6.2.3 resulting in rapid wear of moving parts.

6.2.3 Engine Lubrication
The primary function of the engine oil system is to reduce friction between moving parts which would otherwise generate heat if not sufficiently lubricated. Other functions include:
Cushioning effect to engine parts subject to shock-loading
Aids as an effective cooling agent (along with air cooling)
Removing heat from the cylinders
Providing a seal between the cylinder walls and pistons
Carrying away contaminants
Operation of the propeller Constant Speed Unit (C.S.U)
Viscosity describes the resistance of an oil to flow and is primarily affected by temperature. Low temperatures increase viscosity (stickiness), creating a dragging effect, hindering its ability to circulate and perform as it should. At high temperatures, viscosity decreases and the oil becomes so thin that it begins to break down, resulting in rapid wear of moving parts. Because reciprocating engines have high operating temperatures and pressures, we require high viscosity oil. Other qualities of suitable lubricating oil include:
High flash point (temperature at which flammable vapors are released)
High anti-friction characteristics
Maximum fluidity at low temperatures
Maximum anti cooling ability
Maximum resistance to oxidation
Be non-corrosive
Lubrication Systems
Reciprocating engines use either a wet-sump or a dry-sump oil system. In a wet-sump system, the oil is located in a sump that is an integral part of the engine. Whereas a dry-sump system makes use of a separate, self-contained oil tank and engine driven pumps to achieve circulation.
The main component of a wet-sump system is the gear-type oil pump, which draws oil from the sump and routes it to the engine. Located before the oil pump is the by-pass valve which allows unfiltered oil to enter the system in case of any blockage. Similarly, an oil pressure relief valve ensures pressure is neither too high as to allow leaks, nor too low so to ensure adequate lubrication. After the oil passes through the engine, it drains back into to the sump, completing the cycle. In some engines, additional lubrication is supplied by the rotating crankshaft, which splashes oil onto portions of the engine.
An oil pump also supplies oil pressure in a dry-sump system, but the source of the oil is located in a separate oil tank. After oil is routed through the engine, it is pumped from the various locations in the engine back to the oil tank by scavenge pumps. Since changes in temperature significantly affects the viscosity of our oil and therefore its effectiveness, an oil cooler which is placed in the airflow (similar to a radiator) and allows for oil temperature regulation. Dry-sump systems allow for a greater volume of oil to be supplied to the engine, as well as inverted flight, which makes them more suitable for aerobatic and turbine aircraft.
The oil pressure gauge provides a direct indication of the oil system operation. It measures the pressure in pounds per square inch (psi) of the oil supplied to the engine. There should be an indication of oil pressure during engine start. Oil pressure should be kept within the limits. Refer to the Pilots Operating Handbook (P.O.H) for manufacturer limitations.
the oil temperature gauge measures the temperature of oil. A green area shows the normal operating range, and the red line indicates the maximum allowable temperature. Unlike oil pressure, changes in oil temperature occur gradually. This is particularly noticeable after starting a cold engine, when it may take several minutes or longer for the gauge to show any increase in oil temperature.
It is important to periodically check the oil temperature during flight, especially when operating in high or low ambient air temperature:

High oil temperature indications may signal a plugged oil line, a low oil quantity, a blocked oil cooler, or a defective temperature gauge.
Low oil temperature indications may signal improper oil viscosity during cold weather operations.

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The oil filler cap and dipstick (for measuring the oil quantity) are usually accessible through a panel in the engine cowling. If the quantity does not meet the manufacturer’s recommended operating levels, oil should be added. The POH or placards near the access panel provide information about the correct oil type and weight, as well as the minimum and maximum oil quantity. Within the filler neck is an oil filter to prevent foreign particles entering the engine compartments. At the bottom of the sump is a quick drain valve to manually remove water or sludge. Checking oil quantity is part of your pre-flight checks and should be done prior to every flight.

6.2.4 intermitted contact with terminals embedded within

6.2.4 Ignition Systems
Principles of Magneto Ignition
In any ignition system the basic necessity is to deliver a powerful electrical current to the spark plugs, so to detonate the fuel/air mixture within each cylinder. Since both the inlet and exhaust valves are closed during ignition, the pistons are forced down the cylinder by rapidly expanding gasses. Work is produced and in turn the crankshaft is rotated and the propeller turns.
Construction and Function
A magneto is simply a permanent magnet that rotates within a conductor and coil to create an alternating electrical current. This current is entirely independent of the aircraft’s electrical system and does not rely on battery power, it is instead a self-exciting entity. The magneto, which can be mechanically or engine driven, generates sufficient electrical charge to the spark plugs in each cylinder after passing through the distributor – igniting at just the right time and in a specific sequence. All of this takes place once the starter is engaged and the crankshaft begins to turn and it continues to operate whenever the crankshaft is rotating.

The distributor, which consists of a rotor that spins inside the non-conductive distributor block and makes intermitted contact with terminals embedded within the block. Each terminal is connected to a spark plug. The rotor (carrying a high voltage charge from the magneto circuit) comes in contact with each terminal, and the current is conducted to the applicable plug in the correct sequence.

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A dual ignition system with two individual magnetos is what is commonly used in small aircraft these days. Separate sets of wires and spark plugs improve the redundancy and reliability in the ignition system. Each magneto operates independently to fire its own spark plug within their allotted cylinders. Ignition of the fuel-air mixture is therefore improved with dual spark ignition and results in a marginally higher power output. In the event of one magneto failing, the other will be unaffected, improving pilot safety considerably. This redundancy allows the engine to continue somewhat normal operation, although engine RPM can be expected to be slightly reduced. Understandably resulting in a lower power output. Operation of the magnetos are controlled in the cockpit through various ignition switch positions:
OFF.
R (right)
L (left)
BOTH / START
Purpose and Principle of Impulse Coupling
A spark is produced in the plugs because the magneto spins a magnet inside an iron coil core. This generates an alternating current within the coil and produces up to 20 000 volts which are used to fire the spark plugs. In order for sparks to be effective, the magnet needs to be rotating at speeds of at least 500 R.P.M. Anything below this results in weaker sparks and reduces engine start-up and running efficiency. Incorrect timing can lead to a premature power stroke known as kick-back. This results from normal magneto timing set for a higher R.P.M settings. Ultimately, this can lead to the crankshaft being forced in the wrong direction. The ignition therefore needs to be delayed on startup (during low R.P.M operations).

This start-up problem is solved through the use of Impulse coupling. An impulse coupling device works in two ways. Spring weights and a spring-loaded coupling are used initially to prevent the magneto from turning. Once the spring is fully wound it releases the magnet which then spins at a greater velocity. The benefits of this are two-fold.
First, it accelerates the rotation of the magnet producing a higher voltage (better spark) and second the ignition spark is delayed during start-up. Once the engine is running, the centrifugal force of the flyweights ensures the impulse coupling is disconnected and does not cause interference during normal operations.

Serviceability Checks
The spark plugs are a useful indicator in determining the engine condition. During each Mandatory Periodic Inspection (M.P.I) the plugs are removed for inspection and testing. Normal engine function is indicated by a light grey coating of the end of the plugs. If detonation is suspected, excessive wear will be a good indication. Improper mixture control will leave Black sooty-like deposits in cases where mixture has not been sufficiently leaned, whereas engines operated with too lean a mixture will leave behind white powdery traces. Black oily deposits suggest excessive oil consumption and if hard brittle deposits are found lodged in the spark plug gap, it means lead in the fuel is not being removed during combustion. If disregarded, these deposits can build up enough to cause the plugs to ground without a spark. This often results in a “mag drop” which can be recognized by a rough running engine and an excessive loss in R.P.M. When this occurs on the ground during magneto checks, aborted the flight immediately.
Operational Procedures
The ignition system can be identified as defective or damaged during the pre-takeoff run-up checks. This is done by observing the reduction in R.P.M that occurs between when the LEFT and RIGHT ignition are selected individually. The maximum allowable reduction and ‘total drop’ limits are listed in the POH. If the engine stops running when switched to one magneto or if the rpm drop exceeds the allowable limit, the aircraft should not be flown until the system is serviced and the problem is corrected.
Possible causes of an unacceptable mag drop could be the result of damaged wires between the magneto and the spark plugs, fouled spark plugs or incorrect ignition timing. “No drop” in R.P.M is also abnormal and should be considered cause for concern. In this case, the aircraft should not be flown and sent in for immediate inspection.
“No drop” is an indication that one of the magnetos is not grounding and can result in a premature start, by simply turning the propeller by hand. Even with the battery and master switches OFF, the magneto is self-exciting and the engine can fire and turn over if the ignition switch is left ON and the propeller is moved. If this occurs, the only way to stop the engine is to starve the engine of fuel by move the mixture lever to the Idle Cut-Off (I.C.O) position. The system should immediately be checked by a qualified AMO. To avoid a premature start, ensure the engine is stopped by moving the mixture to the I.C.O position thereby draining the fuel lines, the magneto switch is turned to the OFF position after each flight and be extremely cautious when in the vicinity of the propeller.
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6.2.4 sufficient electrical charge to the spark

6.2.4 Ignition Systems
Principles of Magneto Ignition
In any ignition system the basic necessity is to deliver a powerful electrical current to the spark plugs, so to detonate the fuel/air mixture within each cylinder. Since both the inlet and exhaust valves are closed during ignition, the pistons are forced down the cylinder by rapidly expanding gasses. Work is produced and in turn the crankshaft is rotated and the propeller turns.
Construction and Function
A magneto is simply a permanent magnet that rotates within a conductor and coil to create an alternating electrical current. This current is entirely independent of the aircraft’s electrical system and does not rely on battery power, it is instead a self-exciting entity. The magneto, which can be mechanically or engine driven, generates sufficient electrical charge to the spark plugs in each cylinder after passing through the distributor – igniting at just the right time and in a specific sequence. All of this takes place once the starter is engaged and the crankshaft begins to turn and it continues to operate whenever the crankshaft is rotating.

The distributor, which consists of a rotor that spins inside the non-conductive distributor block and makes intermitted contact with terminals embedded within the block. Each terminal is connected to a spark plug. The rotor (carrying a high voltage charge from the magneto circuit) comes in contact with each terminal, and the current is conducted to the applicable plug in the correct sequence.

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A dual ignition system with two individual magnetos is what is commonly used in small aircraft these days. Separate sets of wires and spark plugs improve the redundancy and reliability in the ignition system. Each magneto operates independently to fire its own spark plug within their allotted cylinders. Ignition of the fuel-air mixture is therefore improved with dual spark ignition and results in a marginally higher power output. In the event of one magneto failing, the other will be unaffected, improving pilot safety considerably. This redundancy allows the engine to continue somewhat normal operation, although engine RPM can be expected to be slightly reduced. Understandably resulting in a lower power output. Operation of the magnetos are controlled in the cockpit through various ignition switch positions:
OFF.
R (right)
L (left)
BOTH / START
Purpose and Principle of Impulse Coupling
A spark is produced in the plugs because the magneto spins a magnet inside an iron coil core. This generates an alternating current within the coil and produces up to 20 000 volts which are used to fire the spark plugs. In order for sparks to be effective, the magnet needs to be rotating at speeds of at least 500 R.P.M. Anything below this results in weaker sparks and reduces engine start-up and running efficiency. Incorrect timing can lead to a premature power stroke known as kick-back. This results from normal magneto timing set for a higher R.P.M settings. Ultimately, this can lead to the crankshaft being forced in the wrong direction. The ignition therefore needs to be delayed on startup (during low R.P.M operations).

This start-up problem is solved through the use of Impulse coupling. An impulse coupling device works in two ways. Spring weights and a spring-loaded coupling are used initially to prevent the magneto from turning. Once the spring is fully wound it releases the magnet which then spins at a greater velocity. The benefits of this are two-fold.
First, it accelerates the rotation of the magnet producing a higher voltage (better spark) and second the ignition spark is delayed during start-up. Once the engine is running, the centrifugal force of the flyweights ensures the impulse coupling is disconnected and does not cause interference during normal operations.

Serviceability Checks
The spark plugs are a useful indicator in determining the engine condition. During each Mandatory Periodic Inspection (M.P.I) the plugs are removed for inspection and testing. Normal engine function is indicated by a light grey coating of the end of the plugs. If detonation is suspected, excessive wear will be a good indication. Improper mixture control will leave Black sooty-like deposits in cases where mixture has not been sufficiently leaned, whereas engines operated with too lean a mixture will leave behind white powdery traces. Black oily deposits suggest excessive oil consumption and if hard brittle deposits are found lodged in the spark plug gap, it means lead in the fuel is not being removed during combustion. If disregarded, these deposits can build up enough to cause the plugs to ground without a spark. This often results in a “mag drop” which can be recognized by a rough running engine and an excessive loss in R.P.M. When this occurs on the ground during magneto checks, aborted the flight immediately.
Operational Procedures
The ignition system can be identified as defective or damaged during the pre-takeoff run-up checks. This is done by observing the reduction in R.P.M that occurs between when the LEFT and RIGHT ignition are selected individually. The maximum allowable reduction and ‘total drop’ limits are listed in the POH. If the engine stops running when switched to one magneto or if the rpm drop exceeds the allowable limit, the aircraft should not be flown until the system is serviced and the problem is corrected.
Possible causes of an unacceptable mag drop could be the result of damaged wires between the magneto and the spark plugs, fouled spark plugs or incorrect ignition timing. “No drop” in R.P.M is also abnormal and should be considered cause for concern. In this case, the aircraft should not be flown and sent in for immediate inspection.
“No drop” is an indication that one of the magnetos is not grounding and can result in a premature start, by simply turning the propeller by hand. Even with the battery and master switches OFF, the magneto is self-exciting and the engine can fire and turn over if the ignition switch is left ON and the propeller is moved. If this occurs, the only way to stop the engine is to starve the engine of fuel by move the mixture lever to the Idle Cut-Off (I.C.O) position. The system should immediately be checked by a qualified AMO. To avoid a premature start, ensure the engine is stopped by moving the mixture to the I.C.O position thereby draining the fuel lines, the magneto switch is turned to the OFF position after each flight and be extremely cautious when in the vicinity of the propeller.
126111046822100

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