Flight Instruments Flashcards
The dial of a typical altimeter is _______
graduated, with the numerals arranged clockwise from 0 to 9. The shortest hand indicates altitude in tens of thousands of feet, the intermediate in thousands of feet, and the longest in hundreds of feet
Adjustments for non-standard conditions are performed by _______
setting the corrected pressure into a barometric scale on the face of the altimeter; only then will the altimeter indicate the precise altitude
Altitude is _______
vertical distance above some point or level used as a reference
There are as many kinds of altitudes as there are _______
reference levels from which to measure those altitudes
Indicated altitude is ______
The uncorrected altitude read directly from the altimeter when it is set to the current altimeter setting.
The vertical speed indicator (VSI), sometimes called vertical velocity indicator, indicates _______
if the airplane is climbing, descending, or in level flight. The rate of climb or descent is indicated in feet per minute. If correctly calibrated, zero would indicate level flight.
The vertical speed indicator is capable of displaying two different types of information:
Trend information which shows an immediate change in the rate of climb or descent
Rate information which shows a stabilized rate of change in altitude
An example of trend information on a vertical speed indicator:
For example, if an airplane maintaining a steady 500-foot-per-minute (fpm) climb slightly lowers its nose, the VSI would immediately sense this change and would indicate a decrease in the rate of climb. This first indication is called the trend. After a short time, the VSI needle will stabilize on the new rate of climb. The time between the change in the rate of climb and until it displays an accurate indication of the new rate is called the lag. Some airplanes are equipped with instantaneous vertical speed indicators (IVSI), which have accelerometers to compensate for the lag of a typical VSI
Airspeed indicator:
The airspeed indicator is a sensitive differential pressure gauge that measures and promptly shows the difference between pitot (impact) pressure and static pressure. When the airplane moves through the air, the pressure on the pitot line becomes greater than the pressure in the static lines. This difference in pressure is registered by the airspeed pointer on the face of the instrument, which is calibrated in mph, knots, or both
Static pressure:
The static pressure is the atmospheric pressure at the flight level of the aircraft.
There are four airspeed types, which can be remembered using the mnemonic _______:
ICE-T
Indicated airspeed
Calibrated airspeed
Equivalent airspeed
True airspeed
Indicated airspeed:
indicated airspeed is the speed shown on the airspeed indicator
Calibrated airspeed:
calibrated airspeed is indicated airspeed corrected for instrument and positional errors.
Equivalent airspeed:
EAS is calibrated airspeed (CAS) corrected for the compressibility of air at a non-trivial Mach number
Or
the speed at sea level, under ISA conditions, that would generate the same incompressible dynamic pressure as the true airspeed (TAS) and altitude at which the aircraft is flying.
True airspeed:
True Airspeed is equivalent airspeed corrected for temperature and pressure altitude.
Airspeed white arc:
This arc is commonly referred to as the flap operating range since its lower limit represents the full flap stall speed and its upper limit provides the maximum flap speed. Approaches and landings are usually flown at speeds within the white arc
Lower limit of white arc VS0:
the stalling speed or the minimum steady flight speed in the landing configuration. In small aircraft, this is the power-off stall speed at the maximum landing weight in the landing configuration (gear and flaps down).
Upper limit of white arc (VFE):
the maximum speed with the flaps fully extended
Or
the maximum permissible speed for the landing flap configuration, which is the full/maximum extended flap setting.
Green arc:
This is the normal operating range of the airplane. Most flying occurs within this range.
Lower limit of green arc (VS1):
the stalling speed or the minimum steady flight speed obtained in a specified configuration. For most aircraft, this is the power-off stall speed at the maximum takeoff weight in the clean configuration (gear up, if retractable, and flaps up).
Upper limit of green arc (VN0):
the maximum structural cruising speed. Do not exceed this speed except in smooth air.
Yellow arc:
caution range. Fly within this range only in smooth air and then only with caution.
Red arc:
never exceed speed. Operating above this speed is prohibited since it may result in damage or structural failure.
All airplanes have six basic flight instruments:
airspeed indicator
attitude indicator
altimeter
turn coordinator
heading indicator
vertical speed indicator
There are two types of turn indicators:
The turn-and-slip indicator and the turn coordinator
Both turn-and-slip indicator and turn coordinator show _______
turn direction and coordination, and also serve as a backup source of bank information in case attitude indicator fails
Both the turn-and-slip indicator and the turn coordinator run on _______
battery power. The gyroscopes of both will start spinning when turning on the master switch. If you don’t hear their gyroscopes spinning, then they aren’t going to work correctly.
If both the turn-and-slip indicator and the turn coordinator lose electrical power _______
a red flag will pop up
Remember the A TOMATO FLAMES acronym, which are the VFR day minimum equipment requirements found in far 91.205:
A - Airspeed indicator
T - Tachometer (for each engine)
O - Oil Pressure Gauge (for each engine)
M - Magnetic Direction Indicator
A - Altimeter
T - Temperature Gauge (for each liquid cooled engine)
O - Oil Temperature Gauge (for each air cooled engine)
F - Fuel Gauges (For each tank)
L - Landing Gear Position Indicator
A - Anticollision Light
M - Manifold Pressure guage (for each Altitude Engine)
E - ELT
S - Seatbelts for each occupant
The turn-and-slip indicator doesn’t show any bank information, but it does show _______
if the airplane is in a left or right turn
If the turn-and-slip indicator needle is on one of the left or right tick marks, then _______
that will indicate the airplane will make a 360 degree turn, in 2 minutes, in the direction of the turn. This equates to 3 degrees per second, which is what we call the standard rate turn
The turn-and-slip indicator operates on a principle known as _______
gyroscopic precession, which basically states that any time I apply a force to a spinning gyroscope, there’s a resultant force that occurs 90 degrees ahead of the force applied along the plane of rotation.
Not only is a gyro rotor able to spin on its axis, but _______
a single gimbal allows the gyro rotor to tilt one direction or another.
When an airplane turns in a certain direction, the turn-and-slip gyroscope _______
turns with it, this places a force on the sides of the gyro rotor, and because of precession the force is transferred to the vertical ends of the gyro rotor, making the bottom part tilt laterally into the turn direction. Since the gyroscope is connected with the instrument’s needle, the needle will move in the turning direction. When the airplane returns to wings level, spring tension returns the gyro rotor to its upright position, and the needle moves back to the center.
That’s how this device works to give the rate of turn in the airplane
In both a turn-and-slip indicator and a turn coordinator, coordination is achieved by an _______
inclinometer, which is a liquid-filled curved tube with a ball inside. Some pilots call it the slip/skid indicator.
In straight and level flight, gravity pulls the ball to the lowest point at the center. When on a turn, as long as the load is perpendicular to the wings, the ball will remain centered. Sometimes a sideways force acting on the airplane displaces the ball either to the left or right.
When making a turn, as long as the nose is aligned with the direction of travel, will the ball remain centered. This is what we call a coordinated turn.
Skidding turn is when the tail of the airplane is outside of the turn, and so the ball will also be outside.
Slipping turn is when the tail is inside of the turn, and so ball will also be inside.
Rudder pedals are used to step in the direction of the ball to align the nose in the direction of the turn
When stepping past the center, just release rudder pressure instead of switching to opposite rudder pressure
This is how the rudder pedals and the inclinometer are used to maintain coordinated flight
A big difference between the turn-and-slip indicator and the turn coordinator is that the _______
gimbal that holds the turn coordinator gyro in, is tilted at a 30 degree angle
The turn coordinator also lets us know the standard rate _______
of turn, but not the bank angle, which is a common misconception
Because the gyro on the turn coordinator is set at an angle (canted), _______
it initially also shows roll rate. Once the roll stabilizes, it indicates the rate of turn.
When your instructor asks you what the turn coordinator is for, you can tell them:
It gives you roll rate and rate of turn
The attitude indicator, also called artificial horizon, shows _______
a miniature airplane and horizon bar, which display a picture of the attitude of the airplane. The attitude relationship between the miniature airplane and the horizon bar, is the same relationship between the real airplane and horizon. The attitude. This instrument gives instantaneous indications of even the smallest changes in attitude
Banks under normal cruising conditions are typically _______
below 30 degrees
Make sure you check the poh for your bank angle limit
The miniature airplane on the attitude indicator can be adjusted _______
up or down to get accurate attitude, but this should be done on the ground. If you have to do it in flight, it should be done in straight and level flight. The knob is twisted to adjust it
An attitude indicator is what type of instrument?
a gyroscopic instrument. Sometimes their gyros use electricity to spin, but most training aircraft use suction from the vacuum system to spin it. If there’s not enough suction on the vacuum system, then the attitude indicator won’t work properly.
The gyro is spun by the air in the vacuum system, and rigidity in space tells us that the spinning motion keeps it rigid in space on a horizontal plane. Gimbals are attached to the gyro rotor axis, allowing the airplane to move around the stable gyro. The gimbal is mounted inside the attitude indicator, which is then connected to the horizon reference arm, and the reference arm connected to the horizon bar on the attitude indicator.
As the airplane rolls and pitches, the horizon bar maintains rigidity in space along with the gyro rotor
On airplanes with digital flight instruments, the attitude indicator _______
is large, and the horizon line spans the entire length of the primary flight display (pfd). The primary flight display uses an attitude and heading reference system (AHRS), which is a box that uses solid-state lasers to sense pitch, bank, and yaw information, which is then sent to the display.
What item was developed to reduce compass reading errors?
A vertical card compass
The horizontal situation indicator (HSI) is _______
an aircraft flight instrument normally mounted below the artificial horizon in place of a conventional heading indicator. It combines a heading indicator with a VHF omnidirectional range-instrument landing system (VOR-ILS) display.
How can pressure altitude be calculated from the aircraft’s altimeter?
Pressure altitude can be calculated by adjusting the aircraft’s altimeter to a standard pressure setting, usually 29.92 inches of mercury (inHg) or 1013.25 hectopascals (hPa), and then reading off the altitude indicated on the altimeter
What is a course deviation indicator (CDI)?
A course deviation indicator (CDI) is an avionics instrument used in aircraft navigation to determine an aircraft’s lateral position in relation to a course to or from a radio navigation beacon
What is a LOC (Localizer?
A Localizer (LOC) (above left) transmits VHF signals (108.1 MHz to 111.95 MHz) to provide aircraft with lateral guidance that allows pilots to ensure their aircraft is properly aligned with the center of the runway during the approach and landing phases of flight
