VICTORIA -- A Vancouver Island man is among the five Canadian Armed Forces members who are still missing after their military helicopter crashed Wednesday during a NATO training exercise off the coast of Greece, killing at least one on board.

The Department of National Defence confirmed Thursday that pilot Capt. Kevin Hagen of Nanaimo was one of six crew members aboard the RCAF CH-148 Cyclone helicopter when it went down in the Ionian Sea Wednesday evening.

The pilot’s brother, Kyle Hagen, told CTV News on Thursday that “Kevin was a perfect brother,” adding “he was truly loyal, compassionate, accepting and supportive.”

Kyle refrred to his brother as “my closest friend,” and said, “I miss him beyond words.”

During his daily briefing in Ottawa Thursday, Prime Minister Justin Trudeau said the body of Sub-Lt. Abbigail Cowbrough of Nova Scotia had been recovered while the five others are still missing.

Along with Hagen, the missing CAF members are Capt. Brenden Ian MacDonald from New Glasgow, N.S.; Capt. Maxime Miron-Morin from Trois-Rivières, Que.; Sub-Lt. Matthew Pyke from Truro, N.S.; and Master Corp. Matthew Cousins from Guelph, Ont.

"All of them are heroes. Each of them will leave a void that cannot be filled," Trudeau said. "On behalf of all Canadians, I want to offer my deepest support to their families, their friends, their shipmates, and their fellow CAF members."

The prime minister was joined by Chief of the Defence Staff Gen. Jonathan Vance who said the Cyclone was returning to HMCS Fredericton when the Canadian frigate lost contact with the helicopter at 6:52 p.m. local time. 

Officials said emergency flares were spotted in the water a few minutes later.

Defence Minister Harjit Sajjan said the cause of the crash is unknown at this time. He said the voice and flight data recorders broke away from the helicopter during the crash and have since been recovered. 

The helicopter was deployed with the frigate as part of NATO’s Operation Reassurance since leaving Halifax in January.

In a brief statement Thursday, NATO said that aircraft from Canada, Italy, and Turkey were continuing to search for the helicopter and its crew, with additional support from Greece and the United States.

Vance said search efforts have been complicated because the helicopter crashed in 3,000-metre deep water.

The RCAF's fleet of Cyclone helicopters has been put on an "operational pause" since the crash to allow investigators to rule out any fleet-wide problems with the aircraft, Vance said.

The Canadian military began using Cyclones for operations in July 2018 after more than a decade of delays with the manufacturer Sikorsky.