I passed all mine first time while working full time - and very long hours too. It was a bit of a nightmare sometimes as I put my social life (what social life) on hold for over a year, but emerged with good grades which is what I wanted to achieve. I found it good to be disciplined - I gave myself clearly defined 'work' and 'study' phases throughout the day and focused exclusively on both in turn so I could get my work done ASAP and escape home in the evening for another couple of hours of study. I also spend almost every weekend in the office (!) as it was much quieter than being at home and it meant there were no distractions. I tried to leave weekend evenings free though and around half of Sunday.
It has been said before, but feedback is the key - I used Oxford for my distance learning and found their feedback to be excellent. I also used the Keith Williams books to supplement my notes for Instruments and Aircraft general. They were very good.
Good luck - it can be done!