INTRO
Amidst the Covid-19 pandemic, the aviation industry is facing plenty of extreme difficulties to operate effectively and find out strategy recovery in the following years. Besides that, the current impact of global fleets in airport ground operations is becoming one of the main priorities, in particular, the taxiing of aircraft is emitted in a large amount of exhaust fume. In fact, aircraft are not designed to be operated for ground operation. There are many global companies launching feasible solutions in order to take into accounts this problem. As a part of end-users at Blagnac airport, we are dealing with four main contractors in the electric taxing market in which they provide different solutions of using towing tractors to lead aircraft in the airport without using aircraft engines.
The first company is known as Wheeltug who is the furthest in process of certification. Their solution is based on an electric engine powered by APU integrated on the front wheel with a key aim to generate powered motor to control aircraft movement on the ground without the main engines running. Motors housed in main landing gear wheel is purposed to control requirement. They allow aircraft to manoeuvre in hard weather condition and difficult ground. In addition, their system surely guarantees the power of taxing between destination. Saving fuel cost and easy maintenance for the fleet operators are seen as two considerable strength of them.
Secondly, EGTS from Honeywell, the company is well-known as complementary capabilities in electric power product and system integration. Their solutions are already demonstrated in Airbus A320. Basically, their operating system is similar to Wheeltug, except for the commitment of a better performance by minimizing consumed fuel. Their target segments concentrate on hub congestion with the average taxi time of about 20 minutes. Disadvantage and main construction problem of Honeywell solution are the problems of heat. Because the system has to be collocated near to brakes on main landing gear what brings several issues as lower efficiency of electric engines and high risk of overheating during rejected take-off. The disadvantages could be stemmed from the complicated problem of integrating system include (monitor system and motor gear) by modifying aircraft structure.
The third competitor is IAI company, the concept owner programme leader in Taxibot, they offer a vast portfolio producing air and missile defence, unmanned aerial systems (UAS), ground robotics, precision-guided weapons, and loitering munitions. With taxi bot, they provide the ground operator with a classic towing car powered by diesel, or a future version by an electric engine. Interestingly, Taxibot does not require drivers, instead of manoeuvring from the cockpit of the pilot and only short e-training is required for the pilots. They do not have any modification in the aeroplane system, no added weight to the aeroplane and no reduction to the cargo space.
Link: https://www.iai.co.il/
Lastly, Smart Airport Systems (SAS), an Alvest Group Company, strives for excellence in its mission to provide sustainable solutions for aviation. They commit to bringing up to 85% reduction of CO2 and other noxious emission and 65% of noise reduction. They have several close partnerships with many giant corporation such as Airbus, Luffthansa LEO, Boeing and even include IAI.
TAXI BOT PRINCIPLE ?
As an above-mention function, Taxibot is towing tractor with special equipment for attaching front wheel of the aircraft. The system is designed in such a way that it allows the tractor to slightly lift up the front wheel and lock it up in position, but with the possibility to control front wheel from the cockpit allowing the pilot to control the system.
When the aircraft is secured in position on Taxibot, control information is handed from tractor driver to a pilot in the cabin. The pilot will control the taxiing in the same way as if he would taxi via engines. Front-wheel, lifted up from the ground, may steer left or right, this steering is captured by sensors and transmitted to tractor control and Taxibot steers same as the aircraft would. In the same way is solved braking, when the pilot uses brakes, brake action on the front wheel is captured by the sensor and Taxibot stops. In fact, the system did not capture the braking action on the front wheel, because the majority of aircraft didn’t use front-wheel brakes, but the system detects higher drag of towed aircraft when pilot applies brakes, by sensoring slight deformation of front-wheel position in the cradle. Accelerating is solved by fact that Taxibot is always accelerating, so when the pilot releases brakes Taxibot starts to move.
Attached to the tractor aircraft taxis to holding position. On holding position Taxibot releases clamps, the aircraft is released and tractor returns back to terminal controlled by its driver again. Aircraft is at holding position and may start engines.
