Parker Velcon Aviation Jet Fuel and Diesel Fuel Filtration Parker Velcon solutions are designed for Energy Institute Qualified commercial aviation jet fuel handling and filtration. View Available Solutions Parker CLEANDiesel filtration solutions designed for ultra clean fuel required by today's Tier 4F and Stage IV high pressure common rail engines. Velcon OS-51288 Aviation Fuel Filter Cartridge - Henrich Velcon OS-51288 Aviation Fuel Filter Cartridge is a 0.5 micron element for a VF-61 housing. This OS series combination coalescer/separator cartridges filter dirt and remove water from aviation fuels. Performance is improved due to Teflon® coated screen separators and reliable radial sump seals.