yes

14%

[5-1o

no

If yes, what is your sleep problem.

Restless sleeper

Circadian disruption

Thoughts/worries

Talk/Snore/Apnea

Pain

Bathroom

26

17

9

7

4

4

If yes, has it been diagnosed by a

physician?

yes

2%

[5-Io

no

26%

De

no answer

Has it ever prevented you from

flying a scheduled trip?

yes

3% /-73o

no

46%

no answer

51% rSrl.

77
36.

37.

38.

39.

a)

b)

c)

40.

a)

SLEEPING IN AIRCRAFT BUNKS

How often have you used a bunk in the past 12 months?

I- I

x = 25.86

1) current aircraft S.D. = 22.16 times

I

x = 19.59

2) other types of aircraft S.D. = 23.74 times

rain max

1 _ >99

rain max

1 _ >99

Based on your current aircraft, which

bunk do you usually sleep in?

upper lower either

Are you able to undress for a

comfortable sleep?

yes no

71% 29%

Is it important for you to undress

for a comfortable sleep?

yes no

74% 26%

How long after getting into the bunk

does it take you to fail asleep?

!- I

x = 42.29 min max

S.D. = 36.60 1 < > 300

mins

What is the typical amount of sleep

you get in the bunk?

I

x = 2:22 rain max

S.D. = 1:22 0:10 < > 7:00

hrs

What is the longest sleep period you

have experienced in the bunk?

- I

x = 3:39 min max

S.D. = 1:46 0:10 < > 10:00

hrs

What is the sho_est sleep period of

time that you would use the bunk

for sleep?

I

x = 1:15 min max

S.D. = 0:54 0:01 -,* > 6:00

hrs

When you have an opportunity

to use the bunk how often do you

experience difficulty sleeping?

never seldom sometimes often majority

of time

How often do you use the bunk

only for rest and not sleep?

never seldom sometimes often majority

of time

D8 _ __o D_ o_o _8 _

78
41. Are you required to spend some time

in the bunk when not flying?

42. If yes, who or what mandates use?

43. What other factors determine bunk

use and rostering?

44. In general, what percentage of cruise

time is made available to you for

using the bunk?

45. Rate your overall attitude about

the bunk.

46. How does bunk sleep affect

your overall alertness?

47. How does bunk sleep affect

your overall performance?

48. How often can you sleep when you

use any of the following.

1) cockpit seat

2) 1st class seat

3) passenger seat

4) bunk

5) at home in bed

yes no

7% 93%

o F_-lo

Result_ were inconclusive.

Seniority/crew decision (S) 162

Length of flight (L) 87

Augmentation (A) 70

Schedule/flight operations (F) 40

Sleep/circadian factors (C) 21

Prefer alternate choice (P) 4

C P

5% 1%

i_,_

23%

I- I

x = 34.18 min max

S.D.= 13.80 % 2 < >99

very neg neg neutral

D8 r_8 r_8 _

very decreased decreased no change

alertness alertness

D8 D8 D8

very decreased decreased no change

performance performance

ra8 D8 _8

pos very pos

improved very improved

alertness alertness

improved very improved

performance performance

never seldom sometimes often almost always

2% 5% 20% 33% 40%

FNO _1 © Free __ Em_

D8 _8 D8 D8 __°

79
49. Pleaserate the following factors and indicate how much

they interfere with or promote your sleep in the bunk?

interfere

1 2

9% 23%

1) quality of sleep surface [-_ {_) _-]

2) heat []_'] _ [_'] 8

10%

3) cold ['_'] 0 _']_

no effect promotes

3 4 5

Fa_ _° D8

4) thoughts running through head

5) random noise events

6) constant background noise

7) background lighting

8) readiness for sleep

9) comfort of clothing

10) low humidity/dry air

11) trips to bathroom

12) someone in the other bunk

13) seat belt sign

14) turbulence

15) privacy

16) bunk size

17) facility size

18) headspace

19) lighting

20) ventilation

21) storage space

22) curtains

_; _8 r_8 D8 m8

4%

©

O%

0

_8 _8 __ r_5 r_8

80
49.

23) sheets

24) blankets

25) pillows

26) other (specify)

interfere promo t es

[Noise 24][ Comfort(bedding) Positive mental attitude

Please rate the following factors and indicate how much

they interfere with or promote your sleep in the bunk?

(results are shown as %'s of total responses in each column)

interfere no effect promotes

1 2 3 4 5

1) quality of sleep surface _ ['_ _ _

2) heat _ _ _ [l_ [__

3) cold _ ['_ [_ _

4) thoughts running through head _ _ _ _

5) random noise events _ _ [-_ _

6) constant background noise _ [_] _ ['_ ['_

7) background lighting _ _ _ [-_

8) readiness for sleep [_] [_] _ _ [_

9) comfort of clothing _ ['_ _ _

10) low humidity/dry air _ _ _ _ [-_

11) trips to bathroom [_] _ _ ['_

12) bunk partner ['_ [_] _ [-_

13) seat belt sign ['_ _ [_ _

14) turbulence _ ['_ _ ['_

15) privacy _-] _ _ _

16) bunk size [_] _ ['_ _

17) facility size _ ['_ _ ['_ [7]

18) headspace _ _ _ ['_

19) lighting _ [_] _ [_] [_]

20) ventilation _ _ [_4=] _

21) storage space ['_ _ _ ['_

22) curtains _ _ _ ['_ [_

23) sheets _ _ ['_ ['_

24) blankets _ _ ['_ _']

25) pillows _ _ _ [-_

2541

81
50. Pleaserate the following on the extent

to which they interfere with strongly interferes no effect

your sleep in the bunk?

1) hunger

2) thirst

3) claustrophopia

4) personal worries

5) respiratory factors

6) other (specify)

152 3 455

Noise 40

B athroom 21

Scheduling 15

Bunk comfort 14

Turbulence 11

Mental attitude 11

Environment 7

51. Please list any other factors that promote good sleep in the bunk.

52.

Environment (E)

Comfort (C)

Ease of mind (M)

Lack of turbulence (T)

Fatigue (FATG)

Length of break (B)

Food (FD)

342

206

56

49

46

34

22

B FD

F

5% 3%

6%

M ,,,_ _ 46%

7% C

27%

When using the bunk, do you do anything to help you get

to sleep or to minimize disturbance of your sleep, such as:

yes no

1) Wear earplugs?

2) Wear eyeshades?

3) Listen to music?

4) Relaxation techniques?

5) Other (specify)

69%

i Read Comfortable clothing

61

23

82
53. Describeany pre-trip strategies you use to help you sleep in the bunk.

Schedule sleep (S) 219

Avoid caffeine (C) 56

Exercise (E) 38

Limit food intake (F) 35

Rest (R) 26

Limit liquids (L) 26

Bring comfort aids (A) 21

Settle problems (P) 12

54. Please suggest how the crew rest facility can be improved to

be more conducive to sleep?

Comfort (C) 312

(mattress,pillows,sheets,blankets)

Sound proofing (S) 187

Larger bunk area (A) 93

Privacy (P) 87

Humidifier/temperature control (T) 78

Darker (D) 76

Crew lavatory (L) 43

A P

% 3%

9% C

13%

L

D 5%

9%

35%

P

10% A S

11% 21%

83
Form Approved

Report Documentation Page OMB No. 0704-0188

Publ_- reposing butd_ lot _is collec_ d _ormation is estinated to av_'_e I _r _r _e, _ _ _ _ _ _, m_ H_ _ _s. _ _ _g _ _

_KI, m:l conC, eting md mte,_ the collec_on of iniormaf_. Sa_d owr, m=_ rega_rrg Ibis burden _e _ _ _ _ _ _ _ d _, _ s_ _ _ _ _. _

_/ashin_ Headquade_ Se_,ic_, D_'ec_orate br Infocmalion O_ and P._, 1215 Jefferson _ W_, _le 1_, _. VA _. _ _ _ _ d _ _ _, _

1. AGENCYUSEONLY(Leaveblank) 2. REPORTDATE

September 2000

4. TITLEANDSUBTITLE

Crew Factors in Flight Operations XII: A Survey of Sleep

Quantity and Quality in On-Board Crew Rest Facilities

6. AUTHOR(S)

Mark R. Rosekind, Kevin B. Gregory, Elizabeth L. Co, Donna

L. Miller, and David F. Dinges

7.PERFORMING ORGANIZATION NAME(S) ANDADDRESS(ES)

Alertness Solutions, Inc.

Cupertino, California 95014

9. SPONSORING/MONITORINGAGENCYNAME(S)AND ADDRESS(ES)

National Aeronautics and Space Administration

3.REPORTTYPEANDDATESCOVERED

Technical Memorandum

5. FUNDINGNUMBERS

548-30-32

8.PERFORMINGORGANIATION

REPORTNUMBER

IH-013

10. SPONSORINCVMONITORING

AGENCYREPORTNUMBER

NASA/TM_2000-209611

11.SUPPLEMENTARY NOTES

Point of Contact: David Neri, Ames Research Center, M/S 262-4, Moffett Field, CA 94035

(650) 604-0658

12A.DISTRIBUTION/AVAILABILITY STATEMENT

Subject Category: 52-03 Distribution: Public

Availability: NASA CASI (301) 621-0390

12B.DISTRIBUTIONCODE

13.ABSTRACT(Maximum200 words)

Many aircraft operated on long-haul commercial airline flights are equipped with on-board crew rest facilities, or

bunks, to allow crewmembers to rest during the flight. The primary objectives of this study were to gather data on

how the bunks were used, the quantity and quality of sleep obtained by flight crewmembers in the facilities, and the

factors that affected their sleep. A retrospective survey comprising 54 questions of varied format addressed

demographics, home sleep habits, and bunk sleep habits. Crewmembers from three airlines with long-haul fleets

carrying augmented crews consisting of B747-100/200, B747-400, and MD-11 aircraft equipped with bunks

returned a total of 1404 completed surveys (a 37% response rate). Crewmembers from the three carriers were

comparable demographically, although one carrier had older, more experienced flight crewmembers. Each group,

on average, rated themselves as "good" or "very good" sleepers at home, and all groups obtained about the same

average amount of sleep each night. Most were able to sleep in the bunks, and about two thirds indicated that these

rest opportunities benefited their subsequent flight deck alertness and performance. Comfort, environment, and

physiology (e.g., being ready for sleep) were identified as factors that most promoted sleep. Factors cited as

interfering with sleep included random noise, thoughts, heat, and the need to use the bathroom. These factors, in

turn, suggest potential improvements to bunk facilities and their use. Ratings of the three aircraft types suggested

differences among facilities. Bunks in the MD-I 1 were rated significantly better than either of the B747 types, and

the B747-400 bunks received better ratings than did the older, B747-100/200 facilities.

i4. SUBJECTTERMS

Fatigue, Sleep, Crew rest, Aircraft bunks, Long-haul

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