Operational Concept Development and Evaluation of Pilots Acceptance of the GLASS SBAS to GLS Converter

Kurzfassung

The wide availability of SBAS and the commonness of GLS equipment on commercial air transportation aircraft led to the development and flight testing of the SBAS to GLS converter by DLR. The aim of this thesis is to develop an operational concept, consisting of an approach chart with corresponding operations that can be applied to implement GLASS technology in commercial aviation. Different factors such as safety, pilot’s satisfaction and clearness of the chart were used to analyze the quality of the chart and the operation. Two different charts with the corresponding operations were developed. One is a modified RNP chart, to which the information required for GLASS is added. The other option is a separate GLS chart, with the remark, that is based on LPV. A crew task distribution model with the focus on Airbus A320 aircraft was developed for both variants. Both charts and the corresponding crew task distribution models were tested with airline pilots in an A320 full flight training simulator. Every pilot flew both approach variants as pilot flying and pilot monitoring. The flight data was recorded for later use and the participants filled in two types of questionnaires. The recorded data shows that both variants performed well, and the aircraft always remained within operational limits. Only few differences could be found. Most of those differences could not be correlated to the approach operation but to other reasons. Only the final intercept was performed slightly better during the RNP operation. The workload was measured during the simulator flights by using the well-known NASA-TLX . Results of these measurements are in favor of the GLS variant, as it results in lower workload for the flight crews. Another questionnaire inquired about the pilots’ preferences and additional feedback. The results also show an advantage of the GLS, as all pilots prefer this variant. These advantages may be a result of the manual tuning of the GLS channel in the RNP variant of the approach. Unlike other approaches on Airbus A320, the backup tuning must be used during the RNP variant. Overall, the GLS is the better variant for implementation with an A320 fleet. Further studies should focus on other aircraft types to verify the results and eliminate the influence of backup tuning. A study with more pilots in a Boeing 737 simulator would complement this study well.