Flight Instruments Flashcards by Zeff Gillespie

PRINCIPLES OF A GYROSCOPE

Rigidity in space - a gyroscope remains in a fixed position in the plane in which it is spinning.

Precession - the tilting or turning of a gyro in response to a deflective force; occurs 90* later in the direction of rotation.

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Describe the ATTITUDE INDICATOR

bank and pitch information

rigidity in space

normally vacuum-driven in GA aircraft but may electrically powered in others

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Describe the HEADING INDICATOR

Rigidity in space

Normally powered by vacuum system in GA aircraft

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What instrument is this

Turn coordinator

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What does a turn coordinator show?

Rate of turn

and

Rate of roll

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What instrument is this?

Turn-and-slip indicator

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What does a turn-and-slip indicator show?

Rate of turn only

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What are the 3 gyroscopic instruments?

Attitude indicator

Heading indicator

Turn indicators

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What are the 3 pitot-static instruments?

Altimeter

Vertical speed indicator

Airspeed indicator

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How does the ALTIMETER work?

Stack of aneroid wafers expand and contract with pressure from the static source

Mechanical linkage between aneroid and display translates pressure to an altitude indication

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Above 18,000’ MSL the altimeter should be set to

29.92” Hg and operate in Flight Levels

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INDICATED ALTITUDE is…

uncorrected altitude on the altimeter when set to local pressure setting

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PRESSURE ALTITUDE is…

altitude above 29.92” Hg plane

Used when flying above transition altitude (18,000’)

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DENSITY ALTITUDE is…

It is used for…

pressure altitude corrected for nonstandard temperature

performance calculations.

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TRUE ALTITUDE is…

altitude above Mean Sea Level

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ABSOLUTE ALTITUDE is…

height above airport elevation

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Describe the VERTICAL SPEED INDICATOR

Diaphragm inside is connected to the static source

Area outside the diaphragm gets static pressure from a calibrated leak

Diaphragm expands or contracts and mechanical linkage moves the needle

Instantaneous VSI (IVSI) solves lag issue

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Describe the AIRSPEED INDICATOR

Diaphragm receives ram air from pitot tube

Outside of diaphragm receives static pressure

Diaphragm expands and contracts and mechanical linkage displays airspeed

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The ATTITUDE INDICATOR should show the correct attitude within…

5 minutes of starting the engine

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What errors is the ATTITUDE INDICATOR susceptible to?

Acceleration (pitch up)

Deceleration (pitch down)

Rollout (after rollout shows slight turn in opposite direction)

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What does the HEADING INDICATOR show?

Shows heading changes, doesn’t measure heading itself

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What must you do to the HEADING INDICATOR for it to display the correct heading?

Calibrate it to magnetic compass to show correct heading

Some can be slaved to magnetic heading source, allowing it to sync automatically

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Older ATTITUDE INDICATORS may be susceptible to what?

Tumble limit

DYNAMIC PRESSURE in regard to airspeed is the result of what?

Impact pressure minus static pressure

What is INDICATED AIRSPEED (IAS)?

Airspeed shown on the Airspeed Indicator

What is CALIBRATED AIRSPEED (CAS)?

IAS corrected for instrument and position errors

What is EQUIVALENT AIRSPEED (EAS)?

CAS corrected for compressibility error

What is TRUE AIRSPEED (TAS)?

Actual speed through the air EAS corrected for nonstandard temperature and pressure

What is MACH NUMBER?

Ratio of TAS to the local speed of sound

What is GROUND SPEED (GS)?

Actual speed over the ground TAS corrected for winds

What is the WHITE ARC on the ASI?

Flap operating range Starts at Vs0, ends at Vfe

What is the GREEN ARC on the ASI?

Normal operating range Starts at Vs1, ends at Vno

What is the YELLOW ARC on the ASI?

Caution range Fly only in smooth air and with caution

What is the RED LINE on the ASI?

Vne

How will static port blockage affect the Airspeed Indicator?

Shows correct airspeed ONLY at blockage altitude Climb - indicates lower speed than it should Descend - indicates higher speed than it should

How will static port blockage effect the Altimeter?

Will freeze on the altitude where it was blocked

How will static port blockage affect the Vertical Speed Indicator?

It will freeze on zero

After verifying a static port blockage what should you do?

Use the alternate static source or Break the VSI window and expect reverse VSI information

When using the alternate static source a _______ static pressure is measured. The ASI will… The Altimeter will… The VSI will…

lower show a faster speed than it should show a higher altitude than it should momentarily show a climb

What is the only instrument affected by pitot tube blockage?

Airspeed Indicator

The ram air inlet of the pitot tube is blocked but the drain hole is open. What will happen the your IAS?

Drop to zero

The ram air inlet and the drain hole on the pitot tube are both clogged. How will your airspeed indicator respond?

It will act like an altimeter No longer reliable

You suspect pitot tube blockage. What should you consider using?

Pitot heat Ice might have formed in the tube

GENERIC INSTRUMENT TAXI CHECK

Airspeed - 0 KIAS Turn Coordinator - wings level, ball centered - turns, correct direction, ball opposite turn Attitude - pitch/ bank +-5* w/in 5 mins Heading Indicator - set and correct Altimeter - set, field elevation +-75’ VSI - 0 FPM Mag Compass - swings freely, full of fluid - deviation card installed - marker beacons, tested NAV & Comms - set GPS - checked and set EFIS Cockpits - PFD/MFD/EICAS - check for X’s, messages, warnings, removed symbols

What are the Magnetic Compass errors and limitations?

Deviation - magnetic interference with compass (radios, magnetized parts, etc) Variation - diff. between true (geographic) north and magnetic north Magnetic Dip - compass dips along magnetic field toward magnetic pole. Unreliable close to poles Accel/decel errors - E/W heading, accel shows temp N turn, decel shows temp S turn North/south turn errors - compass leads to north, lags to south Oscillation error - combo of mag dip, accel/decel and N/S turn errors

What is AHRS?

Attitude and Heading Reference System Measures and sends attitude and heading information to the PFD for display More accurate and reliable than traditional gyro systems

What is an ADC?

Air Data Computer Replaces the mechanical pitot-static instruments Takes inputs from pitot, static and temperature ports and computes airspeed, true airspeed, vertical speed and altitude

What computes and displays command bars on the attitude indicator to help you fly a selected heading, course or vertical speed?

Flight Director

What does the Flight Management System (FMS) do?

- Gives guidance to the autopilot and flight director - Monitors and selects the best navigation source for accurate positioning

Describe the EFIS

Electronic Flight Instrument System AKA “glass cockpit”

What is a PFD?

Primary Flight Display Shows flight data such as attitude, altitude, airspeed, VSI, heading and rate tapes

What shows a variety of info like moving maps, systems status, weather and traffic?

Multi-Function Display (MFD)

In the US, when operating below 18,000’ MSL…

Regularly set the altimeter to a station within 100 NM

Nemonic for when you’re flying from an area of high pressure to low pressure or from an area of hot temps to low temps

High to low - Look out below

This error occurs at altitudes above 10,000’ and airspeeds faster than 200 knots as air begins to “compress” in the pitot tube causing CAS to indicate higher that it should

Compressibility Error