Some of you have sent me stories about the emergency evacuation ramp that accidentally fell a United Airlines 767-300 before landing at Chicago O’Hare Airport on Monday afternoon. This will be a more technical article, but let’s first understand how something like this happens. Did someone actually open the emergency exit door? For now, it’s a mystery.
On July 17, 2023, UA12, United Airlines Flight 767-300 flying from Zurich (ZRH) to Chicago (ORD), lost its emergency evacuation slide while approaching Chicago O’Hare International Airport. The pilot and flight attendants on board did not appear to be aware that the aircraft was lost, as maintenance personnel noticed it upon arrival.
But residents of the 4700 block of North Chester in Chicago must have noticed something: their day was suddenly interrupted by a loud roar. The landslide hit Patrick DeWitt’s roof, damaging the roof before sliding down and into his backyard.
A few hours later, United Airlines workers in military uniform began to assemble it. A spokesperson for United shared:
”We contacted the FAA immediately and are working with our teams to better understand the circumstances of this case.”
So how did it happen in the first place? The answer may lie in the unique way that the exit rails on the 767 wings are stored on the outside of the aircraft rather than inside the doors.
The Boeing 767 has airstairs on the inside rear of each wing to facilitate the evacuation of passengers via exits above the wing in the event of an emergency. The slide deployment is initiated by opening the exit hatch from the inside. Sunroof opening motion activates an electrical switch that simultaneously (1) activates a relay to ground any position command sent to the hydraulic spoiler power controller main actuator and (2) activates the spoiler lock actuator by turning the inner spoiler. bottom position. After a two second delay (from actuation of the spoiler actuator), the latch release actuator is activated. The latch open actuator unlocks the escape hatch door and actuates the door open actuator located inside the escape hatch. Sliding sunroof with sliding sealing plate assembly for evacuation rotates outward by means of a drive. When the door is opened, the mechanical connection to the high pressure bottle causes the gas to be released to inflate the slide.
But notice the bold type. When cocked, opening the outlet above the wing causes the bolt to deploy. So what’s going on here? If so, is the cockpit really out of the loop at all?
Or is it possible that the shutter somehow fell (because it didn’t open) and the exit door didn’t actually open?
When a similar incident happened on a Delta 767 in 2019, it turned out that the airflow broke the shutter, but in this case the shutter opened.
On Monday, a United Airlines Boeing 767 crashed into an emergency exit ramp while approaching ORD. While there were reports of property damage, there were no reports of injuries.
We will be following this story for updates from the FAA and United to better explain how this happened. So far, what are the theories? Can passengers partially open the side exit doors?
Matthew is an avid traveler who calls Los Angeles his home. Every year he travels over 200,000 miles by air and visits over 135 countries. Working in the aviation industry and as a travel consultant, Matthew has been featured in major media outlets around the world and uses his Live and Let’s Fly blog to share the latest aviation industry news, frequent flyer program reviews and in-depth reports on his activities. . trip around the world .
The sentence in bold in Canada’s report could be the answer: “A sunroof opening motion actuates an electrical switch and simultaneously (1) actuates a relay to ground any position command sent to the hydraulic spoiler power controller main drive, and (2) ) Activate the spoiler lock actuator to rotate the inner spoiler to the lower position. After a two second delay (spoiler actuation) the latch release actuates.
Assuming some short circuit or other electrical fault triggers the sequence, the sequence activates the ramp shutter in the same way a hatch opens. Perhaps the pilot received some kind of error or spoiler warning and (if received) decided to continue landing. Apparently, on the ground it was obvious that the bolt group was deployed, perhaps even the passengers on the wing observed it.
Was Delta Airlines involved in a similar incident in 2019? If Delta exists, then United should also exist. If there is no Delta, then Unulated should not be either.
What does the best CEO in the industry have to say about running the best airline in the world with the best fleet, network, food and drink? He usually can’t keep his mouth shut!
Don A – Exactly. If he had just been STFU and run the airline, it could have done better. Obviously he is a very smart guy.
I’m nervous about flying with United… I haven’t flown with them in a long time without delay due to a technical issue that I found out about later. I have no doubt that they are doing the necessary scheduled maintenance, but for some reason my United planes are constantly breaking down. Which does not inspire confidence in their charts. It also made me think about security in a way that I’m not used to.
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Post time: Aug-09-2023