I just made Oneworld Emerald on AA and have some extra flying this year and was considering joining BA. The posters over in the oneworld forum thought these questions were better asked here. They deal with qualifying flights and length of the membership year. The goal is BA silver with plans to use the miles to upgrade WT+ to clubworld.

Is a flight just before the 1st qualifying BA flight eligible for accruing tier points? The routing would be JFK-PHX on AA, surface to LAX, then BA flights LAX-LHR-HEL-LHR-CAI. That’s 620 tier points and 4 BA sectors. Would a BA codeshare on Finnair count as a BA sector? I chose JFK-PHX as it is more than 2000 miles and is in first (A class) so it should be 180 tier points. My guess is tht the AA flight may not accrue BA tier points unless it was flown on the same day as the BA flight.

How long is the requalifying period if the flight that passes the threshold is on the 1st day of the month? E.G., if my qualifying flight is 1-Oct, is the requalifying period 1-Oct to 30-Sep or is it 1-Nov to 31-Oct? What would be the requalifying period if the date was 18-Sep?

Does the 12 month period for requalifying start once you reach 600 tier points or is it delayed until the end of the initial 12 month period. If I reach BA silver in Oct, then fly the requalifying flight in Jan, do I have 12 months status from Jan to requalify or is it 12 months from the original Oct date later in the year. Should one wait until the end of the 12 month requalifying period if my intention is only to maintain BA silver status?

Lastly, does the business and first class bonus over base miles flown apply to all OW flights? I understand that the 25% bonus for BA silver only applies to BA and QF flights.