Feasibility analyses for paired approach procedures for closely spaced parallel runways

Abstract

In current air traffic operations in the U.S., closely spaced parallel runways (CSPRs) separated by less than 2500 feet (ft) can be used to conduct simultaneous parallel operations using visual separation. Once below visual approach minima, such dual runway operations are no longer possible.

Kinematic Modeling of Separation Compression for Paired Approaches to Closely-Spaced Parallel Runways

“…The figure shows two options for the separation window (i.e. the green box), the full length of the box applies to a procedure that allows the fast aircraft to pass the slow aircraft 1 and the hashed boundary applies to a procedure that does not allow the fast aircraft to pass 6 . The former requires the trail aircraft to be equipped with a collision alerting and avoidance system that is designed for the tight vertical and longitudinal separations in the paired approach.…”

“…For the paired approach with passing, the procedure terminates for the fast aircraft at the threshold. As with the slow aircraft, this required separation is converted into a procedure termination altitude for the faster aircraft, h PTF : (6) where, D CS is the collision-safe distance. If passing is allowed, this variable is zero.…”

Analytical Assessment of Simultaneous Parallel Approach Feasibility from Total System Error

“…Figure 1 depicts the longitudinal geometry of the paired-approach procedure, either with the option of passing 1 or without the option of passing 6 . The fast aircraft must maintain a longitudinal distance from the slow aircraft in a range defined to avoid two hazards.…”

“…TSE is often modeled as statistical variation and typically is defined using a probability density function (PDF). 1,6 Therefore, Monte-Carlo simulations are a favored tool for assessing the wake-safe gate. However, definitions of safety used for such operations often require that a wake encounter be a very rare event during normal operation; one catastrophic wake encounter per billion flights T is typical.…”

“…However, definitions of safety used for such operations often require that a wake encounter be a very rare event during normal operation; one catastrophic wake encounter per billion flights T is typical. 6 Using a Monte-Carlo simulation to assert the required rarity of a wake encounter with confidence, therefore, requires a massive number of runs. Even for low-fidelity, fast-time simulations on modern computers, such runs do not lend themselves to rapid turn-around during the early stages of investigation when the goal is to eliminate the infeasible regions of the solution space and to perform trades among the independent variables in the operational concept.…”