This one is a dud right out the door. looks real good on paper, but when you look at actual airline operations it stinks to high heaven.
It will weigh several hundred pounds and be one more complex problem to break and then you need to find a tug and there is NEVER an extra one around.
The cost in fuel to carry that several hundred pounds around will negate an economic benefit from not running the engines for taxi. the environmental benefit will also lose because of the extra fuel needed to carry it being dumped in the high altitude where it does most damage and not on the ground.
The noise will still be there because the APU is louder than the engines until about 50-60 percent full takeoff thrust.
Just think of the horsepower required to get a 765K 777 moving again after stopping on a 1 degree incline. the motor might get it going again but it will be several minutes before it will be moving faster than a few MPH and if there happens to be a 20 knot headwind forget it.
It would be easier to put some kind of in ground tram that hooked to the nose gear and pulled it around kind of like a steam catapult, but even then you will have to start the engines and wait for warmup and then start pre flight check.
Nope, 3 million spent on this already and its never going to see the light of day.
