The aircraft was already parked on the apron, since in spite of the fact that we had contracted (and paid) for a hangar, that hangar was still filled with an old ATR52 that was being repaired and painted. But actually, it was quite comfortably cool inside HALO, thanks to an efficient air conditioner. In the hectic hours before takeoff, the cabin is so crowded with all the scientists getting their instruments ready that it is almost impossible to move around, and I sat down in the hangar instead.
I was a bit anxious at this time: Was the aircraft really going to work? Would the instruments perform? Would we be able to convince ATC to let us do the “crazy” flight patterns that our work required? Would I be able to navigate the aircraft through the complex manoeuvers that cloud profiling required? Would the pilots consider the cloud passages safe enough to make these runs time after time? Would too much ice accumulate on the aircraft to keep working?
Looking at the sky I could see that the cirrus in Manaus region was quite dense, which might be a problem for some of our radiation measurements and might suppress cumulus convection. But, to my relief, cumulus had been building since about 1030L (1430Z) and the sky beckoned us to start cloud sampling.
(Photo credits to Meinrat Andreae, Steffen Gemsa, Florian Ewald, Emma Järvinen, and Daniel Fütterer)