Chilling audio captures final moments before Boston-bound plane vanished.

A Gulfstream G-100 air ambulance with six people on board went missing early Saturday while flying from Bermuda to Boston. The Coast Guard is searching waters off Nantucket.

• 1:20 a.m. ET: the FAA issued a Search and Rescue Alert for the aircraft.
• The plane departed L.F. Wade International Airport in Bermuda.
• The aircraft, tail number CGRJP, is registered in Canada and operated by Latitude Air Ambulance.
• Search crews include Air Station Cape Cod, a Nantucket lifeboat crew, and the cutter William Sparling.

Why it matters: A medical transport flight carries patients requiring urgent care. Six people — identities not released — are unaccounted for over open ocean.

• FlightAware data put the scheduled flight at roughly two hours in length.

How 34 sources split on this story

What’s next: The Coast Guard said updates would follow as information becomes available.

• The Rescue Coordination Center is coordinating with the FAA to locate the aircraft.
• Who are the six people on board, and what was the nature of the medical transport?
• What caused the plane to lose contact with the FAA?
• Has any wreckage or signal been detected by search crews?