Section 7. Airport Arrival Rate (AAR)

  1. PURPOSE

To establish standards for determining the airport arrival rate (AAR).

  1. POLICY

Airport runways are assets of the National Airspace System (NAS). System-wide standards for AARs enable the Air Traffic Organization (ATO) to manage these assets in the most efficient manner.

  1. DEFINITIONS
  1. AAR: A dynamic parameter specifying the number of arrival aircraft that an airport, in conjunction with terminal airspace, can accept under specific conditions throughout any consecutive sixty (60) minute period.
  2. Airport Primary Runway Configuration: An airport runway configuration which handles three (3) percent or more of the annual operations.
  1. RESPONSIBILITIES
  1. System Operations Services is responsible for the development, establishment, and implementation of AARs at select airports in the NAS.
  2. The Deputy Director of System Operations (DDSO) in collaboration with Terminal Facility Managers must:
  1. Identify the airport primary runway configurations for airport(s) identified by System Operations Services.
  2. Establish optimal AARs for airport(s) using the method detailed in paragraph 10-7-5, Calculating AARs.
  3. Review and validate the airport primary runway configurations and associated AARs in February of each year, or at more frequent intervals if required.

NOTE-

In the event consensus cannot be reached between facilities, the DDSO will make the final determination.

  1. DDSOs must ensure that the data is entered in the National Traffic Management Log (NTML) under the runway template.
  2. Consistent with paragraph 10-1-6, Selecting Active Runways, Terminal Facility Managers must ensure efficiency at airport(s) within their jurisdiction consistent with the goals outlined in the Administrator's Flight Plan.
  1. CALCULATING AARs
  1. Calculate optimal AAR values for each airport runway configuration for the following weather conditions:
  1. Visual Meteorological Conditions (VMC)- Weather allows vectoring for a visual approach.
  2. Marginal VMC- Weather does not allow vectoring for a visual approach, but visual separation on final is possible.
  3. Instrument Meteorological Conditions (IMC)- Visual approaches and visual separation on final are not possible.
  4. Low IMC- Weather dictates Category II or III operations, or 2.5 miles-in-trail (MIT) on final is not available.
  1. Calculate the maximum runway arrival capacity for each runway using the following methodology:
  1. Determine the average ground speed crossing the runway threshold and the spacing interval required between successive arrivals.
  2. Divide the ground speed by the spacing interval or use TBL 10-7-1, Maximum Runway Capacity, to determine the maximum runway arrival capacity.

FORMULA:

Ground Speed in knots at threshold / Spacing Interval at runway threshold in miles

NOTE-

When the maximum runway arrival capacity is a fraction, round down to the next whole number.

EXAMPLE-

  1. 130 / 3.25 = 40 Runway capacity = 40
  2. 125 / 3.0 = 41.66 Runway capacity = 41

TBL 10-7-1

Maximum Runway Capacity

Threshold Ground Speed

Miles Between Aircraft

2.5

3

3.5

4

4.5

5

6

7

8

9

10

130 Knots

52

43

37

32

28

26

21

18

16

14

13

140 Knots

56

46

40

35

31

28

23

20

17

15

14

  1. Identify any conditions that may reduce the maximum runway arrival capacity. These factors include, but are not limited to:
  1. Intersecting arrival/departure runways.
  2. Distance between arrival runways.
  3. Dual purpose runways (shared arrivals and departures).
  4. Land and Hold Short utilization.
  5. Availability of high speed taxiways.
  6. Airspace limitations/constraints.
  7. Procedural limitations (missed approach protection, noise abatement, etc.).
  8. Taxiway layouts.
  9. Meteorological conditions.
  1. Determine the adjusted runway arrival capacity by adjusting the maximum runway capacities using the factors in subparagraph c for each runway used in an airport configuration. Total the adjusted runway arrival capacities for all runways used in an airport configuration to determine the optimal AAR for that airport runway configuration.
  1. OPERATIONAL AARs
  1. When using an airport primary runway configuration, the associated optimal AAR must be utilized. The DDSOs must ensure that the responsible person at the Aviation System Performance Metrics (ASPM) airports document the runway information in the NTML.
  2. Real-time factors may dictate dynamic adjustments to the optimal AAR. These factors include, but are not limited to:
  1. Aircraft type/fleet mix.
  2. Runway conditions.
  3. Runway/taxiway construction.
  4. Equipment outages.
  5. TRACON constraints.

These factors will be included in the facility log. The DDSOs must ensure that the responsible person at the ASPM airports document the information in the NTML.

  1. A dynamic adjustment to the AAR is subject to the review and approval of the Director of System Operations, ATCSCC.
  2. Non-primary configurations at ASPM airports must be entered in the NTML as “Other,” and free-text used to describe the configuration and associated AAR.