ASA Powerplant Codes

Question 1

What is meant by a hot section inspection?

Answer 1

An inspection of the hot section of a turbine engine. The hot section includes the combustors, the turbine, and the exhaust system.

Question 2

What is meant by on-condition maintenance of a turbine engine?

Answer 2

The monitoring of the engine performance at regular intervals and determining when maintenance is required based on certain operating parameters specified by the engine manufacturer.

Question 3

What checks of a turbine engine are necessary to verify preflight condition?

Answer 3

a. Inspect the cowling and all air inlet areas and attachment of the engine to the airframe.

b. Inspect the inlet guide vanes and the first stages of the compressor or fan blades.

c. Check for unusual noise when the compressor is rotated.

d. Inspect the rear turbine and exhaust system.

e. Check the quantity of the lubricating oil for the engine and the constant-speed drive unit.

f. Check the ignition system for operation by listening for the sparks.

Question 4

What are three types of flow-indicating systems used for turbine engines?

Answer 4

Vane-type flow meters, synchronous mass-type flow meters, and electronic motorless mass flow meters.

Question 5

What do mass flow systems measure?

Answer 5

The mass of the flow. This is affected by the density of the fuel which is in turn affected by the fuel temperature.

Question 6

In what units is an electronic motor less mass flow meter system calibrated?

Answer 6

Pounds per hour of fuel flow.

Question 7

What is indicated in a turbine engine if the fuel flow for all conditions is high?

Answer 7

If there are other instruments abnormalities, there are possibly damaged turbine components.

Question 8

Who is authorized to repair a fuel flow indicating system?

Answer 8

The components can be repaired only by an FAA approved repair station certificated for the particular instruments.

Question 9

Where can you find the electrical power requirements for a fuel flow indicating system?

Answer 9

In the aircraft maintenance manual.

Question 10

Where in the fuel system is the fuel flow transmitters located?

Answer 10

Between the fuel control and the fuel nozzles.

Question 11

What factors must be considered when determining wire size?

Answer 11

a. System voltage

b. If the circuit has an intermittent or continuous load

c. Current

d. Distance in feet of the wire run

e. The temperature rating of the wire to be used

f. The ambient temperature of the area where the wire will be installed

g. The number of wires in the wire bundle

h. The percentage of time the wire bundle will be loaded

I. The maximum altitude the wire will see

Question 12

What kind of electric starting system is used on many of the smaller turbine engines?

Answer 12

a starter-generator

Question 13

Why are air-turbine starters superior to electric starters for large turbine engines?

Answer 13

They are light weight for the torque they produce

Question 14

Where does an air-turbine starter get its air for starting the engines on a jet transport airplane?

Answer 14

From an APU, GPU, or from a running engine.

Question 15

What prevents too high an air pressure from overspending an air-turbine starter?

Answer 15

The air shutoff and regulating valve.

Question 16

Where does an air-turbine starter get its lubricating oil?

Answer 16

It has a self-contained lubrication system with the oil held in the starter housing.

Question 17

What device in an air-turbine starter warns an aviation mechanic if there are any metal chips or particles in the oil?

Answer 17

Magnetic chip detectors warn of any metal contamination in the oil.

Question 18

What is the function of a capacitor in a magneto?

Answer 18

The capacitor minimizes arcing at the breaker points, and it speeds up the collapse of the primary current as the breaker points open.

Question 19

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

Answer 19

the primary circuits is connected to ground.

Question 20

What is checked when a magneto is internally timed?

Answer 20

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 21

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

Answer 21

In the BOTH position.

Question 22

What is the E-gap in magneto timing?

Answer 22

The E-gap angle is the position of the rotating magnet where the primary current flowing in the magneto coil is the greatest. The breaker points open when the rotating magnet is in its E-gap position.

Question 23

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 23

The ignition switch is not grounding the magneto primary circuit.

Question 24

Why do aircraft fuel metering systems for reciprocating engines have mixture controls?

Answer 24

The air density decreases as the aircraft ascends, causing the mixture to become richer. The mixture control allows the fuel to be decreased to maintain a fuel-air mixture ratio that produces the desired power.

Question 25

What does an air-fuel mixture ratio of 12:1 represent?

Answer 25

12 pounds of air and 1 pound of fuel.

Question 26

How does a pressure-type carburetor operate?

Answer 26

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 nozzles located at this point, the drop in temperature due to fuel vaporization makes place after the air has passed the throttle valve and at a point where engine heat tends to offset it. This, 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 filed under all operating conditions.

Question 27

What parameters are normally sensed by a turbine-engine fuel control?

Answer 27

a. Power lever angle.

b. Compressor inlet total temperature.

c. Compressor RPM

d. Burner pressure.

Question 28

What is meant by trimming a turbine engine?

Answer 28

Adjusting the fuel control for the proper specific gravity of the fuel and for the proper idle and full throttle RPM.

Question 29

What are two types of electronic fuel controls for turbine engines?

Answer 29

Supervisory electronic engine control and full-authority digital electronic control.

Question 30

What position should the flight deck fuel metering control (or fuel condition lever) be set to for starting a turbine engine?

Answer 30

The normal starting sequence is:
1. Rotate the compressor with the starter
2. Turn the ignition on
3. Open the engine fuel valve, either by moving the throttle to idle or by moving a fuel shutoff lever or turning a switch

Question 31

What does a fuel-injected engine have that prevents the loss of induction air if the air inlet filter should become covered with ice?

Answer 31

An alternate air valve allows warm air from inside the engine cowling to flow into the fuel metering system.

Question 32

What would be the effect on engine operation of an air leak in the intake pipe for one cylinder?

Answer 32

That cylinder would run lean and detonation could occur

Question 33

What must be inspected on the cooling system of an air-cooled engine?

Answer 33

All of the baffles and air seals must be in place and in good condition.

Question 34

Why should an air-cooled engine not be run up to high power without the cowling installed?

Answer 34

The engine depends on the cowling to force air through the cylinder fins to remove the excess heat.

Question 35

Why do some air-cooled engine installations have cowl flaps?

Answer 35

Cowl flaps produce a low pressure on one side of the engine to pull air through the cooling fins on the cylinders.

Question 36

What document describes the proper use of cowl flaps on an air-cooled engine?

Answer 36

The pilot’s operating handbook.

Question 37

What is meant by the beta range of operation of a turboprop propeller?

Answer 37

This is the mode of ground operation, and it includes starting, taxing, and ground reverse operation.

Question 38

What controls the blade angle of a propeller when operating in the beta range?

Answer 38

When operating in the beta range, blade angle is controlled by the position of the power lever.