We've all seen circling minimums published on regular approach charts. But have you ever flown an approach that wasn't designated to any particular runway, and has nothing but circling minimums published?
Trim tabs are a secondary flight control surface that helps you reduce (or eliminate) the need to place pressure on the yoke or rudder to keep your airplane flying straight and level.
GPS and DME are two separate systems that calculate two different types of distance. GPS calculates your distance across the ground, while DME calculates slant range.