I'll echo the sentiment that 3 weeks vacation is above average but your 6 on call per week kinda sucks. The way I look at it, my time off has diminishing value the the less time in advance I know it's there. Last year I only flew 200 days for my 91 job, but it was impossible for me to plan trips because I was always on call, making my vacation time my only true 'free' time.