Enstrom 480, Goshen, Ind., Aug. 5, 2005–The NTSB determined the landing accident was caused by “ground resonance experienced by the pilots.” The student pilot/owner was flying the turbine helicopter, accompanied by a 2,107-hour CFI, when it experienced ground resonance and disintegrated. The helicopter’s tail was sheared from the body and landed 30 feet away, the front seats about 10 feet away.
Broadband cabin noise, which can greatly fatigue passengers in even the most finely appointed business aircraft, could be a thing of the past if a new system from Britain’s Ultra Electronics and Qinetiq makes it to market. Early next year the partners are expecting to flight test new-generation hybrid active/passive mounts positioned between the fuselage and cabin trim panels.
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.
U.S. and European Union officials are making last-ditch efforts to negotiate a settlement to their long-running dispute over hush kits bringing Stage 2 aircraft into compliance with current Stage 3 noise limits. Both sides want the deeply divisive matter resolved at the September 25 meeting in Montreal of the International Civil Aviation Organization assembly.
The European Union’s research program on noise reduction, Silence(r), officially ended in June with promising results. It explored all noise sources, from engines to landing gear and flaps. However, although it achieved a reduction of five decibels in aircraft noise, several more leads need to be developed to reach the ambitious target of cutting a full 10 dB from average noise levels by 2020.
E-A-R Specialty Composites (Booth No. 331) has broken ground for a new 11,500-sq-ft acoustic test center designed to increase the Indianapolis company’s test and analysis capabilities.
Cessna Citation S550 Bravo, Dillon, Mont., May 3, 2007–The ATP-rated owner-pilot and a passenger were killed when the Citation Bravo crashed on a circling instrument approach at Dillon in VMC. A witness reported hearing a loud engine noise followed by a “plop.” He said the engine noise was loud, diminished, then got loud again. He spotted a large cloud of black smoke and a fire outside the airport boundary fence.
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.
It’s probable that a bent-down microphone jack receptacle–a non-OEM installation–found near the base of the copilot’s control column prevented aft movement of the yoke, causing a Challenger 600 to overrun the runway during takeoff from Tupelo Regional Airport, Miss., on March 9, according to a Bombardier Advisory Wire sent to operators of 600-series Challengers.
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.
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