Aircraft tugs: towbar, towbarless, Taxibot and maintenance tows

An Airbus A380 weighs hundreds of tonnes at departure – and yet at the gate it is pushed back by a vehicle barely taller than a compact car. Aircraft tugs are among the most inconspicuous and at the same time most important pieces of equipment on the apron. Without them there would be no pushback, no repositioning between two rotations and no way into the hangar. This guide explains the two basic designs, with and without a towbar, shows what sets the Taxibot apart from ordinary tugs, and why maintenance tows are often the most exciting movements of the evening for spotters.

Aircraft tugs: the short answer

An aircraft tug moves an aircraft on the ground without its engines providing thrust. It pushes the aircraft backward out of the parking position, pulls it across the apron or maneuvers it into a hangar to the millimeter. There are two basic designs: tugs connected to the nose gear by a towbar, and towbarless tugs that grip and lift the nose wheel. There are also special forms such as main-wheel tugs for smaller aircraft, remote-controlled small tugs for hangars and the semi-automatic Taxibot, which takes aircraft to the runway.

The range is enormous. For light aircraft, hand-guided mini tugs with a few kilowatts of power are enough. For large passenger jets, tugs weighing around 70 tonnes are used. The weight is not an end in itself: a tug can only put as much force on the asphalt as its tires have grip.

Design 1: tugs with a towbar

The classic way is the towbar. It connects the tug’s tow hitch to a fitting on the nose gear. All pulling, pushing and steering forces run through this bar. The tug itself is a heavy, low vehicle with high pulling force, and the aircraft follows it like a trailer – except that during pushback it is pushed backward and the driver has to steer the aircraft almost upside down, so to speak.

The most important component of the bar is inconspicuous: the shear pins. These breaking points give way when forces get too large, for example with too tight a steering angle or a jerky start. Better a cheap pin breaks than an aircraft’s nose gear. The flip side: if the connection breaks, the aircraft keeps rolling unbraked. That is why a brake operator usually sits in the cockpit during towbar tows – a pilot or a technician trained for the job, who can brake at any time.

How important this is was shown by an incident in Santiago de Chile in March 2016: a Boeing 747-400 came loose from the bar while being towed for fueling, nobody was at the brakes in the cockpit, and the aircraft swung into a vehicle. People were injured, and two engines were damaged.

Towbars are mostly type-specific: nose gear differs in height, fitting and permitted forces. A handler with mixed traffic therefore needs a stock of bars for the A320 family, the Boeing 777-300ER or the Airbus A380 – and space to store them. You often see the bars lying at the edges of apron positions.

Design 2: towbarless tugs

Towbarless tugs do without the intermediate piece. At the rear they have a kind of fork or cradle that they drive up to the nose wheel with. Flaps or gripper arms close around the tires, then a hydraulic system lifts the nose wheel slightly. The aircraft sits with its nose “piggyback” on the tug.

This trick brings several advantages at once:

• More traction with less weight: Part of the aircraft’s weight presses on the tug’s wheels. It can therefore be built lighter than a towbar tug of the same class.
• No fleet of towbars: Depending on the model, one cradle fits many aircraft types, and the logistics of dozens of towbars disappear.
• No brake operator strictly required: Because no bar can break, the tug controls the aircraft directly. Whether someone nevertheless sits in the cockpit for a particular operation is up to the airline and the handler.
• Higher speed: For longer tows, according to common figures, up to about 30 km/h is possible – a noticeable difference on long routes between hangar and terminal.

Well-known examples of this design are the AST models from the German manufacturer Goldhofer. The downsides: towbarless tugs are more complex and more expensive, and the forces they may introduce into the nose gear are strictly limited by the aircraft manufacturers. The tugs therefore typically monitor this with their own sensors.

Criterion	With towbar	Towbarless
Connection	Bar between tug and nose gear	Tug grips and lifts the nose wheel
Traction	solely from the tug’s own weight	own weight plus a share of the aircraft’s weight
Brake operator in the cockpit	usually required	not strictly required, depending on procedure
Fleet mix	matching bar needed for each type	one cradle for many types
Cost and technology	robust, simpler	more complex, more elaborate
Speed when towing	rather low	up to about 30 km/h

Special forms: main-wheel tugs and small tugs

Not every aircraft needs a 70-tonne vehicle. For smaller aircraft there are main-wheel tugs, which grip one wheel of the main gear with rollers. One example is the PowerPush from the manufacturer Schopf. Here the pilot steers the nose wheel and operates the parking brake, while a person on the ground guides the tug and talks to the cockpit.

In hangars and general aviation, remote-controlled small tugs are also common, such as the Schleppmaxxe from Aero Friedrichshafen. The operator walks alongside the aircraft and so has the wingtips and the tail in view himself – a big advantage in a full hangar.

The military goes its own way: tugs for aircraft carriers, caverns and shelters are particularly compact, have small turning circles, and some also supply smaller jets without an auxiliary power unit with onboard electrical power.

Pushback: everyday use at the gate

A tug’s most frequent job is pushback. At gates with a jet bridge, the aircraft stands nose-in toward the terminal and cannot taxi backward under its own power. The tug pushes it out onto the taxilane, turns it toward the taxiway and disconnects. During pushback, depending on the procedure, the engines may already be started; a mechanic or ramp agent keeps contact with the cockpit via headset or walks alongside the aircraft as a walkout assistant.

One detail that spotters at the fence rarely see: before the tow, the aircraft’s nose wheel steering is usually hydraulically disconnected, so that the tug’s steering forces don’t work against the steering system. Only after disconnecting is it released again, and the ground crew shows the cockpit the corresponding pin or flag. How clearance, communication and procedure work in detail is explained in the article Pushback explained. Where pushback fits into the overall sequence of a turnaround is shown in the guide to the turnaround.

If you listen in on the radio, you know the phraseology that goes with it. Which unit is responsible for what is sorted out in the article Delivery, Ground, Tower, Approach; the job behind clearance on the apron is described in Apron control.

The Taxibot: towing to the runway

An ordinary tug disconnects after pushback, after which the aircraft taxis to the runway on its engines. This is exactly where the Taxibot comes in. The semi-automatic, towbarless tug was developed by the Lahav division of Israel Aerospace Industries (IAI) and has a diesel-electric hybrid drive. After pushback it stays on the aircraft and pulls it on along the taxiways to just before the takeoff position.

The special thing: it is steered from the cockpit. The pilots operate steering and brakes as in normal taxiing. Sensors in the nose wheel cradle register the steering movements and translate them into movements of the tug. After disconnecting, the Taxibot drives back along the taxiways. The main engines are started only shortly before takeoff.

The milestones of its development:

• 2014: LEOS, a subsidiary of Lufthansa Technik, tests the version for narrowbody jets such as the A320 and Boeing 737 at Frankfurt Airport. After certification tests are completed, the Taxibot is approved for towing operations in November 2014.
• November 25, 2014: A Lufthansa flight from Frankfurt to Nuremberg is the first commercial flight taken to the runway by Taxibot with passengers on board. Regular service in Frankfurt follows from February 2015.
• 2016 to 2018: Certification tests of a widebody version run for widebody aircraft such as the A380 and 747.
• October 2019: Air India is the first airline to use the Taxibot regularly, on flights from Terminal 3 of Delhi Airport.

The promise: less fuel burn, less noise and exhaust on the apron, parking positions freed up faster. Manufacturers and operators have cited considerable savings potential for this; however, reliable, independently measured figures for continuous operation are hardly publicly available. How widespread the Taxibot is at individual airports in October 2026 cannot be reliably quantified from public sources – what is certain is that it has remained a niche solution and the vast majority of jets still taxi to the runway under their own power.

Maintenance tows: the movements in the evening

Besides pushback and the Taxibot, there is a third major category: the maintenance or positioning tow. Aircraft are towed when they move from a remote stand to a gate, are parked overnight, need to go to the wash bay or to de-icing – and above all when they go into the hangar. For one tow, it isn’t worth starting engines and rostering a cockpit crew. Instead, technicians sit on board and operate the brakes, radio and lighting.

Such tows often take place in the evening and at night, when there is less traffic on the apron. At large maintenance sites such as Hamburg Airport, where Lufthansa Technik has its headquarters, or in Frankfurt, you then see aircraft gliding along the taxiways without engine noise – sometimes with covered sensors, open flaps or even without engines. What happens inside the halls is described in the article Aircraft maintenance from A-check to C-check, and an overview of shipyards worth visiting for spotters can be found under Maintenance companies and shipyards in Europe.

What you can recognize at the fence as a spotter

With a little practice, you can read from the movement what is going on:

• Backward out of the position, short distance, engines start: classic pushback.
• Long distance along taxiways, no engines running, beacon light on the tug: positioning or maintenance tow. Often a follow-me vehicle drives ahead.
• Tug hangs directly under the nose without a bar: towbarless.
• Long bar visible between tug and nose wheel: towbar tow, usually with a brake operator in the cockpit.
• Aircraft is towed to the holding point, tug drives back alone: Taxibot operation.

For taxi movements it helps to know the names of the routes – that is explained in Taxiways, holding points and signs. Where the aircraft park and why some positions can only be reached by tow is covered in the guide to Gates, jet bridges and remote stands. Where you can generally stand best in Frankfurt is shown in the Frankfurt spotting guide; you have a good view of taxi traffic there from the Zeppelinheim viewing platform, and in Hamburg from the Affenfelsen.

You get really close on apron tours. How such tours work is covered in Airport tours and apron tours and Airside spotting. The daily work of the people who drive the tugs is described in Working on the apron.

What to watch for

• Keep terms apart: Pushback is a procedure; tugs and the Taxibot are vehicles. Not every tow is a pushback, and not every towbarless tug is a Taxibot.
• No judgment from a distance: Whether a brake operator sits in the cockpit or exactly which tug is used is decided individually by airline, handler and airport.
• Note the times: Hangar tows and repositionings often follow fixed patterns in the daily routine. If you know them, you can plan more precisely.
• Mind the light: Many tows run at dusk or at night. Fast lenses and a steady hand matter more here than long focal length.

Conclusion

Aircraft tugs are the airport’s quiet workhorses. Towbar tugs are robust and universal, but require matching bars and a brake operator in the cockpit. Towbarless tugs lift the nose wheel, gain traction and speed as a result and save the towbar logistics. The Taxibot has shown that aircraft can also be towed all the way to the runway, but it has remained a niche. For spotters, the evening maintenance tows are especially interesting: they put aircraft in front of your lens that you never see like this in normal flight operations.