Frontier Flight Diverts to Chicago After Cabin Leak

A lavatory sink leak flooded the main cabin of a Frontier Airlines flight headed from Denver to Detroit, prompting an emergency landing in Chicago.

Updated on Nov. 11, 2026 in Air Travel

Wide photograph of a generic twin-engine airliner parked on a damp airport apron under overcast skies, with a tug vehicle at its nose. — A Frontier Airlines flight bound for Detroit diverted to Chicago O'Hare on Tuesday after a lavatory sink leak flooded the main cabin, with no injuries reported. AI Illustration. Upload story photo >

Frontier Airlines flight 3655, which left Denver International Airport shortly after 10:15 a.m. bound for Detroit Metro Airport, diverted to Chicago O'Hare International Airport after the front lavatory sink began leaking and water flooded the main cabin. The pilot declared an emergency and received permission to land at O'Hare, and no injuries have been reported.

Why it matters

The pilot raised concern that the volume of water could damage electronics, which is why the flight was diverted rather than continuing to its destination. The incident shows how a relatively contained plumbing fault in an aircraft cabin can quickly become a safety issue requiring an unscheduled landing.

The aircraft was on Frontier flight 3655 from Denver to Detroit when it diverted, and it is parked at gate M40 at Chicago O'Hare while maintenance is performed. The stub does not provide the volume of water that leaked, and the cause of the leak has not been identified.

The players

Frontier Airlines

Frontier Airlines is a low-cost United States carrier operating domestic and international routes out of hubs including Denver.

Chicago O'Hare International Airport

Chicago O'Hare International Airport is one of the busiest airports in the world and a major hub for United Airlines and other carriers.

The details

A traveling plumber on the flight shut off the water, but a significant amount had already leaked into the main cabin before it was stopped. The pilot told air traffic control of the concern over potential electronics damage and requested to land at O'Hare, where permission was granted.

Flight 3655 departed Denver International Airport shortly after 10:15 a.m. Mountain Time on Wednesday, November 11, 2026.
The flight diverted to Chicago O'Hare International Airport after the lavatory leak.
The plane is scheduled to take off again from O'Hare at 3:49 p.m. the same day.

Season Trajectory

Diversions caused by cabin systems faults, rather than engines or weather, are a recurring category of in-flight disruption. This incident follows that pattern, where a plumbing problem forced an unplanned landing and a same-day return to service.

Passengers on a diverted flight may face a long delay before continuing to their destination, so travelers connecting through Chicago O'Hare should allow extra time and check their airline's app for updates. Keeping a backup itinerary and rebooking options handy can reduce the impact of a sudden diversion.

The takeaway

Even a contained plumbing fault can force an emergency diversion, so travelers should keep flexible plans when flying. Building in buffer time for connections is the most practical safeguard against unexpected landings.