The Forward Slip to Landing, the Airspeed Indicator That Lies When You Need It Most, and the Three Mistakes Every Examiner Sees on Checkride Day

The forward slip is one of the most misunderstood maneuvers in basic aircraft control - not because it’s technically complex, but because crossed controls feel wrong by design, and the airspeed indicator becomes unreliable at the exact moment you’re depending on it. The Airman Certification Standards (ACS) require every private pilot candidate to demonstrate it, yet most students arrive at their checkride with only three or four total slips in their logbook. That’s not enough to fly it confidently when it counts.

What Is a Forward Slip, and How Is It Different from a Skid?

The terms slip and skid describe opposite control geometries, and the difference matters.

In a slip, the nose is pointed in a different direction than the actual flight path. The aircraft moves partially sideways through the air, and that sideways presentation to the relative wind dramatically increases drag. The result: a steep descent without a corresponding increase in airspeed. You go down fast without going fast.

In a skid, the tail swings wide in the direction of the turn - think of a car with its rear end sliding out. At low altitude, a skid is dangerous because it sets up the cross-controlled stall accident chain. The student overshoots final, kicks in aggressive rudder to haul the nose toward the runway, and the outside wing stalls before there’s altitude to recover.

A forward slip is not a skid. You are not turning, not in an inadvertent condition, and you have altitude to manage. Context changes everything.

When Should You Use a Forward Slip?

The classic scenario: you’re high on final with nowhere to put the extra altitude. Maybe the pattern ran wider than planned, maybe the wind on downwind fooled you, maybe the sight picture at an unfamiliar airport isn’t what you expected. You have three options - go around, manage with configuration changes, or slip.

The forward slip also has specific applications beyond a high final:

• Flap malfunction. If flaps are stuck up, you’re landing faster and flatter. A slip adds drag in a clean configuration and steepens the approach angle.
• Engine-out emergencies. Without throttle to manage the glide path, a slip gives you altitude control on the way into a short or confined field.

One critical note before flying any slip: some aircraft prohibit slips with flaps extended. Certain older Cessna designs, some experimentals, and other airframes carry placard prohibitions or partial-flap limitations because of pitch behavior or control effectiveness specific to that airframe. Read your pilot’s operating handbook (POH) and know what your checkride aircraft says before the examiner asks.

How Do You Fly the Forward Slip?

Step 1: Choose a direction. Slipping left means left aileron with right rudder to hold the nose on runway heading. Slipping right means right aileron with left rudder. Either direction works on a straight-in with no crosswind. Some instructors prefer to match slip direction to any crosswind component present, so you’re already partially set up for the crosswind correction at the flare.

Step 2: Apply the inputs together. Apply 15 to 30 degrees of bank with aileron, and simultaneously apply opposite rudder to prevent the bank from becoming a turn. The aileron banks the aircraft; the rudder holds the nose pointed at the runway. The aircraft now presents its side to the relative wind and descends steeply without accelerating.

Step 3: Stop scanning the airspeed indicator. The pitot tube measures ram air pressure from air flowing directly into its opening. When the aircraft is slipping sideways, the angle of the relative wind to that opening changes, producing a reading that can be falsely low or falsely high - which direction, and by how much, depends on the specific aircraft and where its pitot tube is mounted. That information is in your POH. During the slip, manage the maneuver by pitch attitude and aim point, not by airspeed.

Step 4: Fly the aim point. The geometry of the aim point works the same as any approach. If it’s rising in your windshield, you’ll land short. If it’s falling, you’ll float past. If it holds steady, that’s your landing spot. The slip changes your descent rate - it doesn’t change how the aim point behaves.

How Do You Exit the Slip?

This is where most checkride mistakes happen.

You cannot exit the slip and flare simultaneously. The aircraft needs a moment to stabilize after the crossed controls are released before the flare begins. Trying to roll wings level, center the rudder, and initiate the flare all at once at 50 feet is asking too much of both pilot and airplane.

Plan to exit the slip at approximately 100 to 150 feet AGL - early enough to fly a brief, clean short final before the flare. If you exit and you’re still significantly high, go around. That is not a failure; that is good airmanship.

When you do exit, roll wings level and release the opposite rudder simultaneously. Both inputs come off together. Rolling wings level while leaving the rudder in creates a skid - exactly what you were not trying to do. Come off both at once, let the aircraft straighten, then fly the short final and flare normally.

After the slip, the nose should be aligned with the runway centerline. If you slipped left and rolled out pointing left of centerline, you drifted during the maneuver. Catch that with a correction on short final before the flare.

Why Does the Slip Feel So Physical?

Slips are more demanding than most students expect. The controls feel heavy because you’re holding them against each other - the aircraft wants to straighten, and you have to consciously prevent it. The natural tendency is to ease off the aileron or let the rudder creep back toward center because maintaining the inputs feels unnatural. The moment you ease off, the slip relaxes and you stop descending aggressively.

Building real proficiency means building the muscle memory to hold those inputs firmly. That takes repetition, not just exposure.

What Are the Three Most Common Checkride Mistakes?

1. Timid inputs. A shallow bank with a little rudder barely changes the descent rate. If you’re going to slip, commit to it. The aircraft can handle 15 to 30 degrees of bank with firm opposite rudder. Half-hearted inputs produce a slip that does nothing useful.

2. Nose yaw during the slip. If the nose drifts in the direction of the slip, there isn’t enough opposite rudder in. The entire purpose of the maneuver is to keep the nose pointed at the runway while the aircraft moves sideways. Add more rudder and hold it.

3. Exiting the slip too late. Students hold crossed controls to 50 feet and then try to recover while flaring. The transition needs enough altitude to let the aircraft stabilize. Exiting at 100 to 150 feet AGL is not too early - if the slip has done its job, let it go and fly a clean short final.

How Do You Build Real Proficiency Before the Checkride?

The ACS requires landing within 300 feet of a designated landing point. A student who slips properly but exits late and rolls out 500 feet down the runway hasn’t met the standard, regardless of how clean the slip looked. The examiner is also watching for genuine judgment - recognizing the actual need for the slip - not a rehearsed sequence.

On your next several solo flights, fly at least one approach as a deliberate slip approach. Not because you’re high - set it up intentionally. Get on a long final, establish the slip at a comfortable altitude, hold it through the approach, and execute the transition and landing. Do this repeatedly, until holding aileron and opposite rudder no longer feels like fighting the airplane.

Then practice it from a genuinely high position. Enter steep on purpose and slip to correct it. The judgment of when to enter and when to exit only develops from flying it in real conditions.

The FAA Airplane Flying Handbook covers slips in a dedicated section and is worth reading the night before a practice session. The Private Pilot Airman Certification Standards defines exactly what the examiner is required to evaluate. Both documents are free downloads at faa.gov.

Key Takeaways

• The forward slip uses intentional crossed controls - aileron and opposite rudder - to create a steep descent without a corresponding increase in airspeed.
• The airspeed indicator is unreliable during a forward slip; manage the maneuver with pitch attitude and aim point instead, and check your POH for how your specific aircraft is affected.
• Apply 15 to 30 degrees of bank with firm, committed opposite rudder. Timid inputs produce a slip that does nothing useful.
• Exit the slip at approximately 100 to 150 feet AGL, rolling wings level and releasing rudder simultaneously - never one after the other.
• The ACS requires landing within 300 feet of the designated landing point. Exit timing and runway alignment after the slip matter as much as the maneuver itself.