Have you ever wondered why you’re ready for take-off and your aircraft isn't leaving? The plane is ready for departure, the weather is nice, other planes are leaving, but your flight is delayed. It’s most likely due to a ground stop (GS).
GSs are a common safety tool utilized by the Federal Aviation Administration (FAA) to control air traffic volume. The FAA Air Traffic Control System Command Center (ATCSCC) can issue a ground stop to slow or halt the flow of aircraft to a given airport.
To execute a GS, the local ATC Tower must notify the FAA ATCSCC to distribute an alert to the airports and airlines affected by the GS. Reasons for a GS can include weather, traffic volume, construction, VIP movements and security incidents/special events.
The most common reason for a GS is weather. If conditions at the destination airport or enroute require implementation of additional safety measures, a flight won`t be able to leave its origin until the GS is lifted. For example, even if the weather is nice in Philadelphia, rain in Orlando or along the route of the flight could cause delays due to an inclement weather GS issued for Orlando. The bottom line, the aircraft won’t take off until the GS is lifted.
There is a three-tier Ground Stop System that can be affected by a Philadelphia International Airport (PHL) GS. A first tier GS affects airports that are within a short distance from PHL — the affected airports are as far north as the New York market airports, as far west as Pittsburgh, and as far south as Raleigh, NC. The first tier GS is the most common, as it is for aircraft that are in the immediate vicinity of the airport.
ATC will hold planes for a short time without a stop. “For instance, if there is a thunderstorm that's rolling through the airspace, ATC will try to time it to where those aircraft won't be affected by the thunderstorm,” said Neil Byers, air traffic manager at the PHL ATC Tower/TRACON. “We'll put in a short-term ground stop, which is about 30 minutes-to-an hour to stop the traffic and give a little break. That's a mechanism that we use to control the throughput of the airport.”
The second tier GS is for any air traffic departing out of the airports in the Boston, Cleveland, Atlanta, Miami, Indianapolis, Chicago areas. Finally, a third tier GS is a stop to all planes inbound for Philadelphia. The only reason why something like that can happen are major events that impact airport operations greatly, such as recovery from a blizzard or hurricane.
While the ATC Tower controls PHL’s runways and taxiways, the Department of Aviation and the airlines' operations handle the terminal and ramp activities. The Department of Aviation's operation centers are responsible for the safety of those areas and can suspend all ramp activities if there is lighting within five miles of the airport.
As a core 30 airport, PHL plays a significant role in the region and the National Airspace System (NAS). The ATC Tower/TRACON at PHL also provides approach control services via RADAR within a 60-mile radius around PHL from the surface up to 13,000 feet. This includes arrival and departure services to Northeast Philadelphia Airport (PNE), Trenton Airport (TTN), Wilmington Airport (ILG), and a number of uncontrolled airports in the Delaware Valley. Each of those airports can issue GS if needed and PHL ATC is responsible for assisting them.