We have undertaken the task of setting magnetic instruments onboard of the HALO plane for a proof of concept mission. The administrative and technical difficulties associated with such an experiment are considerable. We had to design acquisition chains, buy and modify scientific instruments such that they fit in the allocated space, while respecting the extremely rigid rules imposed in order to have the ”permission to fly” for such an aircraft. It is unfortunate that the original objective to survey the Aegean Sea had to be dropped. The data acquired are nonetheless of good quality and the HALO aircraft, equiped with these magnetic acquisition chains, is very likely suitable for solid Earth exploration campaigns. In that this experiment is a great success. The experience gained during the long preparation of the mission and the test flights is extremely important and valuable for the success of forthcoming aeromagnetic missions.