The U.S. Coast Guard suspended its search Sunday evening for a medical evacuation jet that disappeared off Nantucket, and the Canadian operator said all six people aboard are presumed dead after crews found a debris field in the Atlantic.

Final minutes of Heartbeat 104

The Gulfstream G-100 left Bermuda’s L.F. Wade International Airport at 11:40 p.m. local time Friday bound for Boston Logan International Airport, according to flight-tracking data reviewed by the BBC. The Federal Aviation Administration lost radar and radio contact shortly after 1:00 a.m. Eastern on Saturday as the aircraft was approaching Massachusetts waters.

Tracking logs show the plane descended sharply—from about 24,000 feet to 11,000 feet—before communications went dark. Recordings published by LiveATC.net and reported by the Boston Globe capture an air-traffic controller asking whether the crew was “coming in blind” and whether they were declaring an emergency; the pilot’s replies were weak or inaudible. The controller later confirmed an emergency declaration. A regional fire dispatcher also alerted ground crews to prepare for a plane reporting an electrical problem before saying the aircraft had lost radio and radar entirely.

Who was on board

Latitude Air Ambulance identified the flight as Heartbeat 104. President Peter Byl said four members of the company’s staff—a flight crew and medical team—were returning a patient and a family escort from Bermuda. Clarence Togeretz, the company’s director of flight operations, told CBC News that two pilots and two clinicians had flown down to collect the patient. Four Canadian nationals and two Bermudian nationals were aboard, authorities said.

Latitude provides international medevac services for patients traveling home for care. The company asked for privacy for the families and said it would cooperate with investigators without speculating on a cause.

Search ends, probes begin

Coast Guard units searched an area southeast of Nantucket through Sunday before calling off active rescue operations. Authorities confirmed that debris located Saturday evening matched the missing jet. The National Transportation Safety Board typically leads U.S. aviation accident investigations; the FAA said it is participating.

“We must now face the heartbreaking reality” that the crew, patient and escort are presumed dead, Latitude said in a statement Sunday. Byl added that the loss was “unimaginable” for employees who work on time-sensitive medical flights where minutes often decide outcomes.

Commercial traffic at Logan continued on Sunday, but the crash revived scrutiny of night medevac routes over open water, where divers and surface ships face limited visibility. Investigators will examine maintenance records, weather and any distress calls as they reconstruct the flight path.