Instrument Systems & Fire Protection

Question 1

Minimum powerplant instruments required by CFR 91.205:

Answer 1

1) Tach for each engine.
2) Oil pressure gage for each engine.
3) Coolant temp for each liquid-cooled engine.
4) Oil temperature gage for each air-cooled engine.
5) Manifold pressure gage for each altitude engine.

Question 2

Types of data important for monitoring the operation and performance of aircraft powerplant:

Answer 2

1) Pressure
2) Temperature
3) Mechanical movement.

Question 3

Types of pressure:

Answer 3

1) Absolute pressure
2) Gage pressure
3) Differential pressure

Question 4

Define absolute pressure:

Answer 4

Pressure referenced from zero, or a vacuum.

Question 5

Define gage pressure:

Answer 5

Pressure added to a fluid by a pump/device. Referenced from the existing atmospheric pressure.

Question 6

Define differential pressure:

Answer 6

The difference between two pressures.
(DeltaP)

Question 7

Most common type of lubricating oil pressure measuring instrument:

Answer 7

Bourdon tube type.

Question 8

Used to measure carb air temps, fuel temps, and oil temps:

Answer 8

Ratiometer instruments.

Question 9

Define EPR:

Answer 9

The ratio of turbine discharge total pressure to compressor inlet total pressure.

Question 10

How do analog instruments measure oil temps?

Answer 10

By measuring the vapor pressure of a liquid in a sealed tube.

Question 11

Two types of instruments that measure temperature electrically.

Answer 11

1) Ratiometer
2) Thermocouple

Question 12

How does a Ratiometer operate?

Answer 12

Temp sensing bulb is immersed in the targeted fluid. The resistance of the wire in the bulb varies with its temp. The voltage allowed to pass through the wire creates a magnetic field that pulls magnet-attached pointer accordingly.

Question 13

Types of thermocouples for recip engines.

Answer 13

1) Bayonet type
2) Spark plug gasket type.

Question 14

Where is a recip engine EGT thermocouple mounted?

Answer 14

In the exhaust stack, within 6 inches of the cylinder head.

Question 15

Turbine EGT is measured how?

Answer 15

By several thermocouples, connected in parallel, arranged around the tail cone, whose readings are averaged together.

Question 16

What are the instruments that measure mechanical movement.

Answer 16

1) Tachometer
2) Fuel flow indicator (vane type and mass fuel type)
3) Torquemeter.

Question 17

Class A fire:

Answer 17

Fire with a solid combustible material.

Question 18

Class B fire:

Answer 18

Fire with a combustible liquid.

Question 19

Class C fire:

Answer 19

Fire which involves energized electrical equipment.

Question 20

Class D fire:

Answer 20

Fire in which metal (such as magnesium) burns.

Question 21

Class A fire zone:

Answer 21

Large volume of air flowing past regular arrangements of similarly shaped obstructions.
(Area where air flows over cylinders)

Question 22

Class B fire zone:

Answer 22

Large volume of air flowing over aerodynamically clean (smooth) obstructions.
(Exhaust shrouds in recip, fireproof liner in turbine)

Question 23

Class C fire zone:

Answer 23

Zones with small amount of airflow through them. (Behind firewall)

Question 24

Class D fire zone:

Answer 24

Little or no airflow.
(Enclosed area inside a wing structure)

Question 25

Class X fire zone:

Answer 25

Large volumes of air flow at an irregular rate. (Wheel well)

Question 26

How does a thermoswitch operate?

Answer 26

When detector is heated, internal strips on which contacts are mounted distort and close the contacts, completing the circuit between loop and ground.

Question 27

How does a thermocouple work?

Answer 27

Two dissimilar metal are welded together to form a loop. A voltage exists in the loop proportional to the to the difference in temperature between the hot and cold junctions at which the wires are joined.

Question 28

Thermocouples are considered to be what type of detection system?

Answer 28

Rate of temperature rise

Question 29

Types of Continuous loop fire and overheat detection systems:

Answer 29

1) Thermistor type (Kidde and Fenwall)

2) Pneumatic type (Lindbergh and Systron-Donner)

Question 30

What are the types of thermistor-type continuous loop systems?

Answer 30

1) Kidde (double conductor)

2) Fenwall (single conductor with ceramic beads)

Question 31

Types of pneumatic-type continuous loop systems:

Answer 31

1) Lindberg (gas absorbing element)

2) Systron-Donner (gas absorbing element and helium gas)

Question 32

Two types of installed fire-extinguishing systems:

Answer 32

1) CO2 systems (engine compartment of older aircraft)

2) HRD (high rate discharge) systems (used on most modern jet transport aircraft)

Question 33

A yellow blown out disk indicates:

Answer 33

Normal discharge

Question 34

A red blown out disc indicates:

Answer 34

Thermal discharge due to an overheat condition

Question 35

HRD bottles contain what?

Answer 35

Halon 1211 or
Halon 1301

Question 36

What is used to break the frangible disk of a HRD bottle?

Answer 36

Powder discharge (Squib)

Question 37

Pulling the fire-pull handle does what six things?

Answer 37

1) Shuts of fuel.
2) Trips the generator field relay.
3) Shuts off bleed air.
4) Shuts off wing or cowl anti ice.
5) Shuts off hydraulic supply.
6) Turns off hydraulic pump warning light.

Question 38

Green arc:

Answer 38

Normal operating range

Question 39

Yellow arc:

Answer 39

Caution range
(Time limited)

Question 40

White arc:

Answer 40

Special operations range.

Question 41

Red arc:

Answer 41

Prohibited range
(Damage to engine will occur)

Question 42

Red radial line:

Answer 42

Do not exceed indication

Question 43

Blue radial line:

Answer 43

Special operating condition

Question 44

Red triangle, dot, or diamond:

Answer 44

Max limit for high transients (such as starting)

Question 45

Yellow arc on carburetor air temp instrument:

Answer 45

Range where ice is most likely to form.

Question 46

Instrument that indicates engine power:

Answer 46

Manifold pressure gage.

Question 47

CFS (computerized fuel system) gives what information?

Answer 47

1) Pounds/gallons of fuel on board.
2) Fuel flow rate (per hour).
3) Fuel time remaining.
4) Amount used since engine was started.

Question 48

EICAS (engine indication and crew alert system) does what?

Answer 48

Replaces many instruments and provides crew with two screens of airframe and engine parameters. Alerts crew of warnings and fully redundant in the case of one screen outage.

Question 49

EICAS primary display parameters:

Answer 49

1) EPR
2) N1
3) EGT

Question 50

EICAS secondary display parameters:

Answer 50

N2
Fuel Flow
Oil temp
Oil pressure
Oil quantity
Vibration

Question 51

How often must instruments be calibrated according to FAR?

Answer 51

Annually

Question 52

Far 91 minimum instrument equipment list:

Answer 52

Tachometer
Oil pressure
Oil temp
Coolant temp
Manifold pressure

Question 53

T/F
A CO2 discharge requires expensive clean up after discharge.

Answer 53

False.
No clean up required.

Question 54

How does Halon put out fire.

Answer 54

Mixes with oxygen chemically and starves the fire.

Question 55

How does CO2 put out fire?

Answer 55

Displaces oxygen and absorbs heat through evaporation.

Question 56

Life limited part on an HRD system:

Answer 56

The squib.

Question 57

T/F
Sensing elements are powerplant items.

Answer 57

False.
Airframe items. Remove before sending out to engine repair shop.

Question 58

Requirements for fire detection and warning systems:

Answer 58

1) Separate detection for each engine.

2) Must not give false alarms.

3) Must not be damaged by oil, water, vibration, temps, or handling.

4) Must operate directly from aircraft electrical system and require minimal electrical current.

Question 59

What types of fire detectors are used for engine fire detection?

Answer 59

Overheat
Rate of rise
Flame detector
Spot