(CNN) -- Rescuers were using the advantages of sunlight to scour the waters of Alabama's Mobile Bay Wednesday in the search for three members of the U.S. Coast Guard missing after a helicopter crash.
The body of another crew member who was on the chopper was recovered by a rescue crew, the Coast Guard said.
The helicopter, an MH-65C, crashed Tuesday night while on a training mission from the Aviation Training Center at Mobile Regional Airport, a statement from the Coast Guard said.
"Our thoughts and prayers are with the families of the crew members during this difficult time," said Capt. Don Rose, commanding officer of Coast Guard Sector Mobile.
Authorities searched for survivors throughout the night and intensified their efforts as daylight broke.
"Particularly when the sun comes up, it gives you a whole different perspective," Rose said Wednesday morning.
The crew members were wearing survival gear, and Rose remained hopeful that they would be found.
Water temperatures overnight were about 60 degrees, with calm winds.
"All of us are out there and feel the pain and grief over seeing one of our own in peril," he said.
Authorities have cordoned off a mile-wide radius around the crash site in Mobile Bay to keep ships out while they search, Rose said.
The cause of the crash is under investigation, the Coast Guard said.
CNN's Samuel Gardner III contributed to this report.