The Circuit
Circuits are flown to promote th orderly flow of traffic, judge changing conditions, get the aircraft in the "landing configuration", mentally adjust the pilot for landing, allow time to minimize stress.
Downwind Leg
The downwind leg begins at 800-1000 feet approximately 45 degrees upwind from the point where the glider will come to rest. At this time a downwind check SWAFTS - STRAPS; WHEEL and WATER, APPROACH AIRSPEED; FLAPS; TRAFFIC; SPOILERS should be done. The aircraft should be trimmed to the appropriate approach speed. There are various formulae to calculate this.
Approach Speed = 1.3Vstall + Vwind (Transport Canada’s
guideline) or,
Approach Speed = 1.5Vstall + .33Vwind (A gliding
alternative)
It is wise to try and judge the crosswind drift on this leg. The
aiming Point is the area where you want to round out the aircraft and you should
be opposite this point at approximately 600 feet on the downwind leg.
Base Leg
As the round out/aiming point passes horizontally
at a 45 degree angle over your shoulder you should be turning on to your base
leg. Crabbing may be necessary to compensate for a crosswind on this leg. Medium
bank turns should be used. No shallow turns! The medium bank turn will
effectively alter the course in most crosswind conditions. Shallow turns may not
accomplish this and can lead to the tendency to use yaw to ‘help’ the turn. This
is can lead to stalls or spins.
Final Leg
Once on final, the aircraft approach
speed should be checked. At this stage you should be 300-400 feet AGL. Use
spoilers/side slip to maintain the glideslope to the Aiming Point and Crab/Side
Slip for drift control.