Slip to a Landing (ASEL, ASES)

Touch down at a proper pitch attitude within 400 feet beyond or on the specified point, with no side drift, and with the longitudinal axis aligned with and over the runway center/landing path — plus maintain a ground track aligned with the runway center/landing path (AI.VII.M.S9).

Read it as −0 / +400 feet. The box is generous compared with the short-field Task (100 feet) or the power-off 180 (200 feet), which tells you what is actually being graded here: not accuracy, but control of the slip and a clean transition out of it.

Also required:

• Plan and follow a flightpath considering altitude, wind, terrain, and obstructions (S3)
• Select the most suitable touchdown point (S4)
• Position the airplane on downwind parallel to the landing runway (S5)
• Configure correctly (S6)
• As necessary, correlate crosswind with direction of slip and transition to sideslip as appropriate before touchdown (S7)

Both are intentional slips — used to dissipate altitude without increasing airspeed and/or to adjust airplane ground track during a crosswind (AFH ch. 9). A slip occurs when the bank angle is too steep for the existing rate of turn, and an intentional one usually requires deliberate cross-controlling of ailerons and rudder throughout the maneuver, because most airplanes have positive static directional stability and naturally try to compensate.

• Sideslip — entered by lowering a wing and applying just enough opposite rudder to prevent a turn. The longitudinal axis remains parallel to the original flightpath, but the airplane moves somewhat sideways toward the low wing. The amount of slip, and therefore the rate of sideward movement, is determined by the bank angle. This is the crosswind-landing tool.
• Forward slip — used to dissipate altitude and increase descent rate without increasing airspeed. A wing is lowered with aileron and sufficient opposite rudder yaws the nose in the opposite direction so the airplane remains on its original flightpath — but the nose no longer points in the direction of the flightpath. The amount of slip, and therefore the sink rate, is determined by the bank angle. The steeper the bank, the steeper the descent.

Teaching line: "Same controls, different purpose. Sideslip fixes drift and keeps the nose straight; forward slip trades comfort for descent and points the nose off."

Two effects at once (AFH ch. 9): slips are characterized by a marked increase in drag — the airplane is flying sideways through the air, presenting the fuselage broadside — and because the airplane is banked, the vertical component of lift is reduced, allowing an airplane in a slip to descend rapidly without an increase in airspeed.

Energy framing for the student: the slip converts altitude into drag work rather than into kinetic energy. That is exactly why it is useful — flaps do the same thing, but a slip is reversible in a way flaps are not.

In order to use the maneuver to lose altitude, power is normally reduced to idle. The pilot controls airspeed using elevator control.

Follow the AFH's own pattern setup, which places the slip where a student can learn it (AFH ch. 9):

Plan the descent such that a forward slip may be used on final approach. Flaps usually remain retracted, and using a forward slip on downwind or base may be a necessary part of the maneuver.

1. "Abeam the point — power to idle. Now we watch the descent."
2. "Not coming down fast enough on downwind — slipping now. Aileron down into the wind, opposite rudder, nose points off but we track straight."
3. "Coordinated turn to base." (The pilot should make a coordinated turn to base.)
4. "Still high — continuing the slip on base. Ongoing evaluation of height."
5. "Coordinated turn to line up with final." (Make a coordinated turn to line up with the final approach course.)
6. "Established on final, plenty of height — slip in, watching the aiming point walk back to where we want it."
7. "Round out beginning — slip out. Wings level, rudder pressure released with the aileron, pitch to the normal glide attitude."
8. "Normal landing from here."

At the appropriate time, when the round out begins, the pilot removes the forward slip and transitions to a normal landing.

Note the two coordinated turns: you slip on the legs, not through the turns.

In most light airplanes, the steepness of a slip is limited by the amount of rudder travel available. In both sideslips and forward slips, the point may be reached where full rudder is required to maintain heading even though the ailerons are capable of further steepening the bank angle. This is the practical slip limit, because any additional bank would cause the airplane to turn even though full opposite rudder is being applied (AFH ch. 9).

If more descent is needed past that limit: lowering the nose not only increases the sink rate but also increases airspeed. The increase in airspeed increases rudder effectiveness, permitting a steeper slip. Conversely, when the nose is raised, rudder effectiveness decreases and the bank angle should be reduced.

That last sentence is a live safety item: a student who raises the nose in a slip without reducing bank has just exceeded the rudder's ability to stop the turn — near the ground.

Discontinuing a slip is accomplished by leveling the wings and simultaneously releasing the rudder pressure while readjusting the pitch attitude to the normal glide attitude. If the pressure on the rudder is released abruptly, the nose swings too quickly into line and the airplane tends to acquire excess speed (AFH ch. 9).

Why it matters on this Task: excess speed at the round out is float, and float on a −0/+400 approach eats the box you have — and on a short runway it eats the runway. The word to coach is simultaneously: wings, rudder, and pitch, together.

Two related listed errors: late transition to a sideslip during landing with crosswinds and landing without the longitudinal axis parallel to the runway (AFH ch. 9).

Lower the upwind wing — when a crosswind is present, the pilot should lower the upwind wing such that the airplane is banked into the crosswind, since slipping into the wind makes it easier to remain on the original flightpath (AFH ch. 9). Slipping with the crosswind is a listed common error: a slip in the same direction as any crosswind.

The transition the ACS requires: as necessary, correlate crosswind with direction of slip and transition to sideslip as appropriate before touchdown (AI.VII.M.S7). Mechanically the controls do not change dramatically — you are already banked into the wind with opposite rudder — what changes is the objective: you stop yawing the nose off for drag and start using exactly enough bank to cancel drift while the rudder holds the longitudinal axis aligned with the runway.

Coaching sentence for the transition: "Stop slipping for drag, start slipping for drift. Nose straight down the runway now."

The standard leaves no ambiguity about the endpoint — no side drift, longitudinal axis aligned with and over the runway center (AI.VII.M.S8).

Fuel flowage, tail stalls with flaps, and airspeed control (AI.VII.M.R7). Each has a source (AFH ch. 9):

1. Fuel flowage — some airplanes have limitations regarding slips; in some cases slips are limited in duration or by fuel quantity. These limitations are meant to preclude fuel starvation caused when fuel is forced to one side of a tank in uncoordinated flight. In an actual engine-out emergency, the time or fuel limitation is irrelevant (unless a prolonged slip caused the engine issue).
2. Tail stalls with flaps — the AFH states the limitation without the mechanism: for aerodynamic reasons there may also be recommendations or limitations related to slips with flaps extended. Consult the manufacturer's AFM/POH for specific airplane information. The mechanism is elsewhere, and an instructor needs it. Most aircraft have a nose-down pitching moment from the wings because the CG is ahead of the CP. It is the role of the tailplane to counteract this moment by providing a downward force, so actions which move the wing away from stall, such as deployment of flaps or increasing speed, may increase the negative AOA of the tail (IFH ch. 4) — the AFH puts the same point in one line: flap extension increases the AOA of the horizontal stabilizer (AFH ch. 13). Push the tail past its own critical angle and it stalls, the download vanishes, and the aircraft nose pitches down — the opposite of a wing stall, and unrecoverable by pulling. A slip adds a large sideslip angle to a tail already flying near its limit with flaps out, which is why some AFM/POHs restrict the combination. The documented tailplane-stall symptoms are worth knowing: elevator control pulsing, oscillations, or vibrations, and the recovery is retract the flaps to the previous setting and apply appropriate nose-up elevator pressure (IFH ch. 4). This is why the AFH's teaching pattern says flaps usually remain retracted for the demonstration — and why "we always slip with full flaps in this airplane" is not an answer, the POH is.
3. Airspeed control — because of the location of the pitot tube and static vents, airspeed indicators in some airplanes may have considerable error when the airplane is in a slip. Recognize a properly performed slip by the attitude of the airplane, the sound of the airflow, and the feel of the flight controls. Reacting to erroneous airspeed indications is a listed common error.

Make the student find their own airplane's limitation in the POH during the brief. It is the kind of thing that is remembered when it was looked up rather than told.

Eight (AFH ch. 9):

1. Incorrect pitch adjustments that result in poor airspeed control
2. Reacting to erroneous airspeed indications
3. Using excess power while trying to lose altitude
4. A slip in the same direction as any crosswind
5. Poor glidepath control
6. Late transition to a sideslip during landing with crosswinds
7. Landing without the longitudinal axis parallel to the runway
8. Landing off the centerline

Errors 6, 7, and 8 are one error with three names, and they are what the no side drift and aligned with and over the centerline elements of the standard exist to catch.

A forward slip is a deliberately high-drag, cross-controlled, low-airspeed-margin configuration, so each of these lands harder here than on a normal approach.

• b. Windshear — a sudden, drastic shift in wind speed, direction, or both (AFH glossary). The specific hazard is compounding: the natural reaction to a sink is to raise the nose, and in a slip when the nose is raised, rudder effectiveness decreases and the bank angle should be reduced (AFH ch. 9) — a student who pulls without reducing bank has just exceeded the rudder's ability to stop the turn, near the ground. Brief the response: slip out first, then fly the airplane
• c. Tailwind — increases groundspeed and shortens the time available in the slip, so the descent that "should" have worked arrives long. Compounded by the ASI problem: airspeed indicators in some airplanes may have considerable error when the airplane is in a slip (AFH ch. 9), so the student cannot cross-check their way out of it. Recognize the slip by the attitude of the airplane, the sound of the airflow, and the feel of the flight controls
• d. Wake turbulence — a wake encounter is a roll upset, and you are already banked with crossed controls. There is no elegant technique answer: this is a spacing decision made on downwind. If wake avoidance requires staying high, the slip is the tool that gets you down — but plan the slip so it can be removed with altitude remaining
• R3b. LAHSO — the slip exists to lose altitude, and a hold-short constraint requires knowing the landing distance available and stopping within it (PHAK ch. 14). A slip that is carried too far leaves excess speed at the round out — if the pressure on the rudder is released abruptly, the nose swings too quickly into line and the airplane tends to acquire excess speed (AFH ch. 9) — and float is exactly what a hold-short distance cannot absorb. You have the final authority to accept or decline any LAHSO clearance; teach declining it while practicing this Task. (Full LAHSO treatment in Task VII.B.)

The common thread to give the student: this Task's answer to nearly every external disturbance is take the slip out early and fly a normal approach or go around — the slip is a tool, not a commitment.

Correct their model, do not soothe them — the distinction is real and it is the safety argument for the maneuver.

Unlike skids, if an airplane in a slip is made to stall, it displays very little of the yawing tendency that causes a skidding stall to develop into a spin. The airplane in a slip may do little more than tend to roll into a wings-level attitude (AFH ch. 9).

The lethal cousin is the skid — bottom rudder in a turn, the base-to-final overshoot correction — which is the opposite input set and which the AFH lists as a normal-landing common error: a skidding turn from base leg to final approach as a result of overshooting/inadequate wind drift correction (AFH ch. 9).

So the teaching sequence is: fly them the slip at altitude, let them stall it, show them the benign behavior — then fly them the skid recognition (not the stall) and let the contrast do the work. A student who understands why one is docile and the other is not will never again file them under the same heading.

Then reattach the real caution, which is not spins: the risk in a low-altitude slip is airspeed control with an unreliable indicator, and rudder running out as the nose is raised (AI.VII.M.R5, R9).

Because a slip is reversible without penalty and flaps are not. In a real emergency that involves engine failure, the ability to use a forward slip provides a pilot with a technique contributing to a better outcome. In that situation, a pilot may initiate a descent using a forward slip much more quickly than by deploying flaps. To reduce the descent, the pilot can remove the slip without penalty. On the other hand, retracting flaps on an approach could lead to an unwanted loss of altitude (AFH ch. 9).

Two more reasons the AFH gives for the maneuver's existence: intentional slips are especially useful in forced landings and in situations where obstacles need to be cleared during approaches to confined areas, and a slip can also be used as a means of rapidly reducing airspeed in situations where wing flaps are inoperative or not installed.

And a fine-control point worth demonstrating: even with full rudder displacement during a forward slip, the pilot can adjust to the left and right of the intended ground track by increasing and decreasing aileron deflection.

Acknowledge the student's actual objection honestly — the AFH does: some pilots try to avoid using forward slips, because an approach with flaps is more familiar and the sideways force on the occupants during a forward slip may seem uncomfortable.

Three ACS risk elements are specific to this maneuver, and each gets a number or a rule in the brief:

• Low altitude maneuvering, including stall, spin, or CFIT (R5) — set a floor for the slip. Above that altitude the student flies it; below it, the slip is out and the approach is normal or you go around. Fly the first several at altitude before ever bringing one to a runway.
• Surface contact with the airplane's longitudinal axis misaligned (R8) — this is the touchdown failure, and the consequence is quantified elsewhere in the AFH: touchdown while drifting or crabbed imposes extreme side loads on the landing gear and, if severe enough, may cause structural failure, and as little as 10° of cornering angle creates a side load equal to half the supported weight (AFH ch. 9). Your trigger is any touchdown that will not be aligned — take the airplane or go around.
• Unstable approach (R9) — a slipping approach is deliberately unstabilized in the conventional sense, which is why the exit point matters. The AFH's floor still governs the airplane: for a typical GA piston aircraft in a traffic pattern, an immediate go-around should be initiated if the approach becomes unstabilized below 300 ft AGL (AFH ch. 9). Brief where the slip comes out and what "stabilized" means from that point down.

Then the exchange: take the controls and calmly announce, "I have the flight controls" — and take them fully, because there is nothing to be gained by having to fight for control (AIH ch. 9).

Simple-to-complex, then known-to-unknown (AIH ch. 9) — when teaching more than one skill at the same time, the simple-to-complex strategy works well; by starting with the simplest skill, a learner gains confidence and is less likely to become frustrated.

A workable progression:

1. At altitude, wings-level sideslip — one wing down, opposite rudder, heading held. The student feels the cross-control and the yaw the airplane wants to make.
2. At altitude, forward slip to a heading, with attention on attitude, sound, and control feel rather than the ASI (AFH ch. 9) — then compare the ASI reading to establish that it may be wrong.
3. Slip entries and exits, repeatedly, emphasizing the simultaneous recovery — wings, rudder, pitch — since the abrupt release is the error that produces excess speed.
4. Slips on downwind and base, where there is altitude and time (AFH ch. 9's own teaching pattern).
5. Slip on final, out at the round out, then the crosswind correlation and the sideslip transition.

Use learner tells — instructor does between steps 3 and 4: the student calls the entry, the bank, the rudder, and the exit while you fly. It surfaces misconceptions before the learner becomes absorbed in controlling the aircraft (AIH ch. 9).