CASA IREX flashcards
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31 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Semicircular cruising altitude rule
- IFR/VFR cruising altitudes depend on magnetic course: 0-179 degrees uses odd thousands, 180-359 degrees uses even thousands, applied above 3000 feet in the US.
- Decision altitude (DA)
- The altitude on a precision approach at which a missed approach must be initiated if the required visual references are not in sight.
- Minimum descent altitude (MDA)
- The lowest altitude on a non-precision approach to which descent is authorized until the required visual references are acquired and the aircraft can land.
- Alternate airport requirement
- Required when destination forecast from one hour before to one hour after ETA shows ceiling below 2000 feet or visibility below 3 statute miles.
- Instrument currency requirement
- Within the preceding six calendar months: six approaches, holding procedures, and intercepting/tracking courses; a six-month grace period follows before a proficiency check.
- Approach category speeds
- Categories based on Vref at maximum landing weight: A below 91 knots, B 91-120, C 121-140, D 141-165 knots, each with its own minimums.
- Minimum safe altitude (MSA)
- Chart depiction guaranteeing 1000 feet of obstruction clearance within 25 nautical miles of the primary navigation facility, usually in quadrants.
- Standard takeoff minimums
- Part 91 baseline: one statute mile visibility for single-engine and one-half statute mile for multi-engine aircraft, unless higher published minimums apply.
- Standard lapse rate
- Temperature decreases about 2 degrees Celsius per 1000 feet in the troposphere, used to estimate freezing level and density altitude effects.
- Ceiling definition
- The lowest broken or overcast layer; VFR in Class E surface areas requires at least 1000 feet ceiling and 3 statute miles visibility.
- Convective SIGMET criteria
- Issued for severe or embedded thunderstorms, hail 3/4 inch or greater, surface winds 50 knots or more, and tornadoes affecting the area.
- Structural icing range
- Greatest airframe icing risk occurs between 0 and -20 degrees Celsius, especially with supercooled large droplets in freezing rain or drizzle.
- Density altitude rule of thumb
- Density altitude rises about 120 feet per degree Celsius above standard temperature at a given pressure altitude, reducing climb and landing performance.
- Freezing rain hazard
- Implies a warm layer aloft above a subfreezing surface layer, producing severe airframe icing and poor braking on the runway.
- Microburst wind shear
- A localized downdraft producing rapid wind shifts near the surface; most dangerous within 1000 feet of the ground where recovery margin is smallest.
- VIP radar levels
- Radar echo intensity scale; VIP 3-4 indicates moderate to heavy turbulence and hail potential within the storm cell.
- VOR radial interpretation
- Radials are magnetic bearings from the station; the CDI shows course deviation while TO/FROM indicates whether the selected course leads toward or away from the station.
- VOR receiver check tolerance
- Maximum error is 4 degrees for airborne and ground checks and 6 degrees for the VOT test; record date, place, and error.
- ILS localizer coverage
- Provides lateral guidance within about 35 degrees each side of runway centerline, usable only within published distances and altitudes.
- Glideslope angle
- Typical ILS glideslope is 3 degrees, giving about 300 feet of altitude per nautical mile from the threshold.
- RAIM prediction
- Receiver autonomous integrity monitoring checks GPS satellite geometry; if RAIM outage is predicted, the GPS approach cannot be flown.
- LPV approach
- Localizer performance with vertical guidance; a WAAS-based RNAV approach providing vertical guidance similar to a Category I ILS.
- DME slant range error
- DME measures slant range, so indicated distance exceeds ground distance; error grows with altitude and is largest directly over the station.
- ADF relative bearing
- The ADF needle points to the station relative to the aircraft nose; magnetic bearing equals relative bearing plus magnetic heading.
- RNP 0.3 meaning
- Required navigation performance where lateral deviation stays within 0.3 nautical miles 95 percent of the time, with onboard monitoring and alerting.
- Center of gravity formula
- CG equals total moment divided by total weight, where each moment is item weight times its arm; result must lie inside the CG envelope.
- Density altitude formula
- Approximate density altitude as pressure altitude plus 120 times the difference between outside air temperature and ISA temperature in Celsius.
- Weight effect on takeoff
- A 10 percent weight increase raises takeoff distance roughly 20 percent and reduces climb gradient, so performance charts must be recomputed.
- IFR fuel reserve
- Part 91 IFR requires enough fuel to destination plus alternate plus 45 minutes at normal cruising speed, with burn monitored en route.
- Load factor in level turn
- Load factor equals 1 divided by cosine of bank angle; at 60 degrees bank it is 2 G and stall speed rises about 41 percent.
- Aft CG effects
- A center of gravity too far aft reduces static stability and pitch force, making stall and spin recovery more difficult.