Data acquisition system certifies business jet noise

The Brüel & Kjær system uses three GPS-synchronised data acquisition stations that are distributed around the test area. They communicate via WiFi, and are controlled from a central monitoring station.

Each remote location measures and records noise and has a webcam, and one station monitors weather data. The central monitoring station controls the data acquisition, uploads data, interfaces to flight-track data and layered weather data, and calculates results.

The system is based on the modular Brüel & Kjær PULSE LAN-XI data acquisition hardware, which provides the measurement data for the official calculation of EPNL levels. This data is corrected, 1/3rd octave noise measurements compliant with the requirements for aircraft noise certification measurements in accordance with ICAO Annex 16, Volume I, amendment 9.

The system can also compute EPNL values including background noise, flight track and weather corrections for test validation and management of the tests. While these calculations are not usable for ICAO compliant certification like the 1/3rd octave noise measurement data is, they help testers ascertain their data is valid before ending the test.

The system can also calculate intermediate results such as OAL, PNL, PNL Tmax, PNLT curve and 10dB down points, which are used during aircraft development testing to ensure designs are on target to meet their requirements.