Canada's Transport Safety Board expects to take another six months before releasing its final report on the crash of Swissair flight 111 two years ago.
The board had hoped to release the report before the end of the year.
The plane went down in Peggy's Cove, off the coast of Nova Scotia, killing 229 people.
The later-than-expected release date for the report stems from the complexity of the investigation.
"We've got about two million pieces of wreckage and 275 kilometres of wiring," said the board's chairman, Benoit Bouchard.
Most of the cost of the investigation, an estimated SFr60 million, has centred on retrieving the wreckage of the Boeing MD-11 jet from the Atlantic seabed, 65 metres below the surface.
The board has already met European families of the victims, and expects to talk to American relatives in the coming months.
Swissinfo with agencies