Variable Thrust Cutback for Aircraft Departure Noise
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Solution Overview
Problem
Current noise abatement procedures for aircraft departure involve fixed altitudes for thrust cutback and restoration, leading to inefficient fuel usage and inadequate noise reduction, as they do not account for variations in aircraft weight and operating conditions, resulting in suboptimal climb profiles and potential non-compliance with community noise standards.
Innovation Solution
A method for computing variable engine thrust during aircraft departure based on real-time sound exposure levels, altitude, and airspeed, using a flight management system to dynamically adjust thrust to meet noise limits while optimizing climb efficiency and fuel economy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If fixed altitude thrust cutback procedures are used, then noise reduction is achieved, but fuel efficiency deteriorates due to excessive time at low altitude
Solution Approach 1:
The patent applies dynamics by transitioning from fixed altitude thrust cutback to a dynamic system that continuously adjusts thrust based on real-time aircraft state (weight, temperature, altitude, speed). The flight management system dynamically computes optimal thrust settings that adapt to changing flight conditions, allowing the aircraft to climb more efficiently while still meeting noise constraints at each moment of the departure procedure.
Solution Approach 2:
The patent implements parameter changes by modifying multiple flight parameters simultaneously - thrust setting, climb rate, and altitude profile - based on computed optimal values. Instead of following a fixed altitude schedule, the system changes thrust parameters dynamically and adjusts climb parameters (vertical speed, pitch angle) to maintain optimal balance between noise reduction and fuel efficiency throughout the departure phase.
2Object-affected harmful factors
If conservative thrust cutback altitudes are specified, then noise compliance is ensured, but climb performance deteriorates and time to reach cruise altitude increases
Solution Approach 1:
The patent implements feedback by continuously monitoring actual flight conditions (altitude, speed, temperature, weight) and comparing them against the computed optimal profile. The flight management system uses this feedback to adjust thrust and climb parameters in real-time, ensuring the aircraft remains on the optimal balance between noise compliance and climb performance. The system continuously computes and applies corrective actions based on deviations from the planned profile.
Solution Approach 2:
The patent applies preliminary action by pre-computing the optimal thrust and climb profile before departure based on known aircraft weight and environmental conditions. The flight management system calculates the entire optimal departure trajectory in advance, including the precise thrust history and climb rate profile needed to minimize noise while maximizing climb efficiency. This preliminary computation allows the aircraft to follow the optimal path from the start of the departure procedure.
3Productivity
If maximum thrust is maintained during climb, then climb performance is optimized, but noise exposure at ground level increases
Solution Approach 1:
The patent implements parameter changes by dynamically adjusting the thrust parameter throughout the climb phase rather than maintaining maximum thrust. The system computes the optimal thrust history that varies continuously during departure, reducing thrust when the aircraft is at altitudes where noise impact is highest and maintaining higher thrust when noise impact is lower. This dynamic parameter adjustment optimizes the balance between climb performance and noise reduction.
Solution Approach 2:
The patent applies periodic action through the cyclic computation and adjustment of thrust settings during the departure procedure. The flight management system continuously computes optimal thrust values at regular intervals or based on altitude milestones, applying periodic adjustments to the thrust setting as the aircraft climbs through different altitude bands where noise impact varies. This periodic optimization allows the system to adapt to changing noise constraints at different climb phases.
Data Source
AI summary
A method of producing a variable thrust cutback of an aircraft during aircraft departure is provided. The method includes the steps of storing expected sound exposure levels for an aircraft in memory, and storing a sound exposure level limit for a navigation flight in memory. The method also includes the steps of determining aircraft altitude and determining aircraft airspeed. The method further includes the steps of computing an engine thrust value that complies with the sound exposure level limit based on the altitude, airspeed and the sound exposure levels, and outputting the computed engine thrust value for use in controlling the aircraft during departure.