Aircraft Brake Control System Runway Contamination Detection
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Solution Overview
Problem
Existing brake control systems for aircraft struggle to accurately detect runway conditions, particularly contamination, which can lead to premature wheel locking and damage, as they rely solely on weight-on-wheel systems and reference speeds without considering the expiration of a time limit for determining ground conditions.
Innovation Solution
A method and system that utilize wheel speed sensors to calculate axle reference speeds, filter raw wheel speeds, and determine if the runway is contaminated by comparing these speeds to an on-ground threshold, delaying braking until the weights are on the ground and the runway is deemed safe, and notifying airport personnel if conditions are contaminated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If braking is applied before wheels reach sufficient velocity, then stopping distance is reduced, but wheel locking and damage occur
Solution Approach 1:
The system performs preliminary detection of wheel velocity and ground contact status before enabling braking. The brake control unit monitors wheel speed sensors and weight-on-wheel indicators to determine when wheels have reached sufficient velocity and the aircraft is confirmed on ground, then transitions to ground mode to permit braking. This preliminary assessment prevents premature braking that could cause wheel locking and damage.
2Reliability
If weight-on-wheel system is used to detect ground contact, then braking safety is improved, but runway contamination detection accuracy deteriorates
Solution Approach 1:
The system uses feedback from wheel speed sensors to detect runway contamination conditions. When the aircraft is on the ground (detected by weight-on-wheel system), the brake control unit continuously monitors wheel velocity through feedback from speed sensors. If wheels fail to reach expected velocities within a predetermined time period, or if abnormal velocity patterns are detected, the system identifies runway contamination and adjusts braking control accordingly, providing both ground contact detection and contamination detection capabilities.
3Reliability
If braking is delayed until sufficient wheel velocity is reached, then wheel locking is prevented, but stopping distance increases
Solution Approach 1:
The system dynamically adjusts braking control based on real-time wheel velocity feedback and runway condition detection. Once wheels reach sufficient velocity and ground contact is confirmed, the brake control unit transitions to ground mode and enables dynamic braking control that adapts to actual runway conditions. If contamination is detected through wheel velocity monitoring, the system modifies braking force application to optimize stopping distance while preventing wheel locking, allowing effective braking sooner than static delay periods would permit.
Data Source
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AI summary
Systems and methods for detecting runway conditions are disclosed. A weight on wheel system may determine that an aircraft (100; 510) is on the ground. Wheel speed sensors (322; 324; 326; 328) may measure the speed of the aircraft wheels. Axle reference speeds may be calculated for each landing gear (110; 120; 130) based on the speed of the aircraft wheels. A weight on wheel time limit may be reached prior to the axle reference speeds reaching an on ground threshold. A brake control unit (310) may determine that the runway (50; 520) is contaminated if the on ground threshold was not reached.