The UK’s Flybe has taken delivery of its 50th Bombardier Q400 airliner, equipped with the 1,000th installation of Ultra Electronics’ active noise control (ANC) system, the Canadian airframe maker announced today.

Previously known as British European, Flybe placed its first Q400 order–for four of the 78-seat turboprops–in March 1999. It placed subsequent orders in 2003, 2005 and 2007, making it the world’s largest operator of the aircraft type. Flybe operates 190 routes in 13 countries and now ranks as the largest regional airline in Europe.
Firm orders for the Q400 have reached 347 aircraft, and as of January 31 Bombardier had delivered 233.

Called the Active Noise and Vibration Suppression (ANVS) system on Bombardier Q Series aircraft, Ultra Electronics’ active noise-canceling device first appeared in what the industry then knew as the de Havilland Dash 8 in 1996. Since then, Bombardier has referred to all turboprops as Q Series airliners, the ‘Q’ designating the word “quiet.”

Ultra Electronics’ ANVS works by attenuating airframe vibration induced by pressure pulses from the propeller blades “beating” against the fuselage. Microphones concealed in the passenger cabin measure noise levels, which then get sent to an onboard microprocessor, together with propeller rpm and cabin pressure differential. The microprocessor then signals active tuned vibration absorbers attached to the fuselage frames to produce out-of-phase counter pulses to reduce the original vibrations, and therefore, noise.

Bombardier also “soft mounted” interior cabin parts using elastomeric snubbers and acoustically sealed joints between components. Modified sidewall and floor panels reduce resonance, and new thermal blankets–the insulation surrounding the cabin structure–improves acoustical properties to absorb noise better.