One of the most tedious things about air travel is the long wait between the door closing and the aircraft pulling away from the gate. To help speed things up, Stirling Dynamics has contracted with WheelTug to design a new nose wheel for Boeing's 737NG jet airliner. The new wheel will contain electric motors powered by the aircraft's Auxiliary Power Unit (APU) that will allow the pilot to back away from or taxi to an airport gate without using engine thrust or a ground tug vehicle.
Modern passenger aircraft may be able to fly near the speed of sound and cross oceans in a matter of hours, but sometimes it can seem they take almost as long to leave or arrive at the gate. According to Flightwatching, 98 percent of pushbacks from the gate take 13 minutes. This delay isn't just annoying to passengers, it's also time lost that could be better spent by the craft being in the air and making money.
The reason it takes so much time is that on the ground a large airliner isn't like a bus. It hasn't any means of propelling itself except by using the thrust from its jet engines or being pushed or towed by a tug vehicle. Both of these options can cause delays because jet exhausts can act as a barrier to other aircraft trying to enter and leave, and tugs need to be hooked up, maneuvered, then disengaged and moved clear. That's assuming there aren't other delays, like broken tow gear.
Built into the nose wheel, WheelTug allows a plane to move backwards and forwards under the control of its pilot without the need of a tug or dealing with jet wash. This simplifies pushback operations, bringing the time down to one minute. WheelTug says it can save a minimum of seven minutes per flight.
The new contract tasks Stirling with the design and certification of a new nose wheel incorporating the WheelTug technology for Boeing. This will involve reverse engineering, wheel analysis, landing gear analysis, safety analysis, and structural stress analysis.
"We are proud to work on this innovative technology with the WheelTug team, this new contract is another step forward in seeing this innovative technology reaching the marketplace," says Stirling's Aerospace Business Manager, Bandula Pathinayake.
Source: Stirling
Of course not, the ground crew will still be out there spotting. And normally the tugs are hooked up before the jetway is pulled away from the aircraft....
And what about the batteries required to get 66 metric tons moving from a dead stop as many airports require the aircraft to be pushed away from the gate before starting their engines....
I’m not sure flying around that added weight will be worth that seven minutes per flight....
This thing may be more useful in assisting forward movement of the aircraft on the taxiway in larger airports where it takes a while to get to the gate, think LAX....
1st, the nose wheel has enough traction at least 95% of the time. Under rare conditions of icy and some uphill, the plane can revert to what it always has done and use the main jets to taxi. The problem of putting an electric motor in the main wheels is basically heat; that is where the brakes are.
The system discussed here will have a 360 degree camera options for situation awareness.
The time savings are very real and documented. More savings can come from letting passengers us both front and rear doors. Jet blasts mostly prevent such a process now.
Other significant savings come from the main jets not sucking up debris. There are also costs for the tug tractors and more often than is generally known, the tractors damage the plane or push it into something.
About 1000 planes are already signed up to add WheelTug (WT). The FAA has approved a plan for the testing that will be needed to certify the system.
The expectation is that airlines will eventually save over $1M per plane per year with WT.
The pollution from main jets running while on the ground is even more important than that from the tractors. There is also a noise issue and safety enhancements. There are now too many injuries to ground personnel, including from jet blast.