When analyzing flight accident data over some period of time, it is clear that the rates of serious accidents per year show a steady decline. For a recent analysis of this see e.g., Landsberg . However, by focusing only on long term trends it is easy to overlook local effects like sudden drops or increases in the accident rates. When using standard statistical methods like regression analysis, local effects have a tendency to be reduced to a few scattered outliers. As a result important issues affecting the accident rates may not be addressed. In this paper we shall study the accident rates for general aviation in USA for the period 1960-2003. In particular we will focus on a special period in the years around 1980 when the aviation business was deregulated. We will show that during this short period the accident rates were significantly lower than one could expect.