The traditional dividing line between small and large commercial transports has been based upon weight and passenger capacity. Airworthiness regulations have been matched to operating rules for each category in a way that permitted considerable economics to the smaller aircraft by comparison with the large.
As technology and passenger demand both advance, this dividing line has become increasingly blurred, through extensions of both weight and passenger capacity as a means of preserving sensible public service, with the result that the development of a new family of commuter aircraft, larger than previously permitted though still smaller than existing jet equipment, has been encouraged.
In spite of this equipment stimulus, growth in the commuter market remains unpredictable, accenting the need for flexibility of design to permit ready adaptation to each new need. It is suggested that the combination of new structural technologies coupled with wider application of systems design practices normally associated with larger aircraft, offers a means of economically providing such flexibility of design. The burgeoning range of smaller energy efficient turboprop engines appears to match this opportunity. In the event that Part 23 of the Federal Aviation Requirements is amended to include aircraft of up to 19,000 lb. gross weight, an opportunity exists to develop a new generation of commuter aircraft with enough flexibility to keep pace with commuter airline needs in the U.S.A.