AIRCRAFT TOWING SYSTEMS

General
System
Description

ATS World Wide (ATS) LLC created an innovative alternative to traditional aircraft tugging and taxiing methods. The system is designed to transport aircraft from the runway via the taxiway to the airport gates and back to the runway without the use of the main jet engines. ATS uses an electro hydraulic powered pullcar and tow dolly system innovatively designed to automatically transport aircraft at airports using the ATS underground channel system. After landing, the pilot taxis to the appropriate taxiway and drives the aircraft nose wheel onto the ATS tow dolly. Once secured, the aircraft's main jet engines are shut down. The aircraft then moves using the ATS underground channel system located beneath the taxiway to the appropriate gate. Prior to departure, the ATS pullcar/tow dolly system pushes the aircraft back from the gate and onto the taxiway. Upon reaching the proper location, the pilot starts the main engines, drives off the tow dolly and positions the aircraft ready for takeoff. ATS is fully integrated into the airport ground control systems and possibly run by ground control personnel located in the tower. The system maximizes safety by optimizing airport taxiway traffic, reduces the need for personnel and equipment in and around flight operations and controls all aircraft movements during taxi and gate operations. ATS is constructing their automated prototype at the Ardmore Industrial AirPark (Oklahoma) with testing scheduled to begin in later this year.

ATS is comprised of three sub-systems, the taxiway channel, pullcars/tow dollies and software.

PULLCAR/TOW DOLLY

The ATS pullcar/tow dolly system transports aircraft from the runway to the appropriate airport gate and back to the runway. The ATS system is a fully automated system that requires no additional actions from the pilot while the aircraft is in the ATS system. ATS safely moves the aircraft using its underground channel system to the appropriate gate. The reverse process is used when a pilot is ready for departure. The pilot always maintains control over the aircraft and can override the ATS system using the aircraft brakes or throttle in case of an emergency.                                                                                      

SYSTEM BENEFITS

The ATS system benefits include:

  • Fuel savings
  • Reduced harmful fuel emissions
  • Increased jet-engine and component life
  • Improved safety with fewer on airport collisions
  • Less noise in and around airports
  • Improved airport throughput by optimizing aircraft movements
  • Reduced operating costs for airports and airlines                        

ATS maximizes safety by optimizing airport taxiway traffic, reducing personnel and equipment in and around flight operations gate area, and controlling all aircraft movements during taxi and gate operations. ATS significantly improves airport safety and eliminates most aircraft collisions with other aircraft and structures. This system dramatically reduces fuel emissions since the engines are powered off during taxiing and gate docking. Shutting off the main jet engines during taxi dramatically reduces harmful exhaust emissions in the atmosphere at airports and surrounding communities. Airports can potentially convert the emission savings into fuel-emission credits and sell them in emission brokerage auctions. Also, reduced airport ground crew manpower and ground support equipment could offset the initial and sustainment costs of ATS. Airline on ground fuel consumption will decrease with airports implementing ATS, which helps decrease airlines operating costs.           

                                                                                           


 

FASTER AIRCRAFT MOVEMENTS

The above chart captures some of the number of flight operations around the world that increase every year. Increased flight operations equate to increased airport ground movements. The more aircraft movements, the more time saved creating increased capacity.

FASTER AIRCRAFT MOVEMENTS during pushback phase

Attaching and detaching an aircraft from the ATS tow dolly occurs within a matter of moments. Currently, pushback (an airport procedure during which an aircraft is pushed backwards away from an airport gate by external power or aircraft engine power) is accomplished in an average of 4 minutes. ATS eliminates these 4 minutes because the aircraft remains attached to the pullcar while stationary at the gate. During pushback, the ATS system immediately begins moving the aircraft along the channel and does not require stopping until the aircraft is at the runway. ATS eliminates waiting for a ground crew, tug or tow bar for gate operations. This also decreases the chances for collisions with ground vehicles.

One of the major advantages of implementing ATS system for aircraft transport at an airport is significant fuel savings. Aircraft engines (on medium and large airfields) burn an average 35 liters or 9 gallons of fuel per minute during taxi. Depending on the type and size of aircraft, fuel usage can very 20-70 liters or 5-18 gallons per minute during taxi. For example, taxi time at Frankfort Airport averages 16 minutes per flight, which translates to burning approximately 560 liters or 148 gallons of fuel on every aircraft movement. Utilizing the ATS system allows the aircraft to power down the main jet engines shortly after landing and conversely, the aircraft is not required to use their main jet engines during taxi until reaching the runway for take-off and only to perform the required engine run-up just prior to takeoff.  Prices of fuel have a significant impact on the amount of savings from fuel usage; see graph below.

The number of flight operations around the world increases every year. Increased flight operations equate to increased airport ground movements. The more aircraft movements, the more time saved creating increased capacity. See chart below:

Crude oil analysts agree the price of oil is predicted to rise in the near future. It may not reach the record levels of $140/barrel, but even at $50-$90/barrel, oil prices affect airline costs. As the price of crude oil increases, the ROI for utilizing ATS gets shorter.

 

 

TAXIWAY CHANNEL

The taxiway channel consists of 15 to 17 meters, or 50- to 60 feet in length modules built into the airport taxiway at approximately 80 cm, or 2- to 6-foot deep and 120 cm or 3- to 4-foot wide. Steel plates cover the channel and it will use a brushes or rubber-seal system to close the 5 cm or 2-in gap between the steel plates. This reduces potential Foreign Object Damage (FOD) down in the channel. The channels are designed with a drainage and heating system where needed to keep the system operating during all weather conditions, such as rain, snow and ice.

FUEL SAVINGS

The ATS system is designed to transport aircraft between runway and gate without aircraft main jet engine power. Depending on the type and size of aircraft, fuel usage for 1 minute of taxiing is 20-70 liters or 5-18 gallons per minute. Average fuel usage for passenger aircraft is 35 liters or 9 gallons per minute while taxiing.

For example, an aircraft taxiing 16 minutes burning 9 gallons of fuel per minute will save approximately €243 or $88 in fuel costs at $2 per gallon per taxi one-way either to or from the gate.   

For example, an aircraft taxiing 16 minutes will save approximately €224 or $244
35 L/min x 16 min = 560 liters x €0.40 = €224
9 gal/min x 16 min = 144 gallons x $1.7 = $244 USD

 

 

Fuel Price

$0.45 USD/gal

€0.40 Euro/Liter

Fuel Consumption

9 gal/min

35 L/min

SAFETY

ATS maximizes safety by optimizing airport taxiway traffic, reducing personnel and equipment in and around flight operations gate area and controlling all aircraft movements during taxi and gate operations. ATS also helps to eliminate aircraft collisions with other aircraft and structures during taxi.

Each ATS pullcar/tow dolly system is equipped with sensors that monitor possible collision areas. In case of an emergency, the pilot can immediately stop or over power the chalks on the tow dolly through the use of the aircraft brakes or throttles to disconnect from the ATS system as needed. The ATS system reacts automatically and adjusts the movement of other aircraft accordingly, while notifying air traffic control and other aircraft about any changes. 

ATS believes that ground accidents will be greatly reduced with the implementation of the complete ATS system.  

                            

                                                                                                                                      

                                                                                                                                                                                                                                

 

                                                                                                                           

INCREASE IN AIRPORT CAPACITY

ATS optimizes aircraft movements, increases airport throughput up to 30%. It also increases the capacity of airports due to increased operational efficiency and the greater capability to stack aircraft closer together because aircraft don’t need to operate their engines between 3 to 5 minutes before takeoff. ATS should enable an airport to service more aircraft at the same time.

                                                                     

TAXI TIME

Taxi time greatly influences the fuel consumption of an aircraft. Approximately 25% of all commercial aircraft are wide-body aircraft, which consume an average of 70 liters or 19 gallons of fuel per minute during taxiing. The remaining 75%-80% of large commercial aircraft are mid-size aircraft, which burn an average of 22 liters or 6 gallons of fuel per minute during taxiing. The overall average of passenger aircraft burns about 35 liters or 9 gallons of fuel per minute. Calculations indicate that the fuel required to taxi is approximately 3%-4% of the entire fuel consumed for flight operations (take-off, flight and landing). In addition, fuel used during taxiing results in large amounts of harmful emissions released into the atmosphere. The table below shows taxi times for the busiest US airports:

SOFTWARE

ATS has a fully integrated software system that eliminates most human touch points and errors. The system software completely orchestrates all aircraft movements from the taxiway to the airport gate and back to the runway. The ATS software suite is planned to integrate with the existing airport traffic control system software and is envisioned to be operated by the ground control personnel.

REDUCED MANPOWER AND GROUND EQUIPMENT

ATS is a fully automated system where airports can significantly reduce ground support equipment and personnel decreasing overhead costs. Some ground support equipment, such as tug vehicles and towbars, are no longer required since aircraft are moved by ATS pullcars and tow dollies.

Current airport operations require 3-4 people and 1 tug to move every aircraft!

GATE OPTIMIZATION

Integration of the ATS ground control system allows for greater optimization of airport gates and quicker departure times. Using ATS, planes will move during their allotted times and slots. ATS greatly reduces negative consequences of human-induced errors by optimizing taxi times, gate pushback and eliminating congestion in the gate area and on taxiways. There will be no more waiting on a gate or for a gate crew or equipment to dock and marshal aircraft. ATS also improves operations during adverse weather conditions such as rain, fog, ice and snow.

Sources of savings:

Eliminates tugs and towbars
Reduces manpower
Quicker aircraft movements
More efficient gate operations
Less congestion in gate area – safer work area
Increased airport capacity

DESIGN & INSTALLATION
TRAINING

DESIGN

ATS World Wide will collaborate with each airport to design an optimal layout for the ATS system to maximize airport capacity and optimize aircraft movement flow. ATS will simulate each individual airport to model the best track layout for the airport and ground traffic flow.

CHANNEL INSTALLATION

Channel modules are built off-site prior to installation on or near the airport depending on the airport. First, a modified "concrete cutting vehicle" cuts the channel into the taxiway, second, a trench is dug and the foundation is constructed and finally the channel module dropped into place and secured. After each channel section is complete, the taxiway can be used for normal airport operations until the entire ATS system installation is complete and operational.

INSTALLATION COST ESTIMATE

ATS World Wide will partner with the airport to determine the optimal taxiway layout of the ATS system, then customize the ATS software suite for control of ground traffic. It is envisioned the ground control operators will to operate the ATS system with input from the airlines. This model is configurable for each individual airport scenario. The software integration is planned late in the installation project schedule to minimize disruptions to airport operations.

 

Installation Estimates

USD

Euro

1 m (1.1 yd) ATS system cost

$3,000

€2,800

1 ATS pullcar cost

$150,00   

€2180,000

Project cost (% of total system cost)

5%

5%

Annual Mx cost (% of total system)

4%

4%


 

OPERATING PARAMETERS

ATS system has a very high rate of return on investment (ROI) after installing the system. Main parameters influencing the ROI are as follows:

Fuel consumption

Number of flight movements

Taxiing time

Length of taxiways

Traffic patterns

Number of gates

These parameters very for each airport and have significant impact on the ROI.

PULL-CAR INSTALLATION

Pullcars and tow dollies are built off-site at a permanent manufacturing facility and delivered to the airport as the channel modules are installed. Pullcars and tow dollies are installed into the channel as required.

ATS OPERATIONS AND MAINTENANCE

ATS is a fully automated system operated by airport personnel through the system software and use of sensors and other technologies on the pullcars and tow dollies to help transport aircraft around airports. A small number of employees depending on the size of the airport is all that is required to operate the entire ATS system. The ATS system is maintained by a like number of employees varying by size of the airport. Maintenance includes software updates, monitoring the track system and keeping the pullcars and tow dollies in top operating condition. The ATS channel, pullcars, and tow dollies will require periodic inspections and maintenance depending on usage and time intervals. Maintenance personnel are trained to manually detach aircraft from the tow dolly in case of emergency and transport aircraft by traditional means. Prior to installation, ATS will work with airport operators to determine the recommended numbers of spare parts, tools and support equipment required to operate and maintain the ATS system.

REQUIRED AIRCRAFT MODIFICATION

REQUIRED AIRCRAFT MODIFICATION

To disconnect from a pullcar, an aircraft will not require any modifications. However, detachment can also occur via ground controllers.

 

INSTALLATION

ATS system installation is accomplished using a modular installation strategy, which seeks to minimize airport downtime. Taxiway channels are modular in design and constructed on-site or near on-site then installed in 8-hour shifts during airport down times such as middle of the night. This allows taxiway and/or gates to return to normal operations in between installations. Disruptions to airport operations are minimized by installing the taxi channels at night. In most European countries, flights are prohibited during the hours of operation 2300 - 0500. This timeframe varies at United States' airports. During this downtime, installation is optimal. During an 8-hour break in airport operations, ATS World Wide can install up to 250 meters or about 300 feet of taxi channel. After the installation of the channel the airport can return to normal operations even though the ATS is not yet operational.

SOFTWARE INTEGRATION

ATS World Wide will partner with the airport to determine the optimal taxiway layout of the ATS system, then customize the ATS software suite for control of ground traffic. It is envisioned the ground control operators will operate the ATS system with input from the airlines. This model is configurable for each individual airport scenario. The software integration is planned late in the installation project schedule to minimize disruptions to airport operations.

ENVIRONMENTAL PROTECTION

By reducing harmful emissions, ATS will help to improve the environment. The global use of ATS could also play an especially important role in improving the environment worldwide. Airports can apply for government grants for environmental protections by implementing ecological-improvement systems such as ATS. The emission reductions may be monetized by converting the savings into emission credits and selling them to companies paying fines for emission violations.

Significant reduction in aircraft fuel consumption, due to not operating engines during taxi under ATS, translates to dramatic reductions in harmful emissions emitted into the atmosphere. They are as follows: 

Carbon Monoxide
Carbon Dioxide
Hydrocarbon
Nitric Oxide

The table below shows savings in emissions of different harmful substances:

Harmful Substance Consumption

Emission from aircraft (oz/gal)

Emission from aircraft (g/L)

Hydrocarbon

0.06

1.71

Carcinogenic Nitric Oxide

0.16

4.60

Carbon Monoxide

0.73

20.62

Carbon Dioxide

0.13

3.70

FUEL PRICES

One of the major advantages of implementing the ATS system for aircraft transport at an airport is significant fuel savings. Depending on the type and size of aircraft, fuel usage for 1 minute of taxiing is 5 to18 gallons (20 to 70 liters) per minute. Average fuel usage for passenger aircraft is 9 gallons (35 liters) per minute while taxiing. Aircraft engines (on medium and large airfields) burn an average 9 gallons (35 liters) of fuel/minute during takeoff. For example, taxi time at Frankfort Airport averages 16 minutes per flight, which translates to burning approximately 148 gallons (560 liters) of fuel on every aircraft movement. Utilizing the ATS system allows the aircraft to power down engines shortly after landing and conversely, aircraft are not required to use their aircraft engines until ready for takeoff. Pilots perform the required engine run-up and preflight systems checks prior to takeoff. Prices of fuel have a significant impact on the amount of savings from fuel usage; see graph below.

Crude oil analysts agree the price of oil is predicted to rise soon. It may not reach the record levels of $140 per barrel, but even at $50-$90/barrel, oil prices affect airline costs. With each price increase of crude oil, the ROI for utilizing ATS gets shorter.

SYSTEM TRAINING

ATS World Wide offers an array of training options for airport personnel, including the use of a customized simulated system, on-site ATS expertise and classroom training.

DETACHING FROM ATS DURING TRANSPORT

At any time during ATS operations, the pilot or ground controller can detach the aircraft from ATS in approximately 45 seconds or less. The pilot can overpower the ATS system through the use of the aircraft brakes or throttles at his or her discretion in case of emergency. After the aircraft detaches from the pullcar it can move under its own power or be towed by traditional means. This event has no impact to other aircraft operating in the ATS system. All other aircraft in the system will receive an alert regarding the detaching event and the system will continue to operate and optimize all other aircraft movements.