6 Airframes, Engines & Aircraft Systems

In the truss construction loads are carried by the

tube frame.

Kevlar is a material most often used in

composite construction.

Examples of truss, monocoque, and composite designs respectively are

Citabria 7ECA, Cessna C-172, and Diamond DA-40.

One advantage that a composite airframe has over metal construction is that it

can be stronger and lighter than metal.

Welded or bolted steel tubes are most often found in

truss construction

Brake systems on light aircraft are most often operated by

hydraulics.

Conventional gear features

main gear and a tail wheel.

Differential braking means

left and right brakes may be operated independently.

One advantage that tricycle gear has over conventional gear is

better visibility while taxiing.

Retractable gear is advantageous because it

offers lower drag than fixed gear

What will happen to a piston-powered aircraft if the main electrical system fails?

The engine will continue to operate because the magnetos are a separate system.

Carburetor heat is normally applied

before reducing power.

Hot, high, and humid conditions have the effect of

reducing the engine power output.

Abnormally high cylinder head temperature is an indication of the engine being

overloaded and can cause detonation and pre-ignition.

One difference between the turbocharger and the supercharger is that the

turbocharger is driven by exhaust gases that would otherwise be wasted.

The primary disadvantage of the supercharger is that it

takes noticeable power away from the engine to run it.

During which stroke is a vacuum developed in the cylinder?

intake

Exhaust Gas Guage (EGT) is a good indication of the

fuel/air mixture.

If you smell exhaust in the cockpit while flying, it is best to

turn OFF cabin heat and ventilate the cabin for fresh air.

Oil pressure should register within . . . . . seconds during a warm start.

30

What is the ratio of air to fuel for best power?

14:1

What would happen if a magneto ground wire or P-lead failed?

The engine will continue to run and remain live even after aircraft shutdown.

Which statement regarding the operation of the waste gate is false?

a) When the waste gate is closed the engine is turbocharged.

b) The waste gate regulates the speed of the turbocharger.

c) The waste gate regulates the amount of exhaust gas directed to the turbine.

d) When the waste gate is closed the exhaust gases bypass the turbine.

When the waste gate is closed the exhaust gases bypass the turbine.

The most basic form of turbine engine is the

turbojet

In a turbojet engine large amounts of outside air are continuously brought in through the

inlet

Two main parts of a turboprop engine are the

Core Engine and the propeller

The exhaust gases of a turboprop engine are responsible for the majority of available thrust. T of F

False

Designers have to balance the amount of thrust that the exhaust produces with the lose of power to the propeller. Most designs produce just enough exhaust thrust to reduce drag during cruise, which is a small amount of thrust compared to the propeller, but still leave the most power available to drive the propeller.

The bypass ratio of a turbofan engine is the ratio of air flowing around the

engine to the air that goes through the core.

The turboshaft engine is similar to the

turboprop engine

Which statement regarding the operation of a turbojet engine is incorrect?

a) The energy extracted by the turbine is used to turn the compressor.

b) Instead of needing energy to turn the blades, the turbine extracts energy from the flow of hot air exhausting from the engine by the turbine blades spinning in the exhaust air.

c) The exit velocity of the by-pass air is less than the free stream velocity, producing thrust.

d) The exit velocity is greater than the free stream velocity, producing thrust.

Feedback

The exit velocity of the by-pass air is less than the free stream velocity, producing thrust.

The compressor of the turbojet acts like many rows of

Airfoils

In a typical jet engine . . . . . lb of air per second is combined with only . . . . . lb of fuel per second.

100 lbs air to 2 lb fuel per second

In the turboprop engine most of the energy created by the

exhaust is used to turn the power turbine

Fine pitch used for

takeoff and climb

For cruise the pilot would set the propeller to

coarse

If not repaired a nick on a propeller blade could lead to

Cracks developping

Propeller RPM is controlled by

Varying the propeller blade angle.

What force applies to tail wheel airplanes when they lift their tail off the runway during takeoff ?

Gyroscopic Precession

The difference between geometric pitch and effective pitch is

Propeller slip

The ratio of thrust horsepower to brake horsepower is

Propeller efficiency

To counteract a windmilling propeller the pilot would

Feather the propeller

Torque from the spinning propeller results in

a turning tendency

While within the governing range, any changes in engine power and or airspeed the governor will

maintain a steady RPM if a constant-speed propeller system is used.

Airspeed and power variations change the load of the engine. In order to compensate for these, the governor is used to change the blade angle of the propeller to keep the RPM constant.

Which statement is correct regarding blade pitch?

Large blade angles load the engine and decrease RPM.

Coarse pitch also means

high pitch

What drives the propeller blades of a full-feathering system towards coarse pitch?

Counterweights and internal springs

Oil pressure boosted by the governor has the purpose of moving the propeller towards

coarse pitch in a single-engine aeroplanes.

As the oil pressure drops on a constant-speed non-feathering system the governor would make the propeller

full fine.

What happens to a centrifugal counterweight and springs propeller system when the engine quits during flight?

Blades move towards the selected propeller RPM by becoming more fine.

Because the engine is still windmilling, the gear still drives the governor. The governor will still operate as usual and change the blade angle, so as to keep the selected RPM setting.

What drives the governor?

Engine

After startup a twin-engine aeroplane's oil pressure

rises moving the propeller into fine pitch.

During takeoff in a constant-speed aeroplane the propeller blades initially move towards

full fine for maximum power.

Which aeroplane operation would move the propeller pitch towards the high pitch stop?

High Speed Descent

During an engine failure in a twin-engine aeroplane the . . . . . gauge is best show which engine has failed.

EGT

When a constant-speed propeller aeroplane is accelerated during the takeoff the blades go from . . . . . pitch to a . . . . . pitch.

full/fine, coarser

Manifold pressure is a measurement of the

fuel/air ratio pressure

In a normally aspirated engine takeoff manifold pressure at full throttle is expected to be

slightly less than static manifold pressure

From before engine start to idle RPM manifold pressure is expected to

drop

The manifold pressure gauge, while the aircraft is parked at 5 000 feet ASL with the engine(s) OFF in standard atmosphere, would read

1 in Hg. = 1 000 feet
5 000 feet = 5 in Hg.
Aircraft is higher than sea level so pressure decreases
That would give 29.92 - 5.0 = 24.95 in Hg.

The correct answer is: 24.92 in Hg

When an aeroplane's piston engine fails in flight the manifold gauge is initially expected to indicate

no significant change

What effect will reducing RPM have on manifold pressure during cruise flight?

cause a rise

Reducing the RPM does create a rise in manifold pressure. To reduce RPM you would bring the propeller lever back. This would cause the governor to sense that there is an over-speed and would move the blades to a higher pitch angle to slow the RPM down. This makes the engine work harder slowing it and creating less vacuum (or draw of air into) as the engine slows, the manifold pressure rises.

What effect will increasing RPM have on manifold pressure during cruise flight?

Cause a Drop

The . . . . . prevents stumbling when the throttle is opened to develop maximum horse power.

accelerator pump

Conditions which can lead to carburetor icing are

temperature range of -13°C to +38°C with high humidity.

What indication may be a signal that your aircraft has carburetor ice?

A gradual decrease in RPM or manifold pressure.

Use of the carburetor heat while taxiing could cause

dust and contaminants to enter the engine

Can Impact ice can form on both carburetor or fuel injected engines.

Both

The engine begins to run roughly after applying carburetor heat. What does this indicate and what should you do?

There is carburetor ice and it is melting. Continue with carburetor heat until the roughness is gone.

Fuel injection can be more efficient than a carburetor because

fuel injection provides a more uniform flow to the cylinders

Carburetor heat is not needed for a fuel injection system because

there is no venturi and associated temperature drop.

The fuel is injected in each cylinder individually, therefore no mixing of air and fuel in a carburetor is required.

One advantage that fuel injection has over a carburetor is

easier cold weather starting.

If impact icing is suspected, the correct action by the pilot of a fuel injected aircraft would be

alternate air ON.

What kind of icing are fuel injected engines subject to?

Throttle nad impact icing

One advantage of an alternator over a generator is

an alternator can produce sufficient power at low RPM.

What action should be taken if a circuit breaker is tripped?

Reset the breaker once only as repeated tripping is a sign of a more serious problem.

What is the purpose of a load meter?

Indicates the total current draw on the electrical system.

What will happen if both sides of the master switch is turned OFF while during a flight?

The electrical system will be deactivated but the engine will continue to run.

Why are circuit breakers or fuses installed in an aircraft?

To provide overload protection for electrical circuits.

What are the purposes of lubrication?

Cooling, sealing, lubricating, and cleaning.

What does viscosity mean in relation to lubricating oil?

Refers to the resistance of oil to flow.

Non-detergent oil is used for

new engines during the break-in period.

What is the main difference between wet sump and dry sump lubrication?

Wet sump contains the oil in the crankcase while dry sump uses an external tank

The purpose of a vent in the lubricating system is to

prevent too much pressure if the system is overfilled

With 100/130 octane rated avgas the number 100 means the

fuel's lean octane rating.

Do all types of fuel have FSII?

Depends on FBO

The purpose for grounding during fueling operations is to

prevent a static discharge and possible fire.

Why do aircraft require fuel pumps?

Fuel tank location does not have gravity to assist in feeding fuel to the engine

The most commonly recommended practice for preventing condensation in the fuel tanks is to

fill each fuel tank after every flight.

How should you identify and confirm the fuel in a drum before fueling?

by the appearance and odour of the fuel.

Hot fueling from drums should be done only:

under controlled conditions in compliance with CAR 602.09, during an emergency & if it is approved in the Company Operations Manual.

What is the major hazard in fueling from a drum during winter operations?

Dry winter air and blowing snow builds up more static energy on the aircraft body.

Identify the proper sequence of grounding.

1. Drum to pump

2. Pump to aircraft

3. Drum to ground.

4. Nozzle to aircraft.

5. Aircraft to ground.

3 - Drum to ground

1 - Drum to pump

2 - pump to aircraft

4 - Nozzle to aircraft

T or F - Increased pumping pressure with a go-no-go filter indicates presence of water in the fuel.

True

The purpose of an outflow valve is to

regulate cabin pressure.

What is the difference between the demand and the constant-flow oxygen system?

Demand systems only provide oxygen when inhaled.

What is the difference between a de-icing or an anti-icing system?

De-icing systems are used when ice is already present.

How is cabin heat usually provided in a single-engine piston powered aircraft?

By routing outside air over a shroud attached to the exhaust system.

A vacuum pump is used for

powering gyro instruments.