W. J. Baars, Stearman, R. O., and Tinney, C. E., “A review on the impact of icing on aircraft stability and control,” Journal of Aeroelasticity and Structural Dynamics, vol. 2, no. 1, pp. 35–52, 2010.
Several years of earlier research was conducted for the U.S. Air Force, related to the impact that warhead-induced damage had on the aeroelastic integrity of lifting surfaces and in turn the resulting upset of the complete aircraft. This prompted us to look at how similar aeroelastic events and aircraft upsets might be triggered by ice accumulation on specific parts of the aircraft. Although seldom studied, icing can also significantly impact the aircraft’s aeroelastic stability, and hence the overall aircraft stability and control, and can finally result in irreversible upset events. In this latter context, classical flutter events of the lifting surfaces and controls can occur due to ice-induced mass unbalance or control hinge moments and force reversals. Also, a loss of control effectiveness caused by limit cycle oscillations of the controls and lifting surfaces may appear, due to significant time-dependent drag forces introduced by separated flow conditions caused by the ice accumulation. A review is presented in this article on the mechanisms that initiate these ice-induced upset events when considering the class of small general aviation aircraft. The review is based on literature and earlier experimental work performed at The University of Texas at Austin. Two commonly observed ice-induced aircraft stability and control upset scenarios were selected to investigate. The first upset scenario that is presented involves an elevator limit cycle oscillation and a resulting loss of elevator control effectiveness. The second upset is related to a violent wing rock or an unstable Dutch Roll event.