BR-ANAC-R-VFRH cheat sheet

Brazilian RPAS rules are issued by ANAC (RBAC-E 94 and related RBAC), complemented by DECEA airspace rules (ICA 100-40) and ANATEL radio approvals.

Visual line of sight (VLOS) is the baseline operating condition for RPA operations in Brazil; BVLOS requires specific authorization from ANAC and DECEA.

Maximum takeoff mass thresholds matter: RPA up to 25 kg fall under simplified RBAC-E 94 rules; heavier aircraft require certification and specific approval.

Operations above 120 m (400 ft) AGL require prior coordination with DECEA, except when flying near structures with applicable offset rules.

Registration with ANAC (SISANT) is mandatory for RPA above 250 g; the registration number must be displayed on the aircraft.

Remote pilot documentation: RPAs used commercially or above 250 g require a pilot certificate/licence appropriate to the operation, with medical fitness where applicable.

No operation over crowds, near airports without coordination, or in restricted/prohibited areas (e.g., security zones) without authorization.

Accident and incident reporting obligations apply; serious incidents must be notified to ANAC/CENIPA within the timeframe set by regulation.

Right-of-way: the RPA must give way to all manned aircraft; the remote pilot must avoid collision and never assume the manned pilot will see the RPA.

RPAS components: aircraft (airframe, propulsion, flight controls), control station (GCS), command-and-control link, and any payload/sensors.

Multirotor control uses differential thrust: increasing one pair of rotors and decreasing the opposite pair produces roll or pitch; yaw comes from rotor drag/torque imbalance.

IMU (accelerometers + gyros) provides attitude and rate data; barometer gives altitude; GNSS gives position and ground velocity; magnetometer gives heading.

Compass calibration errors and magnetic interference from metal or power lines are a leading cause of loss-of-control and fly-away events.

Battery management: LiPo cells are nominally 3.7 V, fully charged 4.2 V; storage at ~3.8 V per cell; never discharge below ~3.5 V per cell in flight.

Failsafe logic: loss of C2 link should trigger pre-programmed action (hold, return-to-home, land); RTH altitude must clear all obstacles on the route.

Preflight inspection covers propellers (cracks, balance), motor mounts, structure, wiring, firmware version, sensor calibration status and battery state.

Geofencing and no-fly databases are advisory aids, not substitutes for the pilot's own airspace and obstacle planning.

Density altitude rises with high elevation, high temperature and high humidity; higher density altitude reduces lift and thrust and lengthens takeoff/climb.

Hover power required increases with mass to the power 3/2 in idealized hover: induced power P ∝ W^(3/2); extra payload costs disproportionately more energy.

Translational lift: in forward flight, induced power drops and effective performance improves up to best-endurance speed; hovering is the most power-hungry regime.

Endurance vs range: best endurance is flown at minimum power speed; best range is flown at minimum power-per-distance speed (higher than endurance speed).

Wind effect: headwind increases energy per ground distance and reduces range; tailwind increases ground speed but can reduce controllability margins.

Battery energy available = capacity (Ah) × nominal voltage (V); usable energy is reduced by cold temperature, high discharge rate and cell age.

Climb performance depends on excess power: rate of climb ≈ (available power − power required) / weight.

Ceiling limits: service ceiling is where maximum climb rate becomes marginal (commonly 100 ft/min for manned rotorcraft); RPA have similar practical limits.

Payload vs altitude trade: adding mass at high density altitude may exceed the power margin, so performance planning must be done before flight.

MTOW (maximum takeoff mass) is a hard limit; planned takeoff mass = empty mass + payload + energy source mass + crew/equipment.

Center of gravity position = Σ(mass × arm) / Σ(mass); arms measured from a defined datum, positive aft or forward as stated.

CG must stay inside the forward and aft limits for all phases; moving mass aft moves the CG aft and reduces pitch stability margin.

Payload placement on multirotors changes thrust sharing between motors; an off-CG load forces motors to work unevenly and reduces control authority.

Moment = mass × arm; adding or removing items requires recomputing total moment and total mass, not just adding weights.

Battery mass is a significant fraction of small-RPA mass; swapping to a larger battery shifts CG and may need counterbalancing.

Loading errors to avoid: exceeding MTOW, exceeding individual motor/thrust limits, and placing heavy items far from the CG.

Verify the load sheet after every change; a common error is using the empty-mass CG for the loaded aircraft.

Hypoxia onset is faster at higher altitude; above ~3,000 m (10,000 ft) supplemental oxygen rules apply to crew in manned operations, and cognitive impairment begins earlier.

Hyperventilation causes dizziness and tingling; treatment is controlled slow breathing, not faster breathing.

Spatial disorientation arises when visual cues conflict with vestibular cues; the pilot must trust instruments and maintain an outside visual reference.

Visual illusions affecting RPA: black-hole approach, size-distance illusion, and loss of horizon at dusk reduce height and distance judgment.

Fatigue degrades vigilance and reaction time; duty limits and rest are regulatory and physiological requirements, not preferences.

Stress and workload: high workload narrows attention and increases omission errors; checklist use and task prioritization reduce error rate.

Dehydration and heat in the ground station increase error rates; cold reduces manual dexterity on the controller.

Crew resource management: clear briefing, closed-loop communication, and assertiveness by the observer prevent many RPA accidents.

Standard atmosphere: sea-level pressure 1013.25 hPa, temperature 15 °C, lapse rate 2 °C per 1,000 ft (6.5 °C/km) up to the tropopause.

QNH is the pressure setting that makes the altimeter read elevation above mean sea level at the ground; QFE reads height above a reference point.

Wind is named by the direction it comes from; runway/heading calculations use the reciprocal for tailwind components.

Crosswind component = wind speed × sin(angle between wind and heading); headwind component = wind speed × cos(angle).

Stable air favors haze, fog and smooth flight; unstable air favors cumulus, turbulence and gusty surface winds.

Thunderstorms contain severe updrafts/downdrafts, hail, lightning and microbursts; RPA must keep well clear of cumulonimbus.

Low-level wind shear and mechanical turbulence near buildings/terrain are amplified close to the ground where RPA operate.

METAR gives current observed conditions; TAF gives forecast; both use UTC and are essential preflight inputs.

True north vs magnetic north: variation (declination) is the angle between them; magnetic heading = true heading − easterly variation (or + westerly).

Track is the path over the ground; heading is where the nose points; the difference is drift caused by wind.

Wind correction angle: WCA ≈ arcsin( (wind speed / true airspeed) × sin(wind angle) ); crab into the wind to hold track.

Great-circle distance uses latitude/longitude; 1 minute of latitude ≈ 1 nautical mile ≈ 1,852 m.

GNSS position error can be degraded by multipath near buildings and by ionospheric conditions; do not rely on a single satellite solution.

Return-to-home relies on a stored home point; if home is set incorrectly or GNSS is lost, RTH may fly to a wrong location.

Map reading and grid references: verify datum and scale; a wrong datum shifts all coordinates by a fixed offset.

Dead reckoning uses heading, speed and time; errors accumulate, so position fixes must be taken regularly.

Preflight: airworthiness check, battery state, firmware, sensor calibration, airspace/NOTAM check, weather check, site survey, and emergency plan.

Site survey must identify obstacles, persons, emergency landing areas, and the C2 link coverage; define the operating volume before takeoff.

VLOS separation minima are set by the operator's risk assessment; keep the RPA clear of persons not involved and never overfly crowds.

Lost-link procedure: verify programmed failsafe (hold/RTH/land), confirm RTH altitude clears obstacles, and be ready to take manual control on recovery.

Emergency procedures: fly away - activate RTH/land, notify ATC if in controlled airspace; fire - isolate battery, use appropriate extinguisher.

Battery emergency: land immediately when the low-battery warning triggers; reserve capacity must cover the return plus a margin.

Handover and crew briefing: define roles (pilot, observer), communication phrases, and abort criteria before flight.

Post-flight: log flight time, anomalies, battery cycles, and report occurrences; inspect for damage before next flight.

Lift from a rotor is generated by mass flow deflected downward; induced velocity increases with disk loading and reduces with larger disk area.

Bernoulli and Newton are complementary descriptions: pressure difference plus momentum change both account for rotor thrust.

Induced power in hover: P_i = T^(3/2) / sqrt(2ρA); increasing disk area A or air density ρ reduces power required.

Translational lift: forward speed reduces induced velocity and induced power, improving efficiency until parasite drag dominates.

Dissymmetry of lift on advancing/retreating blades is balanced by flapping and cyclic pitch; retreating blade stall limits forward speed.

Torque reaction: main rotor torque must be countered by a tail rotor, coaxial rotors, or differential thrust in multirotors.

Ground effect reduces induced velocity near the surface and lowers power required; it is lost above roughly one rotor diameter.

Vortex ring state: descending vertically with low forward speed causes recirculation, loss of thrust and high vibration; recovery is forward speed and reduced collective.

Standard phraseology: read back clearances, use "roger", "wilco", "say again", and the ICAO alphabet (Alfa, Bravo, Charlie...) for spelling.

Distress call "MAYDAY" (three times) is for grave and imminent danger; urgency call "PAN-PAN" (three times) is for urgent but non-immediate danger.

Frequency bands: VHF airband 118–137 MHz for voice; UHF and satellite links used for some RPA C2; check approved frequencies for the operation.

Call sign and position report format: station called, own call sign, position, altitude/height, intentions.

Transponder/SSR codes: 7700 emergency, 7600 radio failure, 7500 unlawful interference; RPA squawk only when authorized/equipped.

Radio failure procedure: continue per published rules, try alternate frequencies, and land as soon as practicable if no contact is re-established.

C2 link is a communication system too: monitor link quality, know the failsafe, and avoid flying beyond the tested link range.

Time is given in UTC (Zulu); use the 24-hour clock and state the time group clearly in reports.