Business aircraft cabins are generally not quiet. Not with the turbulent boundary-layer rush of air around the fuselage at Mach 0.85 and the whine of a couple of jet engines no great distance from the comfy chairs. Then there are the pumps, hydraulics, fans, gears, actuators, electric motors, worn bearings and air distribution through the metal ductwork, not to mention the occasional hum of the microwave and induction oven, the rattling of glasses and flatware in the galley and that giant sucking sound coming from the lavatory.
The FAA’s final rule on civil tiltrotor noise limits and conditions for noise compliance measurement becomes effective March 11. It amends regulations governing noise certification standards and establishes new noise limits and procedures to ensure that noise-reduction technology is incorporated in tiltrotors.
The FAA issued a proposed rule on Tuesday that is aimed at reducing noise generated by new helicopters certified under Part 36 (noise standards) of the FARs. If adopted, the rule would impose standards already adopted by ICAO.
A new noise-cancelling headset introduced in April at the Aircraft Interiors Expo in Hamburg, Germany, is set to find a market in business and private aviation.
Middletown, R.I.-based Avid claims the headset “effectively reduces environmental external noise by 85 percent with a 20-decibel maximum noise attenuation.” Forty-millimeter speakers, said an Avid spokeswoman, “ensure crisp, clear sound and well defined bass.”
Just a few years ago Eurocopter scored a major coup at an HAI Heli-Expo show, amazing the crowds by introducing a new helicopter as a completely certified aircraft instead of a promise-laden prototype encumbered with the usual waits for first flight, inflated claims of launch customers and delays in FAA approval. Instead, Eurocopter presented its EC 130 as a done deal.
Noise is everywhere–annoying, tiring and sometimes painful. Since the early days of aviation, when a roaring, clattering engine sat on a wooden frame close to the pilot, and the wind whistled through the wire bracing like a banshee chorus, engineers have sought to make the process of manned flight less noisy. And they have succeeded, to a degree.
Business aircraft crews and passengers are generally aware of the danger of prolonged exposure to noise in terms of hearing loss. Now there is a growing body of evidence that prolonged exposure to a combination of high-intensity and low-frequency noise may pose far more serious health threats.
All jet and transport-category airplanes (those with an mtow of 12,500 pounds or more) for which application of a new type design is submitted on or after January 1 this year have to meet new noise certification levels. Stage 4 is a cumulative 10 EPNdB (effective perceived noise level in decibels) less than Stage 3 limits. Virtually all in-production business jets will qualify to be recertified under Stage 4.