Boston: A medical evacuation aircraft carrying six people has disappeared from radar while flying from Bermuda to Boston, prompting a US Coast Guard search operation off Nantucket, Massachusetts.

A search operation is underway off the coast of Nantucket after an air ambulance carrying six people disappeared from radar during a flight from Bermuda to Boston.

The aircraft lost contact with the Federal Aviation Administration early Saturday while travelling towards Boston Logan International Airport, according to the US Coast Guard.

Air and surface units have been deployed to search an area south of Nantucket for the missing aircraft and those on board.

Aircraft made sharp descent before contact was lost

The aircraft is believed to be a Gulfstream G100 operated by Latitude Air Ambulance, a medical aviation company based in Hamilton, Ontario.

Flight-tracking data identified the aircraft as operating the Bermuda-Boston route under the callsign HTT104.

Available tracking information shows that the aircraft underwent a rapid descent shortly before communication was lost. The aircraft reportedly dropped more than 9,000 feet over roughly two minutes.

The final tracking signal was received shortly afterwards in the area where the Coast Guard's search is now focused.

The tracking data may help investigators establish the aircraft's last known position, but it does not establish what happened to the aircraft.

Medical evacuation flight

Latitude Air Ambulance Director of Flight Operations Clarence Togeretz said the aircraft had been carrying out a medical evacuation in Bermuda. The company operates medical transport flights using aircraft including Gulfstream G100/Astra jets.

The identities and conditions of the six people aboard have not been released. Authorities have also not confirmed whether the aircraft was carrying a patient, medical personnel or other passengers.

The US Coast Guard has deployed both aircraft and surface vessels to the search area south of Nantucket.

There has been no official confirmation that the aircraft crashed, and authorities have not yet determined what caused the loss of contact. The search operation is focused on locating the aircraft and determining the fate of everyone aboard.