Effective Crew Scheduling Strategies on
Ultra-Long-Range Flights
John R. Fare
Johnson & Johnson Aviation
Introduction: Current and Future Demands of Our Customers
As many of us know, our customers, e.g. owners, business executives, and charter passengers,
are increasingly demanding longer flights and shorter layovers. The needs of our aviation
segment are demanding longer range aircraft that fly higher and faster. The days of long
layovers and crew changing every flight are over. The newest ultra-long-range aircraft, i.e.
Gulfstream, Global, Boeing, and Airbus, are capable of 7,000+ nautical mile range with
endurance up to 14 hours. These capabilities are putting conventional city pairs that were
previously crew changed at an intermediate tech stop within non-stop reach of one flight crew.
In my experience at J&J, it is not uncommon for our executives to want minimum time on the
ground before returning home. We have an increasing amount of flights to Europe that are
turning in 12–14 hours with the same crew. Our customer’s time is valuable and we want to be
able to meet the demands of their busy schedules while maintaining safety and efficiency.
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
1
Alertness in the Aircraft
There are three distinct factors that determine the alertness level of the flight crew. The three
factors are:

Circadian Rhythm

Sleep Propensity/Pressure

Sleep Inertia
Circadian Rhythm
Our bodies are set on a 24-hour biological clock that we refer to as our circadian rhythm. The
physiological purpose of our circadian rhythm is to regulate our body’s functions such as:
sleep/wake episodes, core body temperature, digestion, neurological and physical performance,
and hormone secretion (Connors, 2005). Synchronization of our circadian clock is done by builtin cues called “zeitgebers” (pronounced “zeitgeebers”) which is German for “time keepers.”
Zeitgebers allow for a shortened circadian clock that correlates to the dark light cycle of 24
hours. Without zeitgebers the body’s circadian clock would be 25.3 hours. Zeitgebers that help
establish our body’s circadian rhythm are: bright light, temperature, social interactions, work and
rest schedules, eating/drinking patterns, and pharmacological manipulation (Caldwell et al.,
2009).
A normal sleep/wake pattern is 16 hours awake with 8 hours of sleep. A person’s body is
expecting to be at rest is between the hours of 0200–0600 (Flight Safety Foundation, 2005). The
circadian low is the time period that our bodies want to be at a restful state, i.e. asleep. The
circadian rhythm experiences two time periods of sleepiness on the 24-hour cycle. The first
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
2
period of sleepiness occurs approximately between the hours of 0200–0500 body adjusted time
and the second is 12 hours opposite between the bodies’ adjusted hours of 1500–1700 (Civil
Aviation Authority, 2007). Pilots crossing multiple time zones and changing work schedules
experience a disruption to the circadian rhythm.
Circadian Adjustment: Phase Advance
Circadian adjustment is more difficult when traveling eastbound due to the shortening of the day,
which creates a phase advance of the rhythm. Eastbound flights require a person to shorten their
24 hour cycle to synchronize their rhythm to the new time zone. Flight crews of eastbound
flights experience a short sleep episode at the beginning of the layover followed by a long sleep
episode towards the end (Gander et al., 1998).
Phase Delay
Conversely, westbound flights lengthen a pilot’s day and require a phase delay to extend the
circadian rhythm beyond the normal 24 hours for synchronization. Crews of westbound flights
experience an initial long sleep episode followed by a nap or shorter sleep episode towards the
end of the layover (Gander et al., 1998).
Adjustment
The term “asymmetrical effect” is used to describe the inequality between eastbound and
westbound circadian adjustment. Data from several studies was averaged to show that westbound
flights crossing eight time zones require 5.1 days to reach 95% of the total re-synchronization of
psychomotor performance rhythm, whereas 6.5 days were required for an eastbound flight
crossing the same amount of time zones (Billiard & Kent, 2003).
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
3
Circadian rhythms re-synchronize towards the new time zone at 92 minutes per day when
traveling westbound and 57 minutes per day when traveling eastbound (Billiard & Kent, 2003).
New York to London with a 5 hour time difference will require 5 days for total circadian
adjustment (57 minutes per day), whereas New York to Los Angles will require 2 days with a 3
hour time difference (92 minutes per day).
Homeostatic Sleep Propensity/Pressure
Homeostasis is the body’s internal mechanism to maintain stability. The normal time of
wakefulness for humans is 16 hours +/- one hour (Wyatt et al., 2006). Duty days exceeding the
normal time of wakefulness are a factor that contributes to cockpit fatigue. A study (Wyatt et al.,
2006, p. R1158) suggests that homeostatic sleep pressure can change with a person’s adjusted
schedule. Flight crews that experience disruption to their normal circadian rhythm can have
either a shortened or lengthened sleep wake cycle. Adjusted cycles have shown proportional
changes in sleep propensity, meaning a sleep wake cycle of 20 hours has an adjusted sleep
propensity of 13 hours and a lengthened cycle of 28 hours has the greatest sleep pressure at 20
hours. Keep the shift in sleep propensity in mind when crew rest is less than 24 hours as one’s
need for sleep will come at a shorter time interval on the subsequent day. A study (Wyatt et al.,
2006, p. 1161) suggests the powerful impact of accumulating sleep pressure even with shortened
periods of wakefulness.
Identified complications from fatigue are: slowed reaction time, degraded cognitive
functions/decision making, decreased alertness, lack of concentration, mood changes to include
irritability and complacency, increase in errors including missed radio calls, checklist items and
sloppiness, and a decrease in stick and rudder abilities (Civil Aviation Authority, 2007).
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
4
Figure 1. Performance Decrements after Continuous Periods of Wakefulness. From p. 16 of
CAA Paper 2005/04, “Aircrew Fatigue: A Review of Research Undertaken on Behalf of the UK
Civil Aviation Authority.”
Sleep Inertia
Sleep inertia is the grogginess that one feels after waking up from a deep sleep. Sleep inertia’s
effects are most prominent when waking up extremely early for a duty day and when reporting
back to duty on the flight deck after crew bunk rest. We’ve all experienced the 0330 wake-up
and are still looking at bloodshot eyes in the mirror even after taking a long hot shower. Sleep
inertia is more prevalent when a nap is preceded by a prolonged period of wakefulness and or
accumulated sleep debt (Gander, Rosekind & Gregory, 1998). Longer in-flight sleep is
encouraged for three-pilot crews but amble time (at least 40 minutes) needs to be afforded to
offset sleep inertia’s effects prior to resuming flight deck duties (George, 2011). Short naps of
40 minutes or less are effective at combating sleep inertia and increasing alertness on extended
duty days and work well when crew bunk rest is not long enough to afford sleep inertia recovery.
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
5
Crew Types and Logistics: Two-Pilot Crew
The most basic standard for crewing business aircraft is the two-pilot crew. Consideration
should be given to time of day, i.e. normal vs. circadian low time periods. The Flight Safety
Foundation recommends that a two-pilot crew be limited to a 14 hour duty period during normal
working hours and 12 hours during circadian low operations.
Augmented or Three-Pilot Crew
This scheduling technique adds a third pilot to a trip and is most effective when a crew bunk or
separated area with the ability to rest in the supine is available. The Federal Aviation
Administration (FAA) has defined the types and “sleep opportunity” of crew bunks aboard
aircraft.
Most modern widebody aircraft have the ability to be fitted with Class 1 crew rest facilities.
Class 1 facilities are completely separated from the cockpit and passenger cabin areas and are
designed with full, flat bunks in rooms with doors that are well insulated, quiet and temperature
controlled (George, 2011). Class 2 rest facilities are not completely isolated from passenger
compartments but they must have first-class or business class style seats that fold flat to at least
80 degrees from vertical. The rest facilities must have curtains that attenuate light and noise and
must be “reasonably free” from disturbances by other crewmembers or passengers (George,
2011). Class 3 rest facilities have chairs that recline 40 degrees with leg and foot supports and
cannot be located in economy class.
Corporate jets lack the space of their larger airline counterparts and aircraft such as the
Gulfstream 5/550 and Global series can only afford Class 2 crew rest facilities. The FAA has
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
6
designated Class 1, 2, and 3 facilities as having a sleep opportunity credit of 75%, 56%, and 25%
respectively (George, 2011). The sleep opportunity credit is a reasonable estimation of the
percentage of sleep a crewmember can expect to get while resting in the applicable facility.
Crew Change
When a trip has a suitable tech stop available and if the duty day is going to exceed either 18 or
20 hours, then a crew change will be the most beneficial to act as a fatigue countermeasure.
Consideration should be given to the logistics of “prepositioning” a crew and weather. Winter
tech stops in Alaska or Scandinavian countries may be logistically more challenging and should
be thoroughly investigated. Again, sleep propensity needs to be considered. Ensure
prepositioned crews arrive at least 24 hours prior to departure and up to 48 hours prior if
circadian adjustment toward tech stop time zone is advantageous, e.g. Honolulu for Sydney
flights.
Fatigue Study: Overview
I decided to start a study to determine the alertness levels of our pilots on all flights that involved
either two- or three-pilot crews that had extended operations during circadian low periods.
Between 2009 and 2010, I collected a total of 86 forms that represented flights between the U.S.
and international destinations in Europe, South America, and Asia. There were 15 pilots and 4
Flight Maintenance Engineers that took part in the study. At J&J, we always fly a three-person
crew with a mechanic acting as flight engineer in the cockpit for takeoff and landing and in the
cabin as a flight attendant while en route.
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
7
Crewing Technique of the Respondents
______________________________________________________________________
Crewing Technique
Frequency
Percentage___________________
2-Pilot Crew
32
37.21%
3-Pilot Crew
54
62.79%
Total
86
100.00%______________________
The hypothesis of my study was to prove that a three-pilot crew was more alert during the last
two hours of a flight to include the top of descent, approach, landing, and post-flight than a twopilot crew.
The alertness scale that I used was developed by Dr. William C. Dement of the Stanford
University’s Sleep Well Clinic.
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
8
Stanford Sleepiness Scale
Scale
Degree of Sleepiness
Rating
1
Feeling active, vital, alert, or wide awake
Functioning at high levels, but not at peak; able to
concentrate
2
3
Awake, but relaxed; responsive but not fully alert
4
Somewhat foggy, let down
Foggy; losing interest in remaining awake; slowed
down
5
6
Sleepy, woozy, fighting sleep; prefer to lie down
No longer fighting sleep, sleep onset soon; having
dream-like thoughts
7
X
Asleep
Figure 2. Stanford Sleepiness Scale. Obtained at http://www.stanford.edu/~dement/sss.html
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
9
Assumptions
All crews were operating through and/or during their circadian low. It was assumed that a twopilot crew consists of two pilots and one Flight Maintenance Engineer (FE). A two-pilot crew
cannot be scheduled over 12 hours of duty during circadian low so all two-pilot crew data that
exceeds 12 hours was from FEs that were part of a three-pilot crew. FEs that were part of a
three-pilot crew were unable to obtain supine rest due to space limitations. FE alertness levels
between duty hour 12 and 20 are assumed to be equal to a two-pilot crew operating during these
extended duty times. A three-pilot crew (augmented) consists of three pilots and one FE. Threepilot crews were used on flights that exceeded 12 hours of duty. All three pilots were afforded
separated supine rest but the FE was not. Flights that exceed 20 hours of duty were scheduled
with an entire relief crew at a predetermined tech stop and were counted as two separate twopilot crews for the study. The last two hours of duty included the top-of-descent, approach,
landing, and securing of the aircraft. Pilots and FEs began their duty day two hours prior to
takeoff and concluded ½ hour after landing at the final destination.
Limitations
The data obtained by the research was subjective and it was impossible for me to determine if the
input from the volunteers was accurate or biased. Non-reportable human factors such as health,
emotional stability, family life, quality of sleep, alcohol/substance abuse cannot be measured to
see how they affected the fatigue of my research participants. Ambient conditions such as night,
daylight, weather, and turbulence were not taken into account in the “Fatigue Study” to see how
they too affected the crew’s sleepiness and rest.
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
10
Methodology
Flight crews received a “Fatigue Study” form whenever a trip would meet the previously
discussed parameters. Duty hour 1 began with the show time at the airport and the duty day
would terminate 30 minutes after landing. Participants would subjectively enter their perceived
alertness level on an hourly basis. Nightly sleep beginning with the night prior to the trip was
also recorded.
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
11
Figure 3. Johnson & Johnson Aviation Fatigue Study Form
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
12
Treatment of Data
The start of duty was changed to reflect body adjusted time according to the previously discussed
correction of 57 minutes per day Eastbound and 90 minutes per day Westbound. The mean of
the Stanford Sleepiness Scale (SSS) values were separated by the following categories:

Two-pilot crews

Three-pilot crews

Start time of duty day
Lastly, all recorded crew rest and sleep during rest periods were disseminated to show the
relationship between duty hour and amount of sleep attained during crew rest.
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
13
Results
Here are the cumulative results of the Fatigue Study:
SSS MEAN FOR THE LAST TWO HOURS OF DUTY
________________________________________________________________________
Crewing Technique
Hour 1
Hour 2____________
2-Pilot Crew
2.23
2.43
3-Pilot Crew
2.20
2.27
______
“Hour 1” and “Hour 2” represent the second to last and last hour of duty of all submitted forms
for respective crewing technique.
SSS During Last 2 Hours of Duty
2.5
2.4
2.3
Hour 1
2.2
Hour2
2.1
2
2 Pilot
3 Pilot
Figure 4. SSS Mean During Last 2 Hours of Duty
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
14
Conclusion
The research data supported the hypothesis that a three-pilot crew is less tired than a two-pilot
crew during the last two hours of duty during extended circadian low operations. SSS data was
consistent and supports the three-pilot crewing technique for extended operations that
conventionally required complete crew swaps at tech stops. The data obtained during the
research process should give managers, schedulers, and pilots increased confidence in using
three-pilot crews to mitigate the risks posed by in-flight fatigue.
2-PILOT VERSUS 3-PILOT SSS PER DUTY HOUR
Crewing Technique vs. SSS
4
3.5
3
2.5
2 Pilot
2
3 Pilot
1.5
1
0.5
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20
Figure 5. Crewing Technique vs. Hourly Mean SSS
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
15
Conclusion
Two-pilot and three-pilot crews exhibit similar fatigue levels until duty hour 11(flight hour 9)
whereas three-pilot crew SSS levels remain significantly lower than two-pilot levels. This result
led my initiative to lower our two-pilot circadian low duty day to 9 hours of flight time.
SLEEP PROPENSITY’S EFFECT ON SSS
SSS averages per duty hour were separated by start time of duty. All start times were adjusted
by the previously discussed factor if away from the home base of Trenton, NJ. The results were:
SSS vs. Adjusted Start Time of Duty Day
__________________________________________
Time
Frequency
SSS ( mean)__
0100
19
2.06
0400
14
1.83
0600
55
1.51
0700
84
2.28
0800
71
1.48
0900
31
1.72
1000
88
1.78
1100
84
1.83
1200
209
1.85
1400
118
1.65
1500
25
1.50
1600
85
1.78
1700
148
1.79
1800
21
2.58
1900
56
1.96
2000
23
2.62
Total:
1131
1.92________
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
16
SSS vs. Adjusted Start of Duty Day
3
2.5
2
1.5
SSS
1
0.5
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 22 23 24
Figure 6. SSS Mean for Entire Flight vs. Start Time of Duty Day
Conclusion
Sleep Propensity does have an effect on the success of the three-pilot crews. There is a
significant increase in SSS of start times between 1800 and 0700. The data shows a definite
limit of 1700 when cumulative SSS levels begin to increase.
DUTY HOUR’S EFFECT ON SLEEP DURING CREW REST
All rest periods were analyzed on the submitted forms and percentage of sleep was broken out to
demonstrate the ratio of sleep compared to the duty hour when a crew rest period was taken. The
results:
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
17
Crew Rest Sleep Percentages vs. Duty Hour
Duty Hour
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Frequency
1
1
7
13
14
16
14
14
13
12
9
9
11
13
10
9
4
3
1
0
Sleeping
0
1
2
6
4
5
9
5
9
10
5
5
6
7
6
6
4
3
0
0
Awake
1
0
5
7
10
11
5
9
4
2
4
4
5
6
4
3
0
0
1
0
% Sleep
0
0
29
46
29
31
64
36
69
83
56
56
55
54
60
67
100
100
0
0
% Awake
100
100
71
54
71
69
36
64
31
17
44
44
45
46
40
33
0
0
100
0
Conclusion
Analyzed crew rest showed an increase in sleep in rest periods taken after the 9th duty hour.
Crew rest taken earlier in flight had less sleep because there was no physiological need due to a
lack of sleep propensity. Crews coming off of rest with little or no sleep did not see as much
SSS reduction as crews with sleep. Crew rest obtained between Duty Hour 10 and 17 was most
beneficial with the highest percentages of sleep which corresponded to lower SSS levels
compared to two-pilot crews with data from FEs that had no provision for sleep. Lower SSS
levels beginning at Duty Hour 11 for three-pilot crews correspond to increased percentages of
sleep obtained while on crew rest.
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
18
Summary

Three-pilot crews are less tired than two-pilot crews on extended circadian low flights

Sleep Propensity must be considered when augmenting
o Consider crew change if flight takes off prior to 0700 or after 1700

Make a strategy for crew bunk rest
o Rostering prior to the flight
o How much time is available? Long nap or short nap? When will there be the
greatest physiological need
o Give priority to the Pilot Flying

Employ In-flight Fatigue Countermeasures
o Cockpit Lighting
o Activity Breaks
o Caffeine
o Social Interaction
PRACTICAL APPROACHES
Example 1:
2 Pilots
Depart KTEB @ 1800 Local
Arrive LFPB @ 0630 Local
12 hour rest period + 2 hours for travel and “unwinding”
Depart LFPB @ 2030 Local
Arrive KTEB @ 2330 Local
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
19
Example 2:
3 Pilots
Depart KTEB @ 0800 Local
Arrive RJTT @ 1230 Local the next day
Figure 7. Chart obtained at National Highway Traffic Safety Administration website at:
www.nhtsa.gov/people/injury/drowsy_driving1/human/drows_driving/wbroch/wbroch_lg
/wbroch_lg.html
References
Billiard, M, & Kent, A. (2003). Sleep: physiology, investigations, and medicine. New York,
NY: Kluwer Academic/Plenum
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
20
Caldwell, John A., & Caldwell, J. Lynn (2003). Fatigue in Aviation: A Guide to
Staying Awake at the Stick. Burlington, VT: Ashgate Publishing Limited
Eriksen, C.A., Torbjorn, E., & Nilsson, J.P. (2006). Fatigue in trans-atlantic airline
operations: Diaries and actigraphy for two- vs. three-pilot crews. Aviation, Space, and
Environmental Medicine, 77(6), 605-612.
Gander, P.H., Gregory, B.S., Miller, D.L., Graebner, R.C., Connell, L.J., & Rosekind, R.
(1998). Flight crew fatigue V: Long-haul air transport operations. Aviation, Space,
and Environmental Medicine, 69(9), B37-B48
Gander, P.H., Rosekind, M.R., & Gregory, K.B. (1998). Flight crew fatigue VI: A
synthesis. Aviation, Space, and Environmental Medicine, 69(9), B49-B60.
George, F. (2011, February). Fatigue risk management. Business & Commercial Aviation,
32-37.
Miller, J. C. (2005, May). Operational Risk Management of Fatigue Effects (AFRL-HE- BRTR-2005-0073). : United State Air Force Research Lab.
Neri, D., Oyung, R., Colletti, L., Mallis, M., Tam, D., & Dinges, D. (2002), Controlled Breaks as
a Fatigue Countermeasure on the Flight Deck. Aviation, Space, and Environmental
Medicine, 73(7)
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
21
United Kingdom Civil Aviation Authority (CAA), Safety Regulation Group. (2007).
Aircrew fatigue: A review of research undertaken on behalf of the UK Civil
Aviation Authority (CAA PAPER 2005/04). Retrieved from http://www.caa.co.uk
Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
22