Traffic Management Initiatives

Overview

National Traffic Management Initiatives are comprised of Ground Delay Programs (GDP) and Airspace Flow Programs (AFP). Only Ground Delay Programs are currently shown on the International Airspace System Status page.

Ground Delay Programs

A GDP is implemented to control air traffic volume to airports where the projected traffic demand is expected to exceed the airport's acceptance rate for a lengthy period of time. Lengthy periods of demand exceeding acceptance rate are normally a result of the airport's acceptance rate being reduced for some reason. The most common reason for a reduction in acceptance rate is adverse weather such as low ceilings and visibility.

Airspace Flow Programs

An AFP is a traffic management process that identifies constraints in the en route system, develops a real time list of flights that are filed into the constrained area, and distributes expect departure clearance times (EDCT) to meter the demand through the area. If an AFP is issued and a flight is included, the pilot will receive an EDCT. Meeting the departure time is important because it allows traffic managers to properly meter flights through the constrained area being controlled by the AFP.

How It Works

Flights that are destined to the affected airport are issued Controlled Departure Times (CDT) at their point of departure. Flights that have been issued CDTs are not permitted to depart until their Controlled Departure Time. These CDTs are calculated in such a way as to meter the rate that traffic arrives at the affected airport; ensuring that demand is equal to acceptance rate. The length of delays that result from the implementation of a Ground Delay Program is a factor of two things; how much greater than the acceptance rate the original demand was, and for what length of time the original demand was expected to exceed the acceptance rate.

Legend

CONTROL ELEMENT: Airport for which the Ground Delay Program has been issued or the FCA relating to the AFP.

START: The time, in Universal Coordinated Time (UTC) that the GDP or AFP will start.

END: The time, in UTC, that the GDP or AFP will end.

Traffic that was originally scheduled to arrive at the affected airport between the program's Start and End time will be issued delay times.

SCOPE: Indicates which traffic is included in the program. Traffic departing from airports under the jurisdiction of the listed facilities will be issued delay times. See Tier Info for an explanation and graphical representation of jurisdictions.

REASON: The reason that the GDP/AFP had to be implemented. Common acronyms used in this field are:

Example:

The above example shows a GDP.  Flights departing from all airports with a destination of Boston--that were originally scheduled to arrive at Boston between 1800 and 2200--will be issued delays.  The Ground Delay Program was issued because of low ceilings and visibility.

Delay Information

Overview

This table shows airports that are currently experiencing delays.

How It Works

Terminal facilities are required to report delays of 15 minutes or more to the Air Traffic Control System Command Center (ATCSCC).  Delays are tracked in 15 minute increments.  Delay times are preceded with either a '+' or a '-' to indicate that the delays are increasing or decreasing.  Because the delays are tracked in 15 minute increments, a single delay entry actually represents a time range.  For example, an entry of +15 indicates that delays are greater than 15 minutes but less than 30 minutes and are increasing.  An entry of -30 indicates that delays are less than 30 minutes but greater than 15 minutes and are decreasing.  Normally delays of less than 15 minutes are not shown.  The one exception to this is when delays for an airport have just gone below 15 minutes. This will be indicated by an entry of -15.

Legend

ARPT: Airport.

ARR DLA: Arrival Delays. Arrival traffic is experiencing delays. This usually indicates that arrival traffic is doing airborne holding.

DEP DLA: Departure delays. Departure traffic is experiencing delays. Depending on the length of delay, traffic will be experiencing longer than normal taxi times or holding at the gate.

TIME: The time, in Universal Coordinated Time (UTC), that the delay information, for the specified airport, was last updated.

REASON: The reason for the delays.

Example

In the first example, Chicago is experiencing departure delays. Delays are currently less than 45 minutes but greater than 30 minutes and are decreasing. The last delay report was received at 1545. Thunderstorms are the cause of the delays.

In the second example, Newark is experiencing arrival delays. Delays are currently greater than 15 minutes but less than 30 minutes and are increasing. The last delay report was received at 1535. Fog is the cause of the delays.