The judge imposed strict suppression orders, meaning the man and other parties cannot be identified, and neither can the location of his workplace.
An affair between the woman, who lived in another part of the country, and the man, who was also married, began in early 2017 after the pair met on a dating website.
The sexual liaison between the pair involved pre-planned meetings at hotel and motels and was uninhibited, including an exchange by text of short videos and consensual recording of their sexual activity.
While the duration of the relationship was disputed, there was no argument it had ended before the woman texted the man's wife to disclose the affair. His marriage broke up.
The woman later called the man's wife detailing how the pair had sex in the control tower and how she had performed a sex act on him while he was handcuffed to a chair in the control room.
Concerns were raised with the CAA, which launched an Aviation Related Concern investigation into the allegations.
The woman repeated her claims about the sexual encounters, including having handcuffed him to a chair while he worked in the control room, to the investigator.
A decision to suspend the man's ATC licence was conveyed to him in December 2018 and, in March 2019, notice of a proposed decision to revoke his licence was made.
In an interview in February 2019, the man admitted the affair and said he had been alone in the control tower with the woman on three separate occasions during two days, but denied sex had taken place.
"He acknowledged that [a sex act] while he was in handcuffs had occurred during the sexual relationship but in a hotel room, not in the control tower."
He also detailed how the woman had tried to blackmail him by threatening to ruin his life if he didn't pay her $50,000.
The CAA director recorded that "on the balance of probabilities" he believed the woman's account and was concerned by the man's risky behaviour while he should have been focused on what he was doing.
"He categorised this behaviour as highly irresponsible, intolerable and demonstrating extremely poor judgment."
The decision to revoke the man's licence was made in mid-2019, and was subsequently appealed.
While Judge Tuohy said he had reservations about the woman's credibility and reliability, he maintained her core allegation the pair had sex in the tower while the man was on duty was inherently plausible.
The evidence was however not sufficiently strong or cogent to satisfy the judge of the most serious aspect of the allegations, that he allowed himself to be handcuffed in his chair while on duty.
"The appellant voluntarily engaged in distracting behaviour which must have impinged on his capacity to react but, in my judgment, it is not sufficiently proven that he engaged in the even more risky and irresponsible behaviour of allowing himself to be physically prevented from doing so."
Judge Tuohy ruled it had not been established the man was not a fit and proper person to exercise the privileges of his ATC Licence.
"I have reached that conclusion despite my finding that he did undertake risky behaviour while on duty, although not quite as risky as that which the director relied upon."
The judge had taken into account the relatively short duration of the man's behaviour, it was unlikely he would engage in such behaviour in the future and his successful and incident-free career as an air traffic controller spanning many years.
Judge Tuohy reversed the CAA director's decision to revoke the man's ATC Licence.
