Fake engineer put lives at risk: court

A pathological liar who faked his way into an aircraft engineer's job with Qantas put the lives of 12,000 passengers at risk, a Sydney court has been told.

Timothy Leslie McCormack posed as a licensed aircraft engineer for almost nine months before his ruse was discovered in July 2007.

By then, he had conducted 30 maintenance checks on planes leaving Sydney Airport.

The 27-year-old pleaded guilty in September to 42 charges including forging a maintenance engineer's licence.

But even after that, his deceptions continued. McCormack faked four character references he tendered to the court prior to his sentencing hearing.

In the NSW District Court on Thursday, Crown prosecutor Paul McGuire criticised a subsequent and legitimate reference provided by Senator Bill Heffernan for McCormack, whose parents live in his electorate.

Mr McGuire objected to part of the reference, saying Senator Heffernan had inappropriately "expressed medical opinion".

Judge Mark Marien said he would determine how much weight he would give to the senator's opinion, but the reference itself was not made public.

Mr McGuire said McCormack became entangled in a "web of deceit" that could have had "catastrophic" consequences for Qantas passengers.

"Although the crown cannot point to any evidence of planes falling out of the sky ... the crown says that the potential that arose because an unqualified and failed engineer was carrying out significant work to major systems on an international aircraft directly put at risk the lives of 12,000 people ... flying out of Sydney Airport," he said.

Judge Marien said there were additional dangers because McCormack, as a supervising engineer, had been checking the work of other junior engineers working on passenger planes.

"This is someone who was not only carrying out maintenance on Qantas jets carrying large numbers of people, but was actually certifying work done by others without qualification," he said.

"(The concern) is the potential of harm that could have occurred."

McCormack's defence lawyer Sydney Jacobs argued his client was a "pathological liar" whose case was the most exceptional he had seen in his entire legal career.

"I've never in 20 years come across a case where a person created a personal universe in their own head," he told the court.

Clinical psychologist Jill Farrelly said McCormack told fantastic stories "to restore a proper sense of self-worth" after the breakdown of a relationship.

As well as lying to get his Qantas job, he told one girlfriend his child was actually his brother's, and told another woman his brother was killed in a motorbike accident in which he received scars to his back.

He then lied to his family to get out of attending his grandmother's 80th, his mother's 50th, and sister's 21st birthday and a cousin's wedding because he was too ashamed to face them after the breakdown of his relationship.

"He wanted to cut himself off from his family because he couldn't face them," Ms Farrelly told the court.

"Things seemed to go wrong in his life after the breakdown of his relationship (with his girlfriend) when she left with their infant.

"This seems to be the start ... of the fantastic lies.

"(He wanted) ... to maintain the image that he's a good man."

Judge Marien is expected to hand down a sentence on December 17.