Private pilot · ACS PA.X.B · Instructor lesson plan

VMC Demonstration

Student pack: Train: VMC Demonstration · Full lesson: Prepare guide

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1 · Objective

By the end of this lesson your student can explain vmc demonstration in their own words, apply it in a realistic situation, and fly it to the ACS standard for PA.X.B.

Why it matters for safety: Below VMC with asymmetric power, the airplane yaws and rolls toward the dead engine, and at low altitude that is fatal. The demonstration shows, at a safe altitude, what the edge feels like and that the recovery is to reduce power, not to add it, so the reflex is right if it ever happens for real.

2 · Assign before the lesson

Pre-work: the free Train pack, VMC Demonstration. Feel the loss of directional control at altitude, and recover at the first sign, within 20° of heading.

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Pack: pilotprep.pro/train/ppl/vmc-demonstration · Full lesson: pilotprep.pro/prepare/ppl/vmc-demonstration

3 · Teach sequence

Key points to land

Published VMC (the red line) is the slowest speed at which you can keep control with the critical engine suddenly inoperative, then hold straight flight with no more than 5° of bank. It is set under fixed conditions: sea-level standard day; maximum takeoff power on the operating engine; the critical engine windmilling with its propeller control in the takeoff position; the most unfavorable weight (the lightest) and the most unfavorable (aft) center of gravity; gear up; wing and cowl flaps and trim in the takeoff position; out of ground effect; no more than 5° of bank toward the operating engine; heading held within 20° with no more than 150 pounds of rudder force.(14 CFR 23.149 (now 23.2135); Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
VMC is about directional control; VS is about the wing. Where the stall would come first (at altitude, or at light weight), a stall with asymmetric power can roll into a spin.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
Configure per the manufacturer (or: gear up, flaps and cowl flaps for takeoff, trim for takeoff, propellers high RPM, critical engine idle with the propeller windmilling, the other at maximum power).(Private Pilot ACS (FAA-S-ACS-6C), PA.X.B.S1)
Enter in a single-engine climb attitude about 10 knots above VSSE or VYSE, whichever is higher, with up to 5° bank toward the operating engine, then slow about 1 knot per second, adding rudder.(Private Pilot ACS (FAA-S-ACS-6C), PA.X.B.S2-S4)
Recover at the first sign of lost directional control, a stall warning or buffet: reduce power on the operating engine and lower the nose. Never add power to the "failed" engine.(Private Pilot ACS (FAA-S-ACS-6C), PA.X.B.S5-S6)
Recover within 20° of the entry heading, then add power on the operating engine only and accelerate to VSSE or VYSE +10/-5 knots.(Private Pilot ACS (FAA-S-ACS-6C), PA.X.B.S7-S8)
Complete the recovery no lower than 3,000 feet AGL, or the manufacturer's higher altitude.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes; Private Pilot ACS (FAA-S-ACS-6C), Appendix 2)

VMC versus stall

Published VMC (the red line) is the slowest speed at which you can keep control with the critical engine suddenly inoperative, then hold straight flight with no more than 5° of bank. It is set under fixed conditions: sea-level standard day; maximum takeoff power on the operating engine; the critical engine windmilling with its propeller control in the takeoff position; the most unfavorable weight (the lightest) and the most unfavorable (aft) center of gravity; gear up; wing and cowl flaps and trim in the takeoff position; out of ground effect; no more than 5° of bank toward the operating engine; heading held within 20° with no more than 150 pounds of rudder force.(14 CFR 23.149 (now 23.2135); Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
Your real VMC differs whenever the conditions do. It goes up with a windmilling propeller (feathering lowers it), an aft CG, lighter weight, more power on the operating engine, and less bank toward it. It goes down with less power (a normally aspirated engine at altitude; a turbocharged one only above its critical altitude), gear extended (keel effect), and ground effect.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
Bank matters most: VMC rises more than 3 knots for each degree of bank less than 5°, and with the wings level control can be lost almost 20 knots above the published red line. Up to 5° toward the operating engine is the certification number, not the way you fly.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
The critical engine is the one whose failure is hardest to control: on twins with both propellers turning clockwise (seen from behind), the left, because of P-factor, accelerated slipstream, spiraling slipstream and torque. Twins with counter-rotating propellers (a Seminole or a Duchess) have no critical engine.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
VMC (red line): minimum control speed. VYSE (blue line): best rate of climb, or least loss, on one engine. VXSE: best angle on one engine. VSSE: safe single-engine speed, the slowest at which an engine may be intentionally failed in training.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
Below VMC, the rudder can't make enough force to counter the yaw from the operating engine, so the airplane yaws and then rolls toward the inoperative engine.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
In a normally aspirated twin VMC falls as density altitude rises (less power), while the indicated stall speed stays about the same, so at some altitude they meet. In a turbocharged twin VMC stays roughly constant up to the critical altitude, then falls. Where they meet, a stall can come before loss of control.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)

Entry and recovery

Configure as the manufacturer says, with takeoff trim, at a safe altitude, clear of traffic. Enter in a single-engine climb attitude about 10 knots above VSSE or VYSE, whichever is higher, with up to 5° of bank toward the operating engine.(Private Pilot ACS (FAA-S-ACS-6C), PA.X.B.S1-S3)
Raise the nose slowly (about a knot per second), adding rudder to hold heading, until the first sign: full rudder and the heading still drifting, a stall warning or buffet.(Private Pilot ACS (FAA-S-ACS-6C), PA.X.B.S4-S5)
Recover: reduce power on the operating engine and lower the nose together. Once control returns, add power on the operating engine only and accelerate to VSSE or VYSE, holding the entry heading within 20°, before power comes back on the simulated failed engine.(Private Pilot ACS (FAA-S-ACS-6C), PA.X.B.S6-S8)
Where the stall would come before loss of control, an instructor can block part of the rudder travel to bring the loss of control well above the stall. That is an instructor technique only, and you still recover at the first sign of lost control, a stall warning or buffet.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
The recovery must be complete no lower than 3,000 feet AGL, or the manufacturer's higher recommendation: plan the entry altitude from that.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes; Private Pilot ACS (FAA-S-ACS-6C), Appendix 2)

Flying it safely

Configuring: a wrong configuration changes the VMC you meet; gear down or flaps out lowers it and hides the edge.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
Maneuvering on one engine: every maneuver is flown with VMC in mind, at blue line or above, with zero sideslip (about 2-3° bank and the ball one-third to one-half out toward the operating engine).(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
Distraction: watch heading, airspeed and the stall warning together; one person, the instructor or evaluator, is ready to restore power.(Risk Management Handbook (FAA-H-8083-2A))
Clear the area, and keep scanning for traffic while you handle the failure.(AC 90-48, Pilots' Role in Collision Avoidance)

Watch for in the airplane: Your instructor watches for a correct configuration, a slow deceleration with increasing rudder, recognition of the first sign, the recovery by reducing power (never adding it on the idle engine), heading kept within 20°, acceleration to the right speed, and recovery complete above 3,000 feet AGL.

4 · Ask your student

In order: recall, then understanding, then applying it. Move up only when the answer shows it.

Recall · What is VMC?
A strong answer: The minimum speed for directional control with the critical engine suddenly inoperative, under the certification conditions.
Understand · Why reduce power on the good engine to recover?
A strong answer: The yaw comes from that engine's thrust; reducing it, and lowering the nose for speed, restores control.
Apply · During the demonstration the stall horn sounds before you lose directional control. What do you do?
A strong answer: Recover immediately: reduce power on the operating engine and lower the nose. A stall with asymmetric power can lead to a spin.

Scenarios to talk through

At full rudder the heading keeps drifting toward the idle engine. What does this mean?
Sound decision: You've reached VMC. Reduce power on the operating engine and lower the nose.
The demonstration is planned at 10,000 feet density altitude in a normally aspirated twin. What's the concern?
Sound decision: VMC may be below the stall speed there; the stall comes first, with asymmetric power. Fly it lower (still completing above 3,000 feet AGL), or the instructor limits rudder.
You lose directional control and instinctively push the idle engine's throttle forward. What's wrong with that?
Sound decision: The recovery is to reduce power on the operating engine, not add power to the other; in a real failure that engine gives nothing.

5 · Common student errors

Slowing too quickly.
Why it matters: You overshoot the first sign.
How to correct it: About 1 knot per second.
Recovering by adding power to the idle engine.
Why it matters: Builds the wrong reflex.
How to correct it: Reduce power on the operating engine.
Flying it with the wings level.
Why it matters: Loss of control comes much faster than the red line suggests.
How to correct it: Up to 5° of bank toward the operating engine.

6 · Completion standard

Configure per the manufacturer; enter about 10 knots above VSSE or VYSE; bank no more than 5° toward the operating engine; slow about 1 knot per second.
Recover at the first sign, reducing power on the operating engine and lowering the nose, within 20° of entry heading; accelerate to VSSE or VYSE +10/-5 knots.
Your student answers each "Ask your student" question in their own words, up to the Apply level, without prompting.
They talk through the scenarios and reach a safe, legal decision, explaining why.
They complete the pack’s quick check and can say what they flagged.

Area trained? Close out with a practice oral focused on PA.X.B: pilotprep.pro/exam?exam=PPL&focus=PA.X.B

7 · References

Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes
Instrument Flying Handbook (FAA-H-8083-15B)
Risk Management Handbook (FAA-H-8083-2A)
Private Pilot ACS (FAA-S-ACS-6C), Areas IX and X (multiengine)
Your airplane's POH/AFM, Emergency Procedures; Performance
14 CFR 23.149 (now 23.2135), Minimum control speed
Airman Certification Standards, task PA.X.B

PilotPrep instructor lesson plan, from the VMC Demonstration lesson (checked against current FAA sources 2026-11-13). A study and teaching aid, not FAA guidance; teach to your own judgment and the current ACS.