Boeing and Safran successfully completed flight tests of passive noise reduction fairings developed by Safran as part of the latest phase of its long-running ecoDemonstrator program. 

The experimental fairings, which were fitted to the landing gear of the Etihad 787-10 used for the 2020 campaign, are designed to reduce noise-generating turbulent flow around the drag and side braces of the main landing gear, and steering mechanism and tow fitting of the nose leg. 

As engines become quieter with each new generation the airframe is becoming a proportionately bigger contributor to community noise around airports. Overall, the landing gear of newer designs like the 787 generates around 30% of the perceived cumulative noise on approach. 

Although Boeing says the experimental Safran fairings are not meant for a production program, the noise data collected during the flights will be used to improve noise modelling and design tools. This could lead to the eventual development of low-noise landing gear configurations for both future aircraft as well as the potential design of retrofit kits. 

The tests, which were conducted in late August at Boeing’s flight test facility in Glasgow, Montana, included 23 passes over a large microphone array. Around 12 gigabytes of data were collected from the flights and detailed analysis is underway. 

“We’re not ready to talk about noise decibels yet,” Boeing ecoDemonstrator technical lead Doug Christensen said. “We seem to hear a reduction, but we haven’t quantified it yet.” 

The low noise modification included airfoil-shaped fairings on the main landing gear and perforated and solid mesh flow deflectors on the nose landing gear as well as to the tow fitting.