In the early hours of the next morning, a female flight attendant was admitted to hospital still in her Pacific Blue uniform showing symptoms of a drug or alcohol overdose.
She told hospital staff she blanked out after being given a pill by Mr A, and woke up at 11.45am with no memory of what had happened.
Mr A told the ERA "she was very drunk and had been in the spa pool for far too long, so she was dehydrated as well", said the report.
A toxicology report showed she had BZP - a drug similar to amphetamine - in her system.
After the party, Pacific Blue suspended and began investigating Mr A. That inquiry followed two in early 2009 into allegations he misused alcohol during an overnight stop in Sydney and separate excessive alcohol and illicit drug use.
Flight operations manager Captain Geoffrey Lowe told the ERA both investigations were dropped because of insufficient information but they suggested a pattern of behaviour.
About four months after the party, Mr A was given a final warning. Police began investigating drug allegations against him a month later.
He finally lost his job in May the next year, with Pacific Blue citing discrepancies in the toxicology report as the basis for dismissal. The ERA said the report "provided viable evidence that illegal substances had been taken at A's party, contrary to the evidence that A had given earlier".
Mr A argued the airline failed to carry out a proper investigation into the party, and "made no effort" to test any of the employees at the gathering for drug or alcohol use. The ERA agreed, but Mr Crichton ruled Mr A was justifiably dismissed.