All eyes are now on Hurricane Florence as it bears down on the East Coast. There will be flight delays and cancellations for several days in the affected cities. Airlines are already making plans to deal with the storm.
How long can flights safely operate as the storm approaches? Flight dispatchers carefully watch the storm movement and receive regular updates from the National Hurricane Center. Larger airlines have professional meteorologists in the dispatch center. Captains and flight dispatchers coordinate the flight plan routing to minimize turbulence. Experience is vital in this process.
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Airports that are used as hubs make plans for all flyable airplanes to depart well ahead of the storm. For last year’s hurricanes, this happened in Houston for Harvey and at Florida airports for Irma. For Florence, it will affect Charlotte, a hub for American Airlines. Disruption of the hub system causes the airline to utilize their “Irregular Operations” plan. This affects flight crews, maintenance and many other functions within the operation.
Flight crews can be stranded in hotels unable to get home for several days. Maintenance that was scheduled has to be rescheduled because the airplane is not where it was scheduled to be. Losing a hub affects flights all over the system; this is why passengers ask, “why does an East Coast hurricane cause delays and cancellations on the West Coast?” The airplane scheduled to fly their flight was coming from the East Coast and is out of position. Patience is essential for everyone during “Irregular Operations.”
Some flights, such as long-haul routes from the northeastern U.S. to South America, will overfly the hurricane. Careful routing around the hurricane-caused thunderstorms allows some flights to fly over parts of the hurricane safely. Other than the thunderstorms, the clouds are well below the normal cruising altitude of a jet. All airliners have onboard weather radar, providing pilots with the location and intensity of thunderstorms. With this information pilots can deviate around the storms safely.
Cruising at 35,000 feet above a hurricane provides a view of these massive storms. While the eye may be only a few miles in diameter, the overall storm can stretch over 1,000 miles. The raw power of nature is evident.
Hurricane-produced thunderstorms can exceed 40,000 feet, making it impossible to overfly them due to the updrafts and downdrafts near the top of the thunderstorm. Usually the wind flow around the hurricane is reasonably smooth, except near the thunderstorms, reducing the likelihood of turbulence. However, pilots listen closely to other flights for any reports of “chop” so they can avoid the area.
The feeder bands with their heavy rain can be seen on the weather radar. This can be where the thunderstorms occur. Consequently, pilots try to plan the flight around the forecast locations of the heavier feeder bands. Dispatchers carefully watch movement on ground-based radar then provide updated information to flights.
As the storm moves onshore with the rising wind, fewer and fewer flights operate into the affected airports. Once the crosswinds reach around 30 knots, flights no longer can take off and land. If the wind is down the runway, it is possible to safely take off and land with higher winds, but consideration must be given to being able to safely getting the airplane out and to the ground crews who must shelter all of the ground equipment and go home to their families to ride out the storm.
Hurricanes can have a major impact on air travel. Airlines do all they can to minimize the disruption, however Mother Nature decides how much disruption and for how long.
John Cox is a retired airline captain with US Airways and runs his own aviation safety consulting company, Safety Operating Systems.
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