Aircraft Instruments

Question 1

How are aircraft instruments classified?

Answer 1

ACCORDING TO THE JOB THEY PERFORM AND THIER PRINCIPLE OF OPERATION

Question 2

What are the 4 main principles of operations for aircraft instruments?

Answer 2

PRESSURE
GYROSCOPIC
MAGNETIC
ELECTRIC

Question 3

What are the 4 ways that instrument information can be displayed?

Answer 3

ANALOG - DIAL OR BAR GRAPH
DIGITAL - NUMERICAL
GRAPHIC
OR ANY COMBINATION

Question 4

What does EFIS stand for?

Answer 4

Electronic Flight Instrument System

Question 5

How is the EFIS displayed and what information does it show?

Answer 5

A CRT OR LCD DISPLAY UNIT.
IT DISPLAYS TO THE PILOT ALPHA-NUMERIC DATA AND GRAPHIC DISPLAYS THAT REPRESENT THE AIRCRAFT INSTRUMENTS.

Question 6

What are the 2 basic types of pressure instruments?

Answer 6

BOURDON TUBE TYPE
DIAPHRAGM OR BELLOWS TYPE

Question 7

What 2 things does a Bourdon Tube measure?

Answer 7

HIGH PRESSURE and Temperature
(Hydraulic, Oil, Oxygen, etc)

Question 8

What do Diaphragms/Bellows measure?

Answer 8

LOW Pressure
(Bellows provide a greater range of movement than Diaphragms)

Question 9

The Pitot Static system is the source of pressure needed for what 4 instruments?

Answer 9

Altimeter
Airspeed
Vertical Speed
Machmeter

Question 10

What is a Pitot Tube?

Answer 10

TUBE WITH AN INSIDE DIAMETER OF APPRX. 1/4” INSTALLED ON THE OUTSIDE OF THE AIRCRAFT. PICKS UP RAM AIR PRESSURE & DIRECTS IT TO THE INSTRUMENTS.

Question 11

What are Static Ports?

Answer 11

SMALL HOLES ON EITHER SIDE OF THE FUSELAGE OR VERTICAL FIN OR SMALL HOLES IN THE PITOT STATIC HEAD
(sense the pressure of the still or static air)

Question 12

What does the Altimeter indicate?

Answer 12

THE HEIGHT OF THE AIRCRAFT ABOVE SEA LEVEL

Question 13

What are the 3 types of altitude?

Answer 13

INDICATED ALTITUDE
PRESSURE ALTITUDE
DENSITY ALTITUDE

Question 14

What is Indicated Altitude?

Answer 14

PRESSURE ABOVE EXISTING SEA LEVEL PRESSURE.
READ DIRECTLY FROM THE INDICATOR

Question 15

What is Pressure Altitude and who uses it?

Answer 15

THE ALTITUDE ABOVE STANDARD SEA LEVEL PRESSURE (29.92Hg)
ALL AIRCRAFT ABOVE 18K ft USE THIS SETTING.

Question 16

What is Density Altitude?

Answer 16

A COMPENSATED ALTITUDE FOUND BY CORRECTING THE PRESSURE
ALTITUDE FOR NONSTANDARD TEMPERATURE.

Question 17

What are the 2 basic types of Altimeters?

Answer 17

NONSENSITIVE (OLD STYLE)
SENSITIVE (3-POINTER TYPE)

Question 18

What are the increments for the 3 needles on the sensitive type altimeter?

Answer 18

Longest Needle: 100ft
Middle (fat) Needle: 1000ft
Smallest Needle (triangle): 10,000ft

Question 19

How is pressure compensated for on the sensitive altimeter?

Answer 19

It is done by the pilot with a Barometric-Pressure setting knob

Question 20

At high altitudes, how is aircraft separation maintained?

Answer 20

ALL AIRCRAFT MUST PLACE THE SAME PRESSURE READING IN THE KOLLSMAN WINDOW

Question 21

WHEN IS IT REQUIRED FOR ALL AIRCRAFT TO PLACE THE SAME PRESSURE READING IN THE KOLLSMAN WINDOW?

Answer 21

AT OR ABOVE 18,000 FT
(Pressure Altitude)

Question 22

Where is the Altimeter located?

Answer 22

MOUNTED IN THE TOP RIGHT-HAND CORNER OF THE “CRITICAL SIX”.

Question 23

When is an Encoding Altimeter used?

Answer 23

WHEN IN HIGH-DENSITY TRAFFIC AREAS.

Question 24

WHAT INSTRUMENT IS REQUIRED ON ALL CERTIFIED AIRCRAFT EXCEPT FREE BALLOONS?

Answer 24

Airspeed Indicator

Question 25

Where is the Airspeed Indicator located?

Answer 25

IN THE **UPPER LEFT-HAND CORNER** OF THE PANEL

Question 26

What are the markings on the Airspeed Indicator and what do they mean?

Answer 26

**RED RADIAL LINE** = NEVER EXCEED SPEED. **YELLOW ARC** = CAUTION RANGE OF SPEEDS. **GREEN ARC** = NORMAL OPERATING RANGE. **WHITE ARC** = FLAP-OPERATING RANGE. **BLUE RADIAL LINE** = ONE-ENGINE INOPERATIVE BEST RATE OF CLIMB SPEED (TWIN ENGINE AIRCRAFT)

Question 27

What unit of measurement does the Airspeed Indicator indicate in?

Answer 27

Knots

Question 28

KNOTS = _____ ________ ______ PER HOUR.

Answer 28

ONE NAUTICAL MILE

Question 29

ONE KNOT =____ ______ ______ PER HOUR.

Answer 29

1.15 STATUTE MILES

Question 30

IF AN INSTRUMENT STATIC-PRESSURE LINE BECOMES DISCONNECTED INSIDE A PRESSURIZED CABIN, WHAT WILL HAPPEN?

Answer 30

THE ALTIMETER WILL INDICATE A LOWER ALTITUDE.

Question 31

ENGINE INSTRUMENTS SHOULD BE MARKED IN ACCORDANCE WITH WHAT?

Answer 31

THE INFORMATION FOUND IN THE **AIRCRAFT SPECIFICATIONS** OR **TYPE CERTIFICATE DATA SHEETS** FOR THE AIRCRAFT IN WHICH THE INSTRUMENT IS INSTALLED. THIS INFORMATION CAN ALSO BE FOUND IN THE **AIRCRAFT MAINTENANCE MANUAL** OR THE **AIRCRAFT FLIGHT MANUAL**

Question 32

WHEN AN INSTRUMENT IS INSTALLED IN AN AIRCRAFT INSTRUMENT PANEL, IT IS THE RESPONSIBILITY OF THE TECHNICIAN PERFORMING THE INSTALLATION TO ENSURE WHAT?

Answer 32

THE INSTRUMENT IS PROPERLY MARKED FOR THE AIRCRAFT IN WHICH IT IS BEING INSTALLED

Question 33

WHAT IS A WHITE SLIPPAGE MARK PAINTED ACROSS THE BEZEL AND THE GLASS OF AN AIRCRAFT INSTRUMENT USED FOR?

Answer 33

TO INDICATE IF THE GLASS COVER HAS SLIPPED OR DEVIATED

Question 34

WHAT DOES THE VERTICAL SPEED INDICATOR (RATE-OF-CLIMB INDICATOR) INDICATE?

Answer 34

INDICATES THE RATE AT WHICH THE AIRCRAFT IS CLIMBING OR DESCENDING.

Question 35

THE VERTICAL SPEED INDICATOR IS A DIFFERENTIAL PRESSURE INSTRUMENT, WHICH IS THE DIFFERENCE BETWEEN WHAT?

Answer 35

ATMOSPHERIC PRESSURE & THE PRESSURE OF THE CHAMBER VENTED TO THE ATMOSPHERE THRU A SMALL “CALIBRATED ORIFICE”.

Question 36

Where is the Vertical Speed Indicator located?

Answer 36

LOCATED IN THE LOWER RIGHT-HAND CORNER OF THE “CRITICAL SIX”.

Question 37

What is Precession?

Answer 37

THE CHARACTERISTIC OF A GYRO THAT CAUSES A FORCE TO BE FELT AT A POINT 90 DEGREES IN THE DIRECTION OF ROTATION FROM THAT POINT.

Question 38

What are the 2 ways that Gyroscopic instruments are **operated**?

Answer 38

PNEUMATICALLY OR ELECTRICALLY

Question 39

What are 2 ways that Gyroscopic instruments are **driven**?

Answer 39

VACUUM PUMP DRIVEN OR ELECTRIC MOTOR DRIVEN.

Question 40

THE KNOB AT BOTTOM OF THE ATTITUDE INDICATOR IS USED TO ADJUST FOR WHAT?

Answer 40

PARALLAX ERROR

Question 41

The Heading Indicator (sometimes called Directional Gyro) senses what?

Answer 41

SENSES ROTATION ABOUT THE VERTICAL AXIS OF THE AIRCRAFT.

Question 42

WHAT IS A LUBBER LINE?

Answer 42

THE LUBBER LINE ON A DIRECTIONAL GYRO IS USED AS A **REFERENCE TO REPRESENT THE NOSE OF THE AIRCRAFT**

Question 43

WHAT IS A STANDARD-RATE-TURN?

Answer 43

3 DEGREES PER SECOND. **360** DEGREE TURN IN **TWO MINUTES**. 180 Deg. PER/MIN.

Question 44

What is a 4 minute turn indicator?

Answer 44

YAW AT 1.5 DEG. PER SECOND

Question 45

What is the Turn Coordinator?

Answer 45

AN ELECTRIC DRIVEN GYROSCOPE THAT SENSES ROLL & YAW WITH A 30 DEGREE TILTED GIMBAL.

Question 46

The magnetic compass requires ___ ____ from any aircraft source.

Answer 46

No power

Question 47

What does the magnetic compass use for its indications?

Answer 47

**EARTH** THE CARD WILL FLOAT AND SPIN WITH RESPECT TO THE **EARTH’S MAGNETIC FIELD**

Question 48

What does the kerosene-like fluid in the magnetic compass do?

Answer 48

HELPS TO DAMPEN OSCILLATIONS AND VIBRATIONS

Question 49

WHAT ARE ISOGONIC LINES?

Answer 49

LINES INDICATING THE ANGULAR DIFFERENCE BETWEEN THE MAGNETIC NORTH POLE & GEOGRAPHIC NORTH POLE

Question 50

WHAT IS AN AGONIC LINE:

Answer 50

THE ONE LINE ALONG WHICH MAGNETIC & GEOGRAPHIC POLES ARE IN ALIGNMENT (No angle - 0)

Question 51

What is deviation error?

Answer 51

AN INACCURACY CAUSED BY MAGNETIC INFLUENCES IN THE AIRPLANE

Question 52

ON THE MAGNETIC COMPASS, NO READING MAY EXCEED ___ DEGREES IN ANY HEADING.

Answer 52

+/- 10

Question 53

What should be done after completing the front of the correction card when swinging a compass?

Answer 53

BE SURE TO TURN IT OVER & DATE THE CARD, PRINT YOUR NAME, SIGN IT, INCLUDE YOUR A&P #, & TOTAL TIME IN SERVICE (TTIS)

Question 54

When should a swinging of the compass be done?

Answer 54

ANYTIME THERE IS AN INSTALLATION OR REMOVAL OF RADIO/ELECTRICAL EQUIPMENT THAT COULD AFFECT MAGNETIC DEVIATION

Question 55

THE FLUX GATE COMPASS USES AN AUTOSYN SYNCHRO SYSTEM WHERE THE SYNCRO TRANSMITTER IS CONNECTED TO THE SYNCRO RECEIVER HOW?

Answer 55

ELECTRICALLY (via wires)

Question 56

A static system pressure check is done how often and in accordance with what?

Answer 56

Required every **24 months** FAR **91.411** & FAR PART **43 APPENDIX E**

Question 57

In simple terms, how is a static system check performed?

Answer 57

ALLOW THE ALTIMETER TO INCREASE TO A 1,000 FT. INDICATION. CLOSE OFF THE SYSTEM (PINCH HOSE), HOLD THIS PRESSURE IN THE SYSTEM FOR ONE MINUTE.

Question 58

What do Accelerometers indicate?

Answer 58

CHANGES **ONLY** ALONG THE AIRCRAFT VERTICAL AXIS

Question 59

A STALL CAN OCCUR AT ANY SPEED, BUT AT ONLY ONE _____ __ ______.

Answer 59

ANGLE OF ATTACK (AOA)

Question 60

WHAT ARE 2 BASIC TYPES OF STALL WARNINGS?

Answer 60

VIBRATING REED TYPE ELECTRIC SWITCH TYPE (**most common**)

Question 61

What does an electric switch type stall warning look like?

Answer 61

METAL TAB SWITCH THAT PROTRUDES FROM THE LEADING EDGE OF THE WING AT THE STAGNATION POINT

Question 62

THE ANGLE OF ATTACK SENSOR DETECTS WHAT?

Answer 62

THE ANGULAR DIFFERENCE BETWEEN THE RELATIVE WIND AND THE FUSELAGE CENTERLINE

Question 63

What are the 2 main types of vacuum pumps?

Answer 63

Wet & Dry

Question 64

WET TYPE PUMPS NEED WHAT FOR POSITIVE PRESSURE SYSTEMS?

Answer 64

AN OIL SEPARATOR

Question 65

What type of pump is used for a Dry pump system?

Answer 65

A CARBON-VANE PUMP THAT WEARS AWAY AT A PREDETERMINED RATE

Question 66

How often must the filter in a Dry pump system be changed?

Answer 66

At Annuals or as suggested by the manufacturers maintenance manual

Question 67

IF USING VACUUM GYROS ON THE AIRCRAFT, WHAT MUST IT HAVE?

Answer 67

A SUCTION GAUGE

Question 68

EXCESSIVE VACUUM IN A VACUUM SYSTEM COULD BE CAUSED BY WHAT?

Answer 68

AN IMPROPERLY ADJUSTED VACUUM RELIEF VALVE

Question 69

How does the Horizontal Situation Indicator show that a particular function is inoperative?

Answer 69

Warning Flags

Question 70

What circuits are the warning flags included in?

Answer 70

IN THE NAVIGATION (**NAV**), THE GYRO (**HDG**), AND THE GLIDESLOPE (**GS**) CIRCUITS.

Question 71

WHAT DETERMINES THE WAY THE INSTRUMENT IS MOUNTED IN THE INSTRUMENT PANEL?

Answer 71

THE DESIGN OF THE INSTRUMENT CASE

Question 72

How are instruments secured to the aircraft?

Answer 72

SOME INSTRUMENTS ARE HELD IN PLACE WITH SCREWS WHILE OTHERS ARE CLAMPED USING A SPECIAL MOUNTING RING

Question 73

WHY ARE MOST ELECTRICAL INSTRUMENTS MOUNTED IN IRON OR STEEL CASES?

Answer 73

TO PREVENT INTERFERENCE FROM OUTSIDE MAGNETIC FIELDS (**The metal traps the lines of flux**)

Question 74

What must you always check when installing an instrument?

Answer 74

THE RUBBER PANEL MOUNTS FOR SECURITY AND WEAR

Question 75

INSTRUMENT PANEL MUST ABSORB _______-AMPLITUDE, ______-FREQUENCY VIBRATIONS.

Answer 75

**High** amplitude, **Low** frequency

Question 76

INSPECT ALL BONDING BRAIDS AND HARDWARE TO ENSURE WHAT?

Answer 76

THAT THEY PROVIDE THE CURRENT RETURN PATH