Cabin Noise Effects on Passengers' In-flight Activities: Communication and Cognitive Performance

Abstract

Passengers’ comfort represents a key concept in the research on user acceptance of modern aircrafts. Aircraft cabin noise may interfere with passengers’ in-flight activities such as communication and cognitive performance and reduce comfort sensation. Experiments were performed in the acoustic laboratory at the DLR-Institute of Aerospace Medicine, Cologne (N=90) and in the aircraft cabin simulator Do728 at DLR-Göttingen (N=109). A 3 (SPL) x 3 (frequencies) design was applied to both studies. Frequencies were applied by the presentation of noise samples recorded at different seat locations in a real aircraft. For front and middle noises, levels of 66, 70, and 74 dB(A) were presented, for noises in the rear section levels of 70, 74, and 78 dB(A) were given. Communication interference was determined by subjective evaluations and the measurement of speech intelligibility of loudspeaker announcements (i.e. number of correctly understood words in the Oldenburg sentence test, Wagener et al., 1999) given at a constant level of 70 dB(A). Noise-induced performance effects were operationalized in the first study by using a three-minute version of a psychomotor vigilance task (PVT), a simple, high-signal-load reaction time test. Since the effect of cabin noise on the reaction times of the PVT was not significant, a three-minute computer version of the d2 test of attention (Brickenkamp, 2002) was designed for the second study. In both studies intelligibility decreased significantly with increasing sound pressure level. Words presented during cabin noise exposure to the front section were understood worse than in any other seat positions. Evaluations of the treatments with respect to subjective speech intelligibility verified this effect. Neither for the PVT nor for the d2 test of attention, a significant influence of sound pressure level and frequency was found by regression analysis.