A life-saving mission was cut short when a plane carrying six members of an organ transplant team went down in Lake Michigan shortly after the pilot signaled an emergency.
Police and emergency workers searched waters Monday to find two pilots, two surgeons and two donor specialists who went down in the Cessna Citation. There was no word on survivors.
Dr. Darrell A. Campbell, chief of staff of the University of Michigan Hospitals and Health Centers, said the thoughts of the university community were with the families of those involved.
"We take consolation in the fact that the team was on a mission to help another," he said.
Federal Aviation Administration spokesman Tony Molinaro said the plane took off from General Mitchell International Airport in Milwaukee at about 4 p.m. and was headed for Willow Run airport near Detroit, a 42-minute flight.
Within five minutes of its departure from the airport, the pilot declared an emergency and requested a return to Mitchell, Molinaro said. But the plane dropped off radar screens just after the pilot made the request and the Coast Guard was contacted.
Divers searched near debris and an oil slick in about 20 feet (six meters) of water, Milwaukee Fire Chief Doug Holton said.
Molinaro said aircraft debris was found about six miles (10 kilometers) northeast of Milwaukee, but no one on board has been found.
The plane was leased by the University of Michigan Health System in Ann Arbor, according to the university. It is owned by Toy Air and based at Willow Run Airport in Ypsilanti, Michigan.
The university said those aboard were a team that was returning from Milwaukee with unspecified organs for transplant to a patient in Michigan.
When system officials found out about the crash, they notified the transplant team in Michigan to stop preparing the transplant candidate. The patient was in critical condition, the university said.
U.S. Coast Guard Capt. Bruce Jones estimated the plane was going 185 mph (298 kph) to 190 mph (306 kph). He said the water temperature is 57 degrees Fahrenheit (14 degrees Celsius) and people could survive for 16 hours.
Rescuers called off the search Monday night after more than six hours and planned to return at daybreak Tuesday.
Russia has left the list of 33 largest holders of US government bonds, after the country disposed of at least a third of remaining bonds