Petty Officer David Weydert says the search continues for the fifth person in 42-degree (5.56 Celsius) seas. Two Coast Guard cutters were racing to the scene Wednesday, about 18 miles (28 kilometers) off the coast.
Why the helicopter went down was not immediately known.
A Navy helicopter rescued the four and took them to a hospital. A spokeswoman for Sentara Norfolk General Hospital referred questions about the survivors' status to the Navy, which did not immediately respond to questions from The Associated Press.
The Navy identified the aircraft as an MH-53E. The helicopter assigned to Helicopter Mine Countermeasures Squadron Fourteen based at Naval Station Norfolk was conducting routine training operations, the Navy said.
Weydert said two Coast Guard vessels, including a cutter, responded to the scene.
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