Transportation Safety Board officials say it could take up to a year to complete the investigation into the plane crash Friday, October 14, that claimed the life of former Alberta Premier Jim Prentice.

They say the 1974 Cessna jet wasn't equipped with cockpit voice or data recorders, nor was it required to be, which will make it tougher to determine what caused the jet to crash just minutes after taking off from the Kelowna Airport.

Among the deceased, were Calgary Optometrist, Dr. Ken Gellatley, who was Prentice's daughter's father-in-law, retired city businessman Sheldon Reid and the pilot, retired RCMP officer Jim Kruk.

Funerals and memorials are being planned for the four victims.

Flags remain at half staff at all public buildings out of respect for Prentice.