submission - Independent Pilots Association

The orderty planning and sequencing of complex trharrors. the abiliry to attend to
several components simulnneously. and thcn flexibl¡ altcr thc focus of
concentrarion. rhe capacit¡ for grasping the context and gst of a complex
siruation, rcsis¡ancc to distraction and intcrfcrence, the abrlqv to follow multi-step
instructions, thc inhibirion of immediate but inappropriarc rcsPons€ tcndencies,
and thc abiliry ro sustain behavioral outpr¡t... may each bccon¡c rnarkedly
disrupæd (Resak, l98t).
Many of tbc functions dcscribcd by Restak are thc sarne funcúoûs Hcssary to a pilot's ability to
competentlY flY an aircrafr.
Meesuring Fetigue
Although the srudies just lisæd do show perforrnancc decrenrenls dræ to fatigue. other studies
have strown no effect (c.g., Roscnthal, 1993), particularly *'hen slecp loss lcvels up to 24 hours,
or small ch¡onic partial slcep loss levels of only one or two hor¡n Pcr day arc uscd. The lack of
dcfinirive rcsuls in panid sleep deprivation srudies rnây þ duc to differcnces in æsting
proccdures. Roscnthat tcsted on four scpa¡atc occasions, wþsreås othcrs ¡csæd only once Pcr day.
in . ror. s€vere stecp deprivation srudy, Thornc (1983) made t-be rc$ilg i¡stn¡nrcnt the primar¡'
task. *,hich lasted 30 mlnutcs of e¿ch hou¡. As slecp loss bcca¡r imrcasingly greåter, subjects
became slower, Thereforc, the tirne to complete the sclf-paced t¿sk r¡creased about 70 perce nt,
and at timcs doubled
Evans er at ( l99l), in a rcvie'*' of fatiguc in combãt, clearly' stalùJ Lhat gudies using embedded
testing. such as Thorne (1983). Angus and Heslegrave (1985), a¡d \lulla¡ey et al. (l9El),
consisrenrl¡,sho* -srearer effecrs of farigue and slecp loss performance decrements tha¡l short
durarion isolared inrusire tesLs Belenk) et al (1986) notes that Jt^rìtr.rìuouS embedded æsting
rcr,eals Iarger performance decremenLs soonerthan does interrruaen¡ tesring. [n Angus and
Heslegrare (1985). anal¡sis of results found a78% decremenl ur en''oJing/decoding performance
and a 43% decremenr rn logical reasorung afrer 24 hours a*aj¡e H.r:lam (1982), using non'
embedded testing, for¡nd no decrerncns and 29%, rcsP€ctivel)
The greater sensitiviry of embe dded æsting is not surprising grcn that tlrey rrrasure performance
for a more prolonged pcnd. Brief, intn¡sive psychomerric tesls. in conrasq a¡e novel a¡d act as a
resr break, distraction, and temporary stimulus, thereby incre¿si¡s sbort ærm mobilization of
effort thus boosting prformance. Tbe use of such an inswment *ould function similar to the
effecr Chambe rs (1961) found in an i¡dustrial output study when outPul rcmains higher when a
r*orker was switched to different jobs periodically than to stå)'al ooc job.
.A.notherexplanation for t̡e varying effects of performance due ro fatrgtrc is that performance is.
Lileralure Reyier'
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