Complex sentence: After the ab-inito phase a candidate possibly progresses to basic trainers/primary trainers, today these are usually turboprop trainers like the Pilatus PC-9 and Embraer Tucano.
Split into simpler sentences: After the ab-inito phase a candidate may progress to basic trainers/primary trainers. These are usually turboprop trainers like the Pilatus PC-9 and Embraer Tucano.