The U.S. Coast Guard called off its search Sunday for six people aboard a medical transport jet that crashed into the Atlantic off Nantucket, Massachusetts. Crews searched about 4,400 square miles of ocean over the weekend and found floating debris, but no survivors, the Maritime Executive and UPI reported.

The jet was a Gulfstream G100, also called an IAI Astra, run by Latitude Air Ambulance. It was flying from Bermuda to Boston. Four crew members from Canada and two passengers from Bermuda were on board. The Federal Aviation Administration alerted the Coast Guard at about 2 a.m. Saturday.

Early flight data show the plane slowed and dropped from 24,000 feet just after 1 a.m., an hour before the alarm went out, the New York Times reported, as cited by the Maritime Executive. The debris lies in about 80 to 90 feet of water, which is within reach of salvage divers if the main wreckage is found. No flight recorder has been recovered.

The search was large. Three planes, three helicopter crews, a motor lifeboat and the cutter William Sparling took part at various points over about 66 hours. Rear Adm. Matthew Lake, who leads the Coast Guard's Northeast District, announced the decision to stop.

Air ambulances like this one link island communities such as Bermuda to mainland hospitals for care they cannot get at home. Crews often fly overnight because patients cannot wait.

It was the second medical aircraft lost off the U.S. coast in a week. A helicopter air ambulance went down off California on Wednesday night.

The cause is now in the hands of investigators. Crash probes of this kind usually lean on radar data, maintenance records and any recovered wreckage.

What we know: Six people were aboard, debris was found, and the search for survivors has ended.
What we don't: What caused the plane to fall, and whether the wreckage and recorders can be recovered.