Aircraft Systems

Question 1

What are two types of oil available for use in your airplane?

Answer 1

Mineral oil -

• Also known as non-detergent oil; contains no additives
• This type of oil is normally used after an engine overhaul or when an aircraft engine is new;
• normally used for engine break-in purposes.

Ashless dispersant

• Mineral oil with additives; high antiwear properties along with multi-viscosity (ability to perform in wide range of temps).
• Also picks up contamination and carbon particles and keeps them suspended

Question 2

What type of oil is recommended for this engine (for summer and winter operations)? (AFM/POH)

Know your plane

Answer 2

Ashless dispersant oil, usually SAE 20W-50 during the colder

months. For temperatures above 60°F (summer), use SAE 40 or

SAE 50.

Question 3

Describe the electrical system on this aircraft.

(AFM/POH) Know your plane

Answer 3

Electrical energy is provided by a 28-volt , direct-current system , powered by an engine-driven 60-amp alternator and a 24-volt battery.

Question 4

Where is the battery located? (AFM/POH)

Know your plane

Answer 4

The battery is located aft of the rear cabin wall.

Question 5

How are the circuits for the various electrical accessories within the aircraft protected?

Answer 5

Most of the electrical circuits in an airplane are protected from an Overload condition by either circuit breakers or fuses or both.

Question 6

What is a bus bar?

Answer 6

• A terminal in the aircraft electrical system to connect the main electrical system to the equipment using electricity as a source of power.
• This simplifies the wiring system and provides a common point from which voltage can be distributed throughout the system.

Question 7

The electrical system provides power for what equipment in an airplane?

Answer 7

Normally the following:

a. Radio equipment
b. Turn coordinator

C. Fuel gauges

d. Pitot heat
e. Landing light

f . Taxi light

g. Strobe lights
h. Interior lights
1. I nstrument lights

J. Position lights

k. Flaps (maybe)
1. Stall warning system (maybe)
m. Oil temperature gauge

n . Cigarette lighter (maybe)

o. Starting motor
p. Electric fuel pu mp

Question 8

What does the ammeter indicate? ( FAA-H-8083-25)

Answer 8

• It shows if the alternator/generator is producing an adequate power
• measurs the amperes of electricity
• indicates whether the battery is receiving an electrical charge. If the needle indicates a plus value, it means that the battery is being charged.
• If the needle indicates a minus value, it means that the generator or altern ator output is inadeqate and energy is being drawn from the battery.

Question 9

What function does the voltage regulator have?

(FAA-H-8083-25)

Answer 9

• Controls the rate of charge to the battery by stabilizing the generator or alternator electrical output.
• The generator/ alternator voltage output is usually slightly higher than the battery voltage. For example, a 12-volt battery would be fed by a generator/alternator system of approximately 14 volts . The difference in voltage keeps the battery charged .

Question 10

Does the aircraft have an external power source receptacle, and if so where is it located? (AFM/POH) Know your plane

Answer 10

Yes, the receptacle is located behind a door on the left side of the fuselage aft of the baggage compartment door

Question 11

What type of ignition system does your airplane have?

Answer 11

• Engine ignition is provided by two engine-driven magnetos, and two spark plugs per cylinder.
• The ignition system is completely independent of the aircraft electrical system.
• The magnetos are self-contained units supplying electrical current without using an external source of power.
• However, before they can produce current, the magnetos must be actuated as the engine crankshaft is rotated by some other means . To accomplish this, the aircraft battery furnishes electrical power to operate a starter which , through a series of gears, rotates the engine crankshaft. This in turn actuates the armature of the magneto to produce the sparks for ignition of the fuel in each cylinder. After the engine starts , the starter system is disengaged and the battery no longer contributes to the actual operation of the engine.

Question 12

What are the two main advantages of a dual ignition system?

Answer 12

a. Increased safety - in case one system fails the engine may be operated on the other until a landing is safely made.

b. More complete and even combustion of the mixture, and consequently improved engine performance; i.e., the fuel/air mixture will be ignited on each side of the combustion chamber and burn toward the center.

Question 13

How does the aircraft cabin heat work? (AFM/POH) Know your plane

Answer 13

Fresh air, heated by an exhaust shroud, is directed to the cabin through a series of ducts.

Question 14

How does the pilot control temperature in the cabin? (AFM/POH) Know your plane

Answer 14

• Temperature is controlled by mixing outside air (cabin air control) with heated air (cabin heat control) in a manifold near the cabin firewall.
• This air is then ducted to vents located on the cabin floor.

Question 15

What are several types of oxygen systems in use?

Answer 15

• Diluter-demand
• Pressure-demand
• Continuous-flow

Question 16

Can any kind of oxygen be used for aviator’s breathing oxygen?

Answer 16

• No, oxygen used for medical purposes or welding normally should not be used because it may contain too much water.
• The excess water could condense and freeze in the oxygen lines when flying at high altitudes.
• Specifications for “aviator’s breathing oxygen” are, 99.5% pure oxygen with not more than two milliliters of water per liter of oxygen.

Question 17

How does a continuous-flow oxygen system operate?

Answer 17

• Provided for passengers
• the passenger mask typically has a reservoir bag that collects oxygen from the continuous flow oxygen system during the time when the mask user is exhaling.
• The oxygen collected in the bag allows a higher inspiratory flow rate during the inhalation cycle, which reduces the amount of air dilution.

Question 18

How does a pressure demand oxygen system operate?

(FAA-H-8083-25)

Answer 18

• similar to diluter demand oxygen equipment, except that oxygen is supplied to the mask under pressure at cabin altitudes above 34,000 feet.
• Pressure demand regulators create airtight and oxygen-tight seals, but they also provide a positive pressure application of oxygen to the mask face piece that allows the user’s lungs to be pressurized with oxygen; this makes them safe at altitudes above 40,000 feet.

Question 19

What is a “pressurized” aircraft?

Answer 19

• sealed unit which is capable of containing air under a pressure higher than outside atmospheric pressure.
• On aircraft powered by turbine engines, bleed air from the engine compressor section is used to pressurize the cabin, and piston-powered aircraft may use air supplied from each engine turbocharger through a sonic venturi (flow limiter) .
• Air is released from the fuselage by a device called an outflow valve .

Question 20

What operational advantages are there in flying pressurized aircraft?

Answer 20

a. It allows an aircraft to fly higher which can result in better fuel economy, higher speeds, and the capability to avoid bad weather and turbulence.
b. It will typically maintain a cabin pressure altitude of 8,000 feet at the maximum designed cruising altitude of the airplane.
c. It prevents rapid changes of cabin altitude which may be uncomfortable or injurious to passengers and crew.
d. It permits a reasonably fast exchange of air from inside to outside of the cabin. This is necessary to eliminate odors and to remove stable air.

Question 21

Describe a typical cabin pressure control system.

Answer 21

The cabin pressure control system provides cabin pressure regulation, pressure relief, vacuum relief.

Question 22

What are the components of a cabin pressure control system?

Answer 22

a. Cabin pressure regulator: Controls cabin pressure to a selected value in the isobaric range and limits cabin pressure to a preset differential value in the differential range.
b. Cabin air pressure safety valve - A combination pressure relief, vacuum relief, and dump valve.

• Pressure relief valve: prevents cabin pressure from exceeding a predetermined differential pressure above ambient / pressure.
• Vacuum relief valve: prevents ambient pressure from exceeding cabin pressure by allowing external air to ente the cabin when the ambient pressure exceeds cabin pressure.
• Dump valve: actuated by a cockpit control which will cause the cabin air to be dumped to the atmosphere

c. Instrumentation - Several instruments use in conjuncktion with the pressurization controller are:

• Cabin differential pressure gauge - Indicates differnce between inside and outside pressure; should be monttore to ensure that the cabin does not exceed maximum allowable differential pressure .
• Cabin altimeter - This is a c he ck on system performa nce . Sometimes differential pressure and cabin altimeter combined into one:
• Cabin rate -of-climb- Indicates cabin rate-of-climb or descent.

Question 23

What is the difference between a deice system and an anti-ice system?

Answer 23

A deice system is used to eliminate ice that has already formed . An

anti-ice system is used to prevent the formation of ice.

Question 24

What types of systems are used in the prevention and elimination of airframe ice?

Answer 24

Pneumatic

• Consists of inflatable boots attached to the leading edges of the wings and tail surfaces.
• Compressed air from the pressure side of the engine vacuum pump is cycled through ducts or tubes in the boots causing the boots to inflate.
• Hot Air - An anti-ice type system; commonly found on turboprop and turbojet aircraft.
• Hot air is directed from the engine (compressor) to the leading edges of the wings.

Question 25

What types of systems are used in the prevention and elimination of propeller ice?

Answer 25

**Elctrically heated boots** - Consist of heating elements incorportated into the boots which are bonded to the propeller. The ice builds up on the propeller on the propeller is heated from below and then thrown off by centrifigual force. **Fluid system** - Consists of an electrically driven pump which, when activated, supplies a fluid, such as alcohol , to a device in the propeller spinner which distributes the fluid along the propeller assisted by centrifugal force.

Question 26

What function does the avionics power switch have?

Answer 26

* The avionics power switch controls power from the primary bus to the avionics bus. * Aircraft avionics are isolated from electrical power when the switch is in the "Off" position. * Also, if an overload should occur in the system , the avionics power switch will move to the " Off' position , causing an interruption of power to all aircraft avionics.

Question 27

What are static dischargers?

Answer 27

* Static dischargers are installed on aircraft to reduce radio receiver interference caused by corona discharge, which is emitted from the aircraft as a result of precipitation static. * Static dischargers ,normally mounted on the trailing edges of the control surfaces, wing tips , and vertical stabilizer, discharge the precipitation static at points a critical length away from the wing and tail extremities where there is little or no coupling of the static into the redio antenna.

Question 28

Within what frequency band does the following type of navigational and communication equipment installed on board most aircraft operate? (AIM) VOR DME ADF ILS

Answer 28

Question 29

Describe the function of the following avionics equipment acronyms: AHRS, ADC, PFD, MFD, FD, FMS, TAWS. (FAA-H-8083-6)

Answer 29

AHRS: attitude and heading reference system. Composed of three-axis sensors that provide heading, attitude, and yaw information for aircraft. AHRS are designed to replace traditional mechanical gyroscopic flight instruments and provide superior reliability and accuracy. ADC - air data computer. An aircraft computer that receives and processes pitot pressure, static pressure, and temperature to calculate very precise altitude, indicated airspeed, true airspeed, vertical speed, and air temperature. PFD- primary flight display. A display that provides increased situational awareness to the pilot by replacing the traditional six instruments with an easy-to-scan display that shows the horizon , airspeed, altitude, vertical speed, trend, trim , rate-of-turn , and more. MFD - multi-function display. A cockpit display capable of prestinting information (navigation data, moving maps , terrain awareness, etc.) to the pilot in configurable ways ; often used in concerning ,vith the PFD FD - flight director. An electronic fli ght computer that analyzes the navigation selection s, sig nal s, and aircraft parame te rs . It presents steering instruc tions on the flight display as command bars or crossbars for the pilot to position the nose of the aircraft over or follow. FMS - flight management system. A computer system containing a database for programming of routes , approaches, and departures that can supply navigation data to the flight director/autopilot from various sources, and can calculate flight data s uch as fuel consumption, time remai ning , possible range, and other values. TAWS- terrain awareness and warning system. Uses the aircraft's GPS navigation signal and altimetry systems to compare the pos ition and trajectory of the aircraft against a more detailed te rrain and obstacle database. This database attempts to detail every obstruction that could pose a threat to an aircraft in flight.

Question 30

What is the function of a magnetometer?

Answer 30

A magnetometer is a device that measures the strength of the earth's magnetic field to determine aircraft heading~ it provides this information digitally to the AHRS, which then sends it to the PFD.

Question 31

If a failure of one of the displays (PFD or MFD) occurs in an aircraft with an electronic flight display, what will happen to the remaining operative display?

Answer 31

In the event of a display failure, some systems offer a " reversion" capability to display the primary flight instruments and engine instruments on the remaining operative displ ay.

Question 32

Additional Study Questions 1. What will the manifold pressure gauge indicate when the engine isn't running? After starting, what will it indicate? Explain. (FAA-H-8083-25) 2. A pilot notices that when applying carburetor heat during an engine runup on the ground, an increase in RPM occurs. What does this indicate? (FAA-H-8083-25) 3. What is the purpose of "differential" aileron travel? (FAA-H-8083-31) 4. While in flight in an airplane with a controllable-pitch propeller, how will the failure of a single magneto affect RPM indication in the cockpit? (FAA-H-8083-25) 5. During gear extension or retraction, the electric hydraulic pump malfunctions and continues to run after the gear has been extended or retracted. How would the pilot detect this malfunction? (AFM/POH) 6. Where is the hydraulic reservoir located on your aircraft? What type fluid does it use? (AFM/POH) 7. What indications will you have if a loss of hydraulic pressure occurs in flight? (AFM/POH) 8. What is the maximum number of degrees the nose wheel will travel left or right of center? (AFM/POH) 9. Where are the brake system master cylinder{s) located on your aircraft? · (AFM/POH) 1 o. If a loss of oil pressure in the propeller occurs, what effect will this have on the propeller pitch and RPM? (~FM/POH) 11. Whe cycling the propeller prior to takeoff in an airplane equip ed with a constant speed propeller, why does the manifold pressure indicator indicate a momentary rise? \ (FAA-H-8tx83-25)

Answer 32

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