Flight Instructor ACS · Area XIII
AI.XIII Multiengine Operations
3 tasks and 72 knowledge, risk management and skill elements. Each code below is a link target: a code from your test report, such as AI.XIII.A.K1, lands on its own line.
Flight Instructor Airman Certification Standards, FAA-S-ACS-25 (November 2023 edition), effective May 31, 2024 and incorporated by reference in 14 CFR 61.14. Text from the FAA’s ACS page, checked on 11 November 2026. If the FAA has published a newer edition since, the codes and wording may differ: the FAA document is the authority.
AI.XIII.A Maneuvering with One Engine Inoperative (AMEL, AMES)
To determine the applicant understands one engine inoperative, can apply that knowledge, manage associated risks, demonstrate appropriate skills, and provide effective instruction.
- AI.XIII.A.K1Knowledge
- Factors affecting minimum controllable speed (VMC).
- AI.XIII.A.K2Knowledge
- VMC (red line) and best single-engine rate of climb airspeed (VYSE) (blue line).
- AI.XIII.A.K3Knowledge
- How to identify, verify, feather, and secure an inoperative engine.
- AI.XIII.A.K4Knowledge
- Importance of drag reduction, including propeller feathering, gear and flap retraction, the manufacturer's recommended control input and its relation to zero sideslip.
- AI.XIII.A.K5Knowledge
- Feathering, securing, unfeathering, and restarting.
- AI.XIII.A.K6Knowledge
- Common errors related to this Task.
- AI.XIII.A.R1Risk management
- Potential engine failure during flight.
- AI.XIII.A.R2Risk management
- Collision hazards.
- AI.XIII.A.R3Risk management
- Configuring the airplane.
- AI.XIII.A.R4Risk management
- Low altitude maneuvering, including stall, spin, or controlled flight into terrain (CFIT).
- AI.XIII.A.R5Risk management
- Distractions, task prioritization, loss of situational awareness, or disorientation.
- AI.XIII.A.S1Skill
- Recognize an engine failure, maintain control, use manufacturer's memory item procedures, and use appropriate emergency procedures.
- AI.XIII.A.S2Skill
- Set the engine controls, identify and verify the inoperative engine, and feather the appropriate propeller.
- AI.XIII.A.S3Skill
- Use flight controls in the proper combination as recommended by the manufacturer, or as required to maintain best performance, and trim as required.
- AI.XIII.A.S4Skill
- Attempt to determine and resolve the reason for the engine failure.
- AI.XIII.A.S5Skill
- Secure the inoperative engine and monitor the operating engine and make necessary adjustments.
- AI.XIII.A.S6Skill
- Restart the inoperative engine using manufacturer's restart procedures.
- AI.XIII.A.S7Skill
- Maintain altitude ±100 feet or minimum sink rate if applicable, airspeed ±10 knots, and selected headings ±10°.
- AI.XIII.A.S8Skill
- Complete the appropriate checklist(s).
- AI.XIII.A.S9Skill
- Analyze and correct common errors related to this Task.
AI.XIII.B VMC Demonstration (AMEL, AMES)
To determine the applicant understands VMC demonstration, can apply that knowledge, manage associated risks, demonstrate appropriate skills, and provide effective instruction.
- AI.XIII.B.K1Knowledge
- Purpose of the maneuver.
- AI.XIII.B.K2Knowledge
- Proper procedures for maneuver entry and safe recovery.
- AI.XIII.B.K3Knowledge
- Factors affecting VMC and how VMC differs from stall speed (VS).
- AI.XIII.B.K4Knowledge
- VMC (red line), VYSE (blue line), and safe single-engine speed (VSSE).
- AI.XIII.B.K5Knowledge
- Cause of loss of directional control at airspeeds below VMC.
- AI.XIII.B.K6Knowledge
- Common errors related to this Task.
- AI.XIII.B.R1Risk management
- Configuring the airplane.
- AI.XIII.B.R2Risk management
- Maneuvering with one engine inoperative.
- AI.XIII.B.R3Risk management
- Distractions, task prioritization, loss of situational awareness, or disorientation.
- AI.XIII.B.S1Skill
- Configure the airplane in accordance with the manufacturer's recommendations, in the absence of the manufacturer's recommendations, then at safe single-engine speed (VSSE/VYSE), as appropriate, and:
- AI.XIII.B.S1aSkill
- Landing gear retracted
- AI.XIII.B.S1bSkill
- Flaps set for takeoff
- AI.XIII.B.S1cSkill
- Cowl flaps set for takeoff
- AI.XIII.B.S1dSkill
- Trim set for takeoff
- AI.XIII.B.S1eSkill
- Propellers set for high revolutions per minute (rpm)
- AI.XIII.B.S1fSkill
- Power on critical engine reduced to idle and propeller windmilling
- AI.XIII.B.S1gSkill
- Power on operating engine set to takeoff or maximum available power
- AI.XIII.B.S2Skill
- Establish a single-engine climb attitude with the airspeed at approximately 10 knots above VSSE.
- AI.XIII.B.S3Skill
- Establish a bank angle not to exceed 5° toward the operating engine, as required for best performance and controllability.
- AI.XIII.B.S4Skill
- Increase the pitch attitude slowly to reduce the airspeed at approximately 1 knot per second while applying increased rudder pressure as needed to maintain directional control.
- AI.XIII.B.S5Skill
- Recognize and recover at the first indication of loss of directional control, stall warning, or buffet.
- AI.XIII.B.S6Skill
- Recover promptly by simultaneously reducing power sufficiently on the operating engine, decreasing the angle of attack as necessary to regain airspeed and directional control, and without adding power on the simulated failed engine.
- AI.XIII.B.S7Skill
- Recover within 20° of entry heading.
- AI.XIII.B.S8Skill
- Advance power smoothly on the operating engine and accelerate to VSSE/VYSE, as appropriate, ±5 knots during recovery.
- AI.XIII.B.S9Skill
- Analyze and correct common errors related to this Task.
AI.XIII.C Demonstration of Effects of Various Airspeeds and Configurations during Engine Inoperative Performance (AMEL and AMES)
To determine the applicant understands the effects of various airspeeds and configurations during engine inoperative performance, can apply that knowledge, manage associated risks, demonstrate appropriate skills, and provide effective instruction.
- AI.XIII.C.K1Knowledge
- Purpose for and elements of demonstration of effects of various airspeeds and configurations during engine inoperative performance.
- AI.XIII.C.K2Knowledge
- Selection of appropriate altitude for the demonstration.
- AI.XIII.C.K3Knowledge
- Proper entry procedure to include pitch attitude, bank attitude, and airspeed.
- AI.XIII.C.K4Knowledge
- Effects on performance of airspeed changes at, above, and below VYSE.
- AI.XIII.C.K5Knowledge
- Effects on performance of various configurations including:
- AI.XIII.C.K5aKnowledge
- Landing gear extended
- AI.XIII.C.K5bKnowledge
- Wing flaps extended
- AI.XIII.C.K5cKnowledge
- Landing gear and wing flaps extended
- AI.XIII.C.K5dKnowledge
- Windmilling propeller on the inoperative engine
- AI.XIII.C.K6Knowledge
- Airspeed control throughout the demonstration.
- AI.XIII.C.K7Knowledge
- Smooth control technique and coordination throughout the demonstration.
- AI.XIII.C.K8Knowledge
- Common errors related to this Task.
- AI.XIII.C.R1Risk management
- Altitude selection.
- AI.XIII.C.R2Risk management
- Entry and recovery procedures.
- AI.XIII.C.R3Risk management
- Loss of control or stall.
- AI.XIII.C.R4Risk management
- Configuring the airplane.
- AI.XIII.C.R5Risk management
- Collision hazards.
- AI.XIII.C.R6Risk management
- Distractions, task prioritization, loss of situational awareness, or disorientation.
- AI.XIII.C.S1Skill
- Demonstrate, describe, and explain effects of various airspeeds and configurations during engine inoperative performance.
- AI.XIII.C.S2Skill
- Demonstrate smooth control inputs when transitioning between various airspeeds and configurations, which include:
- AI.XIII.C.S2aSkill
- Landing gear extended
- AI.XIII.C.S2bSkill
- Wing flaps extended
- AI.XIII.C.S2cSkill
- Landing gear and wing flaps extended
- AI.XIII.C.S2dSkill
- Windmilling propeller on the inoperative engine
- AI.XIII.C.S3Skill
- Maintain appropriate airspeed, attitude, and altitude combinations for the various configurations.
- AI.XIII.C.S4Skill
- Return to normal cruise flight at the altitude and heading specified by the evaluator.
- AI.XIII.C.S5Skill
- Analyze and correct common errors related to this Task.
Other areas in this standard
FI.I Fundamentals of Instructing6 tasksAI.II Technical Subject Areas16 tasksAI.III Preflight Preparation3 tasksAI.IV Preflight Lesson on a Maneuver to be Performed in Flight1 taskAI.V Preflight Procedures6 tasksAI.VI Airport and Seaplane Base Operations2 tasksAI.VII Takeoffs, Landings, and Go-Arounds15 tasksAI.VIII Fundamentals of Flight4 tasksAI.IX Performance and Ground Reference Maneuvers6 tasksAI.X Slow flight, Stalls, and Spins9 tasksAI.XI Basic Instrument Maneuvers5 tasksAI.XII Emergency Operations7 tasksAI.XIV Postflight Procedures2 tasks
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Last updated 11 November 2026.