Flights divert for all kinds of reasons, though this has to be one of the more unusual ones, as reported by The Aviation Herald.
United Boeing 737 cockpit window opens after takeoff
This incident happened on Tuesday, April 18, 2023, and involves United Airlines flight UA1274 from Hartford (BDL) to Washington (IAD). The flight was operated by a nearly nine-year-old Boeing 737-900 with the registration code N66825, and was carrying 178 people on board.
The early morning flight was scheduled to depart at 6:00AM and land at 7:23AM. The flight took off more or less as scheduled from runway 24, at 6:11AM, though it didn’t make it very far. The pilots leveled off at 4,000 feet and then declared an emergency, reporting that a window in the cockpit had popped open after takeoff.
You can hear the air traffic control audio from the incident below. As you can hear, there’s quite a bit of background noise with the cockpit window open.
The aircraft safely landed back in Hartford 18 minutes after departing, at 6:29AM.
Interestingly this wasn’t just a case of the plane returning to the airport, the cockpit window being closed, and the flight departing once again. Rather the aircraft remained on the ground for around 12 hours, only again departing at around 6:30PM that evening, operating a flight to Chicago.
It wasn’t reported what exactly caused this incident. Did the pilots just open the window while on the ground to get some fresh air and forgot to close it properly, or what exactly happened? I remember back in the day when I was taking flight lessons, my flight instructor would regularly open the window while flying to get some fresh air, but that was a Cessna 172, and not a Boeing 737. 😉
What happened to the passengers?
With United taking this Boeing 737-900 out of service for a while, what happened to this flight? Well, United sent a “rescue” Boeing 737 MAX 9 to Hartford from Washington. The jet only arrived in Hartford shortly after 11AM. Passengers were then boarded, and the flight ended up departing at 12:21PM and arriving in Washington at 1:16PM, after a 55 minute flight.
In the end, the flight arrived in Washington just under six hours after the scheduled arrival time. That’s pretty rough for a flight of just 325 miles!
A United Airlines Boeing 737 had to return to Hartford shortly after takeoff, after a cockpit window popped open on departure. The plane landed safely in Hartford under 20 minutes after departing. What wasn’t as quick was the replacement flight, as passengers had to wait around six hours until a replacement aircraft was sent.
What do you make of this United Boeing 737 incident? Any theories as to what could lead to a cockpit window popping open in this way?
Perhaps the window was opened while the plane was undergoing cleaning & refueling, and a small stone or similar debris got stuck in the latching mechanism, which prevented the window from latching when it was closed? If this was not noticed, maybe just the air resistance was enough to shove in the window? Love the blog, by the way!
I don’t know what could have cause the window situation, but I am very glad that the pilots immediately took the plane back. If they considered it a hazard and unsafe, then it definitely was. Thank God it didn’t lead to something tragic. I am grateful for the miracle of being able to fly, but it can be tiring, and at a times uncomfortable. It’s ok!
This is ironic! I was on a flight to ATL from SFO and we were removed from the plabe due to the cockpit window! I was so shocked that I posted the pic on my FB feed! It appears their maintenance is terrible!
On hot days if we had to spend a lot of time in the pattern, we would routinely open a cockpit window on our KC-135 (707). Was a bit windy but it cooled the non-air conditioned airplane off fairly well. It was easy enough to shut if we needed to. I'd be surprised if the 737 doesn't use the same style window.
When you don't close the window, it comes open. They are plug style windows. This is why you haven't heard of this happening before. It didn't blow out of the A/C, it came open to the inside.
I think the more surprising part of this otherwise useless post is finding out United flies out of Hartford.
Interestingly enough, Boeing has produced a training video covering this exact topic: the 737 sliding cockpit window suddenly opening during takeoff. They emphasize that it’s not an emergency, but a substantial distraction that can be readily dealt with. The window can be easily closed while in flight. However, there’s a catch to it (literally - a release catch that allows the window to be slid forward back to its closed and locked position), and if...
Interestingly enough, Boeing has produced a training video covering this exact topic: the 737 sliding cockpit window suddenly opening during takeoff. They emphasize that it’s not an emergency, but a substantial distraction that can be readily dealt with. The window can be easily closed while in flight. However, there’s a catch to it (literally - a release catch that allows the window to be slid forward back to its closed and locked position), and if you’ve never seen or operated it before, it can be fiddly. The pilots must have either not been familiar with the training or the window operation, or the event was compounded by some other factor that led the crew to decide the safest course of action was to return to the field.
I’ve been following the blog for 10 years. Have you written about your flight lessons?
You mean lessons on how to get into the mile high club?
Closely looking at the interior handle position should be indicative if it's not in it's normal position. Has any maintenance been done to the window recently, say to cure a whistling sound during pressurization of the a/c? A Window is typically rigged so the linkage goes over center to prevent outside air pressure from blowing the window open even if a locking latch on the inside handle is depressed as part of the sequence to...
Closely looking at the interior handle position should be indicative if it's not in it's normal position. Has any maintenance been done to the window recently, say to cure a whistling sound during pressurization of the a/c? A Window is typically rigged so the linkage goes over center to prevent outside air pressure from blowing the window open even if a locking latch on the inside handle is depressed as part of the sequence to manually open the window by various personnel.
Even if not "latched" closed, pressurization would prevent the window from opening, it is designed to move inward first, then slide aft. If that window was in the hole it's not "popping open"
The 737 pressurizes to no more than 0.125 PSId during takeoff, which is not very much, to allow for exits to be opened in the event of a rejected takeoff and the airplane subsequently failing to depressurize. The airflow load on the exterior of a partially-unlatched sliding window is sufficient to overcome that low pressurization differential and push the window inwards.
Yes, also the sliding window track is designed with a pitch to allow the window to fully roll open with only gravity once the lock clears the cam.
I’ve seen some poorly rigged windows which can be a frustrating task.
When this happened before the wrong bolts were used to secure the window. First thing to check is the maintenance log.
First item in the flow and also a checklist item. Someone may be getting some extra training.
No windows "Pop" open. The side window slides back on a substantial track. I suspect windshield cleaners(who lean out this window to clean) did not properly latch it....
It reminded me a little of the BA5390. Just the open cockpit window part. Luckily, the pilot was not sucked partially out of the window, where he remained until the jet landed. BTW - that pilot returned to flying just a few months later and stayed with BA for over 10 years, then Easyjet.