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The aviation industry is concerned someone will die before authorities determine what is causing a mysterious engine problem that has resulted in at least three mid-air engine failures in northern Australia.

The Civil Aviation Safety Authority (CASA) has warned a key engine component is wearing out much faster than it should, and has taken the step of urging pilots operating R-22 or R-44 helicopters in the northern regions of Australia — particularly those using them for mustering — to be aware of the risks.
Many in the aviation industry believe the problem stems from changes to aviation gas — with one senator worried it may have inadvertently seen an increase of fuel sniffing in remote Indigenous communities.
"It is highly dangerous, you've got to be able to rely on your machine when you are doing this sort of work, that's the bottom line," said John Armstrong, a veteran pilot with more than 40 years of experience."Most of the air maintenance organisation across northern Australia are particularly worried that we are getting nowhere with asking for assistance."

Though pilots have labelled the lack of urgency in resolving the matter "disturbing", the potential risks extend beyond mustering.

A worker at a commercial charter airline, who didn't want to be identified, said they were seeing the issue frequently, and have had engines return with serious damage.
Only luck, they say, has prevented a major accident.
'Get it on the ground as soon as possible'

Engineer Campbell Elliott has been working on choppers for more than 20 years, and says he has evidence of dozens of parts showing burn damage or erosion.
"Last year hit us big time and then this year has just been absolutely ridiculous, like widespread … so it's been a real issue," he said.

The problem first showed up more than 18 months ago, but the cause is still unknown.

Many are suspicious of changes to aviation gas.

Lead content has been reduced from 0.86 per litre to 0.56 — however, the fuel company that supplies the North Viva Energy is yet to disclose when those changes were made or why.

The company is also yet to provide an analysis of what is in their fuel, despite repeated requests from the industry.
"We are doing a lot of research in terms of fuel which is an area normally outside of our expertise and jurisdiction to better understand the fuel supply and manufacturing processes," said Peter Gibson from the Civil Aviation Safety Authority (CASA).

"If [pilots] do have a rough-running engine in flight they need to be very careful with the handling of that aircraft and get it on the ground as soon as possible."
Concerns fuel changes could increase sniffing

Part of CASA's investigation into the issue will centre around changes to avgas, brought about from sniffing in Indigenous communities.

Children as young as seven were experiencing lead poisoning after breaking into planes to sniff avgas in 2016.

A spokesman for the Federal Transport Minister Michael McCormack also confirmed "environmental and health concerns via federal legislation" prompted modifications.

However, in order to compensate for lower lead content, aromatics in avgas may have risen from 1 per cent to as high as 16 per cent.

That has raised a red flag in Canberra.Senator Seiwert helped introduce legislation to mandate low aromatic fuel for cars in the Northern Territory in 2012, in a bid to reduce sniffing rates.

"If there was a decision made for that that has led avertedly to further sniffing occurring obviously we want to see that addressed," she said.

"So I think we need to understand if that has occurred what the level threat is what the accessibility is and take action."

While any investigation drags on, many are adamant a fatality is imminent.

Fuel distributor VIVA energy declined the ABC's interview request, but said in a statement: "As yet, no definitive cause has been attributed to these engine failures and the matter is currently being investigated."

The ABC understands some aviation companies are now considering legal action.

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a key engine component is wearing out much faster than it should

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It is not yet clear if other operators of piston aircraft should take precautions.

Many in the aviation community have been privately expressing concerns for the past 12 months about the large number of helicopter engines with cylinders that have eroded or become damaged after only a few hundred hours in the air.

CASA has now declared it a problem, and stated it is seeing "increasing evidence of premature exhaust valve and valve guide wear, due to elevated combustion temperatures that will lead to degraded engine performance".

It is widely theorised the problem may be linked to the reduction of lead in aviation gas supplied to northern Australia a few years ago, from 0.86 to 0.56 per gram.

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