This incident happened on Monday, July 17, 2023, and involves United Airlines flight UA12 from Zurich (ZRH) to Chicago (ORD). The flight was operated by a 25-year-old Boeing 767-300 with the registration code N666UA (yes, of course the registration code had to be “666”).
The 9hr22min flight was routine until close to landing. While the aircraft was on final approach to Chicago O’Hare’s runway 28C, an evacuation slide separated from the aircraft and landed in the backyard of a house underneath the approach path, around 2.5 miles from the end of the runway.
Thank goodness there were no injuries. Below you can faintly see security camera footage of the slide falling.
The crew didn’t even realize this happened
How was the discovery made that a United Boeing 767 lost its emergency slide? It wasn’t the pilots. Rather, once the plane landed in Chicago, maintenance workers noticed the missing slide.
Separately, residents inside the house where the slide landed heard something when this incident happened. They went outside, and then found the slide in their backyard. They dragged it to the front of their home, where it was turned over to police.
How is it possible that the pilots didn’t notice that they lost one of the emergency slides during the final descent? Well, according to some comments over at The Aviation Herald, on the 767, the overwing escape slides are stored in the main part of the fuselage, and not in the doors, as you’d find at other exits. As a result, there is no EICAS (Engine Indicating and Crew Alerting System) associated with this, which would alert the pilots.
Below you can see what the deployment of this particular slide is like. This is supposed to be automatic when the overwing exit opens while it’s armed, but there’s no indication that there was any attempt to open the exit. Perhaps there was some sensor malfunction, or something.