FFP,
I'm not an IFA but I've done a wee bit of investing and it has done me no harm.
AVC's are tax efficent, since your investment is effectively added to by the tax man. Good if you are on non pensionable pay (which flying pay is) and even better if you are a higher rate tax payer (which you probably are).
If you are risk adverse, you can get into a fixed yield fund - or you can spread your funds if you want to gamble a wee bit.
I would advise personal research unless you have an IFA you can completely trust.
In theory AVC are best if you are staying to 55, but I got in one (big time!) at 38 and made it paid up at 47 when I left. It will spit out in a few years and supplement my pension when I hit 55.
That said if i had put that money into property I would have made a killing, so you pays your money and you takes your chance.
No doubt I'll get flamed for this, but property may be worth a shot in the next year or so when it bottoms out.
good luck