Speech intelligibility during runway incursions

Abstract

Aviation can be considered today one of the safest forms of transport on the planet. A major factor in aviation safety is the existence of air traffic controllers, the individuals in direct contact with flight crews through voice-over radio and issuing clearances to prevent collisions between aircraft. The communication between controllers and pilots happens through the use of standardized phraseology, with the purpose of achieving efficient, clear, concise, and unambiguous communications. For situations not prescribed in phraseology manuals, plain language shall be used, the spontaneous, creative and non-coded use of a given natural language. Despite the current standardized and rigid structure of voice interactions in aviation, communication and language problems are still commonly listed as contributory factors of accidents and serious incidents. This study investigates the nature of intelligibility and comprehensibility problems arising during controller-pilot interactions, specifically within the context of Runway Incursions (RI). The first moment of this work was composed of a literature review aiming to attain a better insight of communicationrelated problems within the context of RI, which resulted into a compilation of the current most often listed factors. In the second part of the research, civilian aircraft pilots were exposed to a number of auditory inputs and had to perform two types of tasks, a partial transcription and a complete read back of the heard excerpts. Intelligibility was measured by the numbers of words recalled of each sentence, as well as the nature of pieces of information being lost. Comprehensibility was analyzed by the difficulty assessed of each audio on a 9-point Likert Scale, along with comments on what made each instruction difficult. The chosen independent variables were the presence of a plain language segment following a completely phraseological instruction, message length and the type of task being performed. The results have shown that transmissions containing the plain language segment have significantly reduced the performance accuracy of participants. Moreover, sentences containing 4 or more pieces of information seem to have increased the occurrence of the serialposition effect, corroborating previous studies regarding the maximum message length to reduce misunderstandings and information loss.