FAA Private Pilot Helicopter (PRH) flashcards

Visual signals from the control tower used to communicate with aircraft that have lost radio communication, with different meanings on the ground versus in flight.

• Steady green (ground): cleared for takeoff; (air): cleared to land
• Flashing green (ground): cleared to taxi; (air): return for landing
• Steady red (ground): stop; (air): give way, continue circling
• Flashing red (ground): taxi clear of runway... actually return to starting point; (air): airport unsafe, do not land

Memory trick: Flashing red on the ground means 'go back to where you began.'

A forward center-of-gravity loading requires more aft cyclic to maintain attitude, reducing the aft cyclic reserve available for maneuvers like the autorotation flare.

• Forward CG causes a nose-low tendency
• Pilot must hold more aft cyclic to compensate
• Less aft cyclic remains available for flare/hover
• Aft CG has the opposite effect, limiting forward cyclic and high-speed flight

Memory trick: Forward CG eats your aft cyclic 'savings account' before you need it to flare.

The height above ground of the lowest layer of clouds reported as broken or overcast, or the vertical visibility into an indefinite obscuration.

• Scattered (SCT) layers do not count as a ceiling
• BKN and OVC layers qualify as ceilings
• Vertical visibility (VV) reported for obscured skies also defines a ceiling

Memory trick: 'Few, Scattered don't count—Broken and Overcast make the ceiling'

The lowest altitude at which the air temperature reaches 0°C, above which structural icing becomes a hazard in visible moisture.

• Found in Area Forecasts and Winds/Temperatures Aloft forecasts
• Icing risk exists above freezing level in clouds or precipitation
• Freezing level can vary geographically and with terrain

Memory trick: Freezing level = the invisible ice line pilots must respect

Special use airspace containing unusual, often invisible hazards such as artillery firing; entry requires authorization from the controlling agency.

• Depicted with a blue hatched border and 'R-' designator
• Entry without clearance may be extremely hazardous
• Status can be checked via ATC, FSS, or the chart's Special Use Airspace panel

Memory trick: Restricted = 'Request' clearance first.

A hinge on a fully articulated rotor blade root that permits the blade to move fore and aft in the plane of rotation, compensating for Coriolis-effect speed changes caused by flapping.

• Also called the drag hinge
• Compensates for Coriolis effect from flapping
• Prevents excessive bending stress at the blade root
• Often paired with a lead-lag damper to control blade oscillation

Memory trick: Lead-lag = the blade 'sprinting and jogging' in its own lane to match speed changes.

A hazardous condition where rotor downwash lifts dust or sand from a dry, unimproved surface, severely reducing or eliminating the pilot's outside visual references during approach or landing.

• Occurs mainly over dry, loose soil, sand, or dust
• Most severe near the ground where downwash concentrates
• Can lead to spatial disorientation and hard/dynamic rollover landings
• Whiteout is the analogous hazard caused by blowing snow

Memory trick: 'Brown dirt, Brownout; White snow, Whiteout'

A hazardous attitude in which a pilot believes accidents happen to others but not to themselves, leading to unsafe risk-taking.

• Antidote thought: 'It could happen to me'
• One of five FAA-recognized hazardous attitudes
• Often leads to skipping checklists or ignoring warning signs

Memory trick: 'AIM-MR': Anti-authority, Invulnerability, Macho, Machismo(resignation)... remember AIIMR — 'Aim Right.'

A warm front occurs where warm air advances over retreating cooler air, producing a shallow slope that generates widespread stratiform clouds and precipitation ahead of the surface boundary.

• Gradual cloud lowering: cirrus to stratus
• Steady precipitation and poor visibility ahead of passage
• Temperature and dew point rise, winds shift after passage

Memory trick: Warm front = slow soak, cold front = sudden slam

14 CFR 61.109(b) sets the minimum flight experience for a private pilot certificate with a helicopter rating at 40 hours total flight time, including 20 hours of instruction and 10 hours solo.

• 40 hours total minimum flight time
• Includes 20 hours instruction, 10 hours solo
• Also requires specific cross-country, night (or additional instrument), and solo cross-country time

Memory trick: 'Forty for flight' — the minimum hour bar for a helicopter private ticket.

Insufficient oxygen reaches the blood due to reduced atmospheric pressure at altitude, impairing brain and body function.

• Night vision degrades starting around 5,000 ft MSL
• Symptoms include euphoria, poor judgment, and blue lips/fingernails (cyanosis)
• Time of useful consciousness decreases rapidly above 25,000 ft

Memory trick: 'Night eyes go first' — vision fades before you even notice you're impaired.

14 CFR 91.215 requires an operable Mode C transponder with automatic altitude reporting for flight within and above Class B and Class C airspace, and in other designated areas such as the Mode C veil.

• Required in Class B, Class C, and the Mode C veil around Class B
• Also required above 10,000 ft MSL over the 48 contiguous states (excluding below 2,500 AGL)
• ADS-B Out also required in most of this same airspace per 91.225

Memory trick: 'C is for Code' — Class C requires your transponder code (Mode C).

The pressure altitude at which a helicopter's maximum rate of climb decreases to a specified minimal value (commonly 100 fpm), reflecting diminishing excess power at altitude.

• Distinct from hover ceiling (IGE/OGE), which concerns hover capability
• Reflects decreasing excess power available as altitude increases
• Commonly defined using a 100 fpm rate-of-climb criterion

Memory trick: Service ceiling = where climbing 'runs out of steam' (100 fpm left)

A dangerous condition in semirigid rotor helicopters where an abrupt forward cyclic push reduces rotor thrust, causing loss of lateral cyclic effectiveness and a fuselage roll that can lead to the rotor hub striking the mast (mast bumping).

• Caused by abrupt forward cyclic (pushover) creating near-zero G
• Lateral cyclic becomes ineffective because rotor thrust is reduced
• Recovery: apply gentle aft cyclic first to restore rotor thrust before correcting roll

Memory trick: Push forward hard, and the tail rotor swings you into the mast.

Prohibits operating any aircraft in a careless or reckless manner so as to endanger the life or property of another, applicable in flight and on the surface.

• Broadest safety regulation in Part 91
• Applies to both airborne and surface operations
• Often cited alongside more specific violations
• Endangerment does not require actual injury/damage to occur

Memory trick: 91.13 is the FAA's catch-all: 'don't be dumb and dangerous.'

An FDC NOTAM is issued by the FAA's Flight Data Center and contains regulatory information such as TFRs, amended minimums, and instrument approach procedure changes.

• Issued by the Flight Data Center
• Contains regulatory/rule changes
• Includes TFRs and IAP amendments
• Different from local NOTAM (D)s

Memory trick: FDC = 'Federal Directives Center' — the rulebook updates.

Increased gross weight requires greater rotor thrust, increasing power required to hover and lowering the hover ceiling.

• More weight requires more lift, more induced drag, more power
• Hover ceiling decreases as gross weight increases
• High density altitude compounds the power penalty of heavy loading

Memory trick: Heavier helicopter, higher power hunger, lower hover height

Fog produced when warm, moist air moves horizontally over a colder surface, cooling to saturation. Common along coasts and in winter over snow-covered ground.

• Requires wind to advect air over cold surface
• Can persist or thicken with increased wind (unlike radiation fog)
• Common in coastal and marine environments

Memory trick: Advection = air on the move over cold ground/water

A cumulative state of exhaustion from continuous high stress or insufficient rest over an extended period, not relieved by a single episode of sleep.

• Persists over days or weeks despite normal sleep
• Reduces performance, judgment, and vigilance significantly
• Requires extended rest and lifestyle changes to resolve, unlike acute fatigue

Memory trick: 'One night fixes acute; many nights needed for chronic.'

Special use airspace designated 'P' where aircraft flight is prohibited at all times for security or other reasons.

• Depicted with a solid blue border and 'P' designation on charts
• Flight is not allowed without specific authorization
• Common examples include areas around the White House and Camp David

Memory trick: P for Prohibited = 'Positively No Entry' anytime.

14 CFR 91.157 requires an instrument rating and IFR-equipped aircraft for special VFR operations at night, except helicopters are exempt from this instrument rating and equipment requirement.

• Applies to takeoff/landing under special VFR at night
• Airplanes require instrument rating + IFR equipment at night
• Helicopters are specifically excluded from this restriction
• Basic SVFR minimums (1 SM, clear of clouds, ATC clearance) still apply

Memory trick: Airplanes need an instrument ticket after dark for SVFR — helicopters get a free pass.

The tendency of a single-rotor helicopter to drift laterally in a hover due to tail rotor thrust counteracting main rotor torque.

• For a counterclockwise main rotor, drift is to the right
• Corrected by rigging or slightly tilting the main rotor mast/disc left
• Distinct from translational lift, which involves airspeed, not hover drift

Memory trick: Tail rotor pushes sideways, so the whole ship slides that way.

Helicopters may be operated at less than the altitudes prescribed for airplanes in 91.119 if operated without hazard to persons or property on the surface and per FAA-established routes/altitudes.

• Applies only to helicopters
• Requires no hazard to surface persons/property
• May require compliance with FAA-designated routes/altitudes
• Reflects helicopter's unique operating capability

Memory trick: Helicopters can 'hover-hop' low if they hurt no one and follow FAA routes.

A two-bladed rotor design in which the blades are rigidly mounted to the hub but the hub itself can teeter (flap as a unit) on a single hinge.

• Also called a teetering rotor
• No individual lead-lag hinges
• Blades are usually underslung to reduce vibration

Memory trick: See-Saw Semirigid teeters together

14 CFR 91.119 sets minimum altitudes: 1,000 ft over congested areas, 500 ft (or 500 ft lateral clearance) elsewhere, with a helicopter exception in 91.119(d).

• (b) Congested areas: 1,000 ft above highest obstacle within 2,000 ft horizontally
• (c) Other areas: 500 ft above surface, or 500 ft from persons/vessels/vehicles/structures if sparsely populated/open water
• (d) Helicopters may operate below these minimums if done without hazard to persons/property on the surface

Memory trick: '1,000 over the city, 500 over the country' – but helicopters get a pass.

A standardized scale (light, moderate, severe, extreme) used in PIREPs to describe the intensity of turbulence based on aircraft response and occupant effects.

• Light: slight, erratic changes in altitude/attitude
• Moderate: definite bumps, changes in altitude/attitude, occupants feel strain against seatbelts
• Severe: large abrupt changes, momentary loss of control, occupants forced violently against restraints
• Extreme: aircraft practically impossible to control, may cause structural damage

Memory trick: 'Light bumps, Moderate jolts, Severe throws you, Extreme breaks control'

A system using engine/transmission-driven hydraulic pressure to reduce the aerodynamic feedback forces a pilot feels through the flight controls.

• Reduces cyclic/collective control forces from rotor feedback
• Pump is typically driven by the main rotor gearbox
• Accumulators may provide brief pressure after pump failure
• Failure results in heavier, but still functional, manual controls

Memory trick: Hydraulics are power steering — lose them, and the wheel (cyclic) gets heavy.

14 CFR 91.141 prohibits flight within a Temporary Flight Restriction established for the movement of VIPs, such as the President, unless specifically authorized by ATC.

• Applies to all aircraft, VFR and IFR
• Violations can result in certificate action and intercept by military/law enforcement aircraft
• Pilots must check NOTAMs before every flight to identify active TFRs

Memory trick: VIP TFR = 'Very Important Perimeter' — stay out unless invited in.

A TFR is a short-term airspace restriction issued by NOTAM to protect people, events, or assets, such as sporting events, VIP movement, or disaster areas.

• Published via NOTAM, not sectional charts
• Common for stadiums, wildfires, VIP movement
• Violation can result in certificate action
• Pilots must check NOTAMs before every flight

Memory trick: TFRs pop up like traffic cones — always check the latest NOTAM 'road report.'

Restricted areas contain airspace where unusual, often invisible hazards to aircraft exist (e.g., artillery fire); pilots must get authorization from the controlling agency before entering when active.

• Depicted on sectional charts with time/altitude info
• Entry without authorization when active is a regulatory violation
• Contact Flight Service or the controlling agency listed on the chart to check status

Memory trick: 'Restricted means Request permission' before you fly through.

The difference between temperature and dew point indicates how close the air is to saturation; a narrow spread indicates high relative humidity and fog potential.

• Spread of 4°F/2°C or less often indicates fog or cloud formation likely
• Spread narrows overnight as temperature drops toward the dew point
• Clear skies and calm winds favor radiational cooling that narrows the spread
• When spread reaches zero, the air is saturated (100% relative humidity)

Memory trick: Narrow spread = Near saturation = Nebulous (foggy) conditions

A hazardous attitude in which a pilot resents or disregards rules, regulations, and procedures, believing they don't apply personally.

• Antidote thought: 'Follow the rules, they are usually right'
• One of five FAA-recognized hazardous attitudes
• Can lead to noncompliance with NOTAMs, ATC, or checklists

Memory trick: A Menacing Idiot Recklessly Ignores rules (Anti-authority, Macho, Impulsivity, Resignation, Invulnerability).

The kinetic energy stored in rotating blades, proportional to blade mass and rotational speed, which determines how quickly rotor RPM decays after an engine failure.

• Low-inertia rotors lose RPM quickly, requiring rapid collective reduction
• High-inertia rotors decay more slowly, giving the pilot more time to react
• Blade mass and radius of gyration both affect stored rotational energy

Memory trick: Light blades spin down fast—like a small flywheel losing spin quickly

An aircraft being overtaken has the right-of-way; the overtaking aircraft must alter course to the right to pass well clear.

• Applies regardless of category of aircraft involved
• Overtaking aircraft may not pass underneath or cut in front
• Right turn is mandatory, not left

Memory trick: 'Overtake to the right, like passing on the highway.'

A distant NOTAM providing information about airport and navigational facility conditions, such as runway/taxiway closures or lighting outages.

• Distributed nationally through the NOTAM system
• Covers airport/facility data like closures and outages
• Different from FDC NOTAMs, which cover regulatory/procedural changes

Memory trick: NOTAM(D) = 'Dirt and Detours' on the airfield.

A risk management tool used during flight planning to categorize hazards into four groups: Pilot, Aircraft, enVironment, and External pressures.

• P = Pilot fitness/experience
• A = Aircraft airworthiness/equipment
• V = enVironment (weather, terrain, airspace)
• E = External pressures (schedules, passengers, get-there-itis)

Memory trick: PAVE the way to safe flight planning.

A pilot may not act as a crewmember within 8 hours of consuming alcohol, with a BAC of 0.04 or greater, or while under the influence.

• All three conditions must be satisfied simultaneously
• 8-hour rule is independent of actual BAC level
• Often called 'eight hours from bottle to throttle'

Memory trick: '8 hours, .04, and no buzz' — all three gates must be clear.

A stable air mass resists vertical air movement, producing stratiform clouds, smooth flying conditions, and often restricted visibility.

• Stratiform clouds and fog are common in stable air
• Precipitation tends to be steady/continuous
• Visibility often restricted by haze or smoke
• Little to no turbulence due to suppressed vertical motion

Memory trick: Stable = 'Smooth and Stuck' (Stratus, Smooth ride, Smoggy visibility)

In a level turn, required lift equals load factor (n = 1/cos bank angle) multiplied by aircraft weight; steep banks dramatically increase the lift and power demand.

• n = 1/cos(bank angle)
• At 60° bank, n = 2 (double weight in lift)
• Lift required = n × aircraft weight

Memory trick: 60° bank doubles your weight in the rotor's eyes—2,000 becomes 4,000

In the Northern Hemisphere, wind circulates counterclockwise and inward around low-pressure centers and clockwise and outward around high-pressure centers.

• Low = counterclockwise, converging, associated with rising air and clouds
• High = clockwise, diverging, associated with sinking air and clear skies
• Reversed in Southern Hemisphere

Memory trick: Low sucks in counterclockwise like a drain; High blows out clockwise like a fan

Pitch angle is the geometric angle between the blade chord line and the rotor's plane of rotation, while angle of attack is the aerodynamic angle between the chord line and the actual relative wind, which is affected by induced flow (downwash).

• Pitch angle is controlled directly by the pilot via collective/cyclic
• Angle of attack also depends on induced flow, so it can differ from pitch angle
• In forward flight, dissymmetry of lift and blade flapping further separate the two angles

Memory trick: Pitch angle is what you set; angle of attack is what the wind actually sees.

A high-speed flight condition where the retreating rotor blade's angle of attack becomes excessive, causing it to stall; risk increases with high airspeed, high gross weight, high density altitude, low rotor RPM, and turbulence or steep turns.

• Occurs at high forward airspeeds near Vne
• Load factor from turns increases blade angle of attack demand
• Recovery: reduce collective, slow airspeed, and level the aircraft

Memory trick: Fast, heavy, hot, and turning—the retreating blade runs out of air.

The downward movement of air through the rotor disk produced as a byproduct of lift generation, which reduces the blade's actual angle of attack.

• Combines with rotational relative wind to form resultant relative wind
• Reduces angle of attack below pitch angle
• Greater near hover, decreases with forward airspeed due to increased horizontal airflow

Memory trick: Downwash drags the wind down, dragging AOA down with it

An unscheduled weather advisory warning of hazardous weather significant to the safety of all aircraft, including severe icing, severe/extreme turbulence, dust/sandstorms, and volcanic ash.

• Applies to all aircraft, unlike AIRMETs which target light aircraft hazards
• Covers severe icing not associated with thunderstorms
• Covers severe/extreme turbulence or clear air turbulence (CAT)
• Covers dust storms/sandstorms lowering visibility below 3SM, and volcanic ash

Memory trick: 'SIGMET is SIGnificant for everyone—big planes included'

A report of actual in-flight weather conditions, such as turbulence, icing, cloud tops/bases, and visibility, submitted by pilots to help other pilots and forecasters.

• Provides real-time, actual conditions rather than forecasts
• Coded format includes location, time, altitude, aircraft type, and conditions
• Especially valuable in mountainous or data-sparse areas

Memory trick: PIREP = Pilots Reporting Exactly what's Present

Certain in-flight and ground occurrences, such as in-flight fires, flight control malfunctions, and overdue aircraft, require immediate notification to the NTSB regardless of whether damage or injury occurs.

• In-flight fire is a listed reportable event
• Notification must be immediate, not delayed
• Applies regardless of outcome/damage
• Distinct from accident/incident written reporting requirements

Memory trick: Fire in flight? Phone the NTSB tonight — no waiting required.

The pilot in command is responsible for closing a filed VFR flight plan with Flight Service upon landing to prevent unnecessary search and rescue activity.

• VFR flight plans are voluntary but recommended for safety
• Pilot must close via radio, telephone, or in person
• Uncanceled flight plans can trigger search and rescue after ETA plus 30 minutes

Memory trick: 'You opened it, you close it' — flight plans are the pilot's responsibility start to finish.

High density altitude (hot, high, humid conditions) reduces air density, decreasing rotor and engine performance.

• High density altitude = less air density = less lift per rotor RPM
• Increases power required to hover and reduces maximum gross weight
• Caused by high elevation, high temperature, and high humidity
• Pilots must consult performance charts before high-DA operations

Memory trick: High, Hot, Humid = High Density Altitude = Helicopter Hurts

ADs are FAA-mandated corrective actions that must be complied with, including any recurring inspection intervals, to keep an aircraft airworthy.

• ADs are legally mandatory, not optional
• Recurring ADs require compliance at each interval
• Compliance must be recorded in maintenance records

Memory trick: An AD is the FAA's homework — skip a due date and you fail airworthiness

Helicopters are exempt from the standard minimum safe altitude rules if operated without hazard to persons or property on the surface.

• Airplanes: 1,000 ft above congested areas; 500 ft over other areas
• Helicopters may operate below those minimums if done safely
• FAA may prescribe specific routes or altitudes for helicopter operations

Memory trick: Helicopters get a 'free pass' from altitude limits as long as it's safe below.

Frost forms when water vapor deposits directly as ice crystals on a surface that has cooled to or below freezing and at or below the dew point, usually on clear, calm nights.

• Requires clear skies for radiational cooling
• Requires calm or light wind
• Surface temperature must be ≤ freezing and ≤ dew point
• Frost disrupts smooth airflow and must be removed before flight

Memory trick: 'Clear, Calm, Cold, and Condensed'—the four C's of frost

A method of estimating a value that falls between two known chart values by proportionally averaging them.

• Find the weight's position between the two known values
• Apply the same proportion to the performance values
• Never round down for conservative planning if unsure

Memory trick: Halfway weight = halfway distance.

Coordinated Universal Time is the standard time reference used in aviation; local times must be converted by adding or subtracting the appropriate zone offset.

• Mountain Standard Time (MST) = UTC-7
• Mountain Daylight Time (MDT) = UTC-6
• Add the zone's offset number of hours to local time to get UTC

Memory trick: Go west, add more — the farther west, the more hours you add to reach Zulu.

The pilot in command is directly responsible for and is the final authority as to the operation of the aircraft during flight.

• 91.3(a): PIC is final authority for the flight
• PIC may deviate from any rule in an emergency requiring immediate action (91.3(b))
• PIC may be required to submit a written report of an emergency deviation if requested (91.3(c))

Memory trick: 'The Captain speaks last' – PIC has the final word.

A condition where excessive collective pitch demands more power than the engine can supply, causing rotor RPM to decay dangerously even with the throttle at full power.

• Common at high density altitude or heavy gross weight
• Blade angle of attack increases beyond what available power can sustain
• Correction requires lowering collective promptly to restore RPM

Memory trick: Overpitching = asking the rotor to climb a hill steeper than the engine can push.

Uneven side-to-side loading shifts the lateral center of gravity, requiring cyclic displacement to compensate; if the CG exceeds lateral limits, the helicopter may not be controllable in all flight regimes.

• Caused by unequal loading side-to-side (e.g., single pilot seat, side cargo)
• Detected by needing sustained lateral cyclic input to hover level
• Exceeding limits can leave insufficient cyclic control margin for maneuvering

Memory trick: Heavy side pulls, cyclic must push back — but only so far.

The upward bending of rotor blades resulting from the balance of lift (up) and centrifugal force (outward); excessive coning reduces effective rotor disk diameter and lift.

• Caused by balance of lift and centrifugal force
• Increases with high load factor and low rotor RPM
• Excessive coning reduces effective disk area and lift
• Can risk blade contact with droop stops or airframe in severe cases

Memory trick: Too much cone = smaller circle = less lift.

A local wind caused by cold, dense air draining downslope into valleys at night due to radiational cooling of mountain surfaces.

• Occurs mainly on clear, calm nights
• Opposite of daytime anabatic (upslope) wind
• Strongest near sunrise before daytime heating begins
• Can create low-level turbulence and wind shear near valley floors

Memory trick: 'Katabatic comes at night, cold air takes flight downhill'

Load factor (G) in a level turn equals 1 divided by the cosine of the bank angle; steeper banks require exponentially more lift and power.

• 45° bank ≈ 1.4G
• 60° bank = 2G
• Increased load factor raises power required and stall/retreating blade stall risk

Memory trick: Steeper bank = heavier 'invisible passenger' the rotor must lift

Changes in collective pitch change main rotor torque, requiring corresponding pedal adjustments to maintain heading.

• Raising collective increases torque, requiring more anti-torque thrust
• Lowering collective decreases torque, requiring less anti-torque thrust
• For CCW main rotors, more anti-torque thrust is achieved with left pedal

Memory trick: Power up, push left, to keep the nose still