Displaying procedural vs. real-time information for paired approaches

One concept for reducing delay pairs aircraft on instrument approaches to closely spaced parallel runways. The trail aircraft of the pair maneuvers to stay in a "safe zone", calculated to be free of collision danger and wake vortex interaction. Two different underlying bases can be used to determine the safe zone. The first is based on procedural information; which assumes that the two aircraft are following a pre-specified approach procedure, thereby presenting a spatial boundary which is predictable, small and unchanging throughout the approach, but which does not account for non-procedural behavior. The second is calculated in real-time from the current states of both aircraft, thereby presenting a spatial boundary which is as large as possible and constantly (sometimes rapidly) changing in size and location. These two safe zones require different pilot actions, yet a simulation experiment utilizing airline pilots failed to detect any difference in pilot control strategy or monitoring behavior. This paper will discuss the results of this experiment and the implications for paired approaches and self-separation tasks.