AIRPORT CAPACITY AND DELAY (BY ME)

capacity

• The practical maximum number of operations that a system can serve within a given period of time

• Measured in aircraft operations per hour

Passenger processing capacity

• the number of passengers that can be efficiently moved through the terminal within a given time

Throughput

• the ultimate rate at which aircraft operations may be handled without regard to any small delays that might occur as a result of imperfections in operations or small random events that might occur

Practical capacity

the number of operations that may be accommodated over time with no more than a nominal amount of delay

FAA defines two measures of capacity

• Practical hourly capacity (PHOCAP)

• Practical annual capacity (PANCAP)

  • These are measured as the number of operations that may be handled, resulting in not more than 4 minutes average delay during the busiest (peak) 2-hour operating period, hourly and annually

Factors Affecting Capacity and Delay 

• Use of runways

• Type of aircraft operating

• Percentage of takeoffs and landings performed

• Climatic conditions

• FAA regulations governing runway use

• Layout of runway, taxiway, and apron environment

• Presence of instrument landing systems

• Runway configuration

VMC (visual meteorological conditions) vs. IMC (instrument meteorological conditions)

Capacity is greatest under VMC vs. IMC

Runway configuration

parallel, single, open-v, intersecting

parallel runways

Parallel runways are classified by the distance between their centerlines, which determines how independently they can be used.

independent simultaneous operations

> 4,300 ft apart — aircraft can take off and land at the same time on both runways

highest efficiency and capacity

dependent simultaneous operations

> 2,500 feet

• Aircraft can still use both runways at the same time, BUT:

• Must maintain separation between aircraft on each runway

• Air traffic control has to coordinate arrivals/departures

treated as a single runway

<2,500 feet

• Too close for safe simultaneous operations

• Only one runway can be used at a time (for arrivals or departures)

Single Runway

• Only one runway available

• All aircraft must:

  • Take off

  • Land

  • Taxi across

Lowest capacity and most delays during busy times

Open-V runways

• Two runways that diverge away from each other (V shape)

• Used when winds allow aircraft to depart/arrive in different directions

Advantages:

• Can allow simultaneous operations if flight paths don’t conflict

Limitation:

• If traffic paths cross → must operate more like a single runway

Intersecting runways

• Two runways that cross each other

Usually treated as one runway because:

• Aircraft paths intersect → safety risk

• Only one aircraft can use the intersection at a time

LAHSO (Land and Hold Short Operations)

• Special procedure where:

  • An aircraft lands and stops before the intersection

  • Allows another aircraft to use the crossing runway

Estimating capacity

• Runway handling only takes off (departure capacity) is a function of two basic operating characteristics:

  • 1. Type of aircraft using the runway

  • 2. The time aircraft needs from start from initial position to leaving the runway environment (runway occupancy time (ROT))

ROT (runway occupancy time)

• The shorter the ROT, the greater the runway capacity

• When a runway is constantly occupied, it is operating at capacity

Departure capacity

impacted by time to roll and rotate

Arrival capacity

impacted by approach speeds and longitudinal separation — impacted by wake turbulence

defining delay

• The duration between the desired time for an operation to occur and actual time of occurrence

causes of delay

• Mechanical repair

• Luggage slow

• Weather

• Aircraft may have been scheduled for departure at the same time as a large number of other aircraft

approaches to reducing delay

• 1. Increased system capacity

• 2. Managing system demand

what makes capacity increases difficult?

• Surrounding community development

• Environmental concerns

• Shortage of property and funding

• Lack of public support

• Rival commercial and residential interests

administrative

• airport authority allocates airport access by setting quotas on passenger enplanements or on the number and type of aircraft operations

reliever airports

• There are 334 reliever airports

• The best region-wide approach would be to divert some traffic to lightly used commercial service reliever airports

GA activity

• At the largest commercial service airports, GA activity accounts for 10-20% of airport use by large business and executive aircraft

quotas or slots

an administratively established limit on the number of operations in or out of the airport per hours

delay

Because delay increases exponentially as demand approaches capacity, a small reduction in the number of hourly operations can have a significant effect on delay 

economic

structure pricing so that market forces allocate scarce airport facilities

demand management

• does not increase capacity, but rather promotes more effective or economically efficient use of facilities

  • Relies on price mechanism and is favored by economists