More than a thousand million passengers are expected to fly in and out of the world's airports this year. By 2015 that number is set to double. According to some experts, if the current accident rate remains unchanged, it is statistically possible that major aircraft accidents will occur more frequently. In some aircraft accidents, the human interface with the aircraft has been identified as the sole (or major) contributory cause. Even in a theoretically survivable impact, many fatalities have occurred during egress from the aircraft, highlighting ergonomic concerns for passengers as well as flight deck crew. Now, with funding from the UK CAA (Civil Aviation Authority), the Cranfield University College of Aeronautics in the UK has begun using what is believed to be the world's first multi-configurable wide-bodied aircraft cabin simulator designed solely for research work. It can be used to replicate sections of aircraft, such as the Boeing 747 and Airbus A340. The simulator is 20 m long and 15 m wide, with a minimum sill height of 5 m above ground. It can be tilted to a steeply angled static attitude and can be filled with smoke. The college has also developed a realistic research flight deck simulator to allow investigation of the effects of increased automation on pilot performance.
The simulators are major elements in Cranfield's internationally funded research facility for the assessment of human performance in aircraft emergencies. The facility is operated by the Human Factors Group, the only university department in the UK specializing in Aviation Psychology. Research carried out by the group has been used to support new regulations aimed at improving the safety of air transport. Prof. Helen Muir, leader of the Human Factors Group and an internationally recognized expert on the subject, said that the cabin and flight deck simulators are fully configurable and extensively instrumented.
The cabin simulator is highly adaptable, with a modular interior so that a wide variety of seats, walkways, bulkhead designs, and exit configurations can be tested and developed. It will also simulate a double-deck layout as used on the 747-400 and as envisaged for the projected Airbus A3XX. Planned research involves emergency passenger evacuations. Cranfield has come up with a novel way to simulate human behavior in an emergency: it offers $10 to the first 50 passengers to exit the aircraft, creating a similar level of urgency to a real-life evacuation.
With regard to the flight deck work, Cranfield stated that there is mounting evidence that modern flight deck avionics systems can reduce pilot situational awareness instead of improving it. An FAA report entitled "The Interfaces Between Flight Crews and Modern Flight Deck Systems" (June 1996) highlighted several problems on the modern flight deck and confirmed the need to better integrate human factors and systems technology to improve aircraft safety. A recent report by British Airways concluded that "glass cockpits have not been as successful as had been hoped in improving situational awareness," and that "degradation of situational awareness ... is a serious problem." Future developments in civil operations that could increase pilot workload and might even overload the flight crew with information are also a concern, according to Cranfield. For example, Future Air Navigation Systems (FANS) may increase the complexity of ATC procedures, and new sensors for Traffic Collision Avoidance (TCAS) and Terrain Reference Navigation may increase the amount of information to be processed by flight crew.
The College of Aeronautics flight deck simulator allows investigation of the effects of high levels of automation on pilot performance. It is a fixed-base unit that integrates existing simulation software and displays with an advanced 180° visual system and modern avionics. Standard airways procedures can be flown by airline pilots with comprehensive data acquisition to capture both flight data and pilot behavior (e.g. heart rate, eye tracking, and skin resistance). The evaluation of various new types of displays, navigation systems, and flight control systems, particularly for pilot-in-the-loop studies, can now be integrated with human-factors analysis.
By exploiting recent advances in the performance of PCs, the College of Aeronautics has shown that an array of them, coupled by Ethernet, can provide a satisfactory real-time (100 Hz) simulation of the equations of motion and aircraft displays at comparatively low cost. This modular approach to flight simulation provides a rapid prototyping facility in which specific flight models, engine models, displays, and sensors can be configured as a set of independently developed software modules.
The advantage of a modular approach to simulation was demonstrated during a recent research program with British Aerospace Systems to investigate the handling qualities of future regional transport aircraft. A real-time model of the Airbus A300-600R (Beluga) aircraft was implemented in less than three days, including the design of an auto-throttle and a C flight control law. The simulator was controlled by a network of PCs (initially four), coupled by Ethernet. The visual display featured a three-channel image generator providing a 50 Hz real-time image, comprising textures, polygons, light points, moving objects, and 2-D overlays, based on a standard visual database form at (Multigen) and driving a 180° field-of-view projection system. Flight and engine data were presented on flat-screen color LCDs and options for flight controls included side-stick inceptors with a full-featured flight management system (FMS).
Typical research programs using these two simulators include the use of eye-tracking sensors to evaluate instrument scanning techniques for "glass cockpit" displays; analysis of cockpit resource management training methods and studies into pilot behavior in monitoring crew operations and assessment of communications between flight crew; measurement of pilot workload over a range of flight deck situations; evaluation of flight deck procedures for future air traffic management systems; passenger safety and survival during evacuation; and design, development, and testing of new display formats and design and analysis of passenger cabin configurations to enhance safety. Cranfield stated that human factors are already driving the design of flight deck innovations, saying that the Rockwell Collins plant in Cedar Rapids, IA, is introducing a 3-D display on Bombardier's Challenger 604 and is developing a "highway in the sky" flight display to be tested later this year on NASA's Boeing 757.
The College of Aeronautics is also launching a Master's Degree program in Human Factors and Safety Assessment. It is hoping that human factors will become as fundamental a part of aircraft design as structural performance and aerodynamics.
Stuart Birch
Aerospace Engineering June 2000
