SSE said it was making good progress on its section of the 137-mile line and is moving into a new phase of the works to the south of Fort Augustus.
The pylons have been erected there and preparations are starting for the installation of the wires. The aircraft will be used for this, and will be operating in the Fort Augustus area between May 13 and 16.
Weather permitting, the helicopter will be used to fly lightweight ropes between the pylons. Seven ropes are needed along the 2.5-mile length. The ropes are attached to a heavy-duty winch in preparation for the next stage, to pull heavy wires over the route.
Then the 12 aluminium electrical overhead wires and a single earthwire are to be pulled into their final positions.
As the helicopter crosses small roads, pathways and the Caledonian Canal, members of the public may be stopped for a maximum of 30 minutes to ensure their safety. The helicopter will be flying approximately 50 metres from the ground when pulling the ropes.
John Buchan, overhead line project manager, said: "We have planned the operations to ensure that the safety of members of the public, and our staff, can be managed properly."