PEACHLAND, B.C. -- Warrant Officer Dan Lamoureux was in a Buffalo search-and-rescue plane almost 300 metres above British Columbia's Okanagan Valley when he spotted a tangled mess of metal in a patch of broken trees.

It was the wreckage of a small plane, a twin-engine Piper PA-30 Comanche, that went down hours earlier, killing a 30-year-old man and critically injuring three others.

"Just to the left of (our) aircraft, I looked down and saw some white and red, you could easily tell that it was scrap metal," Lamoureux said in an interview Tuesday, a day after the fatal crash.

"I'm looking for anything that looks odd to me, so this wreckage caught my eye. It was something out of the normal, and a lot of broken trees. "

Lamoureux was returning to the 19 Wing Comox air force base on Vancouver Island from a training mission Monday afternoon when a WestJet airliner reported picking up an emergency locator beacon.

It took the Buffalo almost two hours before the crew finally located the wreckage in an area near the community of Peachland on the west side of Okanagan Lake. The plane left Penticton en route to Boundary Bay, south of Vancouver.

Lamoureux and another search-and-rescue technician strapped on their parachutes, aimed for an open field a short distance from the crash site and jumped out of the Buffalo, which by then was more than 750 metres above the ground.

When they landed, they set into the trees on foot.

"From a distance, we yell, 'Hello, hello, we're search and rescue, we're here to help!"' recalled Lamoureux.

"And, oh my God, I couldn't believe I heard a response from a female voice."

The search-and-rescue technicians eventually reached the crash site, where they found what was left of the plane on the forest floor. Its wings were broken off and the fuselage was no longer in one piece, he said.

One person, later identified by the coroner as 30-year-old Jayson Dallas Wesley Smith of Vancouver, was dead.

The woman who called for help was sitting up and able to talk, while the two other survivors were unconscious, said Lamoureux.

Soon after, firefighters, police and paramedics arrived at the scene. An air ambulance and a military Cormorant helicopter landed in the open field.

As the firefighters and search-and-rescue technicians removed the survivors, the air ambulance transported two of them, including the most serious, to hospital. One of those two patients was later transferred to Vancouver, said the Transportation Safety Board.

The third was airlifted in the Cormorant to Kamloops.

"Everything worked like clockwork," said Lamoureux, crediting the various agencies involved.

The survivors' precise conditions were not known, although a spokeswoman for the BC Coroners Service said at least one of the patients was "not doing at all well."

The Transportation Safety Board sent two investigators to the scene, where they were expected to examine the aircraft before attempting the delicate task of speaking with survivors.

Lamoureux said it appeared the plane entered the trees from the open field, though he wasn't sure whether the aircraft may have been attempting to land.

Bill Yearwood from the Transportation Safety Board said it was too early to determine whether the plane was landing. He said the aircraft had not caught fire, which will make it easier for investigators to piece together what happened.

Another spokesman for the safety agency, John Cottreau, said it's not clear when investigators would be able to speak to the survivors.

"They're going to want to play it by ear, take their time," Cottreau said, referring to interviews with survivors.

"These folks have been through a trauma, so they're going to wait for an appropriate time."

The crash occurred in the same area where a de Havilland Beaver crashed in a ball of flame in May, killing all three aboard. At the time, witnesses said that aircraft appeared to be trying to gain altitude but could not climb quickly enough to avoid the steep terrain.

Two years ago, another plane crash involving a Piper Comanche that departed from Penticton killed four people. That plane, a single-engine aircraft, crashed in August of 2010 near Apex Mountain.

The Transportation Safety Board didn't conduct a full investigation of that crash, but a coroner's report concluded a combination of the plane's weight and hot, thin air likely contributed.

The weather in the area was above 30 degrees on Monday, according to Environment Canada.

Cottreau stressed it was far too early to speculate on what caused Monday's crash.

"But certainly, meteorological conditions are one of the things that we look at every time."