Empirical Studies Concerning Aural Alerts for Cockpit Use Leading to an Aural Alerting Signal Categorization Scheme
Burt, Jennifer L.
MetadataShow full item record
The only way to simplify and promote the effective use of an alerting system that must be comprehensive in its coverage of hazardous or non-normal conditions is to convey top level information that provides an indication of criticality and identity. In an attempt to reduce the number of aural alerting signals presented in aircraft flight decks, this investigation pursued advances toward the development of a simple aural alert categorization scheme that provides flight deck function and urgency level information. In Experiment 1, 20 subjects having "normal" hearing threshold levels provided magnitude estimation urgency ratings for a series of aural alerts. These ratings revealed that subjects perceived low, moderate, and high urgency levels within each of four equally urgent aural alerting sets. In Experiment 2, 12 subjects having "normal" hearing threshold levels participated in a brief training session and then performed a sound identification task in conjunction with an automated and manual tracking task. Sound identification data revealed that subjects correctly identified the alerting set (i.e., major flight deck function) and urgency level associated with each of 12 aural alerts in 96.53% of the trials occurring during automated tracking and in 95.83% of the trials occurring during manual tracking; furthermore, subjects correctly identified each alerting set, urgency level, and aural alert equally often during each tracking task condition. Electroencephalogram (EEG) data recorded throughout the performance of each tracking task condition revealed that manual tracking required a significantly higher level of attentional engagement than automated tracking. Subjective assessments of workload collected after the performance of each tracking task condition revealed that a significantly higher level of workload was experienced during the manual condition of the tracking task than during the automated condition of the tracking task. Collectively, this investigation's results indicated that acoustic parameter manipulations can be used to create four distinctive alerting sets that each convey three levels of urgency and that these alerting sets and urgency levels can be accurately identified when two levels of workload and attentional engagement are experienced.
- Doctoral Dissertations