The Transportation Safety Board is sending a team to a remote B.C. island to investigate a fatal float plane crash.

On Friday morning, the Cessna 208 Caravan went down on Addenbroke Island, approximately 100 kilometres from Port Hardy, killing four people on board.

The Joint Rescue Co-Ordination Centre Victoria received a distress signal from the aircraft.

"They received a signal from an electronic location transmitter, which indicated there may be an issue with the Cessna 208," explained Capt. Jenn Jackson. "They attempted to contact the crew through nearby aircraft, as well as the owner, but those were unsuccessful. And the crash was confirmed when a passing fishing vessel discovered the crash."

Jackson said Addenbroke Island is uninhabited and has one lighthouse. The lighthouse indicated there was heavy cloud cover, moderate winds and light rain at the time of the crash.

One of the challenges of the rescue mission is the distance and remoteness of the island, Jackson said. 

About six hours after the plane went down, the Royal Canadian Air Force airlifted five survivors to paramedics in Port Hardy.

Two patients in serious condition were then airlifted to Vancouver, while the other three in stable condition were taken to a nearby hospital.

The chartered flight was operated by Seair Seaplanes and took off from its Richmond terminal Friday.

Seair issued a statement Friday evening, confirming the downed aircraft belonged to the company.

"We are currently working with first responders and authorities and have immediately suspended all flights," a spokesperson for the airline said. "Our thoughts are with those involved in the crash and their loved ones and [we] are devastated by this fatal accident."

On Saturday, the TSB confirmed a Richmond-based team is headed to Addenbroke Island to investigate what caused the deadly crash.

"Our mandate is to investigate accidents to advance safety," spokesperson Chris Krepski told CTV News. "We are going to the accident site to gather information from there. From there, we'll see where the investigation takes us and find the cause and intervening factors and if need be, issue some safety communications."

Krepski said the flight was on its way to a remote fishing lodge about 22 nautical miles south of Bella Bella. 

RCMP are notifying families and next of kin of the four victims.