Interview with Prof. Dr. Markus Rapp (click on the picture)
In time for the start of the Berlin Air Show (ILA) and coming straight from joint flight trials with NASA in Palmdale, California, the German Aerospace Center (DLR) Falcon 20 E research aircraft landed at the Berlin Show Ground, where NASA, DLR and the Canadian National Research Council (NRC) held a press conference on 21 May 2014 to discuss their cooperation and to present initial results from the NASA-led ACCESS-II mission (Alternative Fuel Effects on Contrails and Cruise Emissions). With a better carbon dioxide balance and significantly reduced amounts of carbon particulates in the exhaust emissions when compared to kerosene, the biofuels demonstrated the potential of renewable fuels for environment-friendly developments within aviation.
In measuring the biofuel exhaust, the researchers from the DLR Institute of Atmospheric Physics concentrated on the identification of carbon particulates and sulphur compounds, and the size distribution of ice crystals contained in the condensation trails. Initial analysis of the measurements has shown that biofuels substantially cut particulate emissions in the exhaust gases – and soot emissions in particular – when compared with standard kerosene. There is also a distinct reduction in both gaseous and particulate emissions of sulphur compounds. The flight trials were also an ideal setting to measure the microphysical properties of condensation trails when using biofuels. This data enables analysis of possible distinctions in the properties of contrails produced by different fuels, as well as their possible impact on Earth's climate.
A NASA DC-8 using a number of different fuels led the flight formation during the research flights. The DLR Falcon and a NASA Falcon trailed the DC-8 at a distance of roughly 100 metres, collecting data on exhaust gas composition. A CT-133 from the NRC provided support during the measurements. The NASA researchers operated the four engines on the DC-8 alternately with regular Jet A1 aviation fuel and a 1:1 mixture of Jet A1 and the biofuel HEFA which is produced using oil from the Camelina plant.
After ILA, the Falcon is sent to Oberpfaffenhofen to be fitted with another suite of instruments before the research aircraft sets off for the DEEPWAVE mission in New Zealand. There, the Falcon will complete a five-week flight campaign in June and July along the Southern Alps to study atmospheric gravity waves. DEEPWAVE is an acronym for Deep Propagating Gravity Wave Experiment. Gravity waves influence the weather and long-term climate-related atmospheric processes. They are produced when disturbances affect atmospheric circulation systems. The main cause of this phenomenon in New Zealand is the mountainous region located directly adjacent to the Pacific Ocean, which triggers atmospheric waves deep into the middle atmosphere at an altitude of roughly 100 kilometres.
Prof. Dr. Markus Rapp
Dr. Hans Schlager