FAA Instrument Rating Airplane (IRA) flashcards

DME measures line-of-sight (slant-range) distance, not true ground distance; the error is greatest when close to the station at high altitude and negligible at greater distances.

• Slant range² = ground distance² + altitude²
• Error is most significant when near the station at high altitude
• Error becomes negligible beyond about 5–10 NM at typical altitudes

Memory trick: 'Close and high means DME lies.'

A risk assessment tool organizing hazards into five categories: Plan, Plane, Pilot, Passengers, and Programming, evaluated at key decision points throughout a flight.

• Plan: route, weather, fuel, alternates
• Plane: aircraft airworthiness and equipment
• Pilot, Passengers: human factors and needs
• Programming: automation setup such as autopilot/GPS/FMS

Memory trick: Plan, Plane, Pilot, Passengers, Programming—check all five before you fly

Structural icing requires both visible moisture (clouds, precipitation) and temperatures at or below freezing; comparing freezing level to cloud layers and cruise altitude identifies risk.

• Icing needs subfreezing temps AND visible moisture together
• Compare freezing level, cloud base/tops, and planned altitude
• Supercooled water droplets exist in clouds well below freezing

Memory trick: Cold plus cloud equals ice—check both before you fly.

Fog formed when cold air moves over relatively warm water, causing evaporation and saturation that produces a smoke-like rising fog.

• Also called evaporation fog or 'sea smoke'
• Forms when cold air overlays much warmer water
• Can create low-level instability, turbulence, and icing hazards

Memory trick: Steam fog: cold air, warm water, smoke on the lake.

The lowest altitude at certain fixes that a pilot must cross when proceeding in a specified direction, established to ensure obstacle clearance for the airway segment beyond the fix.

• Depicted with a flag symbol and altitude on en route charts
• Overrides a lower MEA before the fix
• Often used where a steep climb gradient is needed between segments

Memory trick: MCA = 'Must Climb Ahead' of the fix

A rough, opaque, milky-white ice that forms when small supercooled water droplets freeze rapidly on contact with an aircraft surface, common in stratiform clouds.

• Forms from small droplets
• Rapid freezing traps air, giving rough texture
• Common in stratiform clouds at colder temperatures

Memory trick: Rime is rough and rapid; clear is smooth and slow.

An AIRMET advisory for widespread IFR conditions (ceilings below 1,000 ft and/or visibility below 3 SM) and/or extensive mountain obscuration.

• Sierra = ceiling/visibility/mountain obscuration
• Tango = turbulence/strong winds
• Zulu = icing/freezing level

Memory trick: Sierra = 'See through mountains? No!' (obscuration)

14 CFR 91.215 mandates an operating Mode C transponder with automatic altitude reporting in specified airspace, including Class B, Class C, above 10,000 ft MSL (with exceptions), and within the Class B 30-NM veil.

• Required in Class A, B, C airspace and above 10,000 ft MSL (excluding below 2,500 AGL)
• Also required within the lateral limits of a Class B 30-NM Mode C veil
• Separate from the general IFR instrument list in 91.205(d)

Memory trick: 'Big airspace, big blip — Mode C required'

Federal regulation prohibiting a person from acting as a crewmember within 8 hours after consuming alcohol, while under the influence, or with a blood alcohol concentration of 0.04 or greater.

• 8-hour rule: no alcohol consumption within 8 hours of flight
• BAC limit: must be below 0.04
• 'Under the influence' clause can apply even if both other conditions are met

Memory trick: 8 hours bottle to throttle, no matter the number

A hazardous attitude in which a pilot feels the need to act immediately without adequate reflection, thinking 'do something quickly' even when a pause for analysis would be safer.

• Antidote thought: 'Not so fast, think first'
• Often triggered by time pressure or perceived urgency
• One of the five classic hazardous attitudes along with anti-authority, invulnerability, macho, and resignation

Memory trick: Rushing without thinking is impulsivity striking

IFR flight under VOR navigation requires the VOR system be checked within the preceding 30 days using an approved method with specified tolerances.

• VOT or ground checkpoint: ±4° tolerance
• Airborne checkpoint or designated radial: ±6° tolerance
• Dual VOR receiver comparison: max 4° difference between receivers

Memory trick: 'Ground=4, Air=6, Dual diff=4' — remember the tolerance triangle.

A non-WAAS IFR GPS may be used for alternate planning only to LNAV or circling minimums; WAAS-only minima like LPV or LNAV/VNAV cannot be relied upon for alternate planning without WAAS avionics.

• Non-WAAS GPS limited to LNAV/circling minimums for alternates
• WAAS-equipped aircraft may use LPV/LNAV VNAV for alternate planning
• This distinction affects flight planning, not enroute nav which may still be fine

Memory trick: 'No WAAS? No vertical guidance for your alternate.'

Arming a mode (e.g., APR, ALT) prepares the autopilot to automatically transition from an active mode (like HDG) to the armed mode once capture criteria are met, without pilot intervention.

• Armed mode shows on the flight mode annunciator (FMA) until capture
• Capture criteria are based on signal deviation and closure rate
• After capture, the mode annunciation changes from armed to active (e.g., LOC/GS)

Memory trick: Arm it, fly toward it, and it grabs the beam automatically.

During two-way radio failure in IFR conditions, a pilot must fly the highest of: last assigned altitude, altitude ATC has advised to expect, or the MEA for the route segment.

• Mnemonic: MEA (Minimum), Expected, Assigned – fly the HIGHEST
• Applies until reaching a fix where a new altitude/route rule applies
• Route flown: as assigned, as vectored, expected by clearance, or filed flight plan route

Memory trick: MEA: pick the highest of Minimum, Expected, Assigned.

A pilot-requested approach in which the pilot proceeds visually to the airport with at least 1 SM flight visibility, remaining clear of clouds, in lieu of completing the full instrument approach.

• Must be requested by the pilot, never assigned by ATC
• Requires 1 SM flight visibility minimum
• Aircraft must be clear of clouds throughout

Memory trick: Contact = pilot's call, 1 mile and clear

FM (From) groups in a TAF indicate a significant, rapid change in conditions beginning at the stated time and remaining valid until the next FM or the end of the forecast period.

• FM is followed by day/hour/minute in UTC
• Each FM group replaces all previous conditions
• Conditions persist until the next FM, BECMG, or TEMPO group takes effect

Memory trick: FM means 'From here forward, forget the old forecast'

The lowest altitude at which an intersection can be determined using an off-course NAVAID facility, based on signal reception, not obstacle clearance.

• Published only where needed for intersections defined by off-course facilities
• May be higher than the segment MEA
• Affects ability to identify a fix, not general obstacle clearance

Memory trick: MRA = 'Must Rise for Antenna' reception

Compass turning errors are reversed south of the magnetic equator: the compass leads (overshoots) near North and lags (undershoots) near South, opposite of Northern Hemisphere UNOS behavior.

• Northern Hemisphere: Undershoot North, Overshoot South (UNOS)
• Southern Hemisphere: reverse — Overshoot North, Undershoot South
• Caused by opposite direction of magnetic dip vector below the equator

Memory trick: South of the line, flip the sign — UNOS becomes ONUS.

A smooth, transparent, dense ice formation caused by large supercooled water droplets freezing slowly on the airframe near 0°C to -10°C.

• Forms from large supercooled droplets (e.g., freezing rain or cumuliform clouds)
• Smooth, transparent, and adheres strongly, hard to remove
• Most hazardous ice type due to weight and aerodynamic disruption

Memory trick: Clear ice is 'clear and near freezing'; rime is 'rough and really cold'.

If, for 1 hour before to 1 hour after ETA, the forecast at the destination is at least 2,000-foot ceiling and 3 SM visibility, no alternate is required.

• Applies only to airports with a published standard instrument approach
• Ceiling AND visibility must both meet or exceed 2,000-3 to skip an alternate
• If either value is below the threshold, an alternate must be filed

Memory trick: '1 hour, 2000 feet, 3 miles — skip the alternate'

When no MEA/MOCA/MCA is established, IFR flight must be at least 1,000 feet (non-mountainous) or 2,000 feet (mountainous) above the highest obstacle within 4 NM of course, rounded up to the nearest 100 feet.

• Mountainous areas require 2,000 ft clearance
• Non-mountainous areas require 1,000 ft clearance
• Always round up to the next 100-foot increment

Memory trick: Mountains need 2,000 — flatlands need 1,000, always round UP

An ATC clearance phrase meaning the pilot is cleared to fly the route filed in the IFR flight plan; altitude and other clearance elements are stated separately.

• 'As filed' applies only to the route, not altitude
• Altitude is always stated separately in the clearance
• Pilot should have a copy of the filed flight plan route available to cross-check

Memory trick: CRAFT: Clearance limit, Route, Altitude, Frequency, Transponder — 'as filed' only covers the R.

A classification (A–E) of aircraft based on 1.3 times stall speed (Vso) at maximum certificated landing weight, used to determine minimums on approach charts.

• Category A: <91 knots; B: 91-120; C: 121-140; D: 141-165; E: 166+
• Pilots may fly a higher category's minimums if circling at faster speeds
• Category determines applicable circling and straight-in minimums

Memory trick: 1.3 Vso decides your letter grade (A–E).

Recommended clearance from severe or rapidly building thunderstorms is at least 20 NM laterally, and 1,000 ft of altitude per knot of wind at storm top if overflying.

• 20 NM lateral clearance for severe/building cells
• Hazards like hail can exist well outside the visible cloud
• 1,000 ft per knot of top-level wind speed when overflying

Memory trick: Twenty miles wide, a thousand feet per knot when you ride over the top.

A published procedure depicting a visual route to a runway, usable only when weather meets the chart's stated minimums and the pilot has the airport or a preceding aircraft in sight.

• Requires visual contact with airport or traffic ahead
• Weather must meet or exceed charted minimums
• Distinct from a standard visual approach, which is not chart-published

Memory trick: See it to Fly it — CVFP needs eyes on the prize

A method to convert a published climb gradient (ft/NM) into a required rate of climb (fpm) based on groundspeed, ensuring obstacle clearance during a departure procedure.

• Formula: Rate of climb (fpm) = gradient (ft/NM) × groundspeed (kt) ÷ 60
• Higher groundspeed requires a higher climb rate for the same gradient
• Climb gradient tables in the front of approach plate books simplify this conversion
• ODPs specify the minimum climb gradient needed to clear obstacles

Memory trick: Gradient times speed, divide by sixty — get your climb rate quickly.

A point along an airway, typically the midpoint between two NAVAIDs, where a pilot changes navigation reference from the station behind to the station ahead.

• Standard COP is midpoint between NAVAIDs
• Nonstandard COPs charted with mileage figures when reception requires it
• Ensures reliable signal reception throughout the airway segment
• Depicted directly on the airway on en route charts

Memory trick: COP keeps you on the clearer signal, not just the closer half.

An IFR-approved GPS with a current database may generally substitute for ADF and DME equipment requirements, except where specifically prohibited by chart or regulation.

• Applies to en route, terminal, and approach procedures
• Exceptions exist for certain final approach segments
• Requires IFR-approved GPS, not just any GPS unit

Memory trick: GPS steps in for ADF and DME — unless the chart says 'not here.'

The airspeed indicator, altimeter, and VSI all derive data from the pitot-static system, but only the airspeed indicator requires both pitot and static pressure.

• Airspeed = pitot minus static pressure
• Altimeter = static pressure only
• VSI = static pressure through a calibrated leak and diaphragm

Memory trick: 'A' for Airspeed, 'A' for both — Airspeed needs both Air pressures.

Freezing rain forms when precipitation falls from an above-freezing layer aloft into a subfreezing surface layer (inversion), while freezing drizzle forms from small droplets within a shallow supercooled stratiform cloud without a warm layer aloft.

• Freezing rain = warm layer aloft + subfreezing surface layer
• Freezing drizzle = shallow stratiform supercooled cloud
• Both indicate hazardous clear icing risk (SLD)

Memory trick: Rain falls through warmth then freezes below; drizzle stays cold throughout.

Fog that forms when moist, stable air is mechanically lifted up sloping terrain, cooling adiabatically to the dew point.

• Requires moist, stable air and sloping terrain
• Cooling occurs adiabatically, not radiationally
• Can occur with wind, unlike radiation fog

Memory trick: Up the slope, air cools — upslope fog forms.

A malfunction where the autopilot's autotrim system continuously drives the trim in one direction, causing unexpected pitch changes; the correct response is immediate autopilot disconnect and manual trim correction.

• Signs include continuous trim wheel movement and unexpected pitch/altitude changes
• Immediate disconnect prevents worsening control difficulty
• Pilots should know the location of the autopilot disconnect switch and trim interrupt switch

Memory trick: Runaway trim? Disconnect first, ask questions later.

A vestibular illusion caused by moving the head out of the plane of a turn, stimulating multiple semicircular canals and creating a sensation of rotation or tumbling on a different axis.

• Occurs during sustained turns when head is tilted (e.g., reaching for a chart)
• Considered one of the most overwhelming and dangerous illusions
• Prevention: avoid sudden head movements during instrument flight, especially in turns

Memory trick: Turn your head, turn the world upside down

A pilot who lets the 6-month instrument currency lapse has an additional 6 months to regain it, but cannot act as PIC under IFR until the tasks are completed.

• 6 months to stay current, 6 more months grace to regain it
• Cannot log IFR PIC time during grace period
• After 12 months total, an IPC is required

Memory trick: Six to stay current, six more to catch up — but stay grounded (IFR) while you do.

PIREPs report icing type, intensity, and continuity (e.g., CONT for continuous, INTMT for intermittent) to help pilots assess in-flight icing hazards.

• IC field lists intensity and type (e.g., MOD RIME)
• RM field may include continuity like CONT or INTMT
• Always cross-reference altitude (FL) and location (OV) with route of flight

Memory trick: MOD RIME CONT means steady moderate icing, not a one-time bump.

Freezing rain forms when rain falls through a subfreezing layer near the surface after originating above a warm layer aloft, creating supercooled large droplets that freeze on contact and form clear ice rapidly.

• Requires a temperature inversion: warm layer aloft, cold layer below
• Produces clear ice which is dense and hard to remove
• Can extend icing beyond the aircraft's normal ice-protected surfaces
• One of the most hazardous icing conditions for aircraft, especially non-SLD-certified aircraft

Memory trick: Freezing rain = 'Fast, Far-reaching, Fierce' ice

A glass cockpit feature allowing display of data from a standby or alternate air data/attitude source onto an affected PFD after failure of the primary source, restoring critical flight instruments.

• Typically activated via a reversionary panel switch or button
• Common in integrated avionics suites (e.g., G1000-type systems)
• Does not require diversion if the reversion successfully restores needed data

Memory trick: When one screen goes dark, 'flip the switch' to borrow the other side's data.

The lowest published altitude between radio fixes on a federal airway that meets obstacle clearance requirements and assures acceptable navigational signal coverage.

• MEA provides both signal reception and obstacle clearance
• MOCA gives obstacle clearance only, with reduced signal guarantee within 22nm of the VOR
• MEAs are shown on the airway segment on en route low-altitude charts

Memory trick: MEA = 'Must Ensure Antenna' — signal AND safety

Fog that forms when warm, moist air moves horizontally over a colder surface, cooling to saturation.

• Common along coastlines with warm air over cold currents
• Can occur with wind, unlike radiation fog
• Often extensive and persistent, difficult to forecast dissipation time

Memory trick: Advection = Air moves; Radiation = Radiates heat away at night.

A rule assigning cruising altitudes based on magnetic course to reduce head-on traffic conflicts: odd thousands for 0°–179°, even thousands for 180°–359° (IFR, below 18,000 ft, no 500 ft addition).

• Applies to IFR flights below 18,000 feet MSL
• Odd thousands (3,000, 5,000, 7,000...) for courses 000°-179°
• Even thousands (4,000, 6,000, 8,000...) for courses 180°-359°
• VFR adds 500 feet; IFR does not

Memory trick: Odd East, Even West — no extra 500 for IFR guests.

A designated point on an airport surface with a published radial used to verify VOR receiver accuracy; allowable error is ±4°.

• Ground checkpoint tolerance: ±4°
• Airborne checkpoint tolerance: ±6°
• Must be logged per 91.171 if used for IFR

Memory trick: 'Ground and dual: 4 is the rule; Airborne alone gets 6, that's the tool.'

A dangerous illusion in which a prolonged coordinated turn goes undetected, and the resulting altitude loss is misperceived as a straight descent, leading the pilot to increase back-pressure and tighten the spiral.

• Occurs during sustained, coordinated turns in IMC
• Pilot senses descent but not the bank
• Correcting only pitch (not bank) worsens the spiral

Memory trick: Feel like falling straight? Check your bank before you pull.

Certain approach lighting systems (e.g., touchdown zone and centerline lights) allow ATC/FAA to authorize reduced visibility minimums under 14 CFR 91.175(f) because they enhance visual references during landing.

• TDZ/CL lighting can reduce required visibility from 1/2 SM (2400 RVR) to 1800 RVR
• Credit is codified in 91.175(f), not by increasing signal accuracy
• Charts note the specific lighting basis for reduced minimums

Memory trick: More lights, more sight, lower minimums allowed.

A rapid change in wind speed and/or direction over a short distance near the surface, often producing rapid airspeed gains followed by losses (or vice versa) that are hazardous during approach and departure.

• Often associated with thunderstorms, fronts, or temperature inversions
• Airspeed fluctuations of 15 knots or more are considered significant
• Go-around is the recommended response if shear is suspected on approach

Memory trick: Gain then lose airspeed near the ground — shear's the word!

A cold front is marked by a narrow zone of cumuliform clouds, brief but intense precipitation, gusty shifting winds, and a temperature drop as it passes.

• Fast movement, steep frontal slope
• Cumuliform clouds and possible thunderstorms
• Abrupt wind shift and temperature decrease

Memory trick: Cold front = quick and cumuliform; warm front = slow and stratiform.

91.169(b) requires forecast ceiling at least 2,000 ft AND visibility at least 3 SM for the period surrounding ETA to avoid needing an alternate; meeting these exactly is sufficient.

• Window is 1 hr before to 1 hr after ETA
• 'At least' means equal values satisfy the rule
• Both ceiling and visibility must be met simultaneously

Memory trick: 2,000 and 3 — meet it exactly and you're free.

Precipitation that evaporates before reaching the ground, often producing strong downdrafts due to evaporative cooling.

• Common under Cb clouds in dry low-level air
• Can produce microbursts and severe wind shear
• Visually appears as streaks hanging from cloud base

Memory trick: Virga vanishes, but the wind it leaves behind doesn't.

Aircraft approach category is based on 1.3 times stall speed in landing configuration (Vso), and the corresponding category's minimums and protected circling area must be used.

• Category determined by actual approach speed, not aircraft type alone
• Must use next higher category if maneuvering faster than category limits
• Circling protected area size varies by category

Memory trick: Speed sets the seat: category follows Vso

LNAV is a lateral autopilot mode that follows the GPS/FMS programmed flight plan track, capable of flying curved legs, unlike a single VOR radial or fixed magnetic heading.

• Lateral guidance only; vertical handled by VNAV/LPV separately
• Can fly curved path legs unlike VOR NAV mode
• RAIM loss triggers annunciated mode degradation, not silent disconnect

Memory trick: LNAV follows the GPS breadcrumb trail, curves and all.

An ATC clearance phrase authorizing a pilot to climb along the lateral path of a SID while complying with all published altitude and speed restrictions at each fix, without needing individual restatement of each restriction.

• Distinct from 'climb and maintain [altitude]'
• Includes compliance with charted altitude AND speed restrictions
• Reduces ATC/pilot communication workload on departure

Memory trick: 'Climb via' means follow the whole chart, not just the sky.

Altitude hold and other autopilot pitch modes rely on static pressure data; a blocked static port feeds erroneous altitude information, causing incorrect pitch commands.

• ALT HOLD uses static pressure trend to control pitch
• Blocked static port causes false altitude perception
• Pilots must monitor raw pitot-static instruments even with autopilot engaged

Memory trick: Bad static data in, bad pitch commands out.

AIRMET Zulu is issued for moderate icing and forecast freezing levels covering a wide area, intended for hazards significant to all aircraft but below SIGMET severity thresholds.

• AIRMET Sierra = IFR conditions and mountain obscuration
• AIRMET Tango = turbulence, strong surface winds, low-level wind shear
• AIRMET Zulu = moderate icing and freezing levels
• SIGMETs are issued for more severe/hazardous conditions than AIRMETs

Memory trick: Sierra=Sky, Tango=Turbulence, Zulu=freeZing

During lost communications, the route to fly follows this priority: Assigned, Vectored (direct to next fix), Expected, Filed.

• A = last assigned route
• V = vector clearance, direct to specified fix/airway
• E = expected route from ATC
• F = filed flight plan route

Memory trick: 'AVEF: Aviators Value Every Flight-plan' in priority order.

A chart note restricting Baro-VNAV (LNAV/VNAV) use below a specified temperature because cold air causes the computed vertical path to fly lower than intended, requiring pilots to use LNAV or circling minimums instead.

• Cold temperatures cause true altitude to be lower than indicated altitude
• Restriction is charted as 'Baro-VNAV NA below [temp]'
• Below the limit, use LNAV (MDA) minimums instead of LNAV/VNAV (DA) minimums

Memory trick: Cold air lies low — below limit, drop VNAV, fly LNAV.

Abnormally rapid or deep breathing, often triggered by stress or anxiety, that lowers carbon dioxide levels in the blood and causes dizziness, tingling, and lightheadedness.

• Symptoms include tingling extremities, dizziness, and visual disturbances
• Often confused with hypoxia but caused by CO2 loss rather than O2 lack
• Treated by slowing breathing rate or talking aloud

Memory trick: Breathe fast, feel tingly, slow it down

An Instrument Landing System (ILS) consists of several ground-based components that provide precision guidance for aircraft during approach and landing.

• Localizer: lateral guidance (runway centerline).
• Glide Slope: vertical guidance (descent path).
• Marker Beacons: range information (distance from touchdown).
• DME (optional): provides continuous distance to the runway threshold.

Memory trick: LGMD: Localizer, Glide slope, Marker beacons, DME.

ILS glideslope signals can be affected by reflections from ground objects or terrain, leading to fluctuations or 'roughness' that make it difficult to maintain a stable vertical path.

• Reflections are a primary cause of instability.
• Can lead to false glideslopes.
• Requires careful monitoring and pilot intervention.

Memory trick: Glide Slope: Ground Reflects, Rough Ride Results.

RNP is a statement of the navigation performance necessary for operation within a defined airspace, expressed as a distance (e.g., 0.3 NM) within which the aircraft's position must be for 95% of the flight time.

• Indicates navigation system accuracy.
• Expressed in nautical miles.
• 95% containment value.
• Includes onboard performance monitoring and alerting.

Memory trick: RNP: Required Navigation Performance is a 'Number' of miles, 95% of the 'Period'.

Standard Terminal Arrival Route (STAR) charts include altitude restrictions at specific fixes, which can be 'at', 'at or above', or 'at or below'.

• Altitude restrictions on STARs guide descent.
• 'A' suffix means 'at or above'.
• 'B' suffix (or no suffix) means 'at or below'.
• A solid line means 'at'.

Memory trick: STARs set the stage for your descent with altitude rules.

Under 14 CFR Part 91.177, when flying IFR off-route or where no MEA/MOCA is prescribed, pilots must maintain specific minimum altitudes: 1,000 feet above the highest obstacle within 4 NM in non-mountainous areas, and 2,000 feet above the highest obstacle within 4 NM in mountainous areas.

• Non-mountainous: 1,000 ft above highest obstacle within 4 NM.
• Mountainous: 2,000 ft above highest obstacle within 4 NM.
• Applies when no MEA/MOCA is specified.
• Ensures obstacle clearance during IFR flight.

Memory trick: Mountainous 2K, Non-Mountainous 1K, Always 4NM!