An international cargo plane on Thursday dumped 6,000 gallons of fuel over the Cape and Islands during an emergency return to New York after a horse aboard the jet escaped its stall.
The pilot of the Air Atlanta Icelandic flight was cleared to dump the fuel, a 20-minute process that began 10 miles west of Martha's Vineyard and was completed over the Atlantic, east of Nantucket.
The Boeing 747-400F had departed John F. Kennedy International Airport about 90 minutes before.
Because landings require less weight than takeoffs, the fuel dump was necessary ahead of the unexpected return, said Dan Wolf, founder and board chairman of Cape Air in Hyannis.
The jet was flying at an altitude of 22,000 feet, high enough for the fuel to evaporate and minimize any environmental impact, Wolf said.
"That amount of jet fuel in the atmosphere is not a good thing, but the quantity is not significant enough to have a major impact," he said.
Loose cargo is the bigger concern, Wolf said, especially when that cargo is a large animal confined to a pressurized airplane.
"The horse managed to escape the stall...We cannot get the horse secured," the pilot told the controller.
"If the horse can move around, it can change the weight and balance of the aircraft," said David Fisichella, president of the nonprofit Cape Cod Aero Club in Falmouth. "The center of gravity of the plane could change so significantly that the plane could become uncontrollable."
The pilot requested a veterinarian to meet the crew upon its safe landing in New York.