As the rest say, it is possible,
I'm an Aeronautical Engineer, doing long hours and studying for the ATPL's. It has been hard, and I am in no doubt it'll remain difficult. I also have other commitments outside work and to be honest I'm scheduled to do three hours a night study for five days a week. I'm lucky if I can do that, but my background helps and I feel I can get away with less but not much. I don't like the idea that I'm scrimping on my studies and want to give it my all, the heart is willing, but by the end of the working day my mind is far from compliant. Having fallen asleep dribbling into my text books. If I could find a job that clears my debts and enables me to live I'd move at the drop of a hat if it gives me a fresher mind for studies and the time to do it.
The key is motivation, I know it's obvious, but it comes easy at the beginning and it'll pull you through but 15+ weeks of no real rest or relaxation takes its toll, and you need to be able to find your motivation, mine jumped down a big hole over December, and the impact is frustration.
Dig deep and you can do it, but something is going to suffer. The means justifies the end!
If I had the cash I'd go full time.
Cheers.
