Ryan Air steward Christopher Strickland was found dead at his studio flat in Rue de Moulin, Charleroi, Belgium, on January 20, 2016.
His father Graham Strickland said the family had discovered the ‘solitary’ 21-year-old had won an interview with airline Qantas and he was ‘happy’ after passing his probation with Ryan Air.
Portsmouth Coroner’s Court heard the steward had not long been back in Belgium when concerned flatmate Michele Besio opened the door to find him dead.
The apartment block was evacuated when the fire service discovered there was carbon monoxide at 88 parts per million in the bedroom.
Mr Strickland’s father said he was ‘totally shocked’ to find there was a boiler in the room.
The inquest on Monday was shown photographs of the flue detached from the boiler.
When family began to probe what happened they were told residents had complained about noises the boiler had made and one resident told the family: ‘If anyone tells you anything different it’s a complete cover-up.’
Mr Strickland has brought a civil case against landlord Laurent Idziak and another owner.
Pathologist Dr Brett Lockyer said there was no sign of a struggle and Mr Strickland died due to hypoxic ischemic encephalopathy.
Addressing the former Southampton resident’s family, coroner David Horsley said: ‘I do think this is the most likely scenario: the pipe has blown out because the boiler has been making noises.
‘I think the explosion is the most likely theory. I have to conclude that Christopher’s death is due to an accident.’