AI.II.D — Principles of Flight
AI.II.D for the Flight Instructor Airplane ACS: official objective, references, and 8 exact knowledge, risk-management, and skill descriptions.
FAA-S-ACS-25, November 2023. This study page does not replace the current FAA publication or an examiner's plan of action.
Official task context
| Certificate or rating | Flight Instructor |
|---|---|
| Aircraft category | Airplane |
| Area of operation | Area of Operation II. Technical Subject Areas |
| Task | Task D. Principles of Flight |
| Task code prefix | AI.II.D |
| Official references | FAA-H-8083-2, FAA-H-8083-3, FAA-H-8083-9, FAA-H-8083-23, FAA-H-8083-25; POH/AFM |
| FAA document | FAA-S-ACS-25 — Flight Instructor for Airplane Category Airman Certification Standards |
| FAA source library | Open the official ACS library |
Official task objective
To determine the applicant understands aerodynamics appropriate to the desired instructor certificate, can apply that knowledge, manage associated risks, demonstrate appropriate skills, and provide effective instruction.
What the ACS code means
- AI identifies the ACS standard family used for this Flight Instructor Airplane document.
- II identifies Technical Subject Areas, the Area of Operation.
- D identifies Principles of Flight, the Task within that Area.
- K, R, and S identify knowledge, risk-management, and skill elements. The number selects the item; a trailing lowercase letter identifies a listed sub-element.
Knowledge elements
| ACS code | Official description | How a mock oral can probe it |
|---|---|---|
| AI.II.D.K1 | Airfoil design characteristics. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| AI.II.D.K2 | Airplane stability, maneuverability and controllability. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| AI.II.D.K3 | Turning tendency (e.g., torque, p-factor, spiraling slipstream, and gyroscopic precession). | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| AI.II.D.K4 | Forces acting on an airplane. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| AI.II.D.K5 | Load factors in airplane design. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| AI.II.D.K6 | Wingtip vortices and appropriate precautions. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
Risk management elements
| ACS code | Official description | How a mock oral can probe it |
|---|---|---|
| AI.II.D.R1 | The basic aerodynamic principles of flight. | Work through a scenario by identifying the hazard, evaluating the risk, and explaining a practical mitigation or decision. |
Skills elements
| ACS code | Official description | How a mock oral can probe it |
|---|---|---|
| AI.II.D.S1 | Deliver instruction on principles of flight, including at least three of the elements listed in K1 through K6. | Describe the procedure, interpretation, or decision process that can be discussed during an oral. Physical aircraft performance remains part of the practical test. |
Difficulty data
Difficulty calibration is ongoing for this Task. A difficulty estimate is published only with a sufficiently large, privacy-preserving first directly recorded assessment sample. Any observed difficulty comes from Checkride AI mock-oral practice assessments and is a practice-data proxy, not an FAA practical-test pass or fail rate.
Difficulty calibration remains ongoing until an item clears the private reporting threshold. Percentages, when available, describe the share who needed review on their first directly recorded assessment. Underlying sample sizes are never published, and historical final states are not backfilled into this measure.
How to use this in a mock oral
A mock examiner can ask you to explain the published elements, apply them to the configured aircraft and airport scenario, identify risks, and defend a decision. The prompts are practice scenarios; they are not claimed to be actual FAA examiner scripts or a prediction of the questions you will receive.
Related ACS tasks
- All Flight Instructor Airplane ACS tasks
85 task-level resources from FAA-S-ACS-25.
- AI.II.C — Runway Incursion Avoidance
Area of Operation II. Technical Subject Areas
- AI.II.E — Aircraft Flight Controls and Operation of Systems
Area of Operation II. Technical Subject Areas
- AI.II.A — Human Factors
Area of Operation II. Technical Subject Areas
- AI.II.B — Visual Scanning and Collision Avoidance
Area of Operation II. Technical Subject Areas