Engine Instruments

Question 1

What is the purpose of engine instruments?

Answer 1

Necessary for the flight crew to properly adjust and monitor engine system operations and for troubleshooting

Question 2

Engine instruments must be mounted in a way that is resistive to what type of vibrations?

Answer 2

High
Amplitude
Low
Frequency

Question 3

What are transient markings?

Answer 3

A diamond, dot, triangle, or a second red radial line, that indicate the absolute max limit

Question 4

What does a slippage mark look like?

Answer 4

A white radial line starting on the instrument case and extending to the face of the glass

Question 5

When is a slippage mark used?

Answer 5

Must be present when range markings are on the glass

Question 6

What do slippage marks do?

Answer 6

Show if the glass has loosened or moved

Question 7

What do bourdon tubes measure?

Answer 7

High pressure or Temperature

Question 8

What are 3 examples of high pressure systems?

Answer 8

Hydraulic
Oil
Oxygen

Question 9

Pressure is directly affected by what?

Answer 9

Temperature

Question 10

What are diaphragms used to measure?

Answer 10

Low pressure
Has high sensitivity

Question 11

What do bellows measure?

Answer 11

Low pressure
Has a greater range of movement

Question 12

What FAR talks about tachometers being a primary engine instrument?

Answer 12

FAR 91.205(b)(4)

Question 13

What do tachometers measure on reciprocating engines?

Answer 13

Crankshaft RPM

Question 14

What do tachometers measure on helicopters and turbines?

Answer 14

Rotor or propeller RPM

Question 15

For turbine engines, the tachometer will indicate in:

Answer 15

Percent of RPM

Question 16

What is the most common type of mechanical tachometer?

Answer 16

Magnetic Drag Cup

Question 17

What is the electric tachometer called that is engine driven and produces a three phase AC current at differing frequencies with different speeds?

Answer 17

Tach Generator
(Higher engine RPM = Higher frequency)

Question 18

The tach generator produces a three phase variable frequency signal that drives what?

Answer 18

A synchronous motor inside the instrument

Question 19

What type of electric motor is commonly used in electric tachometers?

Answer 19

Synchronous motor

Question 20

The indicator of a tachometer system is responsive to changes in?

Answer 20

Frequency

Question 21

Why do helicopters require a minimum of two synchronous tachometer systems?

Answer 21

One indicates engine RPM and the other for the main rotor RPM

Question 22

What unit in an electric type tachometer system sends information to the indicator?

Answer 22

The three phase AC tach generator

Question 23

An electric tachometer uses a synchronous motor which is governed by the tach generator’s:

Answer 23

Frequency

Question 24

In what units are turbine engine tachometers calibrated?

Answer 24

Percent of engine RPM

Question 25

Where is the oil temperature probe placed?

Answer 25

**In the oil line where the oil enters the engine** (after cooling) ((So that it can give an indication of the efficiency of the oil-cooling system))

Question 26

What circuits are used for electrical oil temperature gauges?

Answer 26

Wheatstone Bridge Or Ratiometer Circuit

Question 27

A thermocouple temperature indicating system is self-contained and requires ___ ______ _____.

Answer 27

No external power

Question 28

The basic measuring device in the instrument used for measuring temperature with thermocouples is what?

Answer 28

A Galvanometer

Question 29

What are thermocouples used on **reciprocating engines** made of?

Answer 29

Iron and Constantan Or Copper and Constantan

Question 30

What is used to indicate the fuel-air ratio being burned inside the cylinders on a recip engine?

Answer 30

The Exhaust-Gas Analyzer

Question 31

How are the EGT probes on a turbine engine wired?

Answer 31

In parallel

Question 32

What are thermocouples used on **turbine engines** made of?

Answer 32

Chromel and Alumel

Question 33

Where are EGT thermocouples located on a **turbine engine**?

Answer 33

Immediately after the last turbine stage

Question 34

What instrument is monitored to determine whether the start is normal or a hot start on a gas turbine engine?

Answer 34

Exhaust Gas Temperature

Question 35

What is Engine Pressure Ratio (EPR)?

Answer 35

A ratio of the turbine discharge pressure to the compressor inlet pressure

Question 36

What is the EPR used for?

Answer 36

To determine the amount of thrust being generated by a turbine engine

Question 37

What is the equation used to determine EPR?

Answer 37

Pt (exhaust) EPR= —————— Pt (intake)

Question 38

Where is the turbine discharge pressure sensor located?

Answer 38

Immediately aft of the last turbine stage

Question 39

What is the Manifold Pressure Indicator (MAP) calibrated in?

Answer 39

Inches of Mercury

Question 40

What does the MAP measure?

Answer 40

The pressure in the intake manifold of a reciprocating engine (Direct measure of engine power output)

Question 41

If a complete break in the line between the manifold pressure gauge and the induction system should occur:

Answer 41

The manifold pressure gauge will indicate the prevailing atmospheric pressure at all engine speeds

Question 42

What does FAR 91.205 state?

Answer 42

Manifold Pressure Indicator (MAP) is required on (boosted) turbo and supercharged engines

Question 43

What are the two types of thermocouples used for Cylinder Head Temperature indicators?

Answer 43

Seal or Gasket And Bayonet type

Question 44

Where are the hot and cold junctions for CHT located?

Answer 44

Hot = at the cylinder head Cold = at the indicator

Question 45

Can thermocouples be altered?

Answer 45

NO NEVER NADA

Question 46

What are the 3 basic types of fuel quantity indicators?

Answer 46

Mechanical Resistance (electric) Capacitance (electronic)

Question 47

Large aircraft consume fuel based on what?

Answer 47

Fuel weight **not** volume

Question 48

Capacitance quantity indicators measure what?

Answer 48

Measures the **weight of fuel** in the tanks rather than the volume

Question 49

Pressure is a direct indication of power output, because…..

Answer 49

Engine power is proportional to fuel consumption and fuel flow is directly proportional to pressure

Question 50

Fuel pressure gauge can be calibrated in ___ __ _____.

Answer 50

Percent of power

Question 51

The fuel flow meter used with continuous flow fuel injection systems is a pressure gauge that measures what?

Answer 51

The pressure drop across the injector nozzles

Question 52

On a twin engine aircraft with fuel injected recips, one fuel flow reads higher than the other in all engine operating configurations. What is the cause?

Answer 52

One or more fuel nozzles are clogged

Question 53

The fuel flow indication system used with many fuel injected opposed engine airplanes utilizes a measure of:

Answer 53

Fuel pressure

Question 54

In an aircraft equipped with a pressure drop type fuel flow indicating system, if one of the injector nozzles becomes restricted, this would cause a decrease in fuel flow, with:

Answer 54

An increased fuel flow **indication** on the gauge

Question 55

What is the most accurate means to determine fuel consumption of a recip engine?

Answer 55

Fuel Flowmeters (Shows amount of fuel in gallons or pounds consumed per hour)

Question 56

What are the 3 synchro units?

Answer 56

Autosyn Magnasyn Selsyn

Question 57

What is the biggest difference between the autosyn unit and selsyn unit?

Answer 57

Autosyn uses AC Selsyn uses DC

Question 58

How is motor driven impeller and turbine fuel flow transmitters designed to transmit data?

Answer 58

Using aircraft electrical system power

Question 59

The fuel flow indicator rotor and needle for a motor impeller and turbine indicating system is driven by?

Answer 59

An electrical signal

Question 60

The fuel flow indication data sent from motor driven impeller and turbine and motorless type fuel flow transmitters is a measure of?

Answer 60

Mass fuel flow