Drones and their place in dangerous working environments

An Australian Transport Safety Bureau (ATSB) investigation into an accident where a Squirrel helicopter struck a powerline pole and crushed to the ground, killing the pilot in the process – has triggered debate among aviation professionals on whether helicopters are still a viably safe option for stringing powerlines during the construction process.

When erecting electricity transmission infrastructure, helicopters have been the workhorses of choice to string the powerlines through, using overhead means. It is a spectacular, if arduous undertaking, which requires expert pilot skills to carry out; and crucially helicopters have been doing it for a long time.

Using a helicopter to string powerlines is said to reduce the environmental impact of the construction, as the line can be strung over ecologically or culturally sensitive areas. It also minimises the need for heavy machinery and other vehicles on the ground along the alignment and reduces the time required to complete the job.

But along the way there has been mishaps, some of which have been tragic.

On this particular day in 2019, the pilot in the AS350B3e Squirrel helicopter was stringing powerlines from the Mount Gunson South substation to the Carrapateena mine site in the Far North region of South Australia when tragedy hit.

“While pulling the draw wire with a nose-high and rearward attitude, the helicopter’s main rotor blades struck the pole about 17 metres above the ground,” the report, which was released two weeks ago, said. “The helicopter subsequently impacted the ground near the base of the pole.

“Several ground crew from the stringing team extinguished a small post-impact fire and removed the pilot from the aircraft to a safe distance. A short time later emergency services and paramedics from the mine site attended the scene and confirmed that the pilot, who was the sole occupant, had received fatal injuries. The helicopter was destroyed.”

Investigators concluded that a safety issue relating to lack of post-training supervision by the helicopter operator was the cause of the accident.

“Shortly after being trained in powerline stringing operations, for unknown reasons, the pilot modified the stringing methodology. In addition to placing the helicopter at low level in the vicinity of the powerline poles, the modified methodology also exacerbated the uptake of dust. This, in combination with the position of the sun and the rearward attitude of the helicopter, likely reduced the pilots’ visibility of the pole and their situational awareness of it.”

The publication of the report has brought discussion among professionals in the aviation industry, with some calling for the replacement of helicopters by unmanned aerial vehicles, which proponents say will do the job much safer.

“There is absolutely no need to be using a helicopter for this dull dirty and dangerous task,” said Philip Rowse, the Chief Pilot Officer at CubePilot, in a post that started the debate. “Companies like Freespace Operations can do this, or provide hardware to do this with zero humans in the flight envelope, significantly less dust generation, and far better situational awareness! Not only have there been no lives lost to unmanned aircraft accidents, but here is an example of a life that would have been saved if the company had used the technology that is available now.”

The argument is drones can do the job just as well as helicopters, and safer too…

To which one of the respondents agreed.

“It the same philosophy where we don’t send men into fundamentally dangerous tunnels or confined spaces when robots can be substituted in their place,” said Ken King, the Co-Founder at Freespace, an Australian manufacturer of heavy-duty drones. “Helicopters hanging around in the ‘Dead Man’s Curve’ flying in very close proximity to structures is a constant battle to beat the odds with only the combination of flight procedures and pilot skill to keep human life from harm’s way.”

King can of course say that, what with him having founded a drone company that is seeking into replace the helicopters in the commercial heavy-lift business. The company has done a good few powerline stringing itself to date, and it reckons the time has come to seriously consider drones as an alternative for such dangerous work.

But to be fair, there may not be enough drones strong enough and enduring enough yet to fully work the powerlines without the help of manned helicopters. And besides, manned aviation pilots are not crazy about being replaced by drones either. As one of the comments said, if this conversation is brought before them “they start hurling expletives.”

“It is a sad day when someone loses their life and I feel for the pilots family,” said Paul Knight, Technical Officer at Bluebushe Airport. “However, that pilot would have trained hard to qualify and would only have been doing that job because of their love for flying. As someone (this was in response to a comment) who doesn’t seem to fly and doesn’t understand what drives people to want to fly you’ll never understand that while it’s very sad that a pilot died they were probably doing something that they wanted to do and enjoyed doing.

“What I find sad is the use of a fatal accident to promote alternative technologies that should stand in their own rights.”

While I wholeheartedly agree that there are many roles for drones in a broad range of industries there are still limitations that in some cases still rely heavily on the human hand/eye coordination.

You can add binocular camera options to achieve 3D vision together with low power optronic ranging devices but all of these add weight and a demand for additional onboard power adding yet more weight. That demands a bigger vehicle and rapidly becomes a circular argument.

Currently I don’t think that we have got the power density in batteries to make an electric air vehicle viable once all the additional equipment demands are included. A hybrid system with onboard generation would seem to offer a better solution for extended flights and greater work loads but as far as I’m aware they are in their early stages.

I’m surprised that more companies have not chosen to take existing proven airframes and remanufacture them to produce unmanned platforms. There are a good many certified lightweight solid state inertial platforms on the market that could be used as a foundation for a remotely operated platform.

Paul Knight

Paul’s submission did not sit well with others, with Airtaxi Now’s Gary Vermaak insisting helicopters were not a safe option.

“Remotely piloted aircraft certainly have big role to play in work like stringing and destringing powerlines, from both a safety perspective and a cost perspective,” said Vermaak. “Up until recently there was no alternative to using helicopters in especially remote inaccessible areas, but drones have shown what is possible with the latest multicopters.

“This was certainly not a leisure flight. Stringing power lines is a serious, but potentially dangerous, job for everyone involved and should only be undertaken by experienced skilled pilots with all the necessary controls and supervision in place. The same would apply to using remotely piloted aircraft to do the job.”

The back and forth went on for some time; and you can enjoy it by following this thread on LinkedIn. But it is an interesting watershed moment for drone technology, as they try to make their mark on yet another industry to which they bring the promise of safety, and also the threat of rendering some pilots redundant.

Drone technology has already proved its safety worth in electricity transmission; being used by engineers and inspectors to check out the power infrastructure in places that are too high and too dangerous for humans to linger too long in. The same applies for inspection of cell towers, which drones have taken over for engineers in many telecommunication companies.

Perhaps it is time serious discussions around drones and powerline stringing were held; as Rob Sutton, an engineer at Mirrigan Aerospace Consulting in Australia summed it up nicely:

“It would be interesting to understand the objections to not using drones for this work, now,” Rob says. “It can’t be regulations, cost or technology capability because all of those things are in place now.

“Maybe it is just because that is the way it has “always” been done, in which case it is time for a serious rethink.”

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