Date of Award

5-2023

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Aerospace, Physics, and Space Sciences

First Advisor

Ralph D. Kimberlin

Second Advisor

Isaac Silver

Third Advisor

Ryan T. White

Fourth Advisor

David C. Fleming

Abstract

Between 2012 and 2021, NTSB has identified over 2200 accidents due to loss of control. The majority of which happened while flying in the pattern. The most challenging phase of a flight is the take-off and landing. During these phases, the pilot initiates a change of configuration of the airplane by lowering or retracting the flaps. Lowering the flaps slows down the plane and increases the lift of the wing but also changes the longitudinal free response of the aircraft. The pitch changes of the plane require the pilot to promptly compensate to keep straight and level flight and avoid a stall. Past research at FIT, involving the flight test of different General Aviation aircraft, suggests that this free response longitudinal change is a factor that can lead to the aircraft’s loss of control. Proper use of the trimming wheel helps the pilot to relieve some of the constant pressure from the yoke, necessary to compensate for the pitch change. It is paramount that pilots from different backgrounds are properly trained to deal with each phase of the flight and each configuration change of the aircraft. This research emphasizes the importance of identifying the underlying factors that lead to spins and stalls in aircraft, rather than solely focusing on reacting to these situations once they have already occurred. By shifting attention to the root causes of these events, such as the aerodynamic interaction between the wing and the tail, it will be possible to identify and mitigate factors contributing to setting a pilot up to lose control of an airplane, resulting in a stall or spin. This thesis focuses on analyzing the NTSB accident reports of the Piper Arrow series that occurred from 1983 onward. This model was produced in two configurations: the Arrow III with a traditional tail and the Arrow IV with a T-tail. The research found that there was a statistically significant difference in the loss of control accident rates between these two models. Through an analysis of these accident reports, this study gathered evidence that longitudinal trim change caused by the extension or retraction of flaps can be considered a key factor contributing to the loss of control of the aircraft.

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