Whether it’s real or on Lost, there’s something about planes flying from Los Angeles to Sydney that brings out the absolute worst in airlines.

A Virgin Australia flight last night was forced to return to LAX after a water system malfunction caused an unbearable stink throughout the plane, and according to some passengers caused human waste to leak onto the plane. “We could see [human waste] go through the aisles, like it was very obvious,” one passenger told the Sydney Morning Herald.

The airline disputes that claim, saying that “The onboard toilets operate on a completely separate drainage system. As the issue was with the aircraft sink, and not the toilets, there was no incident of leaked human waste.”

Either way, when your airplane smells so bad that they actually walk through the cabin offering you masks and turn the plane around, that’s a pretty crappy flight.

[via NY Daily News]