Engine And Instruments Flashcards
Gyroscopic Instruments
attitude indicator (A1) / artificial Horizon (AH)
- Heading Indicator/ horizontal situation indicator (HSI)/ directional gyro (DG)
- Turn coordinator (TC) turn and slip
Pressure Instruments
Airspeed Indicator (ASI)
Vertical speed indicator (VSI)
Altimeter (ALT)
What is the Altimeter?
Measures altitude
White Arc
Flap operating range
VSO
Lower limit of white arc
The stalling speed or minimum steady flight speed in the landing configuration
VFE
Upper limit of white arc
Maximum speed with flap extended
Green Arc
Normal operating range of the aircraft
VS1
Lower limit of green arc
The stalling speed or the minimum steady flight speed obtained in specified configuration
VN0
Upper limit of green arc
Maximum structural cruise speed. Don not exceed this speed unless in smooth air
VNE
Red line
Never exceed speed ( will damage the aircraft)
Yellow Arc
Caution range, fly only if there is smooth air
VA
Maximum manoeuvre speed
Maximum speed at which full control deflection is permitted.
VB
Turbulence penetration speed
A speed which ensure that an encounter with severe Turbulence will not cause damage.
VFO
The maximum flap operating speed
Maximum speed that the flaps can be extended or retracted.
Describe pitot, static port and pitot static probe.
Pitot tube - measure the total pressure
- total pressure =dynamic
+ static pressure
Static port - measure the static pressure
Pitot static probe - measure both pilot and static pressure in the probe.
Calibrated Airspeed - CAS
Corrected for instrument and position error
Placement of pitot tube and airspeed indicator can cause errors
True Airspeed ( TAS )
Corrected for altitude and non standard temperature
Speed of the aircraft relative to the airmass in which its flying.
Ground Speed (GS)
Speed of an aircraft relative to the earth surface.
What are the effect of AIR, ASI, VSI if Pitot tube is blocked?
ALT - Not Affected
ASI - Climb overread, Decent underread
VSI - Not affected
What are the effects of ALT, ASI and VSI , if one static source is blocked?
ALT - inaccurate while sliding/ slipping
ASI - inaccurate while sliding/ slipping
VSI - inaccurate while sliding/ slipping
What are the effects of ALT, ASI and VSI, if both static are blocked?
ALT - descent change with altitude ( if blocked before take off - field deviation)
ASI - underread climb, overread descent
VSI - shows the vsi before blocked.
What are the effects of ALT, ASI and VSI, if both pitot and static is blocked ?
ALT - Constant
ASI - Constant
VSI - Constant
What happens to the air pressure when it climbs and descent?
Climbing- Air pressure decrease
Descending- Air pressure increase
What happens to the ASI when the static is blocked during climb and decent?
SUC - static, underread, climb
SOD - Static, overread, descent
What happens to the ASI when the pitot tube is blocked during climb and descent?
PUD - Pitot, underread, descent
POC - pitot, overread, climb
What if happen if ice formed on the pitot tube during flight?
If pitot tube was blocked by the ice during flight , ice can be removed by applying pitot heat.
Pitot can be heated very fast avoid grabing!
Why do we have to synchronise the heading indicator and Best time to synchronise ?
Because of the friction it drifts from its position, so it will have to synchronise with the compas
Before the flight on the ground
Aircraft in the straight and level in smooth air
Check every 15 minutes
Three oil function that are vital to contuine operation of the engine
- It lubricates - provide an unbroken surface to support and separate metal surface
- It cools - absorb heat from engine components and dissipates it to the airstream as it pass through the cooler.
- It cleans - carries microscopic particles of carbon or metal and deposit them in the filter.
What should you do if the engine temperature becomes too hot during a long climb ?
Select the mixture to a richer setting
Open the cowl flaps
Climb at a higher IAS
Reduce engine power
What should you do if the engine temperature becomes too low during a long descent?
Check that the cowl flap are closed
Descent at a lower IAS
Increase engine power
What is the result of a engine operatimg with oil temperature too low ?
Cold oil becomes thick and sticky (high viscosity). Lubrication becomes less effective and oil becomes more difficult to pump to move so pressure rises.
What oil pressure threat would affect the safety of am aircraft and its passengers?
When there is no oil pressure.
For lubrication to be dobe oil must be pumped.. If oil pressure fails, metal to metal contact occurs and serve damages occur within minutes leading up to complete failure of the major engine.
What is the reason for a warm up period before take-off?
To ensure the oil is brought to the correct viscosity.
If it’s too cold, oil is too thick to flow and if it’s too hot it may no longer form an unbroken film across metal surfaces promoting high engine wear and eventual damage.
Magneto ignition
A magento is a generator. It a spark that produces its electric current by spinning a magnet in the vicinity of coils. It does not require any outside power.
During a pre take off check , the pilot notices no drop in RPM when the switches are moved from both to R and the engine contuines to run smoothly. What is the cause for this?
There is a fault in the ignition switch or wiring.
A magneto is turned ‘off’ by providing a pathway to carry its current away to ‘earth’ before it can be boosted to high voltage. When the switch is placed in ‘R’ position , the left magneto should be connected to earth. If there is something wrong with switch or wiring. The pathway is not available so the magneto continues to spark.
The engine contuines to run on both magnetos
When does oil fouling of spark plugs occur?
After long periods of operation at taxi or idle power.
Any oil that’s makes its way to the combustion chamber is burned or expelled from the engine along with the exhaust gases. At Low power settings the temperature within the cylinders is too low to burn all of its oil. It collects around the spark plugs and prevents sparks.
What is the purpose of an impulse coupling?
To provide sparks when engine is being cranked during start up.
Without impulse coupling the magneto would not be turning fast enough to produce a proper spark while engine is being cranked. It makes it possible to start engine with very low roational speed.
Is it safe to operate the propeller the electrical system is off and the magento switches are selected to off.
No. It’s not safe because if there is a switch or wiring fault the magento remains live even thou it’s in the off position. A small movement of the propeller can be enough to trigger the sting and cause the magneto to flick producing spark.
When should you set the directional gyro?
When the aircraft is in steady wings-level flight in smooth air.
What instruments rely on the static vent to give a reliable reading?
ASI, VSI, ALT
What is the significance of the white arc on the face of the airspeed indicator?
It indicates the safe speed at which the areoplane may be operated with flap
Function of battery
Store electronical energy for the system to use when the alternator is not operating.
Function of the Alternator
Supply all the electrical demands of the system during flight and keep the battery fully charged.
What should the normal reading of the centre zero ammeter be?
A constant small charge.
It’s places in the battery circuit. If the system is not working ammeter should indicate the current which is flowing to keep the battery fully charged. This should be small current.
What would happen when you contuine cranking the engine which is difficult to start?
Overheating and damage to the battery or starter motor
Difference between circuit breaker and fuse
A circuit breaker may be reset after it has been tripped bust fuse cannot. Fuse melts when a high current attempts to pass through it. When that happens it’s no longer usable.
What indicates the onset of detonation in an engine ?
Vibration, rising temperatures and reduced indicated air speed.
What accompanies when applying carburettor heat when ice is present in the carburettor?
A drop in engine RPM followed by rise.
Ice takes time to melt so when carburettor heat is applied there is an initial rpm drop then when the ice melts the rpm will increase. When the carburettor heat control is placed back into the cold position, the rpm will return to normal.
What will happen when the application of carburettor heat when no ice is present in the carburettor?
The rpm drop as usual when carburettor heat is applied then there won’t be a change. Rpm will remain at the reduced value.
What is the reason for filling the tanks of an aircraft which is left parked over night in cold weather?
To prevent water from collecting in the tank due to condensation.
The pressure exerted on the piston during the power stroke increases as the amount of gas induced…
Increases and combustion temperature increases.
What happens when the throttle is moved towards the fully open position?
Manifold pressure increases and gas flow decreases.
Best action to take at the onset of detonation in an engine
Select mixture fully rich and decrease the power.
Cause of detonation
Too much heat.
What is the colour of 100 octane low lead [ 100 LL ] aviation fuel ?
Blue
100/130 octane - green
Sequence for the four strokes of the four-stroke internal combustion engine?
Induction, compression, power and exhaust
(Suck, squeeze, bang , blow)
IF AVTUR was misidentified as AVGAS and added to the tanks of a piston engine aircraft. What would occur?
AVTUR is designed for use in jet engines. It has low tolerance to the combustion conditions inside a piston engine. Heavy detonation will occur, with engine power loss and engine damage.
If a blockage in a fuel tank vent in a gravity fed system is not discovered and removed before flight. What would happen?
The engine may fail completely due to fuel starvation..
Vent allows air to flow into the tank to replace the fuel left.in Gravity fed system, a vent blockage will create a suction in the tank which is capable of preventing any further fuel from flowing- no fuel left.
What is the measure of the octane rating of a fuel ?
Resistance to detonation.
Fuels with a high octane rating contain additives which allow normal combustion to contuine at temperatures and pressures which would normally cause detonation..
What are the different types of fuels and their colour?
AVGAS 100/130 - Green
AVGAS 100LL - Blue
AVTUR - Clear
MOGAS - Greenish or bluish ( regular), yellowish (midgrade), pink ( premium)
Symptoms of detonation
Rising cylinder or oil temperature indication
Power loss
Engine vibration
A pinging sound coming from the engine
Aircraft fuel systems
- Fuel tank to store fuel
- Vent to allow air to flow into the tank to replace fuel used
- Drain to allow sample of fuel to be inspected for contamination
- Selector value to allow the fuel flow to be turned on and off
- Fuel quantity gauge to allow the pilot to monitor the fuel quantity.
Factors affecting engine power output
- Amount of gas induced into the cylinder
- Temperature reached during combustion
- Position of throttle control
- Engine rpm
- Mixture condition
- Supercharging
What is the piston engine made of?
Cylinders
Pistons and piston rings
Inlets and exhaust valves
Crank shaft
Cam shaft
Spark plugs
Difference between carburettor and throttle
Carburettor mixes fuel and air to produce a fuel/air mixture
Throttle controls the amount of fuel/air mixture to the cylinders.
What is Carburettor Icing and the three different types?
Carburettor icing forms as a result of drop in temperature in the carburettor.
There are ;
1. Impact icing
2. Throttle icing
3. Fuel icing
Describe impact Ice
- Formed by the impact of moist air at temperatures between -10°C to 0°C
- it forms when visible moisture such as rain, clouds etc are present.
- can happen in all power setting
- also effects fuel injection engines.
Describe Fuel ice
- When the moist air freezes from cooling it causes fuel vaporization
- occurs between 4°C to 27°C ( may even occur higher) - relative humidity is higher than 50%
- ice will form in the inner surface of the carburettor
- forms at and downstreamfrom the point that fuel is introduced into the carburettor.
Describe Throttle Ice
Because of fuel evaporation it decrease in air pressure and temperature.
- occurs when temperature is 21°C and the humidity is 80% in low power
- common type of engine icing.
Why is Carburettor icing is dangerous?
When rpm drop , increase power then more fuel freeze up then rpm drop again.
What do carburettor heat do?
- directs heat, unfiltered air into the carburettor
- melts ice
- prevent ice forming
- provide alternate air source
Disadvantage of carburettor heat
Degrades engine performance by 15% because the air is unfiltered.
What happen when ice is present and non present in carburettor heat?
Present
- decrease in rpm, followed by gradual increase in rpm when ice melts
- engines runs smoothly when ice is melt
Not present
- RPM decreases and then remains constant
If the left magneto shows abnormal RPM drop + rough running and the right magneto shows normal RPM drop … what is the possible situation?
Possible fouled left plug
If the left magneto shows normal RPM drop and the right magneto shows engine stop running … what is the possible situation?
Possible fouled right magneto
If the left magneto shows normal RPM drop and the right magneto no RPM drop … what is the possible situation?
Possible left magneto fail to earth
What does different colour of exhaust smoke indicate?
Blue - oil leak and engine burning oil
Black - combustion incomplete, mixture too rich
What is a oil temperature and pressure gauges
Oil pressure gauge
- provides a direct indication of the oil system operation
- ensure the pressure of oil supplied to the engine.
Oil temperature Gauge
- measure temperature of oil
- changes slowly unlike oil pressure.
Monitor both gauges to see how engine is working
What are the chances of normal or high oil temperature with low oil pressure?
- high chance of engine damage
- engine may quit at any time
LAND ASAP
What are the chances of high oil temperature with low oil pressure?
Engine overheating,
try increasing cooling,if further problems occur LAND ASAP
What are the chances of low oil temperature with normal oil pressure?
- normal situation, usually happens on a cold day.
- wait til Temp is green..
Describe Oil cooler
Air cooled engines - uses outside air to cool engine and heated oil
- oil travels under oil pressure from oil sump through engine system.
- heated oil travels through oil cooler and filter before being returned to the sump.
Describe fuel pressure gauge
- measured in the fuel lines
- found on fuel injected gauges
- sometimes depicted as a fuel flow gauge
- indicates if the pumps are workings
- sudden fuel drop turn on auxiliary fuel pump
How to avoid fuel contamination?
- drain fuel before each flight
- fuel should be drained from the strainer quick drain and from each fuel tank sump into a transparent container and then checked for dirt and water. ( water sink)
- avoid refuelling from fuel drum
- refuel full piror overnight before parking.
Load meter
Reflects the electric load
When all electrical components are turned off, it reflects only the amount of charging current demanded by the battery
Read zero if alternator fail
What does the alternator generator do?
Convert rotational energy into electrical power , produce direct current and alternators create alternating current.
Describe the hydraulic system
Used in the brakes of light aircraft
- operatedby rudder pedals
- work by transmitting very high-pressure and force with a small volume of hydraulic fluid.
- if mixing different hydraulic fluids happen -> fullbrake power may not be obtained.
What does a normal operation of hydraulic system fee like?
- frim feeling with stopping power
- rebound after let go
Why are brakes spongy?
Possible air in the brake lines.
Why is there no rebound in the hydraulic system?
Possible hydraulic leak
When do you check the hydraulic system?
Before taxi and before landing
What is VSI?
Vertical Speed Indicator
- measures the rate of change of the static pressure
- the rate of climb or descent is indicated feet per minute (fpm)
- required static info only
What is ASI?
Airspeed Indicator
- measure the dynamic pressure ( T -S= D)
- indicates difference between pitot and static pressure gauges.
- required both pitot and static info.
Alternate static air
- provide alternate static source
- due to the venturi effect of air flowing around the fuselage , air pressure inside the flight deck is lower than the exterior pressure
So;
Alt - higher altitude than usual
Asi - greater than the actual speed
Vsi - shows a momentary climb and then stabilises if the altitude is held constant
Supercharger
Engine driven-air pump or compressor that provides compressed air to the engine to provide additional pressure to the conduction air.
Different ways to disconnect autopilot systems
- pressing a button on yoke/side stick
- pressing the autopilot engage/ disengage button on system itself
- pulling the autopilot circuit breaker ( in emergency)
- switching off avionics
Autopilot made for?
To relieve the pilots workload allowing more time to concentrate on flight management, communications, lookout and system monitoring.
Single- axis autopilot
Autopilot on a single axis
Two channels in single axis autopilot
Roll channel only
- AKA wing-leveller
- Able to change heading, follow navigation and approach routes.
Pitch channel only
- Altitude hold is connected via pitch servo and can be combined with an existing roll channel to create a dual -axis autopilot system.
- Electric trim, auto trim and vertical Speed command are all pitch- channel functions (most dangerous function).
Stall warning systems
Audible warning
Stick shaker
Angle of attack
Describe propeller overspeed
- a fixed-pitch propeller RPM will increase as airspeed increase.
- Throttle should be closed to prevent overspend.
- Most likely to occur when high speed - high power combinations
IVSI
Instantaneous vertical Speed Indicator
Indicating the rate of climb or descent at a given moment with little or no lag as displayed in a vertical speed indicator (VSI)
- Turning may displace the accelerometer pump causing flase climb/descent indication.
- IVSI are not reliable in steep turns
Compass
instrument that indicates the bearing, or angle of the direction in which an aircraft is pointing in the horizontal plane.
- indicate magnetic heading or bearing, bearing referenced to a radio signal source, or bearing with respect to an inertially maintained line of position.
- if the fluid in the compass has bubbles or leaks or card below is not present it’s not serviceable.
Service checks for compass
- Glass is clean
- No discolouration of the fluid inside the compass has occurred
- No bubbles are visible inside the compass unit
- It is indicating within 5 degrees of a precise heading.
What are deviation cards
- Tells you the boats error on different headings. As an example, this card tells us that there is a error of 2 degrees to the west when heading due north.
