Towing airplanes: Will it save fuel?

A controversy is growing over a move to save energy on that part of airplane travel which occurs on the ground rather than in the air. The US Department of Energy (DOE) would like to find an airport, with the full cooperation of the airlines using it, to test its theory that towing -- rather than taxiing -- aircraft between the gate and the runway could save millions of gallons of fuel. A recent Peat, Marwick & Mitchell study for the DOE claims that as much as 40 million gallons of fuel a year could be saved by such tows at Chicago's busy O'Hare Airport alone.

The Federal Aviation administration (FAA) and the airlines themselves have strong reservations about the idea from the standpoint of safety, economics, and speed.

For the moment, everyone appears to agree that some solid answers to these concerns must be found before a full- blown demonstration project gets under way -- if one ever does.

"The consensus is that more investigation is needed before we move ahead," notes Edgar Gregory, who has been working on the project for the DOE's conservation division. "[But] I am convinced that it's something that needs to be tried, and I'm looking to find a way."

One development on which much of his hope hinges is a high-speed tug tractor used in Paris by Air France to tow empty planes. Capable of connecting up with the plane's nose wheel in a matter of seconds and moving at speeds up to 35 m.p.h., it would average about three times the speed of a typical tow by a US tractor and would be faster even than the current taxiing system using plane engines. But how fast and how well it would work with a fully loaded aircraft is another question.

Both the FAA and the airline industry admit to strong concerns about the safety of towing for both passengers and aircraft. They insist the nose wheel and landing gear were never designed to endure the stress of being pulled by a towbar. They point to a McDonnell Douglas study done for the FAA a few years back, when that agency was interested in towing from a noise abatement standpoint. The study suggested that the strain of towing could well be harmful , requiring more inspection and replacement of parts in the nose gear. Airlines also admit to concern about the delay the procedure might build into the takeoff and landing schedule and the overall cost.

"The advantages aren't as obvious as they first might appear, and the airlines aren't that enthusiastic," observes John Wesler, director of the FAA's Environment and Energy Division. "Frankly, i don't think the FAA will get that far with the idea."

Despite the controversy, a DOE demonstration test remains a distinct possibility. Industry spokesman concede that airlines might be willing to try it jointly at one US airport. To date Seattle-Tacoma International Airport has been approached on the idea and has indicated some interest. But an airport spokesman says that more information as well as a firm commitment from airlines and government funding sources are needed.

"We've had people come to talk to us, but we're not sure we're going to do anything," is the cautious response of Pete WiSe of the airport's operations d epartment.