A Delta Air Lines flight traveling from Paris to Seattle was forced to make an unexpected stop in London after the crew reported a mechanical issue involving an onboard lavatory, the airline said.

Delta Flight 81 departed Paris-Charles de Gaulle Airport on Aug. 13 bound for Seattle-Tacoma International Airport when the issue prompted the flight crew to divert to London Heathrow Airport.

The Airbus A330-900 was carrying 209 passengers and 13 crew members at the time, according to information provided by Delta.

As the aircraft approached Heathrow, the flight crew declared an emergency with air traffic control because the plane would be making an overweight landing, the airline said.

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Despite the emergency declaration, the aircraft landed normally and safely at Heathrow.

Delta maintenance personnel then serviced the Airbus in London in an effort to address the lavatory-related mechanical issue.

“We apologize to our customers for their experience and delay on Delta Flight 81 from Paris-Charles de Gaulle to Seattle, which diverted to London Heathrow after the crew reported a mechanical issue involving an onboard lavatory,” a Delta spokesperson said in a statement to Fox News Digital.

“This is not the experience we strive to provide, and we’re focused on getting our customers to their destinations as quickly and safely as possible.”

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A Delta Air Lines Airbus A330-900, registration N812NW, is pictured at Leonardo da Vinci–Fiumicino Airport in Italy on July 8, 2025. Delta Flight 81 was operated by an Airbus A330-900 carrying 209 passengers and 13 crew members when it diverted to London. (Massimo Insabato/Archivio Massimo Insabato/Mondadori Portfolio via Getty Images)

Once maintenance work was completed, the aircraft was able to depart Heathrow — but the disruption meant passengers still faced an additional detour before reaching their intended destination on the West Coast.

Instead of continuing directly from London to Seattle, the flight headed to New York’s John F. Kennedy International Airport because of the crew’s available duty time, according to Delta.

Passengers cleared U.S. Customs at JFK before continuing their journey to Seattle.

The unusual itinerary ultimately took the 209 passengers from Paris to London, then across the Atlantic to New York before they could continue on to Seattle.

Passengers prepare to board a flight at London Heathrow Airport on June 27, 2026. Delta Flight 81 made an unscheduled stop at Heathrow while traveling from Paris to Seattle after its crew reported a mechanical issue. (Marc Fernandes/NurPhoto via Getty Images)

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Delta did not provide additional details about the specific mechanical problem involving the lavatory or what maintenance was required to address it.