This is rare, but not unheard of…
Tail-heavy United Boeing 737-900 tips
On Friday, September 17, 2021, United Airlines operated a 1hr52min flight from Los Angeles, California (LAX), to Lewiston, Idaho (LWS). This charter flight was carrying the USC football team, ahead of the USC vs. Washington State game, which happened over the weekend. The flight was operated by a nine-year-old Boeing 737-900ER with the registration code N78448.
The flight operated without a hitch, until it arrived at its destination. At some point during the disembarkation process, the aircraft’s nose wheel lifted off the ground, and the plane “tipped” backward.
In the picture posted on social media, you can see that bags were being offloaded through the forward right cargo door, and on top of that passengers were being disembarked through air stairs via the forward left door.
There were no injuries to those still onboard the plane, and for that matter the plane didn’t seem to sustain any serious damage, as it flew a couple of days later from Lewiston to Houston.
How can planes “tip” like this?
United Airlines has issued the following statement regarding the incident:
“United flight 2509 flying from Los Angeles, California to Lewiston, Idaho landed without incident. Due to a shift in weight and balance during the offloading process, the tail of the aircraft tipped backward. No injuries were reported among our customers, crew or ground personnel. The return flight was on a different aircraft as originally planned.”
As you can see, United Airlines blames this incident on “a shift in weight and balance.” Of course one has to wonder how something like this could happen, since planes fly around the world every day, and rarely do we see something like this.
There are probably a few things at play here. For one, over time aircraft manufacturers “stretch” planes, and the 737-900 is currently the longest version of the 737 in service. As a result, the plane is also the most prone to something like this happening.
As you might expect, there’s a solution to this. Typically when airlines operate the 737-900, they use a “tail stand” while disembarking passengers. The purpose of the tail stand is to prevent exactly what happened here. The catch is that these devices are generally available at airports, and it’s not a device that’s carried with the plane.
Lewiston is an airport that typically only serves regional jets, so it seems safe to assume that the airport didn’t have any 737 tail stands.
Even without tail stands, it’s not like the plane is actually supposed to “tip” in this way. Clearly the pilots and ground crew didn’t anticipate this, or they would have taken action to prevent it.
While with normal procedures the plane wouldn’t tip, just enough went wrong that it became an issue:
- Luggage is seemingly being removed through the forward cargo door, so maybe a lot of weight had already been removed there
- Passengers disembark front to back, so perhaps passengers weren’t moving forward that quickly, and for that matter maybe the average passenger weight in the back of the plane was higher than usual; it is stated that the players were seated in the front and support staff and coaches were seated in the back, but I’d still think they’d weigh more than your average airline passengers (since there are fewer children, women, etc.)
Without a tail stand, deplaning and unloading a 737-900 sure is a delicate balancing act…
A United Boeing 737-900 tipped on its tail while deplaning passengers after a charter flight from Los Angeles to Lewiston. Ultimately this could have been prevented by using a tail stand, but it’s not surprising one of those wasn’t available at an airport that typically only gets service from regional jets.
Even without a tail stand, these incidents shouldn’t happen. I guess there was just the perfect storm of not enough weight in the front of the plane (in terms of passengers and bags/cargo), and too much weight in the back of the plane.
No one was injured, and it seems the plane wasn’t damaged significantly, so we’re just left with a pretty cool story, and a heck of a picture.
What do you make of this United “tipping” incident?