Simmod PRO! - Case Study

Simmod PRO at LAX

Los Angeles International Airport (LAX) – Runway 25L/25R End-around Taxiway Alternative

In order to reduce runway incursions between aircraft at LAX on Runways 25L and 25R, several airfield alternatives were studied.  One such alternative involved building an end-around taxiway that would allow aircraft landing on  Runway 25L to avoid crossing the active departure runway, Runway 25R, when taxiing to their gate.  However, aircraft that taxi on the end-around taxiway would penetrate the Runway Protection Zone (RPZ) for departures from Runway 25L and 25R.  In order to accurately assess the operational impact, a direct relationship between aircraft on the end-around taxiway and aircraft departing from Runway 25L and 25R was required. The operational impact this relationship has on the airfield needed to be quantitatively assessed. 

Simmod PRO! Solution

Several layers of ground simulation logic needed to be implemented to insure that the operations were being modeled accurately.  The sophisticated Simmod PRO! logic included rules to answer questions such as:

When should arrivals to Runway 25L exit to the south and use the end-around taxiway versus taking the more direct path to their gate by exiting to the north and crossing Runway 25R.?

When there are no departures on their way to the departure queue for Runway 25R, arrivals to the outboard Runway 25L are allowed to exit to the north (to the right).  However, once arrivals start exiting to the south and using the end-around taxiway, all subsequent arrivals must also exit to the south.  Once the departure queue is empty for fifteen continuous minutes, arrivals may once again exit to the north.

How long should an aircraft holding short of the RPZ on the end-around taxiway be forced to wait before priority shifts?

If a single aircraft has waited for five minutes or there are six holding in line, then departure operations are held.  Departures continue to hold until taxiing aircraft have cleared the RPZ.


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