Forward Slip to a Landing

Same control inputs — bank one way, opposite rudder — different purpose and geometry.

Forward slip: the longitudinal axis is yawed well off the flightpath; the airplane presents its side to the wind for maximum drag, so it descends steeply without gaining airspeed. The ground track continues straight toward the runway.

Side slip: the longitudinal axis stays aligned with the runway; the bank kills crosswind drift. That's the crosswind landing tool.

On a slipped approach in a crosswind, I fly the forward slip and then transition to a side slip before touchdown so the wheels meet the runway aligned (AFH ch 9).

When I'm high and need to lose altitude without gaining speed: flap failure, a power-off approach (engine-out practice or the real thing), obstacle-clearance approaches, or salvaging a high final when a go-around isn't the better answer. It's energy management — the slip converts altitude into drag heat instead of airspeed. Into which wind? Slip into the crosswind (low wing upwind) so the transition to the sideslip for touchdown is seamless.

• Entry: reduce power to idle (typical), lower the upwind wing with aileron, and apply opposite rudder — enough to yaw the nose away from the bank so the track stays on the extended centerline.
• Airspeed: pitch controls airspeed, and the attitude will look unusually nose-low; hold the approach speed.
• Steepness: controlled by bank angle, with rudder to match — up to full rudder deflection as the limit.
• Recovery: level the wings and release the rudder simultaneously, then re-trim and re-establish the normal approach or transition to the sideslip for touchdown (AFH ch 9).

Not necessarily. With the fuselage yawed to the relative wind, the static ports (and pitot) sit in disturbed flow, so the ASI can misread — commonly reading low or fluctuating, direction depends on the airplane and which side the ports are on. The answer is attitude flying: set a known pitch attitude for approach speed before entering, hold it, and treat the ASI with suspicion until the slip is out. Stall awareness stays high, though a properly flown forward slip at approach speed has healthy margin.

Flaps: some aircraft prohibit or advise against slips with full flaps — disturbed airflow over the tail can cause pitch oscillations or, in the extreme, reduced elevator authority (tail-stall territory in some types). Check the POH and placards for your airplane; many, including most PA-28s, have no prohibition.

Fuel: in a prolonged slip with low fuel, the fuel can slosh away from the tank outlet and unport it, starving the engine — the reason slips are held only as long as needed, and why I'd favor the tank on the low wing being the feeding tank if selectable (the ACS calls out fuel flowage explicitly, PA.IV.M.R7).

Touch down at a proper pitch attitude within 400 feet beyond or on the specified point, no side drift, longitudinal axis aligned with and over the runway center or landing path — which means the forward slip must transition to a side slip (or wings-level in calm wind) before touchdown. Ground track stays on centerline throughout. And the standing rule behind all landing tasks: go around if the approach can't be completed within tolerances.

• Touching down misaligned (the slip held too long — side loads on the gear)
• The unstable approach dressed up as a slip (a slip is a controlled tool, not a dive at the runway)
• Airspeed control given the unreliable ASI
• LAHSO implications if accepting land-and-hold-short
• The low-altitude maneuvering/stall-spin picture: cross-controlled flight close to the ground demands that the airspeed and attitude discipline be non-negotiable

The forward slip is cross-controlled by design but flown at approach speed with the nose down — the deadly cousin is the skidding base-to-final turn, which is the opposite input set.