The sister of a missing Alberta pilot whose plane vanished without a trace into the B.C. mountains one week ago has been told the official search effort is nearing an end.

Tammy Neron said, when her family met with search and rescue officials on Friday, they were told military crews may be called off the search as early as Sunday night when they are expected to complete a third aerial sweep of the area.

"The weather from Sunday onwards will be sunny and if we have just a few more days with the search and rescue I am certain they will find him," Neron wrote on her Facebook page.

"This was not great news, but we are not giving up."

Bound for the Villeneuve airport northwest of Edmonton, Dominic Neron of Sherwood Park and his passenger Ashley Bourgeault were flying from Penticton, B.C., when the single-engine aircraft vanished off the radar near Revelstoke.

'As each day passes we need to hold them closer in our hearts.' -Tammy Neron

Neron, 28 and Bourgeault, 31, have been dating for a few years and were the only people aboard.

There has been no trace of the missing couple since.

If the missing plane isn't spotted soon, the case will be handed over to the RCMP as a missing persons investigation, Tammy Neron said.

Neron said the family is praying for her brother, a journeyman electrician set to celebrate his 29th birthday next month.

Despite the dire circumstances, the family remains optimistic that Neron and Bourgeault will be found.

"As each day passes we need to hold them closer in our hearts," Tammy Neron wrote.

"We need everyone's prayers and love more then ever right now ... stay positive and strong."

On Saturday, Cpt. Zlatko Neral with the Victoria Joint Search Co-ordination Centre said, while crews have given no clear end date for the search, the operation will likely come to an end within a matter of days.

"They're discussing it but I don't have a time yet," Neral said. "I don't know, but they told us to keep going."

Heavy snowfall, low clouds and densely treed terrain has made the search more difficult and poor weather conditions continue to plague the operation.

On Saturday morning, a CC-115 Buffalo aircraft dedicated to the search was unable to fly due to bad weather in Rogers Pass, said Neral. A CH-149 Cormorant helicopter will be deployed instead.

"Today's weather is worse than yesterday," said Neral. "For where we wanted to search, it's not even too suitable because of the tightness of the terrain and mountainous nature of the terrain, so we're waiting for the Cormorant to launch."

On Friday, RCMP Cpl. Dan Moskaluk said Penticton RCMP are helping the Victoria Joint Search Co-ordination Centre in the search for the missing couple and plane.

'We need everyone's prayers'

Rescue centre spokeswoman Katelyn Moores said earlier this week that the search area had been narrowed to a region 18 kilometres outside Revelstoke.

She said the grid was refined based on more complete information from radar and the cellphone tower that picked up a signal from the pilot's phone at about the same time the plane was reported missing.

Tammy Neron said she will be driving to Revelstoke on Saturday, where family members will be postering the town with photos of the missing couple and the plane.

They are also asking for information on a survival kit they believe was aboard the downed plane. The person who sold it could have invaluable information on the search.

"We need to know who sold this kit to him because the contents of the survival kit could help search for things such as a coloured tent or tarp included in the kit," Tammy Neron said.

"Dominic, he takes every precaution, and would ensure there was a survival kit."