'Brain fart' led Vic firefighter to arson

A "brain fart" led a volunteer firefighter who thought of the CFA as family to deliberately light two bushfires on Melbourne's outskirts he later helped put out.

Keegan Danielz, 20, will now spend 15 months in a youth detention centre after pleading guilty to two counts of recklessly causing a bushfire and one charge of persuading a person to commit perjury.

He lit the bushfires in Silvan, east of Melbourne, on March 21 this year when there were fire restrictions in place.

Then Danielz called the local fire station to report the blaze and joined crews from three trucks who responded to the emergency.

Days later, as police began investigating, he asked a friend to lie about sharing a meal together at the time of the fire.

When Danielz and his friend failed to appear on CCTV footage from the fast food outlet they nominated, the friend admitted it was a false alibi and police confronted Danielz.

"You said you had a brain fart, saying you were in a s*** or shonky mood before the fires were lit," Judge Peter Kidd told the Victorian County Court on Wednesday.

Danielz told police "what I did was idiotic and dangerous and I don't even know why I did it".

Given his CFA qualifications as a wildfire firefighter, Danielz's offending was particularly serious.

"The lighting of bushfires is repugnant," Judge Kidd said.

"You had increased insight into bushfires.

"They can be, and often are, calamitous and fortunately this did not occur here," Judge Kidd said.

Sentencing Danielz, the judge said he had not shown adequate remorse.

Danielz had denied lighting the second fire, despite admitting the first blaze.

"You were anything but contrite," the judge said.

A psychological assessment found Danielz had a borderline personality disorder with difficulties forming healthy attachments due to his fractured upbringing between South Africa and Australia.

During his early years in South Africa he had witnessed his uncle being killed and he had a bad relationship with his father.

But given his youth and good work ethic, Danielz also has good prospects of rehabilitation, the judge said.