Weather Often Clogs Arrival, Departure Corridors

Those living around Tampa, FL are no strangers to inclement weather, particularly in the summertime. Late afternoon thunderstorms are the norm during the hottest months... and hurricanes remain a distinct possibility, as well (case in point: as of Monday afternoon, Tropical Storm Fay was forecasted to hit the area later this week, as at least as Category 1 hurricane.)

"Thunderstorms take out a lot of area in Florida, where you also have to take in account the military training areas off both Florida coasts," says Larry Newman, a Boeing 757 pilot and chairman with the Air Line Pilots Association. "That doesn't leave a lot of airspace."

Fortunately for pilots in the area, air traffic controllers say they're used to routing planes around hazardous weather. The Tampa Tribune recently chronicled some of their efforts, in a rather detailed report.

Five arrival and five departure corridors are used by controllers at Tampa International Airport... and it's not uncommon for a storm band to block at least one of those routes, forcing ATC to route traffic into the airport around the storms. To ward off traffic backups -- both on the ground, and in the air -- controllers employ a variety of methods that allow more planes to operate within areas that are clear.

One of those plans is the "cap and tunnel" strategy. Arriving traffic is placed in a racetrack-shaped holding pattern, and then vectored by ATC onto a single approach corridor. Inbound traffic is then directed to fly lower than usual, to allow outbound planes to overfly arriving traffic with at least the required 1,000 foot vertical separation.

"Thunderstorms block arrival and departure corridors, so we often are forced to use one corridor," Mark Kerr, a senior FAA controller at Tampa International, told the paper. "That makes it much more intense, getting a pilot through a gap in the weather."

Those efforts are part of the FAA's Severe Weather Avoidance Plan, or SWAP. In June alone, the FAA implemented SWAP around TPA on 25 days; the plan is used frequently around Tampa through the middle of September.

While guidelines are in place to manage traffic in times of inclement weather, it also takes a special breed of controller to handle the added challenges.

"Some handle it very well, while for others it is more stressful," said Rob Draughon, traffic management supervisor for the Jacksonville ARTCC. "It is the supervisor's discretion of who they assign where."

As most pilots know, when flying in close proximity to thunderstorms it's not the lightning that can cause problems -- it's turbulence, specifically the violent updrafts and downdrafts that can upset even large commercial airliners. "We generally steer well clear of thunderstorms which always present problems for us," said Newman.

Despite the likelihood of severe weather around TPA, the airport is consistently within the top-20 rankings for on-time performance during summer months. Admittedly, that's partly due to the fact Tampa isn't a hub for any airline... but Draughton gives controllers much of the credit.

"Work is more intense during SWAP, but air traffic controllers in Tampa, Orlando and Jacksonville are awfully good at it," he said. "Tampa and Orlando are nationally recognized for thunderstorm activity. But compared with New York or Washington, the only time air traffic stops in Central Florida is when thunderstorms are right over the field."

FMI: www.tampaairport.com, www.alpa.org, www.faa.gov