Use of Task Timeline Analysis to Assess Crew Workload

Abstract : As systems have become more sophisticated, the role of humans in operating and maintaining them has grown more complex. There has been a steadily growing recognition that human characteristics, particularly limitations and abilities, must be considered in some depth in system design if design objectives are to met. The size and role of the crew represent critical design decisions. Mission performance has a direct relationship to the ability of the crew to carry out all of the required functions. If necessary functions overload the crew, some will be omitted and others ineffectively performed. If this is the case, automation may have to be considered. If the crew is underloaded, boredom and reduced performance may result, in addition to unnecessary costs being incurred. An additional crew member will increase weight, design costs, fuel expenditures, and training costs. It has been estimated that, for a commercial aircraft, an additional flight crew member can result in a 4 to 5 percent increase in direct operating costs. In the same manner, for a military aircraft fleet of 200 with a life-cycle of 20 years, costs can amount to several hundred million dollars for each additional crew member. Issues of crew size were so critical in preliminary design work for proposals on antisubmarine warfare (ASW) and airborne warning and control system aircraft (AWACS) that Douglas Aircraft Company conducted research on the problem.