Aircraft Systems Part 2/2 Flashcards
Name parts of a spark engine ignition system
L & R magnetos, spark plugs, high tension leads, ignition switch
Name 5 positions of the ignition system
- Off
- R (right)
- L (left)
- Both
- Start
Where is the permissible RPM decrease from the Mag switch listed?
AFM or POH
If there is an excessive RPM drop or the engine stops running from switching to 1 magneto, what could be the cause?
- Fouled plugs
- Broken or shorted wires btw mags & plugs
- Improperly timed firing of plugs
No drop in RPM is
NOT normal. Airplane should not be flown.
Engine can still fire if
Ignition is left on even with battery and master switches off
Name functions of the engine oil system
- Lubrication
- Cooling by removing friction
- Removing heat from cylinders
- Providing a seal between the cylinder walls & pistons
- Carrying away contaminants
Reciprocating engines use either:
- Wet sump oil system (oil located in a sump and pumped)
2. Dry sump oil system (oil contained in a separate tank and is circulated via pumps)
Describe what the oil pressure gauge does.
It ensures the pressure in lbs/sq. inch (PSI) of the oil supply to the engine.
High oil temp could indicate:
- A plugged oil line
- Low oil quantity
- Blocked oil cooler
- Defective temp gauge
Low oil temp could indicate:
- Improper oil viscosity for cold weather
Where can you find the correct oil type, weight, and quantity for your airplane?
AFM - airplane flight manual
POH - pilot operating handbook
Air-cooling is less effective than liquid cooling when?
Low airspeed especially with high power (ground operations, take-offs, go arounds)
High speed descents provide excess air and can…
shock cool the engine subjecting it to abrupt temp fluctuations
Operating an engine at a temp higher than its designed for can cause:
- Loss of power
- Excessive oil consumption
- Detonation
- Damage such as scoring the cylinder walls, damaging the pistons and rings, burning and warping valves
To avoid excessive cylinder head temperatures:
- Increase airspeed
- Enrich mixture
- Reduce power
What is detonation?
An uncontrolled explosive ignition of the fuel/air mixture within the cylinder
What does detonation cause?
Excessive temp & pressure, engine overheating, roughness, loss of power
Detonation is characterized by what?
High cylinder head temps and is most likely to occur at high power settings
Operational causes of detonation include:
- Use of a lower fuel grade than recommended
- Operation at high MAP with low RPM
- Operation at high power with excessively lean mixture
- Extended ground operations or steep climbs, with reduced cylinder cooling
How can you prevent detonation?
- Use proper fuel grade
- Fully open cowl flaps for ground operations
- Use an enriched mixture and shallower angle for takeoff and initial climb
- Avoid extended high power, steep climbs
Preignition occurs when?
When the fuel/air mixture ignites prior to the normal ignition event
Pre-ignition is usually caused by:
Residual hot spot in combustion chamber often created by
- a carbon buildup on a spark plug
- a cracked spark plug insulator
- or other cylinder damage which allows sufficient heat to build to ignite the fuel/air mixture
What does preignition cause?
- loss of power and high operating temperature
- Severe engine damage, as it places pressure on piston while still in compression stroke
Fact about detonation and preignition
Often occur simultaneously, and one may be caused by one another
Two classifications that apply to fuel systems in small aircraft
Gravity feed & fuel pump systems
2 pumps in fuel pump systems:
- Engine driven pump
2. Electric/ auxiliary/ boost pump
The octane number/ performance number of a Av gas (aviation gas) designates the what:
Anti-knock value or knock resistance of the fuel mixture in the engine cylinder. The higher the grade, the more pressure the fuel can withstand without detonating.
Low grades of fuel are used where
-In low compression engines because these fuels ignite at a lower temperature.
Higher grades of fuel are used in:
Higher compression engines because they ignite at higher temperatures but not prematurely
Suspended water droplets in the fuel can be identified via:
A cloudy appearance or as a separate, clear, layer on the bottom of the fuel sample.
Common electrical system voltage:
14 or 28 Vdc electrical system
Name the common components of the electrical system
Alternator, battery, master battery switch, alternator/generator switch, bus bar, fuses, circuit breakers, voltage regulator, amp-meter/load meter, wiring
Turning on the master ON switch provides current to:
All electrical systems except the ignition system
What is the bus bar used for?
A terminal system to connect the main electrical system to the equipment using electricity as a source of power
The bus bar simplifies what
The wiring system and provides a common point from which voltage can be distributed throughout the system
What is an ammeter used for?
It shows whether the alternator is producing an adequate supply of current and whether the battery is receiving an electrical charge.
What does a positive and negative value on the ammeter indicate?
Positive: shows the charging rate of the battery
Negative: shows more current is being drawn from the battery than is being replaced
Full scale minus deflection on an ammeter indicates:
Indicates a malfunctioning of the alternator/ generator
Full scale positive deflection on the ammeter indicates:
Indicates a malfunction of a regulator
What does a load meter indicate
Shows the load on the alternator/ generator
A load meter reflects what
the fraction of the alternator/ generator’s output capacity demanded by electrical components and the battery
When all electrical components are turned off, the loadmeter reflects what
It reflects only the amount of charge and current demanded by the battery
What are hydraulic systems used for on small airplanes?
- Wheel brakes
- Retractable landing gear
- Constant speed propellers
What are hydraulic systems used for on large airplanes?
- Flight control surfaces
- wing flaps
- spoilers
List basic components of a hydraulic system
- Reservoir
- Pump (hand, electric, or engine driven)
- filter to keep fluid clean
- Selector valve to control the direction of flow
- Relief valve to relieve excess pressure
- Actuator
Landing gear employing a rear mounted wheel is called:
conventional landing gear or tailwheel
Landing gear employing a front wheel are referred to as
Nosewheel or tricycle gear
Name 3 advantages of tricycle gear airplanes
- Allows more forceful application of brakes on high speed landings at high speeds without causing the aircraft to nose-over
- Permits better forward visibility for the pilot during takeoff/landing/taxiing
- Prevents ground-looping and swerving due to the CG being ahead of the main wheels
Tail wheel landing gear aircrafts are good for:
- Providing adequate ground clearance for larger propellers
- Better suited for operations on unimproved fields
Negative aspects of tail wheel airplanes:
- Directional control on the ground is more difficult in conventional gear airplanes, due to the CG being behind the main wheels
- Lack of good forward visibility when tail wheel is on or near the ground
