Honeywell and high-tech company Safran say they have completed the major phase of testing of their electric green taxiing system (EGTS).
Developed by EGTS International, a joint venture between Honeywell and Safran launched in 2011, the EGTS technology allows aircraft to avoid using their main engines during taxiing and instead taxi autonomously under their own electrical power.
Similar to a hybrid car using electrical power at slow speeds, EGTS will improve airline operating efficiency during taxi operations and cut fuel consumption by up to 4 percent per flight cycle, the partners say. EGTS will also reduce and carbon and nitrogen oxide (NOx) emissions during taxi operations.
The companies expect to introduce EGTS to the market in 2016.
Because an aircraft’s main engines are optimized for flying rather than taxiing, they burn a disproportionate amount of fuel during ground operations. With a short- or medium-range aircraft spending up to 2.5 hours of its time on taxiways every day, EGTS could save about 600 kilograms of fuel used during taxiing from being consumed daily, according to Honeywell and Safran estimates.
EGTS allows aircraft to push back autonomously and then taxi between gate and runway without engaging the main engines by using the Auxiliary Power Unit (APU) generator to power electric motors in the main landing gear. Each of an EGTS-equipped aircraft’s powered wheels is fitted with a control system, giving pilots total control of the aircraft’s speed and direction during taxi operations. In addition to reduced fuel burn, the system will also generate further savings by reducing engine and brake wear and minimizing the risk of damage to engine turbines from foreign objects on the tarmac.
The component system and aircraft testing program has accumulated more than 3,000 hours of testing on seven bespoke testing benches and rigs, including on-ground maneuvers in Toulouse, France, on an A320 modified by the joint venture for the EGTS development program, the companies say.
Since this aircraft’s “first move” in April, the EGTS fitted to it has logged close to 160 kilometers (100 miles) of rolling tests. These tests evaluate the system in various load configurations and runway conditions, through a series of complex maneuvers such as pushback, tight turns and U-turns, according to varying specifications of acceleration and speed.
The next major milestone of the testing program will be to conduct these same maneuvers at speeds up to 20 knots, at full performance and with the aircraft at maximum take-off weight (MTOW).