PRIVATE - SYSTEMS

What are the pitot-static instruments?
The airspeed, altimeter, and vertical speed indicator.

Basically describe how the airspeed indicator works?
The airspeed indicator compares the ram air pressure from the pitot tube to the static pressure from the static port.

Briefly describe how the altimeter works?
A sealed component (aneroid wafer) inside the altimeter casing expands and contracts with changes in pressure which are sensed through the static port. For example, during a climb outside pressure decreases which causes the sealed component inside the altimeter casing to expand showing an increase in altitude.

Describe how the vertical speed indicator works?
During a climb, outside pressure decreases which causes a component inside the VSI to condense. At the same time pressure outside of the internal component decreases as well but at a slower rate through a calibrated leak. The result is a pressure differential that is attempting to equalize. This pressure differential translates to show the appropriate climb or descent rate.

What happens to the altimeter and vertical speed indicator when the static port becomes blocked?
The VSI will read zero, and the altimeter will freeze on the altitude at which the blockage occurred.

What happens to the airspeed indicator when the static port becomes blocked?
When flying above the density altitude at which the blockage occurred, the airspeed will read lower than normal. When flying below the density altitude at which the blockage occurred, the airspeed will read higher than normal.

What happens to the airspeed indicator when the just the inlet of the pitot tube becomes blocked?
The airspeed will indicate zero.

What happens to the airspeed indicator when the inlet and outlet of the pitot tube is blocked?
The airspeed will react like an altimeter.

How do you fix a blocked static port?
By using an alternate static source, if equipped, or cracking the face of the VSI, if absolutely necessary.

How do you fix a blocked pitot tube?
By turning on the pitot heat.

How is the heat for pitot tube created?
The pitot tube is electrically powered.

What are the vacuum instruments?
The attitude indicator and heading indicator.

What provides vacuum power for these instruments?
An engine driven vacuum pump.

What is rigidity in space?
When a gyro spins at very high speeds it will attempt to remain in a fixed position.

Describe how the attitude indicator operates?
A stream of vacuum air flows through the instrument and spins a horizontally mounted gyro. Due to the principle of rigidity in space, you now have a simulated horizon to reference.

Describe how the heading indicator operates?
Vacuum air flows through the instrument and spins a vertically mounted gyro. The gyro is attached to a gear, and when the aircraft changes heading, it rotates the gear which shows a change in heading.

What are the indications of a failing vacuum pump?
A very low suction gauge reading, a frozen heading indicator, erroneous pitch and bank indications on the attitude indicator, and an annunciator light, if the airplane is equipped with one.

How is the turn coordinator powered?
In most planes it is electrically powered.

How does the turn coordinator operate?
An internally spinning gyro operates off the principle of precession.

How would recognize a failed turn coordinator?
There is a red flag that would appear on the instrument.

What is the difference between a slipping turn and a skidding turn?
A slipping turn is when not enough rudder is applied, and a skidding turn is when too much rudder is applied.

How does the compass operate?
It operates off the magnetic pull from the magnetic north pole.

What are the four errors associated with the compass?
Acceleration, dip, deviation, and oscillation errors.

When flying on a south heading and the aircraft accelerates, what happens to the heading indicated on the compass?
Nothing, north and south headings are the only headings which the compass is unaffected by the de/acceleration error.

During a turn to the north using your compass, you should start your roll out 30 degrees prior to 360. Why is the lead off heading 30 degrees?
This is based on the latitude of where the aircraft is located. If you fly further north, you will need to start the roll out sooner since you are at a higher latitude.

How many gallons of fuel are in the fuel system?
In a Cessna 152 there are 26 gallons total, 24.5 gallons are usable in standard range tanks.

Can you ever use the unusable fuel?
No, never. It is only there to be used as a sump to collect contaminates in the fuel tanks.

What type of fuel can your airplane use?
The Cessna 152 can use 100 (green) and 100LL (blue).

If you attempt to use 80 (red) grade fuel, what will happen?
You may experience detonation, which can lead to engine deterioration and eventually an engine failure.

How does the fuel transfer from the tanks to the engine?
In a Cessna 152 the fuel flow is gravity powered.

If you look on the fuel diagram, you will notice the fuel tanks are vented. What is the reason for this?
Vents relieve pressure in the fuel tanks by either allowing air to flow into the tanks during under pressurization or allowing fuel to flow out of the vent during over pressurization.

How much horsepower does the engine have?
The Cessna 152 engine has 110 horsepower at 2550 RPM.

How many cylinders does your aircraft have?
The Cessna 152 has 4 cylinders.

What is meant to have a direct drive engine?
There are no gears connecting the propeller to the engine. It's when the engine speed is the same as the propeller speed.

What is meant to have a normally aspirated engine?
There is no turbocharger installed, and as you climb you will lose performance.

How many magnetos and spark plugs are there?
There are 2 engine driven magnetos and 8 spark plugs.

Will the engine run on only one magneto?
Yes, having two magnetos is only for redundancy and increasing fuel burn efficiency.

What are the procedures for an engine fire in-flight?
Shut off all fuel supply to the engine, increase airflow to the engine, declare an emergency, and prepare for a forced landing.

What is the purpose of engine oil?
Among many, the common reasons are to cool, to clean, to seal, and to lubricate.

What is the acceptable range of oil quantity?
4-6 quarts for a Cessna 152,
but it's a good idea to have a personal minimum of 5 quarts.

What is the difference between mineral oil and ash-less dispersant oil?
Mineral oil is used during the first 50 hours of a new engine break in, and ash-less dispersant oil is used after the first 50 hours.
Oil has different SAE ratings. What does SAE refer to?
The lower the SAE number, the lower the viscosity. A low SAE should be used during cold weather operations, while a higher SAE should be used in warmer temperatures.

How does the carburetor heat work?
Instead of ducting filtered outside air to the carburetor, unfiltered hot air from inside the engine compartment is used in order to remove carburetor icing.

How does the cabin heat work?
Air flows through a shroud which covers an exhaust pipe. Since the exhaust pipe is hot, the air inside the shroud is heated and then ducted into the cabin.

Do you see any problems associated with the design of the cabin heating system?
If there is a leak in the exhaust pipe, carbon monoxide will enter the cabin causing carbon monoxide poisoning.

What would you do if you expected carbon monoxide poisoning?
You would need to turn off the heater and open the air vents.

Basically, what does the electrical system consist of?
An alternator, a battery, an ACU, an ammeter, bus bars, circuit breakers, and a master and avionics switch.

What is the difference between an amp and a volt?
Simply put, an amp is a flow of electrical current, whereas a volt is a storage of electrical current.

How many volts is the electrical system?
The electrical system in the Cessna 152 has a 28 volt capacity.

What is the purpose of the alternator?
The alternator provides a constant charge to the battery, and power to the various electrical components.

How many amps is the alternator?
60 amps.

Where is the alternator located?
It is located at the front of the engine. It is the lower component that is attached to the belt.
What is the purpose of the battery?
The purpose is to provide electrical power to the starter during engine start, and to provide a reserve of electrical power if the alternator fails.

Where is the battery located?
The battery is located in the rear portion of engine compartment.

How many volts is the battery?
24 volts.

How many amp hours is the battery?
It ranges between batteries, but it is safe to assume 15 amp hours.

What do the circuit breakers do?
They protect electrical components from excessive electrical loads.

Why do the circuit breakers have numbers on them?
This indicates the amp limit of the electrical component. You can also determine the remaining battery life by dividing the battery amp hours by the total amount of electrical load being used.

What is the procedure when a circuit breaker pops out?
Wait one minute, monitor the ammeter, turn off the "popped" electrical component if possible, push back in the CB, turn back on the electrical component, and if the CB pops out again leave it out and conduct the flight without that item.

What pilot actions are required for an overcharge or undercharge ammeter indication?
Overcharge, you should turn off the alternator with either the left side of the master switch or by pulling the alternator circuit breaker. With an undercharge, you should attempt to recycle the alternator.
Once again always refer to your POH for final guidance.

Under what circumstance would you turn the master switch off in flight?
Anytime you suspect an electrical fire, or are trying to conserve electrical power.

Would the engine be affected by turning off the master?
No, the magnetos are self contained.


How do the brakes work?
When the pedals are pressed, hydraulic brake fluid is compressed which then applies pressure to the brake pads which pushes them against the rotor.

What are flaps used for?
The flaps are used to increase the descent rate without increasing airspeed.

How are the flaps powered?
They are electrically powered.