Noise cancelling technology has shown promise in reducing the negative effects of noise on performance in aviation. Within the laboratory, ANR technology employed in military helmets have been shown to attenuate as much as 6 dB of A-weighted noise when compared to passive style ear muffs (Pääkkönen and Kuronen, 1998). During flight, these helmets have been shown to attenuate as much as 8 dB of A-weighted noise compared to passive noise reduction helmets. Subjective reports from pilots reflect favourably on ANR technology with pilots claiming that ANR technology made radio communications louder and more clear (Pääkkönen et al., 2001). Similar results have been obtained in the passenger sector of commercial aviation. Moreover, in a study examining intelligibility differences between passive headphones and ANR headphones, Molesworth and Burgess found that using ANR headphones increased the recall and accuracy of information presented (Molesworth and Burgess, 2013).