In-flight simulation for training? (1968)

Problems related to the training of pilots to fly future very large, high-performance com- mercial transports are discussed. It is shown that both safety and economics make the de- velopment of more effective flight simulation devices very important. The complementary use of ground-based and in-flight simulation appears to offer a training system for these new aircraft which may better satisfy these requirements than do existing systems. Areas of pos- sible application of in-flight simulation are discussed. Contributions to the training of test pilots made by the use of variable stability airplanes are also discussed. The latter are based upon a number of years of actual experience in this type of training. ODIFICATION of the in-flight stability and control characteristics, or handling qualities, of aircraft has been performed by variable stability aircraft for nearly 20 years. This work has been done to determine handling qualities requirements, to experimentall y examine theories or hypotheses that have been advanced relative to handling qualities requirements, or to evaluate in flight the expected characteristics of a specific airplane. With the exception of special demonstration training programs which have been a part of test-pilot school programs for the past eight years, in-flight simulation has not been applied to pilot training. The variable stability airplane18 contains special sensors and servo control equipment that modify the response of the airplane to the inputs, or commands of the pilot and also modify the response of the airplane when it is subjected to disturbances. The statics and the dynamics of these re- sponses and the pilot's control force and displacement char- acteristics can be changed in flight by adjustment of the computer portions of the automatic control equipment. A safety pilot monitors the standard controls of the airplane and can at any time, and in a split second, deactivate the variable stability system and take control of the normal airplane in which the special equipment is installed. Therefore, it is possible to permit the evaluation (or trainee) pilot to expe- rience flight conditions which are demanding enough that control may be lost, without a significant possibility that adequate control cannot be promptly regained. The spectacular increases in the capabilities of commercial transport aircraft of the relatively near future are widely ap- preciated. Characteristics which are inherent in the very large subsonic transports (Jumbo Jets) and the supersonic transport (SST) are great size, great weight, and great speed. These characteristics yield the ability to move a large number of passengers a great distance in a short time. A satisfactory cost results when measured in cost per seat- mile of transportatio n supplied. The cost per flight hour, however, is another matter, and this will be unavoidably high. Since training is a function of flight hours in the air- craft rather than seat-miles per flight hour, the cost of pilot training in the actual vehicle will be high. Also, the flight characteristics of these very large, high-performance aircraft will undoubtedly differ from those of their predecessors, and the absolute need for safe and thorough crew training is so obvious that it scarcely needs stating. These factors make the importance of simulation for the crew-training program apparent and underscore the need for effective simulation methods which will provide the required training with a min- imum of flight in the actual airline transport. In-flight simulation has characteristics that make it appear to be attractive for pilot training when integrated with existing simulation techniques. In fact, the complementary integration of ground-based and in-flight simulation may well yield the most effective simulation system for train- ing which can be established. It must be stated at the outset, however, that thoughts regarding such a system are specula- tive. This precaution must be observed since in-flight simulation has not yet been used for pilot training, and since the form of an in-flight simulator which may be best suited to training is only now being developed. Need for Improved Simulation Techniques