AIRCRAFT HANDLING QUALITIES

The assessment of handling or flying qualities of airplanes depends in the final analysis on pilot opinion. The earhest requirement (ref. 12.30) simply stated, “During this trial flight of one hour it (the airplane) must be steered in all directions without difficulty and at all times be under perfect control and equilibrium.” From this simple but hard-to-interpret statement has evolved a much more quantitative and sophisticated set of criteria. These are still far from perfect, and the introduction of each new class of vehicle, STOL (ref. 12.30), rotorcraft, SST, etc., requires a reassessment of the existing criteria for application in the new situation.

When a pilot flies an aircraft he forms subjective opinions concerning the suitability of the man-machine system for performing the assigned task. In arriving at an assessment he is influenced by many parameters. These

508 Dynamics of atmospheric flight range over a wide spectrum and include:

1. Aircraft stability; response to external disturbances such as turbulence.

2. Aircraft controllability; the response of the aircraft to actuation of the controls.

3. Cockpit design; the ease with which instruments can be read; the comfort of the seat.

4. View from the cockpit; on landing approach is a sufficiently clear view of the ground provided?

5. Mission; e. g. high-altitude cruise, landing approach in a crosswind.

6. Pilot’s background and emotional and physical state; the familiarity of the pilot with the present aircraft and mission; impaired functioning arising from emotional and physiological factors.

7. External environment; visibility and weather conditions.

The term handling qualities is used to refer to those characteristics of the aircraft which the pilot considers to influence the ease of performing the mission. Much of the work in the area of handling qualities has centered on the determination of the influence of aircraft stability and control. It is the aim of this research to establish general specifications, to ensure that future vehicles can complete their intended missions safely, efficiently, and with a minimum of pilot fatigue.