Northwest WorldPerks has brought back “Fly Free Faster,” a perennial favorite that promotes partner activity. Members can earn 10,000 miles by completing one “qualifying activity” and then earning five partner credits by Sept. 30.

What, pray tell, is a qualifying activity? Well, that’s the thing that makes this a Northwest promotion, not just a boon for its partners. Take two domestic roundtrips, one international roundtrip, successfully apply for the WorldPerks Visa card, or purchase a WorldClubs membership.

Once that’s out of the way, start collecting your partner credits. These range from signing up for MCI or Earthlink to ordering flowers, or can be as common as renting a car or staying at a hotel partner — almost anything goes.

Registration is required by Sept. 15. Check out http://www.nwa.com/offers/fff2005 for the scoop.