Although rare, it is not uncommon.
United Boeing 737-900 Tips for Tail-Heavy Customers
United Airlines flew a 1hr52min flight on Friday, September 17, 2021 from Los Angeles (CA) to Lewiston (Idaho). The charter flight was carrying the USC Football team ahead of the USC-Washington State game that took place over the weekend. A nine-year-old Boeing 737900ER registered under N78448 was the pilot of this flight.
The flight went smoothly until it reached its destination. The aircraft's nose wheel lifted off of the ground during disembarkation, and the plane tipped backwards.
The picture was posted to social media. You can see that bags were being loaded through the forward cargo door. On top of that, passengers were being taken through air stairs via forward left door.
https://twitter.com/DSJR1/status/1439033962853109765
The plane flew from Lewiston to Houston a few days later with no injuries.
How is it possible for planes to tip like this?
United Airlines issued the following statement in response to the incident:
United flight 2509, which flew from Los Angeles, California, to Lewiston Idaho, landed safely. The aircraft's tail tipped backwards due to an imbalance in weight and weight during offloading. Our customers, crew and ground personnel were not injured. The flight back was not on the same aircraft that was originally planned.
United Airlines attributes the incident to a shift of weight and balance. We rarely see such an event on planes flying around the globe every day.
There may be a few factors at play. One, aircraft manufacturers tend to stretch out planes over time. The 737-900, currently in service, is the longest version of the 737. This makes the plane more susceptible to such an event.
There is a way around this, as you would expect. Whenever airlines fly the 737-900, they typically use a tailstand to disembark passengers. This is exactly why the tail stand exists. These devices can be found at airports and are not meant to be carried onboard.
#AvGeekQuiz: Which type of aircraft requires a tailstand to prevent tipping? pic.twitter.com/4MCqlWrmKQ AirlineGeeks (@AirlineGeeks) May 14, 2017
Lewiston is an airfield that serves regional jets so it seems safe that there weren't any 737 tail stands at the airport.
Even without tail stands it doesn't seem like the plane is supposed to tip in that way. Evidently, the ground crew and pilots didn't see this coming. They would have taken steps to stop it.
Although the plane would not tip under normal circumstances, it was a problem when something went wrong.
The forward cargo door appears to be open and luggage is being taken out. This could indicate that a lot of weight has been removed.
The passengers disembark from the plane front to back. It is possible that passengers were not moving as quickly as usual. Although it was stated that the players were in the front, while the support staff and coaches were in the back, I still believe they would weigh more than average airline passengers (since there are less children and women).
Deplaning and unloading a Boeing 737-900 is difficult without a tail stand.
Bottom line
After a charter flight between Los Angeles and Lewiston, a United Boeing 737-990 tipped its tail as it was deplaning passengers. This could have been avoided if the tail stand had been available, but it's not surprising that one wasn't available at an airport that receives service only from regional jets.
These incidents should not happen even if there is a tailstand. It was a perfect storm, with too much weight at the back and not enough in front (in terms passengers and bags/cargo).
There were no injuries and the plane was not damaged in any significant way. We are left with a cool story and a great picture.
What do you think of the United tipping incident.
