Das Projekt "Neuartiges System fuer das Schleppen von Flugzeugen ohne Zugstange" wird vom Umweltbundesamt gefördert und von Krauss-Maffei Verfahrenstechnik GmbH durchgeführt. Objective: The aim of the project is to save jet fuel at airports by using a new system of towing aircraft from landing/take off points to terminal instead of running aircraft on their own turbine. At the same time, the new towing system without tow bar helps to reduce environmental impacts (i.e. noise, smoke, exhaust gases). It is expected to achieve an energy saving of about 3500 TOE/year per B-747 aircraft. Expected payback is between 3 and 5 years at commercial level. General Information: Conventional aircraft towing requires a tow bar. Danger of 'jack-knifing' during barking restricts towing speed. Other inconveniences are: - manual coupling and uncoupling is time consuming and inefficient - to provide a multiplicity of different tow bars is complex and expensive. High speed towing from terminal to starting point is not possible, therefore, on taxi-ways, aircraft run in many cases on their own turbine power which results in high fuel consumption and negative environmental impact. The proposed system picks up the front wheel and combines the tractor and plane as an integrated system so that high speeds (30 km/h) are available under safe conditions. The new tractor can handle current aeroplanes ranging from 100 tons (TU 154) to 380 tons (B 747) with 2 engines of 600 HP. The system structure is a U welded structure containing all the components. A 2 cylinder hydraulic device, electronically controlled, lifts up the aircraft front-wheel in a supporting structure. For the demonstration phase, a considerable number of measurement points will be provided on the tractor and the aeroplane to evaluate the operating conditions from technical and economic point of view. Achievements: In total, Krauss-Maffei has up to now sold eleven PTS 1 units (six to Lufthansa, Frankfurt, two to Lufthansa, Munich under a leasing arrangement, one to United Airlines, San Francisco, two to Japan Airlines, Tokyo-Narita). One PTS 2 is operated by Lufthansa at the new Munich Airport. Negotiations for further purchases in Europe, the Far East and Northamerica are on the way. Towing of aircraft to the take-off with PTS 1 has been successfully practised by Lufthansa in Frankfurt for several months. Introduction of this procedure in big scale is, however, still pending due to operational organizational and legal (not technical) obstacles. Whereas, during development had been assumed that aircraft fuel savings would only be achievable in towing the aircraft to the runway, it has meanwhile been experienced that also maintenance towing is an important source of energy conservation: In San Francisco, PTS 1 is used for replacing maintenance taxiing (with aircraft power) by maintenance towing. This saves the airlines aircraft fuel in the order of nearly one million dollars per year. This leads to a relatively short period for return on investment. Similar values could be expected in Japan. In general, it can be stated that cost-energy and environmental conscious airlines are...