HI.II.D — Principles of Flight
HI.II.D for the Flight Instructor Rotorcraft ACS: official objective, references, and 15 exact knowledge, risk-management, and skill descriptions.
FAA-S-ACS-29, 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 | Rotorcraft |
| Area of operation | Area of Operation II. Technical Subject Areas |
| Task | Task D. Principles of Flight |
| Task code prefix | HI.II.D |
| Official references | FAA-H-8083-2, FAA-H-8083-4, FAA-H-8083-9, FAA-H-8083-21, FAA-H-8083-25; POH/RFM |
| FAA document | FAA-S-ACS-29 — Flight Instructor for Rotorcraft Category Helicopter Rating 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
- HI identifies the ACS standard family used for this Flight Instructor Rotorcraft 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 |
|---|---|---|
| HI.II.D.K1 | Lift, weight, thrust, and drag. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| HI.II.D.K2 | Airfoils, including terminology, definitions, and types. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| HI.II.D.K3 | Torque effect and translating tendency. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| HI.II.D.K4 | Gyroscopic precession. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| HI.II.D.K5 | Blade flapping and coning. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| HI.II.D.K6 | Coriolis effect. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| HI.II.D.K7 | Pendular action. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| HI.II.D.K8 | Dissymmetry of lift. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| HI.II.D.K9 | Retreating blade stall. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| HI.II.D.K10 | Translational lift, including effective translational lift (ETL). | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| HI.II.D.K11 | Transverse flow effect. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| HI.II.D.K12 | Aerodynamics of autorotative flight. | Explain the element, apply it to a scenario, and connect the answer to current references or aircraft information when relevant. |
| HI.II.D.K13 | Rotor system characteristics. | 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 |
|---|---|---|
| HI.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 |
|---|---|---|
| HI.II.D.S1 | Deliver instruction on principles of flight, including at least three of the elements listed K1 through K13. | 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 Rotorcraft ACS tasks
65 task-level resources from FAA-S-ACS-29.
- HI.II.C — Runway Incursion Avoidance
Area of Operation II. Technical Subject Areas
- HI.II.E — Flight Controls
Area of Operation II. Technical Subject Areas
- HI.II.A — Human Factors
Area of Operation II. Technical Subject Areas
- HI.II.B — Visual Scanning and Collision Avoidance
Area of Operation II. Technical Subject Areas