An original noncertified prototype system was developed and prototyped by the team of Honeywell, L3 and Safran. Due to falling fuel prices in 2013, competitive complications within the companies, the prototype system certification was not commenced. The current team is leveraging the previous technology, is focused on system FAA certification, and includes former L3 team eTaxi members from the 2013 prototype. In addition, the best of the hybrid vehicle engineering companies and Standard Aero’s FAA certification team are committed to seeing the industry changing system being FAA certified.
No- The GTS system is not required to be operational for aircraft use as the aircraft can taxi on its main engines if the eTaxi system is not operational. The system is totally disengaged from the aircraft when not in use or if the system is not operational. If the system is disengaged or not operational the aircraft can be taxied with the main engines.
No- The pilot steers the aircraft using the existing tiller nosewheel steering system along with the use of aircraft brakes if required. The GTI system allows for more precise speed control compared to using the main engines. An operational check out using Level A pilot training with video training and line check operational training may be used.
No- In our analysis it is expected that no modifications to the aircraft or landing gear will be required.
Yes. The design of the GTI system and installation does not interfere with the existing tow tug attachments on the aircraft nose gear if needed.
No, Airline standard operating procedures (SOP’s) require both engine taxi operations for the stability of the aircraft during taxiing during heavy snow and ice conditions. For most operators this will only be a few days a year as in most cases the taxiway and ramp are clear of ice and snow the majority of the year.
No, for most airlines the APU operates during most of the taxi time already and is running at 100% of rated RPM so there should be no significant reduction of APU life.
Green Taxi has received strong traction from major carriers including Delta, SkyWest and Alaska along with the FAA providing Green Taxi with a $5.6 million grant for the development of the system after significant due diligence.
The GTS system is capable of being installed on any aircraft or wheeled helicopter that has an APU (Auxiliary Power Unit) installed. Target commercial aircraft models include the Embraer E-170/175/190/195 regional jets, MHIRJ CRJ, Airbus A220/320/321, and Boeing 737 series. Target military aircraft include the C-130, C-17, KC-46A, and CV-22, aircraft.
Airbus has provided a No Technical Objection (NTO) for the GTS on the Airbus A320 and Boeing has agreed for GTS to use their extensive system patent. Embraer is assisting the project along with MHIRJ.
Development of the FAA conforming prototype system is underway for the E-175 and FAA certification is expected to take about 12–24 months.
After conforming prototype completion and FAA DER testing, approximately 12–24 months are required to complete FAA Supplemental Type Certificate (STC) certification.
The system will also be designed to meet EASA (European Union Aviation Safety Agency) standards, and the EASA approval will be based upon the US FAA STC approval. GTS will work closely with the regulatory authorities in other countries to achieve operational approval of the system based upon customer requirements.
The system will provide the aircraft operators with a 50% rate of return on the lease cost.
The Green Taxi System reduces brake applications per taxi cycle by at least 30 applications during a taxi operation which will extend carbon brake life by approximately 2-3× and delivers around $30,000 in annual brake savings per aircraft.
The amount of extra fuel required to carry the system weight of under 300 lbs for one year per aircraft ranges is approximately $10,000 per year depending on the type of aircraft, flight hours and routes flown. The cost to carry will be approximately 5% of the total financial savings the system provides.
The system saves up to $416,294 per year per aircraft in direct cost savings from fuel, brakes, and pushback, in addition to its environmental benefits.
Each equipped aircraft saves approximately 1,210 metric tons of CO₂ annually, equivalent to removing about 260 passenger vehicles from the road each year (EPA standard of 4.6 mtCO₂/vehicle). In addition, the system reduces ground operation emissions (CO, NOₓ, HC, SO₂, PM) by up to 85%.
Yes.
Military aircraft like these are often parked close to each other in unimproved environments. Starting the engines to taxi out can blow sand and dirt into the engines/system of aircraft parked nearby. The GTS avoids this issue. Tactical advantages include a low noise signature and elimination of FOD (Foreign Object Damage), increasing operational readiness and tactical surprise. Target military aircraft include the C-130, C-17, KC-46A, and CV-22, aircraft.
Yes.
The GTS system installed on a helicopter avoids the need for main rotors turning to taxi the aircraft, eliminating dangers to buildings, personnel, and other aircraft, along with a lower noise signature.
No. The system is not required to be operational for aircraft use and is not an MEL item. If the system is disengaged or not operational, the aircraft can be taxied with the main engines.
The pilot steers the aircraft using the existing tiller nosewheel steering system and brakes if required. The GTS allows for more precise speed control than engines. Training can be Level A with video and a line check; simulator training is not expected to be required.
The GTS will allow taxi speeds up to a maximum of 25 knots. Average eTaxi speed will depend upon slope and taxiway condition. The eTaxi system will stop pilots from needing to brake/reaccelerate due to engine thrust, providing a smoother ride for passengers.
No. For most airlines, the APU already operates during taxi and runs at 100% RPM, so there should be no significant reduction in APU life.
The operating goal is to not have the eTaxi operate when one or both engines are operating.
The total system weight will be under 300 Lbs.
60–75% of the total weight is carried on the landing gear. The remainder is in the electronics bay and flight deck.
The system has a failsafe disconnect if a fault is detected, when airborne, or if ground speed exceeds 25 knots.
The GTS is expected to last the life of the aircraft. Components are designed to heavy-duty hybrid standards (truck, tank, naval drives). Systems can be inspected and reinstalled on new aircraft after overhaul.
Installation can be completed in ~150 man-hours (2 days during C or D checks).
The permanent magnet A/C motors are reliable with long life, like EVs. Since distances are short, motors should last the life of the aircraft with periodic inspections.
The crew activates reverse mode with wing-walkers ensuring safety. Reverse taxi speeds are 3–5 knots, configurable. SOPs from reverse thrust taxiing will guide usage.
Existing reverse thrust taxi SOPs will be leveraged. SOP approval will be developed with customers and certifying agencies.
Yes. With engines off, slight dynamic braking is available reducing brake wear.