powerplant wrong sections

What position should the crankshaft be when a magneto is being timed to the engine?

The piston in cylinder number 1 should be about 30° before top center on the compression stroke.

What is checked on engine runup to determine the operational condition of the engine?

Idling RPM, manifold pressure, engine acceleration, maximum static RPM, magneto drop, ignition switch safety check, propeller pitch change, oil pressure, fuel pressure, and fuel flow.

How are the four strokes of a reciprocating engine similar to the sections of a turbine engine?

Intake = air inlet section

compression = compressor section

ignition & power = combustion & turbine sections

exhaust = exhaust section.

What type of turbojet engine is commonly used in commercial aviation?

High-bypass turbofan engines.

What is meant by trimming a turbine engine?

Adjusting the fuel control so the engine develops the correct idle and trim speed RPM.

What type of equipment should be used to determine that a turbine engine Is performing up to the standards specified by the engine manufacturer?

A JetCal analyzer/trimmer has all of the instrumentation and cables to determine the EGT, EPR, and other parameters specified by the engine manufacturer.

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

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

What do mass flow systems measure?

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

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

Pounds per hour of fuel flow.

What is Indicated in a turbine engine If the fuel flow for all conditions Is high?

If there are other instrument abnormalities, there are possibly damaged turbine components

Who is authorized to repair a fuel flow indicating system?

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

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

In the aircraft maintenance manual.

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

Between the fuel control and the fuel nozzles.

What is used as the rectifier in a DC alternator?

Six solid-state diodes.

Why is it not necessary to flash the field of a DC alternator after overhaul?

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

How many electrical phases are in aircraft alternators?

Three.

What is the advantage of using AC power over DC power?

AC can be stepped up to higher voltages, reducing current and enabling smaller, lighter wiring.

What is the frequency of AC voltage used in aircraft?

400 Hz.

What factors must be considered when determining wire size?

System voltage

intermittent or continuous load,

current,

wire run distance,

wire temperature rating,

ambient temperature,

number of wires in wire bundle,

percentage of time wire will be loaded,

max altitude.

Whether we it is a single conductor in free air

Voltage drop

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

Reduces friction,

seals and cushions,

removes heat,

cleans inside the engine,

protects against corrosion,

performs hydraulic action.

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

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

How is oil pressure regulated in an aircraft engine?

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

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

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

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

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.

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

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.

What is an all-weather spark plug?

A shielded spark plug that has a recess in the shielding in which a resilient grommet on the ignition lead forms a watertight seal.

What is meant by the reach of a spark plug?

The length of the threads on the spark plug that screw into the cylinder head.

What is the difference between a hot spark plug and a cold spark plug?

A hot spark plug has a long path for the heat to travel between the nose core insulator and the spark plug shell. In a cold spark plug, the heat has a shorter distance to travel, and the spark plug operates cooler than a hot spark plug.

What is the advantage of fine-wire spark plugs over massive electrode spark plugs?

Fine-wire spark plugs have a firing end that is more open than that of a massive electrode spark plug. The open firing end allows the gases that contain lead to be purged from the spark plug so they will not form solid lead contaminates.

Why is it important to keep spark plugs in numbered holes in a tray?

To track the internal condition of the cylinders and diagnose issues like detonation or overheating.

Why should a torque wrench always be used when installing spark plugs?

To avoid poor seals from being too loose or damaging the plug and threads from being too tight.

What kind of gauge should be used to measure the electrode gap in spark plugs?

A round wire gauge.

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

A starter-generator.

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

They are lightweight for the torque they produce.

Where does an air-turbine starter get its air for starting engines?

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

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

The air shutoff and regulating valve.

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

From a self-contained lubrication system in the starter housing.

What device warns if there are any metal chips in the oil of an air-turbine starter?

Magnetic chip detectors.

How is ice prevented from forming on the nose cowl, nose dome, and inlet guide vanes of a turbine engine?

Hot compressor bleed air flows through passages in these components to elevate the surface temperatures sufficiently to prevent ice from forming.

What is the purpose of an augmentor on a reciprocating engine exhaust system?

The augmenters are designed to produce a venturi effect to draw an increased airflow over the engine to augment engine cooling.

How does a reciprocating engine muffler decrease noise?

Exhaust gases from the cylinders are combined into a common manifold that contains a section of the exhaust where the volume increases (expansion chamber), slowing the gases down, diffusing the flow through internal baffles, and reducing the noise.

What is a jet aircraft hush kit?

A hush kit is an aerodynamic device that defuses the flow of exhaust from older turbojet engines, by reducing the noise caused by high-velocity jet exhaust.

What does the pilot do to change the RPM of an engine equipped with a constant-speed propeller when it is operating within the constant-speed range?

The pilot moves the propeller pitch control. This changes the compression on the speeder spring inside the governor which moves the pilot valve. The pilot valve directs oil into or out of the propeller to change the pitch of the blades. The change in pitch changes the air load on the propeller which changes the RPM.

What is the difference between a controllable propeller and a constant-speed propeller?

Basically, it is the control system. A controllable-pitch propeller uses a manually operated oil valve to control the pitch, and a constant-speed propeller uses a governor to control the valve.

When making a magneto check, should the propeller control be in low-pitch or high-pitch?

It should be in the low-pitch, high RPM position.

Where do you find approved lubricants for a constant speed propeller?

In the maintenance manual for the propeller.

What repairs can a mechanic with a Powerplant rating make to a propeller?

Only minor repairs or minor alterations.

Where can examples of acceptable repairs to aluminum alloy propeller blades be found?

In AC 43.13-1B Chapter 8, Section 4 and propeller manufacturer’s service manuals.

Is it permissible to cold straighten a damaged aluminum alloy propeller blade?

No, it may cause hidden damage making it nonrepairable.

What would be the classification of maintenance for shortening a propeller blade?

Major repair.

May transverse cracks in a metal propeller blade be repaired?

No, any transverse crack requires rejection of the blade.

What damage to an aluminum alloy propeller blade can be repaired by a Powerplant mechanic?

Small roughness, nicks, and scratches in the leading edge.

How are small nicks removed from the leading edge of a propeller blade?

File them out with a fine file or stone, leaving a smooth contour.

How can you determine that a surface scratch in a propeller blade is not actually a crack?

Clean the damage out to a saucer-shaped depression and spray the area with a dyepenetrant liquid. Allow it time to seep into a crack if one is present, then wipe all of the liquid off the surface. Spray the area with a developer. If the damage is actually a crack, the developer will pull the penetrant out and it will form a visible line.

Who is authorized to perform major repairs to a propeller?

An FAA-approved propeller repair station.

What checks and maintenance is a mechanic with a Powerplant rating allowed to make on a propeller?

Check track, remove small nicks, check dynamic balance, and lubricate the propeller.

What adjustment can a Powerplant mechanic make to a propeller governor?

Adjust the maximum RPM stop.

What instrument is used to measure the blade angle of a propeller?

A universal propeller protractor.

Where is the propeller protractor placed to measure the propeller blade angle?

At a distance from the center of the propeller hub, as specified in the manual.

What are the basic steps for removing a typical propeller?

1. Remove the spinner and safety wire. 2. Support the propeller and mark alignment. 3. Unscrew mounting nuts, protect threads. 4. Place the propeller on a cart for transport.

What alignment method is used to align a propeller to the engine?

Special studs or dowel pins align the propeller to reduce operating vibrations.

What ls the function of the capacitor in a magneto?

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

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

The primary circuit is connected to ground

What Is checked when a magneto is internally timed?

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.

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

In the Both position.

What is the E-gap in magneto timing?

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.

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?

The ignition switch is not grounding the magneto primary circuit.