Radar images from Norwegian flight DY1156 to Munich show the aircraft changing route and landing back at Oslo.
The flight, which took off from Oslo Airport at 9:34am on Saturday, had been due to land in Munich at 11:45am.
But it turned around near the Swedish border over the Skagerrak sea, flew north and then circled before landing back at Oslo.
Flight mapping website FlightRadar24 tweeted details of the unexpected change in course.
‘Is there a plumber on board?'— Flightradar24 (@flightradar24) January 30, 2018
A Norwegian flight with 84 plumbers on board turned back to Oslo this weekend because a problem with the toilets.
🔧🚽 https://t.co/lUPlJIxGMU #DY1156 pic.twitter.com/s6KgfLJZkg
"It is correct that DY1156 from Oslo bound for Munich was forced to turn back to Oslo because a fault was found with the toilets on board. The aircraft circled over Hedmark to burn fuel so that it wasn't too heavy to land," Fatima Elkadi, communications officer with Norwegian, told Dagbladet on Saturday.
A further twist to the story emerged when the newspaper flushed out information revealing that 85 people from the Norwegian plumbing industry - of which around 60 were plumbers from the Rørkjøp company - were on board the aborted flight.
The sanitation technicians were travelling as part of a work trip, according to the report.
"So many plumbers on an aircraft and it has to turn back due to toilet trouble. That is enough to make you laugh," Hans Christian Ødegård, a plumber from Ulstein who was on the flight, told Dagbladet.
Rørkjøp CEO Frank Olsen also told the newspaper that the passengers took the situation with good humour.
"We'd have gladly fixed the toilets, but it must unfortunately be done from the outside and we didn't want to take a chance on sending out a plumber at 10,000 metres' altitude," Olsen said.
The flight was rescheduled for later the same day.
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