Masters Theses


Ryan J. Smith

Date of Award


Degree Type


Degree Name

Master of Science


Aviation Systems

Major Professor

Ralph D. Kimberlin

Committee Members

Frank Collins, Fred Stellar


This thesis presents a test methodology for establishing reference approach speeds for General Aviation (GA) aircraft that have been modified with Short Take Off and Landing (STOL) kits. Supplemental certification information included with the kits usually lists aircraft performance after modification as "equal to or better than" performance listed in the original aircraft flight manual. As the aircraft may still be operated in accordance with the original flight manual procedures, the supplemental information may not address changes in aircraft operational speeds. However, to realize actual performance gains, pilots must become familiar with tire stability and control characteristics of the aircraft at speeds slower than those listed in the flight manual. Kit manufacturers desire to claim the greatest decrease in landing distance possible and thus advocate the slowest flyable approach airspeed. However, the variability of aircraft condition and mechanics' skills may introduce a large disparity in aircraft performance and handling qualities following kit installation. Thus, it is impractical to apply one best approach speed for all aircraft. The task of determining this best approach speed is left to individual owner/operators of modified aircraft. The goal of developing the test methodology presented in this thesis is to create a step-by- step checklist of practical flight test techniques that will allow owner/operators to determine the best reference approach speed for STOL kit modified GA aircraft. The objective is to develop and validate the use of a handling qualities tracking task as a means of identifying the limiting approach airspeed. A balance of performance and handling qualities concerns were addressed while following Federal Aviation Regulation (FAR) Part 23 and Advisory Circular 23-8A guidelines for small aircraft certification. Actual flight test data was collected for demonstration purposes using a 1953 Cessna 170B modified with a Horton STOL-CRAFT aftermarket STOL kit.

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