|A Tupolev TU-154M is seen in this file photo. REUTERS/Sergei Karpukhin
The Russians won't be looking to snap pictures of Niagara Falls when their observation flights leave Canadian Forces Base Trenton, Ont., on Tuesday under the 20-year-old Treaty on Open Skies.
Instead, they're more likely to want to examine Canadian air bases or energy infrastructure, says one international security expert.
"It's hardly to be written off that they may have in mind a closer look at some of that infrastructure, including pipelines," said David Harris with Insignis Strategic Research.
The Russian aircrew could also try to intercept electronic communications while flying over Canada, though that is expressly forbidden under the Open Skies treaty.
If they did intercept that information, Harris said it could tell the Russians "something about radar installations that we have for our domestic protection what they look like when they're turned on" - handy data to have for future "unauthorized" flights.
Even with sophisticated spy satellites in orbit around Earth, Harris said observation flights are still useful.
"Over-flights still have a place when it comes to certain detail, certain perspectives on objects below," he said.
This week's flights are all legit and authorized by Canada under the treaty that allows 34 countries unimpeded observation of each other's territory in hopes of strengthening "peace, stability and co-operative security." The Russians still have to submit a flight plan for their Tupolev TU-154M, allow Canadian military personnel to fly with them and submit their observation equipment to inspection.
The treaty limits the allowable resolution of any photographic equipment used.