CAA NZ AME Instruments flashcards
CAA NZ AME Instruments · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Pitot pressure
- Total (ram) pressure sensed at the forward-facing pitot tube; combined with static pressure it drives the airspeed indicator's capsule deflection.
- Static pressure source
- Undisturbed ambient pressure taken from flush static ports; supplies the ASI, altimeter and VSI. Blockage causes all three to misread simultaneously.
- Blocked static port in climb
- Trapped static pressure stays higher than ambient, so the ASI over-reads and the altimeter under-reads as the aircraft climbs away from the trapped pressure altitude.
- VSI capillary leak
- A calibrated restriction in the static line slows pressure changes to the VSI capsule, making deflection proportional to rate of change rather than instantaneous pressure.
- Altimeter subscale setting
- The barometric reference dial; set to QNH it reads altitude above mean sea level, to QFE height above datum, to 1013.25 hPa pressure altitude.
- White arc meaning
- Flap operating range on the airspeed indicator, bounded below by VSO (stall in landing configuration) and above by VFE (maximum flap extended speed).
- Yellow arc meaning
- Caution range between VNO (maximum structural cruising speed) and VNE (never-exceed speed); flight in this range is only for smooth air.
- Compass deviation
- Aircraft-specific magnetic error caused by onboard electrical and ferrous interference, measured during a compass swing and recorded on a deviation card.
- Magnetic variation
- The angular difference between true north and magnetic north at a geographic location, shown on charts as isogonic lines and applied when converting headings.
- UNOS compass rule
- When turning through north the compass undershoots, when turning through south it overshoots; used to anticipate magnetic compass behaviour during turns.
- Rigidity in space
- A spinning gyroscope rotor maintains its plane of rotation in inertial space, providing a stable reference for attitude and heading instruments.
- Gyroscopic precession
- An applied force on a spinning rotor produces apparent movement 90 degrees later in the direction of rotation, the principle behind rate gyros and turn indicators.
- Blocked pitot with open drain
- Ram pressure cannot enter but the drain admits static pressure, so the ASI behaves like an altimeter: it reads higher in climb and lower in descent.
- Pressure altitude
- Altitude indicated when the altimeter subscale is set to the standard datum 1013.25 hPa or 29.92 inHg; used for flight levels and performance calculations.
- Density altitude
- Pressure altitude corrected for non-standard temperature; high temperature or low pressure raises it and degrades engine, propeller and wing performance.
- True to magnetic conversion
- Add easterly variation to true heading to obtain magnetic, subtract westerly variation; then apply deviation from the compass card to reach compass heading.
- Airspeed indicator capsule
- A diaphragm exposed to pitot pressure internally and static pressure externally; the differential deflection is mechanically displayed as indicated airspeed.
- VNE red radial
- Never-exceed speed marked as a red line at the top of the yellow arc; exceeding it risks structural damage from dynamic pressure and flutter.
- Pitot heat pre-flight check
- Confirm the pitot heater draws current and the element heats, and that static drains and ports are clear and unblocked before flight into instrument conditions.
- Altimeter lag error
- Mechanical friction and capsule elasticity cause a small delay in the altimeter responding to rapid pressure changes, most noticeable in high-rate climbs or descents.
- Turn coordinator gyro axis
- The turn coordinator uses a rotor tilted about the roll axis so it senses both rate of turn and rate of roll, showing coordination during roll-in and roll-out.
- Attitude indicator erection
- Vacuum or electric gyros are erected to the local vertical by pendulous vanes or torque motors, correcting slow precession errors during coordinated flight.
- Heading indicator precession
- The heading gyro drifts from real heading due to Earth's rotation and bearing friction, so it must be realigned with the magnetic compass periodically in level flight.
- Machmeter principle
- Computes the ratio of true airspeed to local speed of sound from pitot and static pressure inputs, displaying Mach number without needing outside air temperature.
- Air data computer
- Accepts pitot, static and temperature inputs and computes airspeed, altitude, vertical speed, Mach and temperature for display on electronic flight instruments.
- Glass cockpit display
- Electronic attitude and heading displays fed by air data and inertial or gyro sensors, replacing mechanical gyros and offering integrated flight and engine information.
- Pitot tube icing
- Ice blocking the pitot inlet causes indicated airspeed to fall toward zero in level flight; pitot heat is the primary defence and must be on before entering icing.
- Static port icing
- Ice over the static ports traps pressure in the lines, causing altimeter freeze, VSI zero and ASI errors; alternate static source is the standard mitigation.
- Alternate static source
- A cockpit or cabin static selection used when the external static ports block; cabin pressure usually differs slightly, so expect small ASI and altimeter errors.
- Compass swing purpose
- Procedure that measures residual deviation on each cardinal heading after compensating magnets are adjusted, producing the deviation card carried in the aircraft.
- Instrument range marking
- Coloured arcs and radials on the ASI dial that must match the approved flight manual envelope; incorrect markings make the instrument unserviceable.
- Angle of attack indicator
- Measures airflow direction relative to the wing chord and displays margin to stall, giving warning independent of airspeed, weight and density altitude.