P2

Question 1

What would likely cause a false fire alarm in a thermistor-type continuous-loop system?

Answer 1

A kinked or pinched continuous-loop element.

Question 2

If there is a break in a single-wire continuous-loop fire detector element, and the system tests bad, will it indicate the presence of a fire?

Answer 2

Yes, even though it tests bad, it will still indicate the presence of a fire.

Question 3

What maintenance is allowed on a continuous-loop fire detection system?

Answer 3

Inspect and replace as needed the continuous-loop element, the controller, and the fire warning bell and/or light.

Question 4

What is used as the rectifier to produce direct current in a DC alternator?

Answer 4

Six solid-state diodes.

Question 5

Why is it not necessary to flash the field of a DC alternator after it has been overhauled?

Answer 5

An alternator field is excited by battery current and residual voltage is not used to start the alternator producing current.

Question 6

If the installed ammeter gauge is redlined at 100 percent of generator or alternator rating, and the regulator does not control current, how is maximum current controlled?

Answer 6

Current is controlled by the pilot or operator of the aircraft by not applying loads greater than redline, except for short, intermittent loads.

Question 7

If placards or monitoring devices are not practical or desired, what practice protects the battery and electrical system?

Answer 7

The generator is sized so that total continuous load of the electrical system does not exceed its capacity.

Question 8

What defines if the electrical load of an aircraft is intermittent or continuous?

Answer 8

The length of time the system is used. If the component or system is used for less than two minutes, it is considered an intermittent load. If it is used for more than two minutes, it is considered a continuous load.

Question 9

How is generator output voltage controlled?

Answer 9

By controlling the field current strength through the use of a voltage regulator.

Question 10

What is synthetic oil?

Answer 10

A lubricating oil that is made by chemically changing the nature of an oil base to give it the needed characteristics. Synthetic oil is the primary oil for turbine engines.

Question 11

Is automotive oil suitable for use in aircraft engines?

Answer 11

No, automotive and aviation oils are formulated for entirely different operating conditions.

Question 12

What is meant by a multiviscosity oil?

Answer 12

It is a lubricating oil with a viscosity index improver that increases the viscosity of the oil when it is hot and decreases the viscosity when it is cold.

Question 13

Where can you find the grade of engine oil specified for a particular aircraft?

Answer 13

In the airplane flight manual or the pilot’s operating handbook for the aircraft.

Question 14

What is straight mineral oil?

Answer 14

It is the lubricating oil as obtained by fractional distillation of crude oil. It does not have any additives.

Question 15

What is ashless dispersant (AD) oil?

Answer 15

A mineral lubricating oil containing additives that disperse the contaminants throughout the oil so they will not clump and clog oil passages. There are no ash-forming additives in AD oil.

Question 16

What are six functions of the oil in an aircraft engine?

Answer 16

a. Reduces friction.
b. Seals and cushions.
c. Removes heat.
d. Cleans inside the engine.
e. Protects against corrosion.
f. Performs hydraulic action.

Question 17

What is the purpose of an air-oil separator, or deerator, in a turbine engine oil tank?

Answer 17

In normal operation, the oil picks up a quantity of air and it is swirled as it enters the deerator. The swirling action releases the air from the oil, and the air is used to pressurize the oil tank.

Question 18

How is oil pressure regulated in an aircraft engine?

Answer 18

A pressure-relief valve senses the desired pressure and sends excess oil back into the engine sump.

Question 19

What is the purpose of the restricted orifice in the line between the oil pressure gauge and the engine?

Answer 19

The restricted fitting helps dampen any pulsations in the oil pressure caused by the pump.

Question 20

What is a hot-tank lubrication system for a turbojet engine?

Answer 20

A lubrication system in which the oil cooler is in the pressure subsystem and the scavenged oil is not cooled before it is returned to the tank.

Question 21

What is a cold-tank lubrication system for a turbojet engine?

Answer 21

A lubrication system in which the oil cooler is in the scavenge subsystem, and the scavenged oil is cooled before it is returned to the tank.

Question 22

Where does a dry sump oil system store oil?

Answer 22

In a reservoir outside the engine through the use of a scavenge pump and external tubing.

Question 23

What two instruments show the condition of a reciprocating-engine lubrication system?

Answer 23

Oil pressure and oil temperature gauges.

Question 24

What must be done to an oil filter when it is removed from the engine?

Answer 24

It should be cut open and the pleated element examined to determine the type and amount of contaminant carried by the oil.

Question 25

What is a spectrometric oil analysis program?

Answer 25

A program in which a sample of oil is taken from the engine at regular intervals and sent to a laboratory, where it is burned in an electric arc. The resulting light is analyzed for the wavelengths of the elements that are present in the oil sample. Traces of aluminum, copper, and iron in the oil indicate wear of the pistons or wrist pin plugs (aluminum), cylinder walls or piston rings (iron), or main bearings or bushings (copper). A single sample is meaningless. There must be a series of samples taken at regular intervals to measure the change in the amounts of these metals.

Question 26

What type of oil quantity indicator is used in most aircraft engines?

Answer 26

A dipstick that measures the quantity of oil in the tank or sump.

Question 27

When should the engine oil quantity be checked on a turbine engine?

Answer 27

As soon as practical after the engine is shut down.

Question 28

Where is the oil temperature measured on a reciprocating engine?

Answer 28

Usually at the oil pressure screen before the oil goes into the engine passages.

Question 29

Why do engine manufacturers recommend that engine lubricating oil be changed at specific intervals?

Answer 29

The oil picks up contaminants and carries them through the engine where they can cause wear. The oil also becomes acidic and causes corrosion in the engine.

Question 30

What is the function of the capacitor in a magneto?

Answer 30

The capacitor minimizes arcing at the breaker points, speeds up the collapse of the primary current

Question 31

What happens in a magneto ignition system when the ignition switch is placed in the Off position?

Answer 31

The primary circuit is connected to ground.

Question 32

What is checked when a magneto is internally timed?

Answer 32

Internally timing a magneto consists of adjusting the breaker points so they will open at the instant the rotating magnet is in its E-gap position, and the distributor rotor is in position to direct the high voltage to cylinder number one.

Question 33

In what position should the Ignition switch be placed when using a timing light on the magnetos?

Answer 33

In the Both position.

Question 34

What is the E-gap in magneto timing?

Answer 34

The breaker points open when the rotating magnet is in its E-gap position.

Question 35

What malfunction in the ignition system would cause an aircraft reciprocating engine to continue to run after the ignition switch is placed in the Off position?

Answer 35

The ignition switch is not grounding the magneto primary circuit.

Question 36

What type of ignition system is used on most turbine engines?

Answer 36

High-intensity, intermittent-duty, capacitor discharge ignition systems.

Question 37

How many igniters are used with most turbine engines?

Answer 37

Two.

Question 38

What are two types of ignition systems used in turbine engines?

Answer 38

High-voltage systems and low-voltage systems.

Question 39

With which type of turbine-engine ignition system is a glow plug igniter used?

Answer 39

A low-voltage system.

Question 40

How is the strength of the magnet in a magneto checked?

Answer 40

The magneto is put on a test stand and rotated at a specified speed. The breaker points are held open and the primary current is measured. The strength of the magnet determines the amount of primary current.

Question 41

In what position is the magnet in a magneto when the greatest change in flux density in the coil core takes place?

Answer 41

It is a few degrees beyond its neutral position. When it is in this position, the breaker points open and the primary current is interrupted.

Question 42

In what position is the magnet in a magneto when the breaker points begin to open?

Answer 42

In its E-gap position, just a few degrees beyond its neutral position.

Question 43

What happens when the start switch for a turbine engine with a starter-generator is placed in the START position?

Answer 43

Current flows into the starter relay which closes and actuates the ignition exciter. Current flows through the series motor coils of the starter generator and rotates the engine until it starts.

Question 44

What happens when the start switch for a turbine engine with a starter-generator is placed in the RUN position?

Answer 44

The starter relay opens, shutting off current to the ignition exciter and the motor windings in the starter-generator. The generator field relay is closed, connecting the voltage regulator to the starter-generator. The output of the generator flows to the bus through the generator circuit breaker.

Question 45

What is indicated if the starter relay chatters rather than locks in when the start switch is placed in the START position?

Answer 45

The battery voltage is too low to supply enough current to hold the relay engaged.

Question 46

What is the purpose of the shear section in an air-turbine drive shaft?

Answer 46

If the ratchet mechanism fails to release and the engine drives the starter to a speed higher than its design speed, the shear section will break and disconnect the starter from the engine.

Question 47

What is the function of a float carburetor?

Answer 47

The float carburetor's function is to measure airflow through the engine induction system and dispense the appropriate amount of gasoline into the airflow for all engine operating perimeters and conditions. It must also provide the fuel in a state that is as vaporized as possible by the time ignition occurs in the engine cylinders.

Question 48

What two things are adjusted when setting the Idling conditions on a float carburetor?

Answer 48

a. Idling RPM by adjusting the throttle stop. b. Idling mixture by adjusting idle needle valve.

Question 49

What would likely cause a reciprocating engine equipped with a float carburetor to hesitate momentarily when the throttle is rapidly advanced from Idle to full power?

Answer 49

A malfunctioning accelerator pump.

Question 50

How does a pressure-type carburetor operate?

Answer 50

A pressure-type carburetor discharges fuel into the airstream at a pressure well above atmospheric. This results in better vaporization and permits the discharge of fuel into the airstream on the engine side of the throttle valve. With the discharge nozzle located at this point, the drop in temperature due to fuel vaporization takes place after the air has passed the throttle valve and at a point where engine heat tends to offset it. Thus, the danger of fuel vaporization icing is practically eliminated. The effects of rapid maneuvers and rough air on the pressure-type carburetors are negligible since its fuel chambers remain filled under all operating conditions.

Question 51

What are the three main parts of a typical turbosupercharger?

Answer 51

Compressor assembly, turbine wheel assembly, and full floating shaft bearing assembly.

Question 52

How is a turbosupercharger (or turbocharger) driven?

Answer 52

Externally driven superchargers derive their power from the energy of engine exhaust gases directed against a turbine that drives an impeller that compresses the incoming air.

Question 53

How is a supercharger driven?

Answer 53

The supercharger is directly driven from the engine and is internal to the engine.

Question 54

Why is it very important that the induction air filters be kept clean and replaced as often as the manufacturer recommends?

Answer 54

Clogged air filters can restrict the air entering the engine.

Question 55

What is meant by a slave engine with regard to propeller synchronization?

Answer 55

This is the engine in a multi-engine airplane whose RPMs follow those set on the master engine.

Question 56

How are propellers on a twin-engine airplane synchronized?

Answer 56

The propeller governor of the master engine is set to the desired RPM. A signal from the master engine governor is sent to the control box which sends a signal to a stepping motor. This motor adjusts the propeller governor and fuel control of the slave engine causing it to maintain exactly the same RPM as the master engine.