The engines on most jet aircraft you will fly on these days are almost all of the high-bypass variety. Engines with high bypass ratios (the ratio of air bypassing the engine core to that flowing through the core) results in lower exhaust speed and thus less noise.
The FAA has mandated that aircraft designed after Janumust be compliant with new, quieter decibel restrictions. The good news is that the noise levels are decreasing, forced by regulation and steady improvements in engine and aircraft design. Surprisingly, Canadian researchers found that “high speed turbulent flow over an aircraft fuselage is responsible for a substantial component of the interior noise, and is probably the most important source of cabin noise for jet powered passenger aircraft in steady cruise.” It’s the plane itself moving through the air delivering most of the cabin noise, and not simply the engines. However, in-flight noise also results from airflow around surfaces such as wings, flaps and landing gear. Passengers intuitively know that the engines are the main source of aircraft noise. So, which aircraft are the quietest aloft? And where should you aim to sit on board? First, What’s Causing the Noise? The truth is my ears perceive the Q400 to be about twice as loud as the A380.Ī 2018 study published in the Journal of Exposure Science & Environmental Epidemiology points the way: how loud you perceive the cabin noise to be depends on the aircraft, and where you sit on board. On the Air France flight, had I been sitting on the lower deck in economy, behind the engines, it would not have seemed quite so quiet. The “Q” of the Q400 is supposed to stand for quiet a noise-cancelling system is built in. There was a dull roar during taxiing and that roar increased to a visceral, low, rapid thumping as the second engine was started and the plane throttled up. The second flight was aboard a Bombardier Q400 turboprop aircraft from Newark to Halifax, Nova Scotia. Of course - lucky me! - I was firmly ensconced in first class, at the front of the plane. I barely even noticed we had taken off, let alone the relatively subtle roar that is the spooling of the engines at takeoff. The first was an Air France Airbus A380 from New York JFK to Paris CDG.