PT1 CHP3 Aircraft Systems Flashcards
What is a reciprocating engine?
The back and forth movement of the pistons
What principle does a reciprocating engine operate?
Converting chemical energy (fuel) into mechanical energy (movement of the propeller)
What are 2 types of ignitions are found in reciprocating engines?
Spark-ignition and compression-ignition
What are the 4 classifications of cylinder arrangements?
In-line, V-type, Opposed (vertical or horizontal) and radial
What are the components of an engine (7) and what are their functions?
Crankcase: the foundation
Cylinder: attached to the crankcase
Piston: moves up and down in the cylinder
Connecting rod: attached directly to the piston and to the crankshaft
Crankshaft: connects directly to the propeller
Valves: intake and exhaust
Spark plugs: light up the fuel/air mixture
What is the 4-stroke cycle?
Intake (suck), Compression (squeeze), Power (bang), Exhaust (blow)
What is the tachometer?
Indicates the speed at which the propeller rotates
What is the Hobbs meter and how is it measured?
Records flight time, hours and tenths (0.10) of an hour (1/10 = 6 minutes)
What are the typical components (6) of the fuel system?
Fuel tanks
Fuel selector valve
Fuel pumps (engine-driven and/or electrical)
Strainer
Primer
Carburetor or Fuel Injection system
What is the flow of the fuel system?
Fuel tanks (Left & Right)
Fuel selector (chose from which tank fuel will be drawn)
Fuel strainer (removes containments) and Primer (send an amount of fuel to the engine only when starting it)
Engine-driven fuel pump (another fuel pump to provide more pressure)
Carburetor or Fuel-injection system (what mixes the fuel/air mixture that is sent to the pistons for the 4-stroke cycle or directs the fuel into the piston)
How many induction systems are there and what are they?
2, Carburetor (mixes fuel and air before the intake manifold) and Fuel-injected ( atomizes the fuel/air immediately before entry into the cylinder or injects fuel directly into each cylinder)
What is the main difference between a carbureted and fuel-injected induction system?
The main difference is the method of how fuel is added, carburetor is pre-mixed and fuel-injected is atomized immediately before entering the cylinder or directly in each cylinder
What are the cockpit controls that regulate the amount of air and fuel that enters the induction system?
Throttle: Controls the amount of air that enters
Mixture: controls the amount of fuel that enters
What are the two types of carburetor systems and how do they differ?
Float-type (most common) and pressure-type, they differ from how fuel is delivered. A pressure-type carburetor delivers fuel under pressure by a fuel pump
What is the operation of a float-type carburetor?
- Ambient air first flows through an air filter (usually located at an air intake in the front part of the engine cowling)
- The filtered air flows into the carburetor through a venturi (a narrow throat in the carburetor, which creates a low pressure area that forces fuel to flow through a main fuel jet located at the throat)
- The fuel then
flows into the airstream where it is mixed with the flowing air - The fuel-air mixture is then drawn through the intake manifold and into the combustion chambers where it is ignited
i. the float-type carburetor acquires its name from the float that rests on fuel within the float float chamber
ii. a needle attached to the float opens the and closes an opening at the bottom of the carburetor bowl
iii. this meters the amount of fuel entering into the carburetor, depending on the position of the float, which is controlled by the level of fuel in the float chamber
iv. when the level of the fuel forces the float to rise, the needle valve closes the fuel opening and shuts off the fuel flow to the carburetor
v. the needle valve opens again when the engine required additional fuel
vi. the flow of the fuel-air mixture to the combustion chambers is regular by the throttle valve, which is controlled by the throttle in the flight deck.
What are the disadvantages of the float-type carburetors?
- They do not function well during abrupt maneuvers
- The discharge of fuel at low pressure leads to incomplete vaporization and difficulty in discharging fuel into some types of supercharged systems
- The main disadvantage is the icing tendency
What is carburetor icing?
Occurs due to the effect of fuel vaporization and the decrease in air pressure in the venture, which causes a sharp temperature drop in the carburetor
What temperature ( F & C) and relative humidity (%) can carburetor icing occur?
Can occur with temperatures as high as 70˚F (21˚C) and relative humidity is above 80%
What is an indicator of carburetor icing?
Early symptoms include decrease in RPM and may be followed up by engine roughness
How can carburetor icing be counteracted?
Turn on carburetor (carb) heat, which is a result of redirecting airflow the burn ice
What are the effects of using carb. heat?
A drop in performance (approx. 100 rpm)
What needs to occur when the aircraft increases in altitude (above sea level)?
- The mixture needs to be leaned (pull back on the throttle)
i. Air becomes less dense with altitude, but fuel density remains the same
What happens if the mixture is too rich or too lean?
- The engine will run rough (pull back on the mixture)
i. Too much fuel flow for the amount of air
What happens if the mixture is too lean and why?
The engine can get very hot due to not enough fuel
What happens if the mixture is too rich and why?
- A loss of power due to too much fuel since its density remains the same, but air density reduces when altitude increases
i. Need to lean the mixture, which decreases the fuel flow, which compensates for the decreased air density in high altitude
What is the procedure to lean the mixture in a carbureted engine for best power?
- Mixture: pull forward
- Throttle: Set 35 rpm below desired setting
i. Lean the mixture until peak rpm
ii. Adjust the throttle to final rpm
1. We are adjusting the throttle because we want reduce the fuel flow
2. Always follow manufacturer’s procedure
What is the procedure to lean the mixture in a carbureted engine for best economy?
- Mixture: full forward
- Throttle: full forward
- Lean the mixture until desired RPM
i. Always follow manufacturer’s procedure
What is the leaning procedure in a fuel-injected engine for best power?
- Set desired power setting
- Lean the mixture until peak EGT (exhaust gauge temperature)
i. Always follow manufacturer’s procedure
What can occur if the fuel is contaminated?
Can lead to a failure in the powerplant
When should the fuel be checked?
During the pre-flight
What should be checked during the pre-flight?
- Proper fuel [type] is used
- Look for water
- Rust or particles
When it comes to fuel, what must you do to ensure you do not encounter fuel starvation?
- Keep track of fuel consumption and monitor fuel gauges throughout the flight
i. Know how much fuel is in the tanks BEFORE takeoff
What can be done to ensure fuel is properly/even distributed from each tank?
Switch fuel flow from each tank periodically
What are magnetos?
“electromagnets” that generate electricity when the engine is running
- How many magnetos are present?
Two (2)
Where are the magnetos connected?
Connected to the engine crankshaft
How are the magnetos controlled?
The ignition switch
Are magnetos dependent on the electrical system? (Yes/No)
No
What does a dual-magneto system ensure?
Redundancy and better performance
How many spark plugs is each cylinder connected to?
Two (2)
What are two types of engine abnormalities? Describe what they are and how they are caused.
Pre-ignition and Detonation
What is pre-ignition?
Caused by carbon deposits that ignite the fuel-air mixture BEFORE the spark plug
i.Rather than the spark plug providing the spark for ignition during the 4-stroke cycle, the carbon deposit provides the spark and causes pre-ignition
What is detonation?
Hot cylinder ignites fuel-air vapors after combustion that is caused by incorrect fuel grade or too lean mixture (high engine temperature; due to not having enough fuel to cool the engine)
What can be done when either engine abnormality occurs?
Reduce power, enrichen mixture to cool down the engine
i. It is difficult to differentiate detonation and pre-ignition as they sound similar
What is the purpose of oil?
Lubricates, cools, cleans, seals, helps prevent corrosion
What is the oil system composed of?
- Oil sump (wet or dry)
- Oil filter
- Oil pump (engine driven)
- Gauges
How is engine cooling achieved
A combination of the oil system and the air (air-cooled engines) or Coolant (liquid-cooled engines)
What can lead to high oil temperatures?
Flying too long with a high pitch angle during take off
What is the use of the Exhaust Gauge Temperature (EGT)?
Determines the proper leaning procedure, measured in the exhausted manifold
- Where does burnt fuel-air mixture go once it enters the waste gate?
- Returns to the turbine, which powers the compressor (turbocharger)
- Exits through the exhaust system
What can the hot air generated from the exhaust system be used for? (3)
- Cabin heat: outside air directed around the muffler
- Carb heat
- Defrosting the windshield
What is the purpose of a Super or Turbocharger?
To increase the density of the air while in flight since pressure decreases with altitude, which can lead to less air going into the engine
i. Air density at 18,000 feet is ½ of that at sea level
1. Supercharger: engine-driven air compressor
2. Turbocharger: exhaust-gas-driven air compressor
What is the process of the turbo charger?
a. Cool air enters through the air inlet and goes through the air filter to remove contaminants
b. Cool air passes the alternate air and enters the compressor, which it is then heated
c. The warmer air moves along to the inter cooler, which it is then cooled
d. The cooled air moves to the engine where the 4-stroke cycle occurs
e. The warm air created from the exhaust of the 4-stroke cycle moves toward the waste gate (valve)
i. Some of the warm air is moves to the turbine, which powers the compressor
ii. Some of the warm air exits through the exhaust pipe
How is engine starting accomplished?
Via a direct-cranking starter system, which is electronically-actuated with power provided by the battery by moving the ignition switch into the START position
What must you ensure before engaging the starter? (3)
- Ensure no one is around the aircraft
- Have your feet on the brakes with parking brakes engaged
- Shout ‘CLEAR PROP’
What do you do to ensure you do not destroy the starter?
Do not use it for too long
What do you not do after the engine is started?
Do not continue to crank
What is a propeller?
A rotating airfoil that creates thrust
What is the propeller connected to?
Directly connected to the crankshaft of the engine (direct drive)
What does the amount of thrust depend on? (3)
- Shape of the airfoil
- Angle of attack (AOA) of the blade
- Speed of the angle
What is a fixed-pitch propeller?
- The angle of the blade is fixed and cannot be changed (set by the manufacturer)
- The speed of the propeller is controlled by the throttle handle
What is a constant-speed propeller?
- The blade angle of the propeller can be adjust based on the flight conditions
- Is adjusted by using the blue lever (controls the RPMs)
- The black lever controls the Manifold Pressure (MAP)
i. Large blade angle = prop grabs more air = more stress on the engine lower RPM
ii. Small blade angle = prop grabs less air = less stress on the engine higher RPM
iii. High MAP with low RPM (high blade angle) can damage the engine
What is the result of a of a large blade angle?
Large blade angle = prop grabs more air = more stress on the engine –> lower RPM
What is the result of a of a large blade angle?
Small blade angle = prop grabs less air = less stress on the engine –> higher RPM
What may be the result of a high manifold pressure with low RPW (high blade angle)?
Damage to the engine
What are typical components for an electrical system and what are each of their functions?
- Battery: starts the aircraft by providing electrical current to the starter; serves as a backup in case the alternator fails
i. A healthy battery usually provides approx. 30 minutes of power if the alternator fails - Alternator/generator: provides electrical current to the aircraft once the engine is ON
- Switches (Master/Alternator)
- Bus bar, fuses, and circuit breakers:
i. Busbar: distributes power to energized components
ii. Fuses: protect electrical systems from damage by interrupting the flow of electricity
1. When blown, need to be replaced
iii. Circuit breakers: protect an aircraft’s electrical system from damage caused by too much current or short circuits
1. The number indicates the maximum amperage before popping
a. Needs to be reset once the problem is fixed - Voltage regulator:
- Ammeter & loadmeter:
i. Ammeter: indicates whether there is a charge TO or discharge FROM the battery
1. Positive number – indicates the battery is getting charged (from the alternator)
2. Negative number – indicates the battery is discharging (alternator failed)
ii.Loadmeter: indicates how much “load” is currently being drawn from the source of electricity - Lots of wires
What is the color, cadence and when are landing lights used?
Solid white, turned on based on checklist
What is the color, cadence and when is the beacon light used?
Flashing red light, turned on before the engine starts and turn off after the engine stops
What is the color, cadence and when are the strobe lights used?
White, fast blinking on both ends of the wings and tail
What is the color, cadence and when are the position/navigation lights used?
Red (L) and Green (R), steady, turned on before the engine starts and turn off after the engine stops
What is an alternator failure?
Ammeter indicates a negative number (battery is discharging); you must pay attention to reduce load, not an emergency, more of an urgency
What is a battery failure and when would you know it failed?
You would not know until engine start the next flight, will not affect flight safety
Are the magnetos a part of the electrical system? (Yes/No)
No
If the battery or alternator fails, will the magnetos fail as well?
No, they will not as they are not a part of the electrical system and may continue to fire
What must you do when/if a circuit breakers pops?
Must find out the root cause and determine what problem needs to be fixed
What do you do if you experience a radio failure?
- In the pattern at a controlled airport, there will be a procedure to follow.
- Outside controlled airspace, then go ahead and land; make sure to exercise extreme caution
What are the primary purposes of the hydraulic system on smaller aircraft? (3)
- Wheel brakes
- Retractable landing gear
- Constant speed propeller (to adjust blade angle)
- What are the two main types of landing gear?
- Tricycle (2 in the front, 1 in the back)
- Tailwheel (1 in the front, 2 in the back)
What are fixed and retractable landing gears?
- Fixed: wheels remain
- Retractable: wheels go into the belly of the aircraft
How and where can you actuate the breaks?
By pressing the top part of the rudder pedals (pushes hydraulic fluid through the lines to slow the aircraft down)
What are the four types of landing gear malfunctions?
- Down: landing gear wont retract
- Up: landing gear won’t come down (if all are stuck then land on the belly)
- Nose gear up, main down: land on the main gears and flair as much as possible
- One main up
What are the ways/positions the flaps can malfunction? (3)
- Up (retracted): simply land at a faster speed
- Down (extended): normal operation
- One side is down: use the rudder and aileron to compensate during landing (aim for a faster speed approach)
What are some scenarios that may arise with an inoperative trim and what action should be taken? (3)
- Inop prior to takeoff, cancel the flight
- Nose-up position, lots of forward pressure will be necessary, landing will be difficult, possibility of stall on landing
- Nose-down position, lots of backward pressure will be necessary, takeoff will be difficult, will be difficult to flair on landing
What is the purpose of a pressurization system in an aircraft?
To maintain a higher pressure inside the cabin to replicate lower altitude
i. Flying at 28,000 ft (4.8 psi) but with the pressure of flying at 8,000 ft (10.9 psi)
What is the atmospheric pressure (psi) at sea level?
14.7 PSI
How is air pressurized in the aircraft?
From the bleed air from the turbocharger/supercharger or from a turbine
- What is depressurization?
The change of air pressure due to the higher air pressure inside the cabin compared to the ambient pressure
What are the types of decompressions? (2)
- Explosive
- Rapid
What is an explosive decompression?
A change in cabin pressure faster than the lungs can decompress (0.5 seconds or less)
What is a rapid decompression?
A change in cabin pressure in which the lungs decompress faster than the cabin
What is the purpose of the oxygen system?
Provides supplemental oxygen
What can occur without supplemental oxygen?
Oxygen deprivation
What altitude does the FAA recommend the use of supplemental oxygen based on the time of day?
10,000 ft during the day
5,000 ft at night
What altitude does the FAA recommend the use of supplemental oxygen during the day?
10,000 ft
What altitude does the FAA recommend the use of supplemental oxygen at night?
5,000 ft
What may ignite if expose to oxygen? (2)
- Oil
- Greases
When flying above 12,500 ft but below 14,000 ft, after how much time must flight crew wear supplemental oxygen?
30 minutes
Between what altitudes must flight crew wear supplemental after 30 minutes?
12,500 ft to 14,000 ft
When flying above 14,000 ft, after how much time must flight crew wear supplemental oxygen?
Immediately (30-minute rule does not apply)
When flying above 15,000 ft is it required that every occupant use supplemental oxygen?
No, it is not
When flying above 15,000 ft, who must be provided with supplemental oxygen?
Every occupant
Who must use supplemental oxygen when flying above 14,000 ft?
Flight crew
What is a deicing device and where are they found?
Removes ice once it’s formed, found on the airfoil
- What is an anti-icing device and where are they found?
Prevents ice from forming, found on the airfoil, windscreen, propeller, and pitot-static system
What is the purpose of the ELT (emergency locator transmitter) ?
Sends a distress signal on the emergency frequency (121.5 MHz) in the event of an impact
What is the emergency frequency? (MHz)
121.5 MHz (243.0 MHz for military)
When must the ELT be inspected?
Every 12 calendar months (last day of the month one year after inspected)
Ex. Inspected on 1/14/20,last day to be inspected is 1/31/21
When must the ELT battery be replaced?
- Used for more than one cumulative hour
- 50% of the battery’s useful life has expired (good for 2 years, after 1 year will need to be replaced)
When can the ELT be tested?
During the first 5 minutes of the hour
