Visual Flight into Instrument Meteorological Condition: A Post Accident Analysis

Abstract

The phenomenon of encountering instrument meteorological conditions (IMCs) while operating an aircraft under visual flight rules (VFRs) remains a primary area of concern. Studies have established that pilots operating under VFRs that continue to operate under IMCs remains a significant cause of accidents in general aviation (GA), resulting in hundreds of fatalities. This research used the Australian Transport Safety Bureau (ATSB) database, which contained a total of 196 VFR to IMC occurrences, from 2003 to 2019, with 26 having formal reports. An explanatory design was adopted, commencing with a qualitative study of the 26 occurrences with reports followed by a quantitative study of all 196 occurrences. Factors investigated included the locations and date of the occurrences, involved aircraft (manufacturer, model, type), pilot details (licenses, ratings, h, and medical), number of fatalities, and causal factors. Fisher’s exact tests were used to highlight significant relationships. Results showed occurrences were more likely to end fatally if (1) they involved private operations, (2) pilots only had a night VFR rating, (3) the pilot chose to push on into IMCs, (4) the pilot did not undertake proper preflight planning consulting aviation weather services, and (5) the pilot had more than 500 h of flight experience. Further results showed occurrences were less likely to end fatally if the meteorological condition was clouds without precipitation, if the pilot held a full instrument rating, or the pilot was assisted via radio. Analysis of the data using the Human Factors Analysis and Classification System (HFACS) framework revealed that errors and violations occur with slightly greater frequency for fatal occurrences than non-fatal occurrences. Quantitative analyses demonstrated that the number of VFR to IMC occurrences have not decreased even though initiatives have been implemented in an attempt to address the issue.