In a bid to more effectively combat the impact of bushfires in terms of threat to life and property, and disruption to power supplies, Australian utility company Powercor started using helicopters for aerial inspection work three years ago. With a Bell 407GXi deployed to track large areas of Western Victoria, the company has become far more effective at cutting back vegetation to reduce the risk of fire spreading, especially where it intersects with about 50,000 miles of powerlines.
Airborne lidar radar technology is used to gather data that generates 3D models to show Powercor exactly where vegetation needs to be cut and allows the company to track growth to plan ahead. Before the company invested in its helicopters in 2021, this task was undertaken on the ground by contractors who sent staff out in cars across difficult terrain and used binoculars to assess risks.
“There were always concerns about the quality and consistency of the data with people on the ground trying to inspect 750,000 spans [the gaps between power poles] and between 13 and 15 million trees,” Ayce Cordy, Powercor’s head of vegetation management, told AIN.
“When we used lidar for the first time, we realized there was a lot more risk than we had thought. The areas of highest risk have the most vegetation and are the hardest to access, so the [ground-based] contractors were finding the task too difficult, and some areas were being missed.”
The helicopters operate mainly from a base at Avalon Airport, near Geelong, with flight crew sometimes being away for several days to survey more remote parts of the state. Two pilots take turns flying the aircraft or operating the lidar equipment, downloading the data between missions. Powercor also operates a pair of Bell 505s.
According to Daniel McQuestin, Bell’s business development director for Australia, New Zealand, and the Pacific Rim, the 407GXi is well suited to challenging missions. “It has a four-bladed, hingeless main rotor system and a composite hub that makes it very maneuverable and stable, complemented by an ability to hover for long periods of time and reliably fly at low altitudes,” he said.
Safety features for the model, which can seat up to seven people (including the pilot), include synthetic vision, terrain and obstacle avoidance, and a tail rotor camera. The flight deck features the Garmin H NXi avionics suite, and the helicopter is powered by a Rolls-Royce 250-C47E/4 engine.
All of Powercor’s flights are conducted in daytime VFR conditions to ensure the best performance for the lidar. Generally, the helicopters fly at between 500 and 1,200 feet above ground level, with the lidar calibrated at 700 feet so that the scanner gets a wide view of the terrain below.
Flying conditions can be challenging on missions that typically last between two and a half and four hours. “Some areas are like a big bowl of spaghetti [with powerlines and vegetation], and the winds can change a lot in mountainous areas,” explained Powercor’s chief pilot, Ian Wallace.
The Powercor crews start their inspection process in Australia’s peak summer months of January, February, and March, with the aim of getting all the flying done by July or August. This gives time to get a complete picture of vegetation that needs to be cleared between August and November, ahead of the peak bushfire season, as part of the utility company’s statutory responsibility.
According to Wallace, the task could not be handled as completely by drones, mainly because there would be too many situations in which line-of-sight operational restrictions would get in the way. The lidar images taken from the helicopters are accurate to within around one inch.
“Bushfire is our number one risk, and this approach is the gold standard for [powerline] inspection,” Cordy concluded.
Other Bell models, including the 429 and 505, are used for inspection tasks around the world. The manufacturer has more than 420 aircraft in service with operators in Australia, where it supports customers through three maintenance, repair, and overhaul facilities at Coffs Harbour in New South Wales and at Redcliffe and Clontarf in Queensland. It also has service bases in Perth and Brisbane.