This study aimed to review methods of subjective tranquillity testing, which were then applied to the New Zealand population. This was done in order to determine the relationship between reported tranquillity values, and the corresponding predicted tranquillities obtained using the TRAPT equation. This was for the case of helicopter noise in New Zealand national parks. This information may potentially be used to assess helicopter noise levels in national parks, and to create a new set of noise management plans for the parks. This study involved two stages of research; a scoping study which evaluated the testing methods, and a pilot study which was used to draw conclusions on the use of the TRAPT equation in the New Zealand context. The pilot study had 32 participants, aged from 23 to 71 years of age, including both males and females, who belonged to European, Maori, Pacific Islander, or Asian ethnic groups. On-site images and sound recordings were taken at the Franz Josef Glacier Valley. These recordings and images were then used in a series of subjective laboratory tests, where participants gave subjective responses to helicopter noise levels based on a series of emotional reactions. Results indicate that although there are strong correlations between helicopter noise and both predicted and reported tranquillity values, those values are significantly different. Therefore, this implies that the New Zealand and British populations respond differently to helicopter noise. In its current state, the TRAPT equation does not accurately predict responses of New Zealanders, and the tranquillity associated where helicopter noise is present for the New Zealand population. For use in the New Zealand context, the TRAPT equation needs to be recalibrated.