Two the flight scenarios contained no unexpected procedures or


Two scenarios were developed using the flight
simulator application. The participants were instructed to fly B-52 simulated aircraft
for 3hours using instrument flight rules (IFR). One Scenario was a
multi-segment flight in which participant flew segments 1(Ada Mun to Plain Regal Airport), 2 (Plain Regal to Aberdeen Mum),
3 (Aberdeen Mum to Wishkah River Ranch Airport, WA). The second scenario was a
single-segment flight mission in which pilots flew from Ada Mun Airport, OK to Wishkah
River Ranch Airport, WA. The administrations of the scenarios were counter
balanced. In addition, to prevent confounding effects, we requested the pilots
to first perform one scenario, and then come back next day to perform the
second scenario. The pilots were told that the simulator flights would be flown
like real flight. Although the flight scenarios contained no unexpected
procedures or emergencies, the pilots were instructed to be ready to respond to
any emergencies that might occur, just like in the real world. In the
multi-segment day, the pilots flew a total of three segments. In the
single-segment day, there were simulator off-motion opportunities to allow
pilots to go to “the back of the plane.” Cued by ATC at the Scheduled time,
they began taxiing and took off. While en route, they made typical use of the
autopilot. Airspace-specific ATC background chatter (recorded prior to the
study) was played back over the pilots’ headsets or overhead speakers to add to
the realism of the flight. At the end of the flight segment, the pilots
conducted a routine descent and landed the airplane, again interacting with
ATC, and taxied from the runway to a designated gate. All flights were
conducted in accordance with FAA instrument flight rules (IFR). Both pilots
practiced a 10-minute Psychomotor Vigilance Test (PVT). They also practiced
filling out the Samn-Perelli (SP) Subjective Fatigue Check card and the
Karolinska Sleepiness Scale (KSS) subjective sleepiness questionnaire. In addition,
the pilots started a paper-and-pencil sleep/wake/duty log and recorded their Scenario
over the past two days. They began wearing an Actiwatch-2 wrist activity
monitor (Mini-Mitter Company, Inc.) to measure estimated sleep times during the
study (see Figure 4).  The pilots kept
the log and wore the wrist activity monitor through to the end of the third day
of the pairing.