ACS study guide

Use the ACS as the test contract: every missed-test code points to an Area, Task, and knowledge element (for example, UA.I.B.K10 means UAS, Area I, Task B, Knowledge element 10). Learn concepts by scenario, not as isolated numbers.

I. Regulations (15–25%)

A. General — UA.I.A

Know when Parts 89 and 107 apply, the regulatory definitions, and the effects of falsifying a certificate or record. Be able to decide whether an event is FAA- reportable and what records or evidence the FAA may inspect.

High-yield concepts:

• An sUAS is an unmanned aircraft and associated elements needed for safe and efficient operation; “small” means less than 55 pounds at takeoff, including everything onboard or attached.
• Report a qualifying accident to the FAA within 10 calendar days. Learn the injury/loss-of-consciousness and property-damage thresholds directly from the current §107.9 before the exam; exclude damage to the sUAS when applying the property threshold.
• The remote PIC must make required documents and the aircraft available to the FAA on request and may need to demonstrate compliance.

B. Operating rules — UA.I.B

Be able to apply, not merely recite:

• Remote PIC authority and responsibility; control manipulation by another person; safe condition; preflight assessment.
• No careless/reckless operation, unsafe dropping, hazardous materials, or one person acting as remote PIC/visual observer for more than one operation at once.
• Yield right-of-way to all aircraft and never pass over, under, or ahead unless well clear. Maintain visual line of sight without relying on binoculars.
• Baseline limits: 87 knots (100 mph) groundspeed; no higher than 400 feet AGL, except within 400 feet of a structure when remaining no more than 400 feet above its immediate uppermost limit; at least 3 statute miles flight visibility; 500 feet below and 2,000 feet horizontally from clouds.
• Controlled airspace authorization is required in Class B, C, D, and the surface area of Class E designated for an airport. Class G does not itself require ATC authorization, but every other rule still applies.
• Night flight requires current knowledge/training and an anti-collision light visible for at least 3 statute miles, with intensity reducible when safety warrants. Know civil-twilight treatment.
• Alcohol/drugs: know the 8-hour “bottle to controls” rule, the 0.04% blood- alcohol limit, impairment prohibition, and testing/refusal consequences.
• Understand the narrow conditions for operations from a moving vehicle and for carriage of property for compensation or hire.
• Transponder and ADS-B Out prohibitions for sUAS unless otherwise authorized.

C–D. Certification and waivers — UA.I.C–D

Know eligibility, the 24-calendar-month recency requirement, drug/alcohol offenses, and which rules can be waived. A waiver is risk-based relief from a specified rule; it is not blanket permission and its provisions must be followed. Airspace authorization and a Part 107 waiver solve different problems.

E. Operations over people — UA.I.E

Learn the four categories as a decision tree. Key distinctions include aircraft weight/impact-energy eligibility, exposed rotating parts, declarations or means of compliance, labeling, maintenance, sustained flight over open-air assemblies, and whether Remote ID is required. “Briefly crossing above someone” is still an operation over a person; do not treat transience as automatic permission.

For any scenario ask:

1. Is each person directly participating, under a covered structure or stationary vehicle, or exposed?
2. Which Category (1–4) is the aircraft and operation eligible for?
3. Is flight sustained over an open-air assembly? If so, does the required Remote ID condition apply?
4. Are night, moving-vehicle, airspace, and site restrictions also satisfied?

Because aircraft declarations and eligible models change, verify operational eligibility against current FAA records rather than inferring it from marketing.

F. Remote Identification — UA.I.F

Distinguish:

• Standard Remote ID aircraft: broadcasts identification/location information from takeoff through shutdown.
• An aircraft using a broadcast module: the pilot must keep the aircraft in VLOS and the module has its own operational/registration considerations.
• Operations in an FAA-Recognized Identification Area (FRIA): follow the FRIA conditions, including VLOS and location boundaries.
• Limited exceptions such as specific FAA authorization or aeronautical research are not general workarounds.

Know broadcast message concepts, product labeling, preflight confirmation that Remote ID is functioning, and what to do after an in-flight failure. ADS-B Out is not a substitute and is generally prohibited for Part 107 sUAS.

II. Airspace and requirements (15–25%)

A. Classification — UA.II.A

Be able to read a sectional chart and identify Classes B, C, D, E, and G both laterally and vertically. Learn the chart symbology and typical—but not assumed— shapes. Determine airspace at the exact location and altitude from chart labels.

Also identify prohibited, restricted, warning, military operations, alert, and controlled firing areas; Military Training Routes; TFRs; parachute operations; National Security Areas; TRSAs; and VFR routes. Know which impose restrictions and which primarily warn of activity.

B. Operational requirements — UA.II.B

Practice scenarios that combine sectional charts, airport data, NOTAMs, weather, and authorization ceilings. Know that a LAANC grid altitude is not permission by itself; receive authorization and comply with its conditions. Check TFRs and NOTAMs close to launch time.

Recognize hazards: manned traffic, towers/wires, unlit structures, thermal plumes, balloons, lasers, precipitation static, wildlife, and night lighting. Learn navigation-light orientation well enough to infer another aircraft's direction at night.

III. Weather (11–16%)

A. Sources — UA.III.A

Decode METARs and TAFs without guessing. Extract station, time in UTC, wind and gusts, visibility, weather, cloud layers/ceiling, temperature/dew point, and altimeter setting. Know the distinction between an observation (METAR) and a forecast (TAF), and the roles of ASOS/AWOS and aviation weather products.

B. Effects on performance — UA.III.B

Explain how density altitude increases with high temperature, high elevation, and low pressure, reducing propeller/motor-airframe performance and usable battery margin. Evaluate wind at altitude, gust spread, turbulence and rotor effects near structures, fronts, stable/unstable air, fog, visibility, icing, thunderstorms, microbursts, hail, lightning, and tornadoes.

Operational habit: set conservative manufacturer- and mission-based limits for wind, gusts, temperature, precipitation, visibility, and battery reserve before launch. Legal minimums are not automatically safe limits.

IV. Loading and performance (7–11%)

Understand weight, center of gravity, balance, stability, and how payload or battery changes affect control, endurance, climb, braking distance, and recovery. Be able to interpret manufacturer performance data and simple loading problems.

Common reasoning chain: more mass or adverse CG → altered stability/control and more power required → higher current/heat and shorter reserve → smaller safety margin, especially at high density altitude or in wind.

V. Operations (35–45%)

A–B. Communications and airports — UA.V.A–B

Know towered and non-towered patterns, runway numbers/markings, heliports and seaplane bases, Chart Supplement data, CTAF, UNICOM, ATIS, call signs, phonetic alphabet, and standard phrasing for altitude, direction, speed, and time. A remote pilot normally monitors to build awareness; do not transmit casually or imply an ATC clearance.

Infer where manned aircraft are likely to be: pattern altitude, approach and departure corridors, base-to-final turns, helicopter routes, and low-level agricultural or emergency activity. Authorization near an airport does not transfer collision-avoidance responsibility.

C. Emergencies — UA.V.C

Preplan actions for lost command/control link, lost GPS, flyaway, low battery, unexpected aircraft/people, weather deterioration, injury, and lithium-battery fire. Configure and verify lost-link behavior for the site; an automatic return- to-home climb can itself create a hazard.

Lithium batteries require inspection, protected transport, manufacturer-approved charging, supervision, cooling before recharge, and isolation of damaged or swollen packs. Use an emergency method appropriate to the battery and setting; coordinate with emergency services when needed.

D. Decision-making and CRM — UA.V.D

Use a repeatable model:

• PAVE: Pilot, Aircraft, enVironment, External pressures.
• 5P: Plan, Plane, Pilot, Passengers/people, Programming.
• IMSAFE: Illness, Medication, Stress, Alcohol, Fatigue, Emotion/Eating.
• Identify hazard → assess likelihood/severity → mitigate → reassess → accept, delay, relocate, or cancel.

Brief who has the remote PIC role, who manipulates controls, what the visual observer reports, sterile-communication moments, handoff words, and who calls an abort. Recognize anti-authority, impulsivity, invulnerability, macho, and resignation; apply their standard antidotes.

E. Physiology — UA.V.E

Know dehydration, heat illness, stress, fatigue, medication and alcohol effects, hyperventilation, visual limitations, dark adaptation, and night illusions. Fitness is an ongoing go/no-go decision, not merely a certification checkbox.

F. Maintenance and inspection — UA.V.F

Follow manufacturer instructions; inspect the entire system before flight, including aircraft structure, props/rotors, motors, attachment points, payload, battery, controller, display, software status, compass/GNSS behavior, Remote ID, and anti-collision lighting when applicable. Record defects, maintenance, firmware/configuration changes, batteries, incidents, and corrective action.

Readiness standard

Do not book the test based on memorization alone. You should be able to:

• Score at least 85% on two fresh, timed 60-question practice tests.
• Explain every wrong answer and map it to an ACS code.
• Read sectional excerpts, Chart Supplement entries, METARs, and TAFs.
• Solve mixed scenarios involving rules + airspace + weather + human factors.
• State why the other answer choices are unsafe or noncompliant.