The Norwegian Air flight, which was scheduled to take off from Oslo for Munich on Saturday, just so happened to be carrying between 60 and 70 plumbers from the Norwegian company Rorkjop traveling to Germany for a work trip. However, even a small army of experts like that were unable to address a malfunctioning lavatory the crew discovered mid-flight, and the plane was forced to turn back and return to Oslo, circling overhead for a while to burn fuel so that it wasn't too heavy to land.
To be clear, the fact that the plumbers couldn't fix the busted loo is not to diminish their ability or skillset. The issue apparently needed to be tended to from outside the aircraft, which would have been a deadly maneuver to attempt at 30,000 feet.
"We would have liked to fix the restrooms, but unfortunately it had to be done from the outside and we didn’t risk sending a plumber to work at 10,000m,” Rorkjop's CEO Frank Olsen said in an interview with the Norwegian newspaper Dagbladet. "There was a good atmosphere in the plane, what with the irony about the broken toilets.”