Chapter 5 operation of systems Flashcards
4 main control surfaces
- Elevators— control the movement of the plane about its lateral axis. PITCH
- Ailerons— controls the airplanes movement about its long. Axis
- Rudder— controls movement of the plane about its vertical axis. YAW
- Trim Tabs— are small, adjustable hinged surface on the aileron, rudder, or elevator control surfaces. Labor saving devices allow pilot to release manual pressure on the primary control
Flight controls operated
Flight control surfaces are manually actuated through the use of either rod or cable system. Control wheel actuated the ailerons and elevator, rudder/braked pedals actuate the rudder
Flaps fucntion
Moveable panels on the inboard trailing edges of the wings. Are hinged so that they may extend downward into the flow of air beneath the wings to increase both lift and drag. Permits slower airspeed and a steeper angle of descent during landing approach. Also shorten takeoff distance
Landing gear system
Consist of tricycle system utilizing two main wheels and a steerable nosewheel. Turbulence spring steel main gear struts provide main gear shock absorption, nose gear shock absorption is provided by combination air/oil shock strut
Braking system
Hydraulically actuated disc-type brakes are utilized on each main gear wheel. Hydraulic line connects each brake to a master cylinder located on each pilot;s rudder petals. By applying pressure to the top of either the pilot’’s or copilot’s set of rudder pedals, the brakes may be applied
Hydraulic fluid
Mineral based hydraulic fluid(MIL-H-5606) odor similar to penetrating oil and dyed red
Steering on ground
Nose wheel steering through simple system of mechanical linkage connected to the rudder pedals. When rudder petal depressed, spring loaded bungee(push pull rod) connected to the pivotal portion of a nosewheel strut will turn the nosewheel
What engine does plane have
Horizontally opposed four-cylinder, overhead-valve, air cooled carbureted engine
4 strokes occur in cylinder
Intake- piston starts its downward travel causing intake valve to open and the fuel air mixture to be drawn into the cylinder
Compression— beings when the intake valve closes, and the piston starts moving back to the top of the cylinder. This phase of cycle is used to obtain a much greater power output from the air mixture once its ignited
Power—begins when the fuel air mixture is ignited which causes tremendous pressure increase in the cylinder and forces the piston downward away from the cylinder head, creating the power that turns the crankshaft
Exhaust— is used to purge the cylinder of burned gases and beings when the exhaust valve opens, and the piston starts to move toward the cylinder head once again
SUCK, SQUEEZE, BANG, BLOW
Carburetor
Process of mixing fuel and air in the correct proportions so as to form a combustible mixture. Vaporizes liquid fuel into small particles and mixes it with air. It measures the airflow and meters fuel accordingly
Carburetor heat system
Carb. Heat valve (controlled by pilot) allows unfiltered heated air from a shroud located aroun an exhaust riser or muffler to be directed to the induction air manifold prior to the carburetor. Carburetor heat should be used anytime suspected or known carb. Icing conditions exist
What change occurs when applying carb heat
Introduction of heated air into the carb. Will result in a richer mixture. Warm air is less dense, resulting in less air from the same amount of fuel. Use of carb can cause a decrease in engine power of up to 15%
Throttle function
Allows pilot to manually control the amount of fuel/air charge entering the cylinders. This in turn regulates the engine speed and power
Mixture control
Regulates fuel-to-air ratio. All planes incorporate mixture control, which the fuel/air can be controlled by the pilot during flight. Prevents the mixture from becoming too rich at high alts, due to decreasing air density. Lean mixture during cross country to conserve fuel and provide optimum power
Fuel injection system
Injects fuel directly into the cylinder or just ahead of the intake valve
- Engine driven fuel pump- provides fuel under pressure from the fuel tank to the fuel/air control unit
- Fuel/air control unit- meters fuel based on the mixture control setting and sends it to the fuel manifold valve at a rate controlled by the throttle
- Fuel manifold valve- distributes fuel to the individual fuel discharge nozzles
- Discharge nozzles- located in each cylinder head, these inject the fuel /air mixture at the precise time for each cylinder directly into each cylinder intake port
- Auxiliary fuel pump - Provides fuel under pressure to fuel/air control unit for engine starting and/or emergency use
- Fuel pressure/flow indicators - measures metered fuel pressure/flow
Ignition system the plane has
Engine ignition is provided by 2-engine driven magnetos, and two spark plugs per cylinder. Completely independent of the electrical system. Magnetos are engine-driven self contained units supplying electrical current without using an external source of current.
Two main advantages of dual ignition
A. Increased safety in case one system fails the engine may be operated on the on the other
B. More complete and even combustion of the mixture, and consequently, impr9ved engine performance I.e. the fuel/air mixture burn toward the center
Fuel system type
Gravity feed. Flows from two wing fuel tanks to a fuel shutoff valve and on the ‘on’ position allows it to flow thru. The fuel is mixed with air and then flows into the cylinders thru the intake manifold tubes
Purpose of fuel tank vents
Fuel level in an aircraft fuel tank decreases,, a vacuum would be created within the tank which eventually result in a decreasing fuel flow and finally engine stoppage. Replaces fuel with outside air, prevents vacuum
Fuel pump
These plans do not have fuel pump
Fuel type
Fuel grade used is 100LL and color blue
Manual primer
Primer’s main function is to provide assistance in starting the engine. The primers draws fuel from the fuel strainer and injects it directly into the cylinder intake ports. Results in quicker, more efficient engine start
Electrical system
28 volt, direct current system powered by an engine-driven 60 amp alternator and 24 volt battery
Circuits
Are protected from an overload condition by either circuit breakers or fuses or both. Same function as fuses except when overload, circuit breakers can be reset
Electrical system provides power for
Radio Turn coordinator Fuel gauges Pitot heat Landing light Taxi light Strobe lights Interior lights Instrument lights Position lights Flaps (maybe) Stall warning system Oil temperature gauge Electric fuel pump
Ammeter
Indicates the flow of current in amperes, from the alternator to the battery or from the battery to the electrical system with the engine running and master switch on, ammeter will indicate the charging rate to the battery. If off-line and is no longer functioning or electrical load exceeds output of the alternator. Indicates discharge
Voltage regulator
Device which monitors system voltage, detects changes, and makes required adjustments in the output of the alternator to maintain regulated system. Does it a low and high RPM
Generator/alternator voltage output slightly higher than battery voltage
The difference in voltage keeps the battery charged, 12 volt battery would be supplied with 14 volts
Cabin heat
Fresh air, heated by an exhaust shroud, is directed to the cabin through a serious of ducts
How is temp controlled in cabin
Controlled my 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
5 basic functions of aircraft engine oil
Lubricates- the engines moving parts
Cools- the engine by reducing friction
Removes- heat from the cylinders
Seals- provides a seal between the cylinder walls and pistons
Cleans - by carrying off metal and carbon particles and other oil contaminants
How carb icing occurs
Vaporization of fuel, combined with expansion of air as it passes thru the carb, causing sudden cooling of mixture. The temp of air passing through the carb may drop as much as 60F within a fraction of a second. Water vapor is squeezed out by the cooling and if temp in carb reaches 32F or below, moisture will be deposited as frost or ice inside the carb
Indication of carb icing
In fixed pitch plane, first indication is loss of RPM
Controllable pitch, drop in manifold pressure
Method in determine carb ice has been eliminated
When heat is first applied will be drop in RPM and if ice is present there will be a rise in RPM (usually with engine roughness) and when carb heat is turned off RPM will rise to a setting greater than that before application of heat and engine should run more smoothly
What conditions are favorable for carb icing
When temps are below 70F and the relative humidity is above 80%. But because of sudden cooling that takes place in carb icing can occur even with temp as high as 100F and humidity as low as 50%
Anti icing equipment
Prevents ice from forming on certain protected surface.
Examples: heated pitot tubes and static ports, carb heat, heated fuel vents, prop bladed with electrothermal boots, and heated windshields
Deciding equipment
Removes ice that has already formed on protected surfaces. Pneumatic boots on the wing and tail leading edges
How decking system works
Upon actuation, boots attached to the wing leading edges inflate with air from pneumatic pump to break off accumulated ice. After few seconds of inflation they are deflated back to their normal position with vacuum assistance
Detonation
Is uncontrolled explosive ignition of the fuel/air mixture within the cylinders combustion chamber. Causing excessive temp and pressure which, if not corrected, can quickly lead to failure of the piston, cylinder, or valves. Can also cause engine overheating, roughness, or loss of power. Detonation is characterized by high cylinder head temperatures and most likely occur at high power settings
Operational causes of detonation
A. Using lower fuel grade
B. Operating with extremely high manifold pressure in conjunction with low RPM
C. Operating the engine at high power settings with an excessively lean mixture
D. Extended ground operations or steep climbs where cylinder cooling is reduced
What action should be taken if detonation is suspected
A. Ensure that proper grade of fuel is used
B. Keep the cowl flaps in full open position while on ground
C. Use an enriched fuel mixture, as well as a shallow climb angle, to increase cylinder cooling during takeoff and initial climb
D. Avoid extended, high power, steep climbs
E. Develop habit of monitoring the engine instruments to verify proper operation according to procedures established by the manufacturer
Preignition
When fuel/air mixture ignites prior to the engines normal ignition event resulting in reduced engine power and high operating temp. Premature burning usually caused by a residual hot spot in the combustion chamber, often created by a small carbon deposit on a spark plug, cracked spark insulator or other damage in the cylinder that causes a part to heat sufficiently to ignite the fuel/air charge.
Can cause severe engine damage, because the expanding gases exert excessive pressure on the piston while still on its compression stroke
Action taken if preignition is suspected
A. Reduce power
B. Reduce the climb rate for better cooling
C.enrich the fuel/air mixture
D. Open cowl flaps
If no drop of RPM when a magneto is turned off (example when the right is turned off)
Meaning left P-lead is not grounding, or the engine has been running only on the right magneto because the left has totally failed
Ammeter indications
Right deflection (positive) - after starting —> power from the battery used for startin is being replenished by the alternator; or if a full-scale charge is indicated for more than 1 min, the starter is still engaged and a shutdown is indicated -during flight —> a faulty voltage regulator is causing the alternator to overcharge the battery. Reset the system and if the condition continues, terminate the flight asap Left deflection (negative) - after starting —> it is normal during start. At other times indicates the alternator is not functioning or an overload condition exists in the system. Battery not receiving charge - during flight —> the alternator is not functioning or an overload exists in the system. Battery is not receiving a charge. Possible causes: master switch was accidentally shut off, or alternator circuit breaker tripped
If ammeter indicates a continous discharge while in flight
Alternator has quit producing charge, alternator circuit breaker should be checked and reset and if still problem
A. Alternator should be turned off, pull the circuit breaker
B. All electrical equipment not essential to flight should be turned off
C. Flight should be terminated and a landing made as soon as possible
Ammeter indicates a continuous charge while in flight
Excessive rate of charge for extended period of time, battery will overheat and possible explosion of battery and electronic components in electrical system would be affected. Overvoltage sensor will shut the alternator dow. Following should be done
A.alternator should be turned off; pull the circuit breaker
B. All electrical equipment not essential to flight should be be turned off
C. The flight should be terminated and a landing made as soon as possible
Oil pressure is low and oil temp is normal
Result of: Insufficient oil
Oil temp remains normal, a clogged oil pressure relief valance or an oil pressure gauge malfunction could be culprit
Partial loss of power in flight
First priority is to establish and maintain a suitable airspeed (Vg) and select emergency landing and remain with gliding distance
Checklist:
A. Check carb
B. Check amount of fuel and switch tank if necessary
C. Check fuel selector valves current position
D. Check mixture control
E. Check the primer control is all the way in and locked
F. Check operation of the magnetos in all 3 positions, both left or right
Engine fire in flight
A. Set the mixture control “idle cutoff’ B. Set fuel selector valve ‘off’ C. Turn master switch ‘off’ D. Set cabin heat and air vents ‘off’ E. Establish 100 KIAS and increase descent F. Execute forced landing checklist
Engine fire on ground
Continue to attempt an engine start as a start will cause flames and excess fuel to be sucked back through the carb A. If engine starts: - increase power to higher RPM for a few moments and - shut down engine and inspect it B. Engine does not start - set throttle to full position - set mixture control to idle cutoff - continue to try engine start in an attempt to put out the fire by vacuum C. Fire continues - turn ignition ‘off’ - turn master switch ‘off’ - set fuel selector ‘off’
Operative off the pitot/static system
Altimeter
Vertical speed
Airspeed indicator
How does altimeter work
Aneroid wafers expand and contract as atmospheric pressure changes, and through a shaft and gear linkage, rotate pointers on the dial of the instrument
Limitations of pressure altimeter
non standard temp, temp variation expand or contract the atmosphere and raise or lower pressure levels that the alt senses
Warm day — pressure level is higher than on standard day and indicates lower than actual alt
Cold day — pressure level is lower than on a standard day. Alt indicates higher than actual
Changes in surface pressure affect pressure levels
Higher than standard pressure — pressure level is higher than on a standard day. Alt indicates lower than actual
Lower than standard — pressure level is lower than a standard day. Alt indicates higher than actual alt
Hot to low or hot to cold, look at below
Absolute alt
Vertical distance of an aircraft above the terrain
Indicated alt
Alt read directly from the altimeter (uncorrected) after it is set to the current altimeter setting
Pressure alt
Alt when the altimeter setting window is adjusted to 29.92. Pressure alt is used for computer solutions to determine density alt, true alt, true airspeed
True alt
True vertical distance of the aircraft above sea level. Airport, terrain, and obstacle elevations found on aeronautical charts and true alt
Density alt
Pressure alt corrected for nonstandard temp variations. Directly related to an aircrafts takeoff, climb and landing performance
Airspeed indicator operate
Sensitive, differential pressure gauge which measures the difference between impact pressure from pito head and undisturbed atmospheric pressure from the static source. Difference registered by the airspeed pointer on the face of the insturment
Limitations of IAS
Subject to proper flow of air in the pitot/static system
Errors of IAS
Position error — caused by static ports sensing erroneous static pressure, slipstream flow causes disturbances at the static port preventing actual atmospheric pressure measurement. Varies with airspeed, alt, and configuration
Density error — changes in alt and temp are not compensated for by the instrument
Compressibility error — caused by the packing of air into the pito tube at high airspeeds, resulting in higher than normal indications
Usually not factor at low airspeeds
IAS
Indicated
What reads on indicator and not corrected
CAS
Calibrated
Corrected for position and insturment errors
Same as TAS on sea level and stand temp
EAS
Equivalent
Corrected for position and instrument errors
And adiabatic compressible flow for particular alt
Same as CAS on stand temp and sea level
TAS
True
Corrected for alt and non standard temp
Speed of airplane in relation to the air mass which it is flying thru
Airspeed limitations not marked on indicator
Va
Vlo
Vx
Vy
Vertical speed indicator operates
Pressure differential insturment. Inside case in an aneriod. Inside aneriod and instrument case are vented to the static system. Case is vented thru a calibrated orifice causes pressure inside the case to change more slowly than the pressure inside the aneroid. Aircraft ascends, static pressure becomes lower and the pressure inside the case compresses the aneroid, moving the pointer upward, showing a climb and indicating number of feet per minute the aircraft is ascending
Limitations of VSI
Not accurate until plane is stabilized. Because of restriction in airflow to static Lin, 6-9 second lag is required to stabilize the pressures. Sudden movement will cause crazy reading and unreliable
Instruments contain gyroscopes
A. Turn coordinator
B. Heading indicator (directional gyro)
C. Attitude indicator (artificial horizon)
Fundamental properties of a gyroscope
Rigidity in space — gyroscope remains in a fixed position in the plane in which it is spinning
Precession — titling or turning of a gyro in response to a deflective force. Reaction to this force does not occur at the point where it was applied. Rather occurs at a point that is 90 degree later in direction of a rotation. Rate at which the gyro precesses is inversely promotional to the speed of the rotor and proportional to the speed of the rotor and proportional to the deflective force
Power sources for gyro
Some planes all are vacuum, pressure, or electrical. Others vacuum or pressure proved power for the heading and attitude, while electrical provides the power for the turn coordinator. Most planes have at least two sources of power to ensure at least one source of bank infor if on power source fails
Vacuum system operation
Engine driven vacuum pump provides suction which pulls air from the instrument case. Normal pressure entering the case directed against rotor vanes to turn the gyro at high speed. Air drawn thru a filter from cockpit and vented outside
Attitude indicator operation
Gyro in the attitude indicator is mounted on horizontal plane and depends upon rigidity in space for its operation. Horizon bar represents the true horizon and is fixed. Plane is pitched or banked about its lateral or longitudinal axis indicating attitude relative to true horizon
Limitation of attitude inidcator
Pitch and bank limit depend on make of instrument. Banking limit from 100 -110 and pitch limits from 60 to 70. If exceed the instrument will tumble or spill and give incorrect indications, until reset. Modern ones usually don’t tumble
Errors of attitude indicator
Usually free of errors. But depending on speed may be slight nose-up indication during rapid acceleration and nose down during rapid deceleration. And possible small bank angle and pitch error after 180 degree. Small errors and correct themselves
Heading indicator operate
Uses rigidity in space. Rotor turns in vertical plane and compass card is fixed to the rotor. Since rotor remains rigid in space, the points on card hold the same position in space relative to vertical plane
Limitations of heading
Exceeding 55 degree of pitch or bank it might tumble or spill and wrong indications until reset
Errors of heading
Because of precession heading will drift or creep from heading which it is set. Could show 15 degree error every hour
Turn coordinator operate
Turn point uses precession to indicate direction and approximate rate of turn. Gyro reacts by trying to move in reaction to the force applied thus moving the needle in proportion to the rate of turn. Slip/skid is a liquid tube with a ball that reacts to centrifugal force and gravity
What info does turn coordinator provide
Shows yaw and roll of plane around the vertical and long axis
Slip
Ball in tube will be on the inside of the turn , not enough rate of turn for the amount of bank
Skid
The ball in the tube will be to the outside of the turn. Too much rate of turn for the amount of bank
Magnetic compass operate
Magnetic needles fastened to a float assembly, around which is mounted a compass card, align themselves paralle to the earths lines of magnetic force. Float housed i a bowl filled with acid-free white kerosene
Limitations of magnetic compass
Jewel and pivot type mounting allows the float to rotate and tilt up to approx 18 degree angle of bank. Steeper bank angles it is unstable and erratic
Oscillation error
Erratic movement of compass card caused by turbulence or rough control technique
Deviation error
Due to electrical and magnetic disturbances in plane
Variation error
Angular difference between true and magnetic north, reference isotonic lines of variation
ANDS
Accelerate
North
Decelerate
South
UNOS
Undershoot
North
Overshoot
South
AHRS
Attitude and heading reference system. Provide heading, attitude and yaw info
ADC
Air data computer. Aircraft computer that receives and processes pitot pressure, static pressure, and temp to calculate precise alt, indicated airspeed, true airspeed, vertical airspeed and air tep
PFD
Primary flight controls. Easy to scan display that shows horizon, airspeed, alt, vertical speed, trend, trim, rate of turn and etc
MFD
Multi function display. Cockpit display capable of presenting info (navigation data, moving maps and etc
FD
Flight director. An electronic flight computer that analyzes the navigation selections, signals, and aircraft parameters. Presents steering instruction on the flight display as command bars or crossbars for pilot to position the nose of the aircraft over to follow
FMS
Flight management system. Computer system containing database for programming or routes, approaches and departures that can supply navigation data to the flight director/autopilot from various sources and can calculate flight data such as fuel consumption, time remaining, possible range and other values
INS
Inertial navigation system. Computer based tracks the movement of aircraft via signals produced by onboard accelerometers. Initial location is entered and all subsequent movement is then sensed and used to keep the aircrafts position updated
Magnetometer fucntion
Device that measures strength of the earths magnetic field to determine aircraft heading. Provides info digitally to the AHRS and sends it to the PFD
FMS/RNAV verification effective dates
Dates shown up on start up screen
AHRS system initialization
Some must be initialized on the ground prior to departure. Allows it to establish a reference attitude and used as benchmark
Standby avionics
Attitude indicator, airspeed indicator, altimeter
Display failure occurs
Will result in partial loss of navigation, communication, and gps capability
One display fails (PFD or MFD)
Some systems offer a reversion capability to display the primary flight instruments and engine instruments on the remaining operative display
ADC fails
Inoperative airspeed, alt, and vertical airspeed indicator shown with red Xs indicates of failure of the air data computer
AHRS fails
Inoperative attitude indicator shown with red X
Loss of magnemoter
Affects AHRS. Heading info will be lost
