Boston Logan International Airport has six runways, which vary in length from 2,557 feet to 10,081 feet. The runways are aligned in three directions with each threshold pointing to a distinct magnetic heading. Generally, aircraft take-off and land into the wind in ideal weather conditions. However, due to Logan being located on the coast, ideal wind conditions are far from common and are just one of the factors that are considered when the FAA selects a runway to use. Other factors that are considered include: Ground visibility, cloud coverage and ceiling, runway and taxiway closures, navigational aids available, irregular operations, inspections, aircraft fleet and peak operational times.
During ideal weather conditions, Logan can accommodate 120 operations per hour when the FAA can utilize a three runway configuration. Runway capacity can be reduced to about 60 operations per hour in poor weather conditions and a single runway configuration.
Possible runway configurations in ideal weather conditions:
Figures 2-5 depicts a three runway configuration in ideal weather conditions when the winds are light, visibility is clear and all three runways are operational. When the FAA selects a runway to be used as part of a configuration, various factors are taken into considerations including: wind speed and direction, other weather conditions, and operational factors, runway availability, fleet mix and peak usage time. The weather trends at Logan Airport favor a northeast-southwest-northwest (NE-SW-NW) runway configuration. The chart below shows which runway configuration would be ideal in the specific conditions:
Primary Runway Configurations
4L, 4R and 9
22L, 22R and 27
33L, 32 and 27
15L, 15R, 9 and 14
Figure 6 depicts Logan's runway use based on the winds and the percentage each configuration is utilized.