Shappell, 1997

Crew Rest and Duty Restrictions for Commercial Space Flight:Recommendations Based Uponthe Scientific Literature

Scott Shappell, PhDMichael Sawyer, MSJessica Patterson, MS

Work sponsored by:FAAVolpe CenterAerospace Corporation

Code of Federal Regulations (sub part 431.43) Reusable launch vehicle mission operational

requirements and restrictions

CURRENT DUTY TIME & REST REGULATION

• No personnel will be scheduled for more than a 12-hour shift during the mission or preceding a reentry mission.

• A minimum of an 8 hour rest period is required after 12-hours of work.

• During the 7 day period prior to the start of the mission, a maximum of 60 hours can be worked.

• No person will work more than 14 consecutive days and after 5 consecutive days of 12 hour shifts, a 48-hour rest period must be given.

Increased reaction time • Timing errors in response sequences• Less smooth control

Reduced attention • Preoccupation with single tasks• Reduced audiovisual scan

Diminished memory • Forget peripheral tasks• Revert to “old” habit patterns

Withdrawn mood • Less likely to converse• Less likely to perform low-demand tasks

Increased risk taking

Increased reaction time • Timing errors in response sequences• Less smooth control

Reduced attention • Preoccupation with single tasks• Reduced audiovisual scan

Diminished memory • Forget peripheral tasks• Revert to “old” habit patterns

Withdrawn mood • Less likely to converse• Less likely to perform low-demand tasks

Increased risk taking

Performance Effects of Fatigue

Subjective vs. Physiological Fatigue

The worst person to ask if he is fatigued or sleepy is the person that you are worried about!

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Circadian RhythmsCircadian Rhythms

SleepSleep Our sleep/wake cycle is closely Our sleep/wake cycle is closely

tied to our circadian body tied to our circadian body temperaturetemperature

a) Cave studiesa) Cave studies

Our sleep/wake cycle is closely Our sleep/wake cycle is closely tied to our circadian body tied to our circadian body temperaturetemperature

a) Cave studiesa) Cave studies

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Stages of SleepStages of Sleep

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SleepSleep Our sleep/wake cycle is

closely tied to our circadian body temperature

a) Cave studies It is the timing of sleep, not

necessarily the amount of sleep, that is important.

Our sleep/wake cycle is closely tied to our circadian body temperature

a) Cave studies It is the timing of sleep, not

necessarily the amount of sleep, that is important.

How Much Sleep Do You Really Need?How Much Sleep Do You Really Need? Sleep requirements vary among individuals.

A minimum of 5 hours of uninterrupted “core” sleep during the circadian trough is necessary to maintain 80% performance in the lab.

In space, where environmental factors, and physical and mental workload can exceed normal limits, the minimum amount of sleep needed to sustain performance is more.

Source: Walter Reed Army Institute of Research

What We Know About Sleep

• While all sleep is beneficial, SWS is more recuperative.• The best time to sleep is during the circadian trough

(between 2200-0800).• Interruptions of nighttime core sleep reduce sleep

quality and effectiveness.• Individuals need roughly 8 hours of sleep to be

properly refreshed.• Sleep loss is cumulative and may take multiple nights

of sleep to fully recover.

United StatesEuropean Union

(EASA, JAA)United

Kingdom Canada Australia

Maximum flight hours in 24 consecutive hours

10 13 10 8 8

Maximum flight hours in 7 consecutive days

30 N/A N/A 60 30

Maximum flight hours in 30 consecutive days

100 N/A N/A 120 100

Maximum flight hours in 28 consecutive days

N/A 100 100 N/A N/A

Maximum flight hours in 365 consecutive days

1000 900 900 1200 900

Minimum consecutive rest hours during 7 consecutive days

24 36 N/A 36

9 hrs. btw 10pm and 6am on 2 consecutive

nights

Commercial Aviation Crew Rest RequirementsCommercial Aviation Crew Rest Requirements

Unique Crew Rest ConsiderationsUnique Crew Rest Considerations

Lodging Considerations in Space Long Duration Flight Limited Trained Relief Pilots Restrictive Work Environment Workload Stress Others …

Code of Federal Regulations (sub part 431.43) Reusable launch vehicle mission operational

requirements and restrictions

CURRENT DUTY TIME & REST REGULATION

• No personnel will be scheduled for more than a 12-hour shift during the mission or preceding a reentry mission.

• A minimum of an 8 hour rest period is required after 12-hours of work.

• During the 7 day period prior to the start of the mission, a maximum of 60 hours can be worked.

• No person will work more than 14 consecutive days and after 5 consecutive days of 12 hour shifts, a 48-hour rest period must be given.

CURRENT DUTY TIME & REST REGULATIONA maximum 12-hour work shift with at least 8 hours of rest after 12

hours of work, preceding initiation of an RLV reentry mission or during the conduct of a mission.

Recommended Modifications/Additions• 8 hours of uninterrupted sleep (not rest as currently

defined).- Sleep should not be pharmacologically induced.

• Sleep should occur during the circadian trough.• Attention should be paid to the quality of sleep

- Domicile vs. temporary lodging (e.g., hotels)• Define “off-duty” to include sleep plus personal time

(hygiene, meals, etc.) and transit time to and from workplace.- Transit time will depend on location of sleep, time of

day (rush hour), etc.

CURRENT DUTY TIME & REST REGULATIONA maximum of 60 hours worked in the 7 days, preceding initiation of an

RLV mission.

• The regulation should address flight time and duty time for flightcrew and duty time for ground personnel.

• Given the unknown stress of space flight, all regulations should reflect a conservative approach.

• Flightcrew- 30 hrs flight time- 60 hrs of duty* Short-haul vs. Long-haul flights

• Ground personnel- 60 hrs of duty* Overtime issues (Air Traffic Model)

CURRENT DUTY TIME & REST REGULATIONA maximum of 14 consecutive work days.

Flightcrew• The nature of space flight may require 14 consecutive work

days; however, consideration should be given to the type of work scheduled with more stressful tasks spaced apart.

• 14 consecutive work days also assumes that flightcrew are fully adapted to space flight, circadian dysrhythmia, and a full 8 hours of sleep during circadian trough.

Groundcrew• While this area has yet to be fully reviewed, 14 consecutive

days seems excessive given the lack of constraints on personnel augmentation.

CURRENT DUTY TIME & REST REGULATIONA minimum 48-hour rest period after 5 consecutive days of 12-hour shifts.

Flightcrew & Groundcrew• This seems like a reasonable recommendation since

actual flight time is capped at 30 hours. • Although we are still researching this particular topic

area, a 48-hour recovery should be sufficient to restore most performance deficits incurred by 5 consecutive days of 12-hour shifts.

RECOMMENDED DUTY TIME & REST REGULATION

Suborbital Flights Orbital Flights

Flight crewGround

crewFlight crew Ground crew

Sleep (hrs) in 24 hours 8 8 8 8

Crew rest (hrs) before and after shift 12 12 12 12

Max. flight time (hrs) in 24 hours (non-augmented) 8 N/A 8N/A

Max. flight time (hrs) in 24 hours (augmented) N/A N/A 12 N/A

Max. duty time (hrs) in 24 hours (non-augmented) 11 12 1112

Max. duty time (hrs) in 24 hours (augmented) N/A N/A 14 N/A

Max. flight time (hrs) in 7 days 30 N/A 30 N/A

Max. duty time (hrs) in 7 days 60 60 60 60

QUESTIONSQUESTIONS

Countermeasures to Fatigue and InsomniaBreak glass in case of emergency

Countermeasures to Fatigue and InsomniaBreak glass in case of emergency

FATIGUEFATIGUE INSOMNIAINSOMNIA

Non-Pharmacological Non-pharmacological

Napping Diet

Light Exposure Exercise

Pharmacological Routine Sleep Times

Caffeine Pharmacological

Other Stimulants Melatonin

Alcohol

Sedatives