On your travels over the years, you may have noticed a pole protruding from the tail of certain aircraft that reaches down to the ground. Known as a tail stand, this device is used to stabilize the rear of an aircraft when it is at rest. The stand is placed beneath the tail during loading and unloading to prevent instability. But why?Without it, some aircraft are at risk of tipping longitudinally, as weight shifts during loading and unloading. Let's see why aircraft need tail stands.

How a tail stand works

Tail stands are a fairly straightforward concept. Fixed beneath the tail, they work as a support stanchion to stabilize an aircraft's tail and prevent it from tipping. Some of them are simple poles, while others use a tripod design. They are used while an aircraft is being loaded or unloaded, when the plane is most at risk of tipping.

ATR 72 Tail Stand
A removable tail stand on an ATR-72. Photo: Olivier Cleynen via Wikimedia Commons

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Whether this entails cargo or passengers, the shifting weight distribution on an aircraft can have costly consequences if the tail impacts the ground. Aircraft operators are fully aware of this and follow the appropriate loading and unloading procedures. A tail stand can work as a failsafe that adds an extra layer of security.

It is the responsibility of airlines and airport handlers to determine whether a tail stand is needed. Airlines will call for one if required and often carry their own stand on their planes. Errors in judgment can result in situations like the video below.

Preventing tail sitting

'Tail sitting' is when a plane's tail tips downwards due to a shift in weight, leaving it sitting on the ground. While this might not sound like a big deal, it can cause airlines expensive delays. Additionally, there is the possibility of damage to the tail and even human injury. In a safety-driven industry, these are things to be avoided.

United 737-900ER
United has mandated the use of tail stands on its Boeing 737-900s for six years now. Photo: Getty Images

As Simple Flying reported at the time, a United Boeing 737 tipped onto its tail after landing at Lewiston Airport last year. The aircraft, carrying the USC Trojans college football team, tipped back after ground crew failed to attach a tail stand. According to reports, half the team was still on the aircraft at the moment it tipped.

The incident occurred even after United Airlines introduced its own tail stands for its 737-900 back in 2016 after a series of tail sitting incidents. The carrier stated:

"Due to a shift in weight and balance during the offloading process, the tail of the aircraft tipped backward."

Certain aircraft are more prone

Given the differences in the structural design of the various aircraft types worldwide, some planes are more at risk of tail sitting than others. For example, stretched planes like the Boeing 737-800 and -900 are known to be at increased risk of this phenomenon, forcing airlines to adopt more careful loading and unloading procedures.

Isles of Scilly Skybus De Havilland Twin Otter
The De Havilland DHC-6 Twin Otter requires a tail stand as the cargo door is behind the aircraft's wheels. Photo: Jake Hardiman | Simple Flying

Freighter aircraft are also prone to tail sitting and will use tail stands more frequently than most passenger planes. Operators and ground handlers must be meticulously detailed in their loading and unloading calculations to avoid tail sitting. Certain tail stands are brightly colored to increase visibility.

As seen in the photograph above, small turboprops like the Twin Otter have small tail stands that can stow away within the aircraft's tail itself. However, widebody passenger, cargo, and military transport jets are a different matter. Their tails are supported by vast ladder-like structures which typically feature a tripod base.

One final notable aspect about tail stands is how little they weigh in comparison to the aircraft that they are used to support. According to Hall Industries, the stand used to support Boeing 737NG series aircraft can be as light as 50 lbs (22.7 kg). Compared to a loading rating of 9,000 lbs (4,082 kg), this represents great strength.

Did you know about the use of tail stands? Have you ever experienced a tail sitting incident? Let us know your thoughts and experiences in the comments.

Source: Hall Industries