Effective Braking - A Key to Air Transportation Progress 690376

Aircraft ground congestion is mounting as a result of air transportation growth and runway limitation. Because highly reliable aircraft braking can contribute to good ground control and alleviation of congestion, effective braking is a key to air transportation growth.

To attain a vantage point for a view of the future, the progress of aircraft braking systems is reviewed. Current areas of study relating to systems, brakes, tires, and runway interface are discussed.

Studies are under way by companies and agencies, both foreign and domestic, for improvement of braking efficiencies to meet future needs. These studies include the topics of brake design, heat-sink material, braking control, tire-runway interface, and tire design. The specific subject of tire-runway interface has received considerable attention during the past few years. The interface phenomenon involves many facets. Particular emphasis has been directed to friction measurements of runways for both wet and dry conditions, aircraft braked roll-out distances while on wet runways, and friction improvements which may be realized through runway grooving and water removal. The above topics are reviewed and an accounting of the work in progress at Douglas in runway water removal and roll-out prediction contract work for the FAA is given.

The current studies are a guide to future developments. A practical look is taken at brake materials, cooling concepts, and skid-control systems which may be expected in the future. Effective aircraft braking cannot be attained without satisfactory surface contact to provide good ground coefficients. Accordingly, tire-runway interface, runway grooving, water control, and runway-friction measuring equipment will contribute to future braking. The most radical concept for commercial air transportation is the use of recovery equipment which can potentially eliminate many braking problems.