The Boeing 777 turned back to Frankfurt about two hours into the flight over the North Sea. The airline attributed the delay in a statement to The Hill to a “maintenance issue with one of the aircraft’s lavatories.”
United said passengers were provided hotel accommodations in Frankfurt and flown to San Francisco on Saturday.
The incident is the latest to hit Boeing, with the company still reeling after a door plug explosion in January led to a federal investigation into quality control and concerns over safety with its aircraft.
It also follows a series of safety incident with United flights, after two bird strikes by aircraft last week, causing diversions and delays but no injuries. Another United flight left seven people injured due to turbulence last week.
The company announced last week that the Federal Aviation Administration will be taking increased oversight over the airline due to the issues.
United also asked certain pilots to take unpaid leave due to overstaffing on Monday, citing delays in aircraft deliveries from Boeing caused by the mass safety inspections.
Boeing declined to comment.
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