"I can assure you that he is very interested in setting the record straight," Roger Yachetti wrote in an email.
Mazza is expected to appear July 18 before a legislative committee that's probing the scandal that's engulfed the organization, but there's one final hurdle to clear before that happens.
Two warrants from Speaker Dave Levac were issued to compel Mazza to testify, but his appearance was put off because two psychiatrists declared him medically unfit to testify.
Mazza took medical leave last December when allegations about questionable business deals made headlines.
A doctor is expected to submit an opinion by July 10 about whether Mazza will be able to testify, Yachetti confirmed. He also plans to accompany Mazza when he appears before the committee.
Many of the witnesses have pointed the finger at Mazza for the controversy that's cast a shadow on Ornge — which is currently under a criminal probe — and created a major embarrassment for the governing Liberals.
Former Ornge employees have described him as "impressive," "brilliant" and a "visionary," but also a tyrant whose volatile temper exploded when they didn't do what he wanted.
The committee has also heard about Mazza's $1.4-million annual compensation package that was hidden from public view, the personal loans he received from Ornge to buy a house and his involvement in hiring his girlfriend, a former water-ski instructor, at Ornge.
Mazza has a lot of explaining to do, but there's more than one side to every story, said New Democrat France Gelinas, who sits on the committee.
"He did not do all of that alone," she said.
"I don't think he set out to rip people off. He didn't start this with the intention of ending up in the fiasco that we have now. I'm interested in hearing his story as to what was the turning point."
There are many questions that need to be asked, said Progressive Conservative Frank Klees, who also sits on the committee. There have been so many different accounts from insiders about what happened that it's hard figure out who's telling the truth.
"We have had nothing but contradictions from one former staff member to another, he said. "It will be interesting to see how Dr. Mazza's story squares with the various versions that we've heard so far."
Klees said he'd like Mazza to explain why he used taxpayer dollars to subsidize a web of for-profit companies, why he was given personal loans without proper documentation and his close relationship with Rainer Beltzner, Ornge's former board chairman.
"No one will be more interested than taxpayers to have the record set straight," he said.
"What I'm hoping is that perhaps we can count on Dr. Mazza, at this stage in his life, to tell the truth."
Auditor general Jim McCarter has criticized the government for failing to oversee Ornge, despite giving it $730 million over five years and allowing it to borrow another $300 million.
The committee has heard numerous stories about people who died while waiting for an air ambulance, about understaffing by Ornge, and about helicopters that were so badly designed paramedics often could not perform CPR on patients.