Aircraft Systems Pt. 2 Flashcards
This provides a spark that ignites the fuel-air mixture in the cylinders
Ignition System
What is an ignition system made out of?
Magnetos, spark plugs, high-tension leads, and an ignition switch
These are designed with two independent ignition systems.
Aircraft piston engines
Aircraft piston engines are made up of _______________________ and a _______________________
two aircraft spark plugs per cylinder, left and right aircraft magneto
This is an engine driven electrical generator that uses permanent magnets and coils to produce high voltage to fire the aircraft spark plugs.
Magnetos
It generates sufficiently high voltage to jump a spark across the spark plug gap in each cylinder
Magnetos
When does the magnetos start?
When the starter is engaged and the crankshaft begins to turn
State the five positions in an ignition switch
- OFF
- R (Right)
- L (Left)
- BOTH
- START
Checking if magnetos are working:
-Switch between “R” and “L” and observe a drop in RPM
-RPM drop should _______________________ on either magneto or ___________________ between magnetos
should not exceed 125 RPM, 50 RPM differential
These are responsible for delivering electric current from the ignition system to the combustion chamber
Spark plugs
This is used to ignite the fuel mixture
Current
This is generated by the aircraft magneto and is conducted through the ignition harness to the spark plug, where it is used to ignite the fuel in the cylinders while containing combustion pressure within the engine
Electricity
Spark plug failing results from the __________________ in aviation fuel?
Tetraethyl lead (TEL)
The fouling arises when low engine operating temperature are coupled with _____________________. Doing this prevents the ______________________________.
running a rich mixture, complete vaporization of TEL
This is designed to provide an uninterrupted flow of clean fuel from the fuel tanks to the engine.
Fuel System
State the two common classifications apply to fuel systems in small aircraft
Gravity-feed and fuel-pump systems
State the four fuel system components
- Fuel Primer
- Fuel Selectors
- Fuel Quantity Gauges
- Fuel Tanks
This utilizes the force of gravity to transfer through fuel from the tanks to the engine
Gravity-Feed system
The fuel tanks in the wings are located below the carburetor, thus requiring a pump
Fuel pump system
State the fuel-pump system’s fuel pumps
- An engine-driven main fuel pump
- An electrically-driven auxiliary pump provided for use in engine starting and in the event the engine pump fails
A hand-operated piston type. It is mounted in the instrument panel and extends through the firewall where fuel intake and delivery lines are attached to the fittings on the left
Fuel Primer
This is used to draw fuel from the tanks to vaporize fuel directly into the cylinders prior to starting the engine
Fuel Primer
This allows selection of fuel from various tanks
Fuel Selection
State the four positions for a common type of selector
LEFT , RIGHT, BOTH, OFF
This indicate the amount of fuel measured by a sensing unit in each fuel tank and is displayed in gallons or pounds
Fuel Quantity Gauges
This is normally located inside the wings of an airplane, have a filler opening on top of the wing through which they can filled. A filler cap covers this opening.
Fuel Tanks
This may stand alone or be co-located with the fuel-tank vent and it allows the fuel to expand with increases in temperature without damage to the tank itself
Overflow drain
This is identified by an octane or performance (grade)
Aviation Gasoline (AVGAS)
True or False. The higher the grade of gasoline, the less pressure the fuel can withstand without detonating.
False. More pressure.
True or False. Lower grades of fuel are used in lower-compression engines because these fuels ignite at a lower temperature.
True
True or False. Higher grades are used in higher-compression engines because these fuels ignite at higher temperature, but not prematurely
True
How is the fuel for aircraft with turbine engines classified as?
JET A, JET A-1, and JET B
What does LL stand for?
Low Lead
How is AVGAS used for aircraft with reciprocating engine classified as?
AVGAS 80, 100, and 100LL
State the fuel related problems
- Pre-ignition
- Detonation
- Vapor Lock
- Fuel Contamination
This occurs when the fuel-air mixture ignites prior to the engine’s normal ignition event
Pre - ignition
The ignition source can be caused by a what? Either a cracked spark plug tip, carbon or lead deposits in the combustion chamber, or a burned exhaust valve, anything that can act as a glow plug to ignite the charge prematurely
Hot Spot
This is an uncontrolled, explosive ignition of the fuel-air mixture within the cylinder’s combustion chamber
Detonation
The fuel and air mixture “explodes” rather than burning smoothly. Because of this explosion, it exerts a much higher force on the piston and cylinder, leading to increased noise, vibration, and cylinder head temperatures.
Detonation
State proper preflight practices
- Take fuel samples from the fuel sumps as directed by your POH and/or checklist
- Carefully observe each fuel sample and check for clarity, foreign objects, and color.
- Visually check the fuel level in the tanks and dont just rely on the fuel gauges
- If you need to add fuel to one or more tanks before the flight, take additional samples of fuel from all sumps after the fuel is added
