Mr Ciaran Haughey has told the tribunal he now accepts his father assisted Celtic Helicopters in getting people to invest in the company.
However, Mr Haughey said his father was never a shareholder.
Mr Jerry Healy SC, counsel for the tribunal, asked Mr Haughey whether his father and the late Mr Des Traynor "were the people who got the original investors together for this company".
Mr Haughey replied: "I believe so. I can't be 100 per cent on that."
Later, however, Mr Haughey confirmed his father helped in the setting up of the company and encouraged people to become involved. He said his father "would have had an interest in the welfare of the company, like any father would in their son's business."
He added: "It is clear now that he offered assistance. I accept that at this time."
At a previous sitting of the tribunal, Mr Ciaran Haughey's business partner, Mr John Barnicle, said that Mr Charles Haughey had no involvement in the running of the firm.
On the issue of shares, however, Mr Ciaran Haughey rejected the suggestion that his father had a financial interest in the company. Mr Michael Curneen, a former lending official with Smurfit Paribas, had said he was told at a meeting with Mr Haughey and Mr Barnicle that Mr Charles Haughey was a 12.5 per cent shareholder in Celtic Helicopters.
Mr Haughey said he had no recollection of the meeting and wished to "strongly refute" Mr Curneen's evidence.
"My father never had and does not have any shareholding with Celtic Helicopters and the mention of 12.5 per cent leads me to believe that Mr Curneen is mistaken because I have checked the share issue and no investor was ever issued with an amount equivalent to 12.5 per cent."
Mr Justice Moriarty asked whether Mr Haughey appreciated the conflict of evidence as Mr Curneen "seems to have no axe to grind" and yet must have got the reference to the shareholding from somewhere. Mr Haughey said he had no problem with Mr Curneen in any other sense but could not accept his evidence.
Mr Haughey was questioned again on why he had referred to his father a query relating to shares in Celtic Helicopters from Dr John O'Connell, a former Fianna Fail minister. Mr Haughey said he did this because Dr O'Connell, as a TD, would have been familiar to his father.
Mr Healy said "what I am suggesting to you, Mr Haughey, and I don't want to be unfair to you, is that your father and Mr Traynor at least knew as much about this company if not more than you do."
Mr Haughey replied: "Mr Traynor assisted in financial advice. I don't know why you include my father in that statement."
In relation to a £150,000 Irish Intercontinental Bank (IIB) loan, Mr Haughey said he had believed at the time of the McCracken tribunal it was repaid with the company's own resources.
He said he was subsequently told by Mr Barnicle that the loan was repaid with £100,000 paid by Mr Traynor for an insurance claim, and £53,868.84 in pre-paid flight hours for Gary Heffernan, a cover name for his father.
Mr Haughey said he accepted the money used to repay the loan in February 1992 came from an Ansbacher account with IIB, although he did not know it at the time.
