It has been claimed that David Ibbotson who was the pilot that flew Emiliano Sala's crashed plane was color blind and not qualified to fly at night.
Emiliano Sala was on board traveling in January to meet Cardiff City players from Nantes before the plane he was boarding crashed into the English channel.
And according to the latest report by BBC Wales, the pilot did not hold a "night rating" on his UK private pilot's licence and he was restricted to flying in daytime hours only.
"Anything that's on the UK licence applies to the US licence as well, so he couldn't do anything more than the UK licence allows.
"Flying outside the restrictions of your licence is illegal and that's likely to affect the insurance cover for the flight,'' the source explained.
David Ibbotson's licence will now be investigated along with the legality of the flight as it is claimed that he had only private licence and was battling £18,000 debts.
The plane disappeared off radar north of Guernsey in the Channel Islands at 20:16 on January 21.
Sala's body was recovered from the wreckage of the plane in early February, but Mr Ibbotson's body has not been found