Cockpit Noise and Speech Interference Between Crewmembers
Author | : |
Publisher | : |
Total Pages | : 20 |
Release | : 1989 |
Genre | : Air traffic control |
ISBN | : |
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Author | : |
Publisher | : |
Total Pages | : 20 |
Release | : 1989 |
Genre | : Air traffic control |
ISBN | : |
Author | : |
Publisher | : |
Total Pages | : 44 |
Release | : 1990 |
Genre | : |
ISBN | : |
Active Noise Reduction (ANR) is a new technology which can reduce the level of aircraft cockpit noise that reaches the pilot's ear while simultaneously improving the signal-to-noise ratio for voice communications and other information-bearing sound signals in the cockpit. A miniature, ear-cup mounted ANR system, developed by Royal Aerospace Establishment, Farnborough, United Kingdom, was tested by U.S. Army Aeroflightdynamics Directorate, Simulation and Aircraft Systems Division, Crew Station Research and Development Branch to determine whether speech intelligibility is better for helicopter pilots using ANR compared to a control condition of ANR turned off. The ANR system was installed in a stock Army SPH-4 flight helmet, and tested in a background of recorded AH-1S (Cobra) cockpit noise, using phonetically balanced word lists, per MIL-STD-1472C. Two signal-to-noise ratios (S/N), representative of actual cockpit conditions, were used: 0 dB and +10 dB for the ratio of the speech to cockpit noise sound pressure levels. Speech intelligibility was significantly better with ANR compared to no ANR for both S/N conditions. Variability of speech intelligibility among pilots was also significantly less with ANR. When the stock helmet was used with ANR turned off, the average PB word speech intelligibility score was below the Normally Acceptable level, per MIl-STD-1472C in the 0 dB S/N levels and exceeded the Exceptionally High Intelligibility level with S/N +10 dB. Keywords: Cockpit communications, Active noise reduction.
Author | : Donald C. Gasaway |
Publisher | : |
Total Pages | : 35 |
Release | : 1970 |
Genre | : |
ISBN | : |
Acoustic noise within aircraft during flight often causes some degree of interference with aural communication. Several methods have been used over the years to identify and predict degrees of speech interference. Six of these methods are discussed: four involve octave-band averaging; two use frequency weighting. The assessment is based on application of each of the six indices to noise levels measured within the cockpits of 191 fixed-wing and 58 rotary-wing aircraft, grouped into 11 categories by engine type. Equivalent speech interference levels obtained from the use of each of the six indices are provided for the acoustic spectra developed for the 11 classes of vehicles. The operational considerations which influence speech interference values are described. Noise attenuation provided by headset devices commonly used by Air Force aircrew members is shown for different groups of noise spectra. Criteria are given for evaluating protected and unprotected exposures to noise that compromise communications. (Author).
Author | : United States. Federal Aviation Administration |
Publisher | : |
Total Pages | : 98 |
Release | : 1992 |
Genre | : Aeronautics |
ISBN | : |
Author | : Jerry V. Tobias |
Publisher | : |
Total Pages | : 18 |
Release | : 1972 |
Genre | : Airplanes |
ISBN | : |
Author | : |
Publisher | : |
Total Pages | : |
Release | : 1967 |
Genre | : Airplanes |
ISBN | : |
Author | : National Aeronautics and Space Adm Nasa |
Publisher | : Independently Published |
Total Pages | : 46 |
Release | : 2018-11 |
Genre | : Science |
ISBN | : 9781729434420 |
Active Noise Reduction (ANR) is a new technology which can reduce the level of aircraft cockpit noise that reaches the pilot's ear while simultaneously improving the signal to noise ratio for voice communications and other information bearing sound signals in the cockpit. A miniature, ear-cup mounted ANR system was tested to determine whether speech intelligibility is better for helicopter pilots using ANR compared to a control condition of ANR turned off. Two signal to noise ratios (S/N), representative of actual cockpit conditions, were used for the ratio of the speech to cockpit noise sound pressure levels. Speech intelligibility was significantly better with ANR compared to no ANR for both S/N conditions. Variability of speech intelligibility among pilots was also significantly less with ANR. When the stock helmet was used with ANR turned off, the average PB Word speech intelligibility score was below the Normally Acceptable level. In comparison, it was above that level with ANR on in both S/N levels. Chan, Jeffrey W. and Simpson, Carol A. Unspecified Center NAS2-12425; NAS2-13188; RTOP 505-61-51...
Author | : Jerry V. Tobias |
Publisher | : |
Total Pages | : 16 |
Release | : 1968 |
Genre | : Airplanes |
ISBN | : |
Author | : Julie F. Rodwell |
Publisher | : Kendall Hunt |
Total Pages | : 662 |
Release | : 2003 |
Genre | : Transportation |
ISBN | : 9780787297626 |
Author | : C. E. Williams |
Publisher | : |
Total Pages | : 79 |
Release | : 1967 |
Genre | : |
ISBN | : |
For various aircraft flyovers, speech intelligibility scores and calculations of AI (Articulation Index) were obtained as functions of time. These data were then used to establish the relation between AI and intelligibility for time-varying noise. A similar relation was also obtained for steady-state simulated jet noise. A comparison of the two relations showed that for a given AI, the time-varying noise provided less masking than the steady-state noise. The difference found between the two relations cautions against the use of relations established for steady-state noise to predict intelligibility scores that might be obtained with time-varying noise. The aircraft flyovers employed in the intelligibility tests were also presented to listeners who were asked to rate them in terms of their acceptability in the home. Using a rating scale having the categories 'of no concern, ' 'acceptable, ' 'barely acceptable, ' and 'unacceptable, ' judgments were obtained in three listening situations: (1) in the presence of radio-TV speech; (2) in the absence of speech; and (3) in the presence of telephone speech. (Author).