The vulnerabilities of Tasmania’s links to the outside world have again been on show, with an errant “big drill” on the mainland and some local roadworks sending the state into a communications blackout for hours.
In what one expert described as an “unfortunate confluence of events,” two fibre-optic cables connecting the state to mainland Australia were cut within the space of two hours on Tuesday, resulting in an outage which lasted over five hours.
Inbound and outbound flights were delayed, banks and ATMs shut down, businesses lost access to EFTPOS and people were unable to access social media.
Tasmanians, no strangers to cable dramas, were mostly without telecommunications for hours.
So, what happened?
The disruptions were caused by two separate cuts to two of the three cables connecting Tasmania to the mainland, occurring within two hours of each other.
About 11am, one of Telstra’s fibre cables across Bass Strait was cut at Frankston, Victoria, by what the company later said was “civil construction” and a failure to “dial before you dig”.
Then, about 1pm, the other Telstra cable was damaged on the Tasmanian side, with the company again blaming “third parties”.
A Telstra spokesperson told the ABC the damage on the Victorian side was due to a “big drill” auger rupturing the cable, with technicians having to haul and reconnect nearly a kilometre of fibre.
Michael Patterson, Telstra’s regional general manager for Tasmania, said “in some circumstances unfortunate events occur … this is what’s happened, at least in terms of one of the outages” — with the other attributed to roadworks in Tasmania.
Telstra said it would have “discussions” with the contractors over the damage.
Failures ‘from time to time’
Each cable is made up of hundreds of fibres bundled together to travel across Bass Strait.
Andrew Connor, of consumer group Digital Tasmania, said that between Melbourne and Hobart there was a lot of equipment involved in running the cables.
“Every 30 to 50 kilometres there’s equipment that regenerates or boosts the signal in the fibre-optic cables,” he said.
“We have two cables, so that if one is impacted the other can carry the load.
“Often we don’t notice these failures, but now a second link has gone down on the same day … it’s the worst-case scenario where there’s almost no connectivity in Tasmania.”
Mr Patterson said the circumstances were “extremely rare”.
“We can’t remember a time when Telstra has had issues relating to both cables to Tasmania that has impacted customers on this scale,” Mr Patterson said.
“Our network across the Bass Strait is configured with multiple redundancies, with the two main links providing backup for each other, and a third smaller link being available for priority traffic, such as triple-0 and voice services, on the very rare chance both main links go down.
Non-Telstra customers were also impacted because other providers use the cables.
Telstra still had some capacity on the Basslink cable — which carries power and data — which is why some calls were getting through.
Is Tasmania particularly vulnerable to being cut off?
Andrew Connor said the incident was a stark reminder on how reliant we are on being digitally connected — and illustrated how vulnerable Tasmanians are.
“Tasmania could always benefit from another fibre-optic cable, a fourth or fifth, so there’s competition, but also guaranteed reliability,” he said.
“There are proposals for new fibre-optic cables with the Marinus Link, and a connection through to New Zealand from Melbourne even.”
Mr Connor said something had to be done and warned another outage could prove “catastrophic” for business and domestic users.
“It really does affect a lot of our lives when these services that we use in Tasmania are based out of mainland data centres or service providers, a lot of mobile phone calls are switched through Melbourne, TV channels all come out of mainland cities, banking is all the mainland as well.”
He urged the Tasmanian government to take action to begin work on establishing another digital connection.
“They let an opportunity pass four or five years ago to get a connection between Sydney and Perth, and we might not be in this situation if we had that other cable out of Tasmania,” he said.
Cable crisis déjà vu
Tasmania’s power crisis in 2015 showed how damage to an undersea cable could have drastic effects across the entire state.
That year, the Basslink Interconnector undersea power cable — which transfers power back and forth between Tasmania and Victoria — was damaged, suffering a major failure and sparking a months-long energy crisis.
The company responsible for the cable at the time was later ordered to pay almost $40 million in compensation to the state, after failing to prove the outage was beyond its control.
Basslink’s cable also failed twice within three months in 2019, including at an above-ground section of the transition station in Gifford in Victoria’s south-east.
Since then, another undersea power cable has been proposed for Tasmania — the $3.5 billion Marinus Link.
While that project has its detractors, after Tuesday’s outage, some Tasmanians might be thinking a new cable cannot come too soon.
