Milwaukee ? No one was believed to have survived the crash of a small plane that was carrying a six-member organ transplant team and their cargo of donor organs, authorities said Tuesday.

The team’s lifesaving mission – carrying unspecified organs from Milwaukee for transplant to a patient in Michigan – was cut short when the Cessna Citation went down Monday night in 57-degree water shortly after the pilot signaled an emergency.

The pilot had reported a problem with its trim runaway system, said John Brannen, senior air safety investigator with the National Transportation Safety Board. The system controls bank and pitch, but it wasn’t clear what caused the problem.

“We will piece together what we can of the wreckage,” Brannen said.

Investigators also planned to look at the aircraft’s maintenance records within the next few days.

Only small parts of the plane had been found so far. Human remains have been found but hadn’t been identified.

Milwaukee County Medical Examiner Jeffrey Jentzen said he likely would have to use dental records and DNA to identify the victims.

“A high-speed impact in water causes explosion-type injuries,” he said.

Those on board were two surgeons and two donor specialists from the University of Michigan Health System and two pilots who regularly fly their transplant missions.

The patient who was to have received the transplant organs was in critical condition, the university said. Jay Campbell, executive director of the Wisconsin Donor Network, declined to say which hospital the team was working with, citing privacy regulations.

The president of the United Network for Organ Sharing, the national organization that coordinates organ transplants, issued a statement calling the transplant team “unsung heroes” even as she said privacy rules prevented the group from sharing information about the flight and transplant.

“Every day, thousands of professionals do their very best to ensure that the donation and transplantation process is successful,” Dr. Sue V. McDiarmid said. “Because of their routine success, the public may not understand the risks they sometimes must take in recovering and transporting organs. They are unsung heroes, willing to take these risks for the purpose of saving lives.”

The university identified those aboard the plane as Dr. Martinus “Martin” Spoor, a cardiac surgeon who had been on the faculty since 2003; Dr. David Ashburn, a physician-in-training in pediatric cardiothoracic surgery; Richard Chenault II, a transplant donation specialist with the university transplant program; Richard Lapensee, a transplant donation specialist with the university transplant program; and pilots Dennis Hoyes and Bill Serra.