Remote towing: the future?

posted on 26th June 2018

Châteauroux airport recently played host to a demonstration of TaxiBot, the innovative new pilot-controllable tractor

TaxiBot, a new towbarless tractor that can be remotely controlled by an aircraft’s pilot while he remains on the flight-deck using the aircraft’s own control systems, was demonstrated to journalists and other interested spectators at Châteauroux airport, not far from Paris, in November and Airside was there to see it.

The tractor, the result of a collaborative programme involving many different companies, has already undergone initial testing with Lufthansa and the recent demonstration was a confident exhibition of its capabilities.

TaxiBot allows an aircraft to be towed without the latter having t   o use engine power; not unusual in itself, but what is different about this vehicle is that it is controlled by the pilot from the flight-deck and incorporates technology that keeps the stress loads on the aircraft’s nose landing gear (NLG) within acceptable limits because the aircraft’s own steering and braking mechanisms – not the tractor’s – are employed.

The aircraft’s nose wheel is connected to a rotary table on the TaxiBot and the vehicle is then manoeuvred by the pilot, using the aircraft’s controls, just as if the plane were taxiing under its own engine power. In this Pilot Control Mode (PCM), the pilot uses the tiller to steer the aircraft and aircraft’s own brakes to decelerate the machine if required; this minimises the stresses and strains on the NLG that would be sustained through tractor braking. The aircraft’s speed is automatically increased to a set, desired level for the airport environment when the pilot is not braking.

No new sensors or instrumentation are needed, and there is indeed minimal change required to the aircraft or airport infrastructure and operating procedures.

In operational use, a TaxiBot would remain in the Driver Control Mode (DCM) on pushback from the stand, when the pilot has very limited visibility for careful manoeuvring. Control would soon be handed over to the pilot and the aircraft would continue on its way, pulled by TaxiBot under his control, until the end of the taxi.  The driver would remain in the vehicle in case of emergencies and so that, once the pilot is in the required position and has called for TaxiBot to be disengaged, the driver could then move the vehicle on to its next task. Meanwhile, the aircraft would start its engines for warm-up and undertake checks for take-off, before moving onto the runway under engine power.

A similar procedure in reverse would be employed after landing and during taxiing – or ‘TaxiBoting’ as it is called when using the tractor in PCM – to the area of the stand.

The benefits of the system over regular towbarless tractors are many, consider its designers, Israel Aerospace Industries (IAI). IAI points to reduced fuel consumption with taxiing aircraft not requiring running engines, and, as a further benefit of that, reduced CO2 emissions; less noise pollution; a decreased threat of engine FOD (foreign object damage); minimal costs for the airport or for any aircraft changes; as well as guaranteed efficient and safe taxiing.

During snowy and icy conditions, the fact that a tractor is used also offers greater stability and less danger of skidding than if the aircraft taxis under its own power and without a tractor.


IAI has been the lead agency on the TaxiBot programme, originating the concept in 2006 and driving the project to this point. It is by no means the only enterprise involved, however, the TaxiBot initiative currently taking in more than half a dozen different companies from numerous countries.

The first of these is Airbus, the Toulouse-based consortium that has played an active role in supporting the TaxiBot initiative. As Frederic Pochet, vice president for business development and international cooperation at Airbus, explains, the company is active in many different programmes not directly involving aircraft but that nevertheless help to promote a successful aviation industry.

Moreover, it is happy to help its customer carriers to improve efficiencies wherever it can, he adds.

It was an A320 – formerly operated by British Airways and already stripped of its engines – that was used in the recent TaxiBot demonstration. Airbus and IAI are said to be in the final stages of creating a joint venture to push the TaxiBot programme forward further.

TLD also joined the project in its early stages and has been responsible for building the prototype TaxiBot that demonstrated its capabilities at Châteauroux. The globally active GSE supplier will also be building three TaxiBots expected to be shipped to Frankfurt for the ‘beta testing’ phase.

If all goes to plan, these vehicles will be used for the first time in active aircraft operations by Lufthansa at its home hub of Frankfurt-Main International airport in summer next year, pulling B737s of the German flag-carrier. If that period of operational testing passes off successfully, and if sufficient orders for TaxiBot are won, TLD will begin series production of the vehicle – possibly as early as 2014 – at an 8,000 square metre facility additional to its existing manufacturing plant in the Tours region not far from Châteauroux. This facility would, says Antoine Maguin, TLD Group chief operating officer, be scaleable, with the capacity to expand by a factor of something like three times its original size in short order should production rates require it.

Lufthansa LEOS, the handler and GSE specialist that is a 100 percent subsidiary of Lufthansa Technik, forms another key part of the TaxiBot collaboration. It was quickly persuaded of the value of the robotic vehicle, enthuses Gerhard Baumgarten, director sales and marketing for Lufthansa LEOS, and came on board as long ago as 2007.

Also amongst the initiative’s partners are Siemens, responsible for the electric drive system that sees two diesel engines provide power to electric generators that in turn drive the tractor’s wheels, and Ricardo, which is responsible for the vehicle control logic and software.

Another major player in the aviation industry airside in Châteauroux on the day of the demonstration was an important potential customer of TaxiBot, Swissport – one of the world’s biggest handlers. Pete Speck, vice president, head of corporate supply and GSE maintenance management, is a big believer in the project. He says that Swissport has “seen a lot of data and it would appear to fit well within our network”.

And John Batten, Swissport’s executive vice president, global cargo, adds that whatever allows Swissport to better serve its customer airlines, is good news for the handler.


The demonstration in France was just the latest phase of a programme that has been going for some years. Originally launched as a project by IAI in 2006, a demonstrator – based on a tractor provided free of charge by TLD, along with a whole load of spare parts – proved the concept during testing in very wintry conditions at Frankfurt-Main airport in December 2010.

A prototype was then built and it was this machine that was employed during the recent display at Châteauroux. Later that week, IAI and its partners were due to host numerous airline representatives – including test pilots who would be able to try their hands at TaxiBoting in PCM. Carriers expected to participate included United, FedEx, Qatar Airways, Lufthansa, China Eastern and China Southern, Air France-KLM and British Airways.

Operational testing with the narrowbody TaxiBot is planned for the summer of next year, while certification is to be gained as quickly as possible – the process is already under way for the narrowbody version and certification of the larger vehicle is expected to begin sometime in 2014; the first TaxiBots are expected to reach the market before the end of 2013, according to IAI.

Cost and benefits – the real issues

The two different types of TaxiBot are expected to consist of an eight-wheel version for handling narrowbody aircraft and a 12-wheeler for widebodied aircraft of B767 or A330 size right up to the superjumbo A380. The first of these is expected to have a unit cost of approximately US$1.5 million, the latter version roughly $3 million.

Thus, while Batten is clear that, for Swissport, “It’s all about collaboration with the airline,” he also cautions that if TaxiBot is to cost so much more than its standard tractor equivalent, there must be efficiencies to gain that are more than sufficient to offset this cost.

Nevertheless, given the many benefits that the system offers an operator, IAI believes that any airline purchasing a TaxiBot tractor will obtain a return on investment within little more than a year; for those carriers opting to lease, their RoI may take a little longer, of course.

Either way, IAI believes the case for a carrier opting for the system is “most compelling”, especially when used at congested hub airports where taxi times are likely to be lengthy and where aircraft can be held in waiting areas prior to take-off, just in order to clear a stand for an incoming plane.

Certainly, for the TLD Group and for COO Antoine Maguin, TLD has put its money where its mouth is. TaxiBot currently represents the company’s single biggest investment in R&D, Maguin confirms. “I am incredibly confident”, he says, noting that “lots of millions of dollars” have already been spent by the company on the initiative, while between 15 and 20 TLD employees are right now solely devoted to the success of TaxiBot.

It combines some of the standard systems and characteristics of other towbarless tractors with the aircraft-like systems required for semi-robotic, remote-controlled application, together with the large amount of redundancy of parts and high mission success rate that an aircraft must achieve, Manguin points out, and that sort of technology requires extensive funding.

Of course, the large amount of finance already devoted to the project by TLD doesn’t guarantee success and movement from the confirmed low rate of initial production of the initial three TaxiBot machines destined for operational testing in Frankfurt does not guarantee that all-important move to series production.

But let Ran Braier, TaxiBot’s program director, have the last word. “This is an amazing programme,” he enthuses. “The atmosphere and the dedication of all involved have been amazing.”