Braking Performance of Towbarless Towing Vehicles during Maintenance Tows

Using a medium-sized Towbarless Towing Vehicle (TLTV) (16.8 tonnes (37,000 lb)) as an example, a comparative analysis is given of braking performance when applying either the TLTV brakes alone or the aircraft brakes alone when bringing a TLTV/aircraft combination to a complete stop from high speed and at maximum braking. It is shown that the stopping distance with tractor braking alone can be up to five times longer than the stopping distance with aircraft braking alone. It is also shown that the nose gear forces generated with aircraft braking alone can be excessive for lighter aircraft but allow a reasonable safety factor for heavier aircraft. Therefore, depending on the tractor/aircraft combination, it is possible to allow an operator in the cockpit of an aircraft being towed to apply the aircraft's brakes during an emergency. Each specific combination of tractor and aircraft should be analyzed separately before making such a determination for that combination.