Can an Airliner Stop Without Using Wheel Brakes or Reverse Thrust?
There's a certain fascination with aircraft braking that may make one imagine finding a backup battery for Quora and taking a vacation. However, the reality of airliner operations often involves a sophisticated mix of braking systems and techniques that can lead to a safe and efficient landing.
Understanding Aircraft Braking
Most aircraft, especially small planes, do not come equipped with reverse thrust or advanced braking systems like autobrakes. Some light aircraft can even land in just a few feet, depending on the runway conditions and wind. However, for larger planes like the Boeing 747-400 and L-1011, braking is a carefully calculated process involving multiple strategies and settings.
Braking Systems and Strategies
Boeing aircraft from the 747-400 to the L-1011 have autobrake systems with varying deceleration rates. These rates range from 4 feet per second squared to 11 feet per second squared. For Airbus aircraft, the same principle applies but the details and settings may differ. The term 'deceleration rate' is crucial, as it includes the effects of reverse thrust, rolling friction, and aerodynamics.
Autobrake Settings and Temperature Monitoring
Autobrake settings can be adjusted during the landing roll, providing a smooth transition that passengers won't even notice. The 747-400, for example, had brake temperature sensors on all 16 main landing gear wheels. Normal readings range from 0 to 4, while readings of 5 to 9 indicate a high range. A reading of 5 corresponds to a temperature of 900°C (1652°F). Pilots ideally aim to arrive at the gate with brake temperatures no higher than 2.
Special Considerations and Emergency Landings
autobrakes are particularly important for landings on contaminated runways or during Category III (CAT III) landings. On a rejected takeoff, the maximum deceleration rate is automatically applied to ensure an immediate and safe stop. This is crucial for the safety of the aircraft and its passengers.
Regulatory and Safety Standards
Airliner operations are designed with safety in mind, and certification processes involve determining and recording official landing distance data, which is used for every flight without the need for reverse thrust. It is precisely because of these stringent safety standards that airliners are capable of stopping efficiently and safely under a variety of conditions.
Conclusion
Yes, an airliner can indeed stop without the use of wheel brakes or reverse thrust. This capability is a testament to the sophisticated engineering and regulations that govern aircraft operations. Whether it's through the use of autobrakes, strategic positioning, or a combination of methods, modern airliners are built to handle a wide range of landing conditions safely and reliably.