A ‘parallel approach’ path to estimating collision risk during simultaneous landings

Airport capacity could increase if, even during inclement weather, independent landings could occur on parallel runways only about half a mile apart. A key question about such operations is whether the collision risk they entail is acceptably low. Pursuing that issue, we explore a method for estimating the chance that a plane on final approach during instrument flight conditions will ‘blunder’ in a way that could imperil nearby aircraft. We argue that the method could yield an attractive combination of high estimation accuracy and relatively low cost.