The Transportation Safety Board has renewed its call for on-board flight recorders on small aircraft following the crash that killed former Alberta premier Jim Prentice – a request the board said it first made 25 years ago.

Mr. Prentice and three others were killed Thursday night after the Cessna Citation they were in crashed north of Kelowna, B.C. The TSB has said its investigation could take more than one year.

Late Monday, the TSB released a statement that said the absence of cockpit-voice and flight-data recorders – which were not required on the Cessna involved in the crash – would make the investigation particularly challenging.

“In Canada, Transport Canada requires medium and large commercial aircraft to be equipped with onboard flight recorders, but there are still no requirements for such recorders on smaller aircraft,” Kathy Fox, the board’s chair, wrote in the statement.

“As early as 1991, the board made a recommendation calling for the upgrade of flight recorder requirements. This latest accident is another reminder of how important these recorders are. If we are to get to the underlying causes of these tragic accidents, Transport Canada and the aviation industry need to take immediate action to address this outstanding safety issue.”

In an e-mail, Transport Canada said it is bringing forward new regulations on cockpit-voice recorders for the minister to review in coming months to bring Canada in line with standards set by the International Civil Aviation Organization and the United States. It did not elaborate on what those regulatory changes will be.

It noted the aircraft involved in Thursday’s accident was not required to have a cockpit-voice recorder because it was certified to be flown by a single pilot.

Twenty-five years ago, following an Ontario crash of a Beechcraft King Air A-100 that killed four people, the TSB called for legislation upgrading flight recorder requirements. It said it could not determine exactly why the aircraft slammed into the ground and a cockpit-voice recorder or flight-data recorder could have pointed to a cause, or associated safety deficiency.

In 2013, following a Yukon crash of a de Havilland DHC-3 Otter that killed one person, the TSB recommended the federal government “work with industry to remove obstacles to and develop recommended practices for the implementation of flight-data monitoring and the installation of lightweight flight recording systems by commercial operators not currently required to carry these systems.”

Monday’s statement said the aviation industry has developed several different lightweight flight recording systems that could be installed in smaller aircraft at a low cost.

“The TSB urges the industry and private corporate aircraft owners to take advantage of the new, low-cost flight recording technology to advance safety in their operations,” Ms. Fox wrote.

The TSB said it is currently in the field phase of the investigation into Thursday’s crash and is focused on collecting information from the site.