EXPERIMENTAL ASSESSMENT AND ANALYSIS OF THE CREW WORKLOAD

The overcrowded air traffic scenario and the steady hi-tech growth within the cockpits of new aircraft may impose levels of workload on aircrew that deserve attention. The extended duty time and the mental workload due to the new monitoring tasks introduced by the “glass cockpit” increase the possibility of lack of situational awareness. The topic of workload assessment is hence an interesting one for flight safety. In collaboration with AirOne, a survey of the overall workload felt by aircrew flying with B737 during short and medium range flight has been carried out using the NASA TLX (Task Load Index) methodology. A brief discussion of workload concept and workload methodologies assessment are given and a survey conclusion is reported. 1. The new role of the aircrews A lot of aviation incidents/accidents are related to the so called “Human Factors”; but how can we define it? Despite the term Human Factors is coming to acquire a wider meaning, we can say that Human Factors is about people in their working and living environments. Human Factors is about the relationship between people and machines, equipment, procedures and with the environment about them. From another point of view, Human Factor can also be seen as a technology devoted to the effectiveness of the systems, which includes safety and efficiency, and well-being of the individual [1]. The Human Factor considerations during the design of new human-machine systems are addressed to the development of working stations and working environments in which the possibility of human error is minimized. This is particularly true in the aeronautical context. In the last decades, we have seen radical changes in aircraft systems and cockpit environment. The advance in electronic and informatics technologies has led to a high level of automation in flight controls and flight management. The development of CRT (Cathode Ray Tube) displays and, more recently, LCD (Liquid Crystal Display) flat panels have radically changed the quantity and the format of the information displayed to aircrews. Aircrews flying modern hi-tech aircraft have to face a new role in the aircraft control loop, a role of manager rather than of bold pilots! Better qualities of “airmanship” are now required as well as high levels of “cognitive performance” and “decision making”. 2. Human Processing Limitations Dedicated pilot training sessions are intended to develop in the aircrew an adequate level of airmanship (i.e. Crew Resources Management and Multi Crew Coordination courses), so that, if we neglect some crucial human inherent and operational factors we could affirm that a trained aircrew could ensure a safe flight. Unfortunately we cannot. On 8 May 1978, National Airlines Flight 193, a Boeing 727, crashed into Escambia bay while on a surveillance-radar approach to Pensacola Regional Airport. The NTSB (National Transportation Safety Board) determined that the probable cause of this accident was the crew’s unprofessionally conducted nonprecision instrument approach in which the pilots failed to monitor the descent rate and altitude. Contributing to the accident was the 1 ICAS 2002 CONGRESS