submission - Independent Pilots Association

shift *orkers (Colligan & Tepas. 1986). night shift *orkers (Rosa & Colligan. 1987). sea *'atch
*orkers (Colquhoun. 1985). and truck drirers (Hanrelin, l9t7). The laner stud¡ also found an
increase in the numbrr of accidents that o\-cur *'hen I 2'hour shifts are used.
This increascd likelihood of accidcnt risk due to long duty pcriods has becn found in other
srudies. The relative risk of an accident at l4 houn of dury riscs to 2.5 times thar of the lowest
pornr in thc f-rst eight hours of dury. Askenedt (1995) rcports accidcnt risks to bc th¡ecfold at l6
hours of duty, whilc Harris and Macki e (1972) fo¡nd a th¡ecfold risk in just over l0 houn of
driving. These levefs of risk a¡e simila¡ to that associaæd with baving narcolepsy or slccp apnca
(L-avþ er d., 1982), or a blood alcohol lcvcl of 0.10 pcrccnt. Wegmann et al. (19t5), in a srudy of
ai¡ carrier pilots, argucd for a duty pcrid of l0 houn with t.5 hours or less of flight duty pcriod.
Time Since Awake
The rcsults of an NTSB analysis of dornestic ai¡ carricr accidens occurring from l97t to 1990
suggest thu time sincc ar*'ake (TSA) was the dominant fatigue-relaæd factor in these accidents
(ì{TSB. 1991). Pcrformancc decrerncns of high tinrc-sincc-awake crews ænded to rcsult from
ineffecrivc dccision-making rather than dc¡erioration of ai¡craft þ¿¡¡dling skills. Thcsc dccrcn¡cnts
were nor felt to be rclucd to tirrrc zone crossings sincc all accidens i¡volved sbort haul flighs
*,ith a rna¡imum of ¡wo tirne zones crosscd. Therc did appcar to bc two pcåks in accidents: in the
morning when ¡irne since awake is low and the crcw has be¿n on dury for about th¡ee to fou¡
hou¡s,anduhentime-since-awakewash.rgh.above l3houn.Similuaccidentpeatsinother
modes of rransportauon a¡d industry hare also bcen rcportcd folkard. 1997). Akerstedt &
Kecklund (1989) srudied pnor trroc a*'ale (fou¡ to l2 hou¡s) and for¡¡d a st¡ong correluion of
accrdenrs uith tirr¡e since a*'ake for all omes of the da¡'. Belenþ et al. (1994) found that flight
time hou¡s lr¡orkload) greatlv incre¿se a.îd add to the lineardecline in prrformance associated
uith unr srnce a*'ake.
Task T¡'pe
The effecu of rask typ€. as they conrribuæ to the buildup of fatigue. need to be considered from
t\Ä o p€rsPe ct¡\'es:
o \\hether certain ac¡ivities can be excluded from duty period time
o \\"f¡erher certain actjvities are inherently more fatiguing and may need to be restricted.
The cunenr regulations regulate only flight time. No limits are provided for dury tirnc. The
resulaiions proposed in the Noticc of hoposed Rulemaking 95- l8 (ì"PRM) allow for the conccpt
of "assrsned time," which also is uffegulated as to maximum limits Tle extent to uhich
acriuries caregorized as non-flight time or a-ssigned time contribute to fatigue has ¡,et to be
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