COLLISION POTENTIAL IN SAILPLANE COMPETITIONS

Abstract

In this paper I have shown that the concept oF collision potential can be useful for analyzing and comparing the risk of alternative situations in today's competition flying. One important result is that if our flying is done with good lift that allows dispersion of the fleet prior to starting we should expect to go several years between collisions during our large national size contests. While this is far more often than the glider/airliner collision potential, it is probably consistent with risk inherent in other action sports. The number of contestants has an important bearing on the risk. Compared to a nationals, the average regional contest with 20-30 or fewer per class, and sequential class launching, has insignificant risk, as long as the lilt is dispersed. Risk increases dramatically with number of contestants so that a modest increase from 60 to 70 contestants will increase risk by over 50%. Lift distribution has by far the greatest influence on the potential for collision during the pre-start phase ol a contest. Marginal lift that forces all ships to concentrate in a few thermals can increase collision potential by two or three orders-of-magnitude. As competing pilots, we have to share thermals so we must treat them as community property. If at any time, the traffic density increases to the point where you are forced to maneuver to avoid immediate collision, then the risk has become unacceptably high.