1. Field of the Invention
This invention pertains generally to aircraft safety systems and more particularly to a system and method for preventing collisions between the wingtips of an aircraft moving on the ground and obstructions.
2. Description of the Background Art
Aircraft are subject to a variety of collision situations both in the air and on the ground. Air traffic control equipment and infrastructure assures safe flight paths. Recently, advanced GPS systems have been proposed to allow pilots to verify separation between themselves and other aircraft.
Yet one form of collision situation has not been fully addressed are the ground incursions that can occur when an aircraft is being taxied near other aircraft and obstructions. These ground incursions may be of the “hangar rash” variety, while in other cases enough damage is sustained to render the aircraft unairworthy.
Airports are often overcrowded with aircraft, while the taxiways are small and may be subject to further encroachment by poorly-parked aircraft. The problem is especially difficult for pilots taxiing in small airports as it is difficult to maneuver the typical 25-40 foot wingspan of a private aircraft or small commercial aircraft amidst a crowded taxiway while keeping the tips from striking other aircraft or obstructions that exist alongside the taxiway. In order to maintain clearance from other aircraft, the pilot must look in front of the aircraft while closely monitoring the wingtips on either side of the aircraft.
The difficulty in judging whether a distant wingtip may strike a distant obstruction, such as the empennage, propeller, or wingtip of another aircraft, should be appreciated. For example, if the tip of the wing is twenty feet (20 ft.) from the pilot, then the pilot must attempt to verify that the nearby obstructions are more than twenty feet (20 ft.) away. Any error in making this distance judgment can lead to damages to both aircraft. The situation is far different from a driver attempting to park a car, because a driver is close enough to the periphery of a car, or even a side of the motor home, to judge the side-distance and generally may only require help in judging the in-line distance to the obstruction.
In considering an aircraft, however, the position of the obstruction is far removed and distance must be judged in relation to a wingtip which is also far removed from the pilot. During taxiing the pilot is continually attempting to judge if an obstruction is in a forward line with one of the other wingtip. Furthermore, it will be appreciated that the pilot must correctly judge the distance well before the tip of the wing approaches the obstruction so that sufficient maneuvering room exists for getting around the obstruction.
As few aircraft have the ability to reverse engine thrust during low speed ground operations, the pilot facing insufficient clearance situation is required to shut down the aircraft and use a tow-bar or get the assistance of a tug if an obstruction is detected too late, such that insufficient maneuvering room exists. The lack of clearance information coupled with the “embarrassment” of exiting the aircraft to check if proper clearance is available or to back up the aircraft, leads many pilots to push a bad situation wherein damage is often the result. In some cases the situation is further aggravated when damage is not reported and aircraft having structural damage or damaged lighting systems may be flown.
As can be seen, therefore, the development of an apparatus and method for tracking wingtip position in relation to forward obstructions can prevent a number of minor collisions, and reduce “hangar rash”. The system and method of preventing aircraft wingtip ground incursions in accordance with the present invention satisfies that need, as well as others, and overcomes deficiencies in previously known techniques.