Date of Award

Spring 2023

Access Type

Thesis - Open Access

Degree Name

Master of Science in Safety Science

Department

College of Aviation

Committee Chair

Brian Roggow

First Committee Member

Maxwell Fogleman

Second Committee Member

William Waldock

College Dean

Timothy Holt

Abstract

As general aviation accident rates are much higher than those of Part 121 air carriers, and the approach and landing phase of flight accounts for more accidents than any other phase of flight, the study of the approach and landing phase of flight is warranted in greater detail. Flight Data Monitoring provides an excellent source of data for the study of individual landing parameters. The intent of this study was to evaluate potential predictors of unstable approaches as well as go-arounds.

Flight data provided by a Part 141 flight school was examined to determine predictors for unstable approaches and go-arounds. The raw data was analyzed using General Electric’s eFOQAâ software, then exported to IBM’s SPSSâ for binomial logistic regression analysis. The independent variables evaluated as predictors for unstable approaches and go-arounds were Aircraft Type, Approach Type, Light Condition, Approach Location, Instrument Approach Procedure Type, and Runways.

Thirty-two percent of the 36,864 approaches evaluated were unstable. Aircraft Type, Approach Type, Approach Location, and Runways were found to be statistically significant predictors of approach stability. A Diamond DA-42 NG is 3.88 times less likely to experience an unstable approach. An approach conducted under VFR is 1.12 times less likely to experience an unstable approach. An approach conducted at an outlying airfield is 1.12 times more likely to experience an unstable approach. Four of the five runways evaluated were found to be statistically significant predictors of approach stability.

Of the 11,939 unstable approaches observed by the study, 75% of those approaches resulted in landings where they should have resulted in go-arounds. Aircraft Type, Light Condition, Approach Location, and Runways were found to be statistically significant predictors of approach stability. A Diamond DA-42 NG is 2.98 times less likely to result in a landing after experiencing an unstable approach. An unstable approach at night is 4.67 times less likely to result in a landing. An unstable approach conducted at an outlying airfield is 1.2 times less likely to experience a landing. All of the evaluated runways were found to be statistically significant predictors of approach stability.

The study revealed significant predictors of both unstable approaches and go-arounds. Potential commonalities among the statistically significant predictors from both dependent variables (Approach Stability and Landing Outcome) include crew experience levels, crew familiarity with certain independent variables, and flight density at the airport. The disparity between IAPs and VFR approaches warrants a further examination of the differences between the two approach profiles. The disparities in go-around and stability likelihoods based on Runways could potentially be attributed to differences in runway width, slope, crew familiarity, and surrounding terrain, but further research is indicated to delve into these possibilities. Regardless of the reasons why, general aviation operators and the flight school specifically can use these results where indicated to tailor education to preventing unstable approaches and increasing the prevalence of go-arounds.

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