The Ground Handling Blog

Mototok's blog for Hangar Professionals

Written by Mototok on November 2, 2021 // 1:00 PM

Transversal movement: thinking outside the box

Transversal

We often fall victim to the fallacy that there is only one way of doing something, that all methods of movement have been discovered and summarily implemented. But this is not true; nothing set in stone dictates that machines must move in strictly linear motion. But all of that has changed with the advent of the Mototok StarTug, an aircraft tug that can move in any direction with no longitudinal lag or lead.

What is Transversal Movement?

This is an important question to ask and a distinction to make for the sake of this product. To understand how vitally important this form of movement is, you need to know what the movement pattern is.

According to our friends at Dictionary.com, it is an adjective meaning to lie in a cross direction. For the sake of our study, the purpose of a transversal movement is to move the aircraft in a cross direction, i.e., perpendicular to the standard plane of motion. Of course, this is not suggesting that the StarTug cannot move longitudinally. On the contrary, it is equally adept in longitudinal movements as all our other products. 

What sets the StarTug apart from the rest of our product line, especially our competitors, is the ability to execute complex and standard movement patterns. It shifts seamlessly between movement patterns with no changing inputs required by the operator. There is no need to unload the aircraft or make any changes whatsoever; it pivots on a dime and maneuvers precisely where you want it to go.

The usefulness of transversal movement is not limited to the interior hangar environment, although it is undoubtedly at home inside of a hangar. In this setting, the StarTug can move an entire hangar of aircraft around to optimize space positively. It can place aircraft in the precise location desired with very little or no movement of other aircraft in the hangar. It is as if you can pick up an airplane and set it down exactly where you want it to be.

How Airplanes Are Made to Move

Before we talk further about the benefits of transversal movement, we need to take a step back and look at the design of an airport.

Airports are designed from the ground up to facilitate aircraft's safe and efficient movement through all action stages. This means an airport is made for the start-up to shut down and build around how airplanes move.

Airplanes are designed for linear movement. Everything about an aircraft, particularly jet aircraft that we are geared toward with the StarTug, is made to move forward and do so at high rates of speed. While taxiways and aprons are designed for slow movements, and airplanes can certainly park and taxi at slow speeds, they are made to move fast. The standard tricycle landing gear configuration has proven over many decades and millions of aircraft movements to be the most reliable and stable configuration to balance weight along with the demands of aircraft landing and ground movement.

Since all private and commercial jets are made in this configuration, airports are designed to support them. Therefore, they are designed with long, wide runways with paved shoulders, wide taxiways with shoulders, and very rigid specifications on the turning radius of aircraft.

Ground support equipment has traditionally been designed around the predictable movement patterns of airplanes. Airplanes, mainly commercial airliners at air-carrying airports, move directly from a runway to the taxiway and taxiway to the terminal area.

Accordingly, aircraft tugs have long been made to pull airplanes from one position to another using the familiar airport infrastructure as an engineering guide. It has been accepted in the design and manufacture of aircraft tugs for many years that the only movement pattern can be longitudinal.

Aircraft tugs began as adaptations of agriculture and industrial tractors because these were the most available vehicles at the time that could have weight added to them, possessed adequate traction, and exceptionally low gear ratios necessary for moving heavy airplanes. But as time progressed, airplanes rapidly grew heavier and heavier. Aircraft tugs were no longer modifications of commercially produced tractors, but their form and function never became any more advanced. They were still ultra-heavy, low geared machines attached to a towbar to pull and push the airplanes along linear motions. In other words, they have not changed or adapted very much to modernity.

How Airplanes Move on the Ground

As we have established, airports are made for the efficient movement of airplanes, either arriving or departing. Of course, this is the essential part of what planes do, but it is certainly not the only thing going on at an airport.

Aircraft maintenance, repair, and overhaul (MRO) facilities are most often located on an airport for the expedience of aircraft repair. It is almost always easiest to bring an airplane to the facility and is, of course, a necessity for airframe repairs.

Aircraft tugs are long designed for moving airplanes along the painted yellow lines on taxiways and parking aprons, but once the aircraft is away from that and in the hangar environment, the needs of the towing personnel change dramatically.

Hangars pose a complicated scenario for ground handlers. Given the high cost of hangars and the regulatory difficulty of adding hangars onto existing airports, space is almost always a premium. So the task is to optimize hangar space by essentially putting as many aircraft in there as possible.

The problem with this is how to put them in there. Using a standard tractor and towbar, it is essentially impossible to strategically place the aircraft in a hangar without first removing all of the occupying aircraft. Second, because of the limitations of moving a plane with a tug and towbar.

GSE configuration is designed to move aircraft along established corridors, which they do pretty well but makes them poorly suited for precision jobs. For example, a tug and towbar configuration have two pivot points of movement. This arrangement is adequate for the long fillets of a taxiway turn or a parking spot but is exceedingly poor for the minute adjustments necessary for parking in the close quarters of a hangar.

It can be done with a towbar, but it is intensely inefficient and much more labor-intensive. Why is it more labor-intensive? Because to safely move an aircraft in a hangar when using a tug requires that you have a driver for the tug and at least one spotter to monitor wing tips and the tail, depending on how tight the fit is. Also, it is prudent to keep a brake operator on the airplane if the tow bar detaches.

How the StarTug Changes Everything

Like the full suite of Mototok tugs, the operator is not required to be in the immediate proximity of the unit during operation. The tug operator can walk around to the areas requiring a spotter and often reduce the team size to just one.

Since the StarTug lifts the aircraft entirely off the ground and captures the tires, a brake rider is no longer required. This serves as one of the marquee safety measures of this unit, too. There is always a lag in braking whenever you are coordinating braking movements between team members. The team supervisor orders the tug driver, and there is generally at least a one-second reaction time. The same goes for a brake operator on the jet. A lot can happen in one-to-two seconds. That can easily be the difference between a precise parking job in a crowded hangar and damaging an aircraft by impacting another object.

The StarTug moves in all horizontal directions: forward and backward, lateral, or at any angle, whether forward or reverse. Best of all, if you need to move the aircraft for a longer distance, especially if you need to move it across controlled movement areas (runways and taxiways), the operator can sit in the cockpit and operate the StarTug. In addition, since the extractable nose gear arm is adjustable, the StarTug can be used on a wide variety of aircraft, including potentially large, wheeled helicopters.

Conclusion

Just because we have been doing things the same way for years does not mean it is the best way to keep doing something. Aircraft ground movement patterns have remained unchanged for decades, and they are long overdue for technological advances. Why settle for antiquated methods and technology that are eating up your time and not allowing you to maximize your space? If you are ready to get the most out of your hangar and your limited personnel, contact Mototok today, and we will give you the upper hand!

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Comments

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