Virgin Blue flight attendants had to use the oxygen masks in the rear toilets of a Boeing 737 during an emergency descent after they couldn’t tell if their crew oxygen masks were working, an investigation has revealed.

In the rush to get oxygen flowing during a rapid depressurisation, one attendant yanked on the tubing, ripping it from its connection and rendering it useless.

The plane, which had departed Coolangatta for Melbourne with 145 passengers on board, experienced rapid cabin depressurisation after its two air supply systems failed.

The pilots, distracted by the unfolding emergency, didn’t immediately tell the cabin crew what was going on, the report said.

The pilots also forgot to turn on engine and wing de-icing systems, which could have created difficulties in flight control had ice formed, air safety investigators have found.

The investigators’ final report into the November 17, 2007 incident was released by the Australian Transport Safety Bureau yesterday, cataloguing multiple technical and procedural failings.

A pressure valve fault triggered the shutdown of one of the two units pumping air into the cabin shortly after take-off. Then, cruising at 31,800 feet, the other air supply unit failed, triggering a rapid loss of cabin air pressure.

Investigators found:

The command pilot’s decision to continue the take-off after the first air supply unit failed was contrary to the airline’s procedures and increased the risk of in-flight technical problems;

Pilots trying to resolve the first air supply fault were distracted during the critical phase of take-off;

Pilots overlooked activating anti-ice systems in icy conditions on ascent and emergency descent;

Pilots were too busy to warn meal-serving crew about the nature of the emergency;

Crew had “inconsistent knowledge” of how emergency oxygen masks worked.

Pilots landed the plane safely at Brisbane Airport with no injuries to people on board.

In response to the report, the airline said: “Virgin Blue has rigorous operating procedures to which we expect all team members to adhere and we are also continuously reviewing and monitoring our operations.

“Ours is not a culture of blame but of continuous learning, training and improvement. As outlined in the ATSB report, Virgin Blue has implemented a range of actions as a result of this incident.”

Investigators say the lessons learned from the incident have been incorporated in Virgin Blue’s pilot, crew and technical training, manuals and procedures.