Originally Posted by
nedsaf
I'm on 11605 status miles and am scheduled to do a return LHR YYC in April, the question I've got is will that 1st flight get me to silver on its own
YYC-LHR earned me 4359 on AC, so will take you to 15964 if you're earning at the same x1.0 rate

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Originally Posted by
nedsaf
I'm eager not to lose any silver miles if I get somewhere

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Presumably you mean Silver benefits here. I'm not sure there are any on AC itself: just about the only benefit for *S is from the 'home' programme's lounges.
If you mean the bonus destiation miles then you'll have to wait a bit longer to get them

, but its only 1000 or so which you can buy if it was make or break for a redemption.