General Electric has developed an automatic computation and throttle control method that could help airlines or business jets avoid fines levied when take-off noise exceeds predefined dB levels measured by noise monitoring stations around certain airports.

In a patent application published on 21 May, the company reveals a system that attempts to satisfy noise constraints through real-time automatic commanding of engine power through the flight management system based on altitude, airspeed, on-board tables of known engine noise characteristics and stored sound exposure levels along a departure route.

GE notes that existing best-practices noise abatement procedures are generic in nature, and do not take into account an aircraft's weight, the ambient temperature, noise limits and other factors. Those generic practices lead to less than optimal performance and fuel economy during the procedures.

To ensure aircraft safety, the algorithm would not command a thrust reduction until the aircraft is more than 800ft (244m) above airport elevation and unless its rate-of-climb with the computed "dB" thrust would be greater than 1,000ft/min (5.08m/s).

Source: Flight International