PHAK 7: Aircraft Systems Flashcards
Reciprocating Engines
What are reciprocating engines?
Engines where pistons move back-and-forth (reciprocate) to produce mechanical energy for work.
Reciprocating Engines
What advancements have improved reciprocating engines recently?
Computerized engine management systems improving fuel efficiency, emissions, and reducing pilot workload.
Reciprocating Engines
How do reciprocating engines convert energy?
They convert chemical energy (fuel) into mechanical energy through combustion in the cylinders.
Reciprocating Engines
What are the two primary types of reciprocating engines?
Spark ignition and compression ignition engines.
Reciprocating Engines
How does a spark ignition engine work?
It uses a spark plug to ignite a pre-mixed fuel-air mixture.
Reciprocating Engines
How does a compression ignition engine work?
It compresses air in the cylinder, raising its temperature for automatic ignition when fuel is injected.
Reciprocating Engines
What are the classifications of reciprocating engines?
- Cylinder arrangement: radial, in-line, V-type, or opposed.
- Operating cycle: two-stroke or four-stroke.
- Cooling method: liquid or air.
Reciprocating Engines
What is a radial engine?
An engine with cylinders arranged in a circular pattern, offering a favorable power-to-weight ratio.
Reciprocating Engines
What is the most popular reciprocating engine for small aircraft?
The horizontally-opposed engine, known for high power-to-weight ratios and reduced aerodynamic drag.
Reciprocating Engines
What is the main advantage of a two-stroke engine?
Higher power-to-weight ratio due to a power stroke on each crankshaft revolution.
Reciprocating Engines
What are the four strokes in a four-stroke engine cycle?
- Intake: Draws fuel-air mixture into the cylinder.
- Compression: Compresses the mixture for greater power.
- Power: Ignites the mixture, pushing the piston down.
- Exhaust: Removes burned gases from the cylinder.
Reciprocating Engines
What innovation did Frank Thielert pioneer for aircraft engines?
Diesel-fueled piston engines capable of running on Jet-A fuel, offering reliability, cost savings, and operational independence.
Reciprocating Engines
Which aircraft commonly use diesel cycle engines?
- Diamond DA40 and DA42 Twin Star.
- Retrofitted Cessna 172 and Piper PA-28 models.
Reciprocating Engines
What is FADEC?
Full Authority Digital Engine Control, simplifying engine control in modern reciprocating engines.
Propeller
What is a propeller?
A rotating airfoil that generates thrust to pull or push an aircraft through the air.
Propeller
How does a propeller generate thrust?
By rotating and creating aerodynamic lift similar to how a wing produces lift.
Propeller
What factors affect the thrust produced by a propeller?
- Shape of the airfoil.
- Angle of attack (AOA) of the blade.
- Engine revolutions per minute (RPM).
Propeller
Why is a propeller blade twisted?
To produce uniform lift from the hub to the tip, compensating for the difference in speed along the blade.
Propeller
What is the angle of incidence on a propeller?
The angle of the blade relative to its rotation, which changes from the hub (highest pitch) to the tip (lowest pitch).
Propeller
What happens if the propeller blade has the same angle of incidence throughout?
- The portion near the hub would have a negative AOA.
- The tip would be stalled, making it inefficient.
Propeller
What are the two main types of propellers on small aircraft?
- Fixed-pitch propellers.
- Adjustable-pitch propellers.
Fixed-Pitch Propeller
What is a fixed-pitch propeller?
A propeller with fixed blade angles set by the manufacturer, which cannot be adjusted.
Fixed-Pitch Propeller
What is the main drawback of a fixed-pitch propeller?
It is only efficient at a specific combination of airspeed and RPM, leading to compromises in cruise and climb performance.
Fixed-Pitch Propeller
What are the two types of fixed-pitch propellers?
- Climb Propeller: Lower pitch, less drag, better takeoff and climb performance, less efficient during cruising.
- Cruise Propeller: Higher pitch, more drag, better cruising efficiency, less effective for takeoff and climb.
Fixed-Pitch Propeller
How is a fixed-pitch propeller mounted?
It may be mounted directly on the engine crankshaft or on a shaft geared to the crankshaft, affecting the RPM relationship.
Fixed-Pitch Propeller
What instrument indicates engine power in a fixed-pitch propeller aircraft?
The tachometer, which measures engine and propeller RPM, calibrated in hundreds of RPM.
Fixed-Pitch Propeller
What controls RPM in a fixed-pitch propeller system?
The throttle, which regulates the fuel-air flow to the engine.
Fixed-Pitch Propeller
How does altitude affect engine power and RPM in a fixed-pitch propeller?
- Higher altitude = lower air density = reduced engine power output.
- The throttle must be opened more at higher altitudes to maintain the same RPM.
Fixed-Pitch Propeller
Why does the same RPM produce different power at different altitudes?
Power output depends on air density, which decreases as altitude increases.
Adjustable-Pitch Propeller
What is an adjustable-pitch propeller?
A propeller with blades that can be adjusted on the ground but not in flight; also called a ground adjustable propeller.
Adjustable-Pitch Propeller
What is a constant-speed propeller?
A type of adjustable-pitch propeller that automatically varies blade pitch in flight to maintain a constant RPM.
Adjustable-Pitch Propeller
Main advantage of a constant-speed propeller?
It efficiently converts engine brake horsepower (BHP) into thrust horsepower (THP) across a range of RPMs and airspeeds.
Adjustable-Pitch Propeller
How is power controlled in a constant-speed propeller system?
- Throttle: Controls power output (manifold pressure).
- Propeller control: Regulates engine and propeller RPM.
Adjustable-Pitch Propeller
What happens when airspeed changes in a constant-speed propeller?
The governor adjusts blade angle to maintain selected RPM, increasing pitch at higher airspeeds and decreasing pitch at lower airspeeds.
Adjustable-Pitch Propeller
What is the constant-speed range?
The range of blade angles between the high and low pitch stops, where constant RPM is maintained.
Adjustable-Pitch Propeller
What happens when a pitch stop is reached?
The propeller behaves like a fixed-pitch propeller, and RPM changes with airspeed.
Adjustable-Pitch Propeller
What instrument measures power output in constant-speed systems?
The manifold pressure gauge, which indicates the absolute pressure of the fuel-air mixture in the intake manifold.
Adjustable-Pitch Propeller
Proper order for power adjustments to avoid engine overstress:
- Decreasing power: Reduce manifold pressure first, then RPM.
- Increasing power: Increase RPM first, then manifold pressure.
Adjustable-Pitch Propeller
Why should RPM and manifold pressure combinations follow manufacturer recommendations?
To avoid overstressing engine cylinders, which can weaken components and lead to engine failure.
Adjustable-Pitch Propeller
Why should RPM and manifold pressure combinations follow manufacturer recommendations?
To avoid overstressing engine cylinders, which can weaken components and lead to engine failure.
FAA SAIB CE-10-21
Why was “best glide” speed insufficient in the incident that prompted FAA SAIB CE-10-21?
For some aircraft, the published best glide speed may not generate enough thrust when the propeller is at the low pitch stop position.
FAA SAIB CE-10-21
What does the SAIB recommend regarding airspeed in propeller overspeed scenarios?
Pilots should be aware that maintaining a lower airspeed than the published best glide speed might generate adequate thrust for level flight.
FAA SAIB CE-10-21
When should a pilot determine a more suitable airspeed during a propeller overspeed?
Only at a safe altitude and when there is enough time to evaluate alternatives beyond landing immediately.
FAA SAIB CE-10-21
Key takeaway for operators and pilots with variable pitch propellers:
Recognize that the necessary airspeed to maintain level flight during propeller overspeed may differ from engine-out best glide speed. Follow emergency procedures and adjust airspeed as needed.
Induction Systems
What is the purpose of an induction system?
It brings in outside air, mixes it with fuel, and delivers the fuel-air mixture to the engine’s cylinders for combustion.
Induction Systems
Where does outside air enter the induction system?
Through an intake port on the front of the engine cowling, which usually contains an air filter.
Induction Systems
What is the role of the air filter in the induction system?
It prevents dust and foreign objects from entering the engine.
Induction Systems
What happens if the air filter becomes clogged?
An alternate air source provides air to the engine, bypassing the clogged filter.
Induction Systems
How is alternate air sourced?
It typically comes from inside the engine cowling and may operate automatically or manually.
Induction Systems
What are the two types of induction systems used in small aircraft?
- Carburetor system: Mixes fuel and air in the carburetor before entering the intake manifold.
- Fuel injection system: Mixes fuel and air immediately before entry into each cylinder or injects fuel directly into the cylinders.
Carburetor Systems
What are the two categories of aircraft carburetors?
- Float-type carburetors: Most common, with idling, accelerating, mixture control, and power enrichment systems.
- Pressure-type carburetors: Deliver fuel under pressure by a fuel pump, usually not found on small aircraft.
Carburetor Systems
What is the main difference between float-type and pressure-type carburetors?
The delivery of fuel:
- Float-type uses gravity and atmospheric pressure.
- Pressure-type uses a fuel pump to deliver fuel under pressure
Carburetor Systems
How does a float-type carburetor operate?
- Air passes through a filter and venturi, creating low pressure.
- Fuel is drawn through the main jet into the airstream.
- A float in the float chamber regulates fuel flow via a needle valve.
- The throttle valve controls the flow of the fuel-air mixture to the engine.
Carburetor Systems
What are the disadvantages of a float-type carburetor?
- Poor performance during abrupt maneuvers.
- Incomplete fuel vaporization at low pressure.
- High tendency for icing due to temperature drops in the venturi and throttle valve.
Carburetor Systems
How does a pressure-type carburetor address the issues of a float-type carburetor?
- Discharges fuel above atmospheric pressure, improving vaporization.
- Positions the discharge nozzle on the engine side of the throttle valve, reducing icing risks.
- Maintains fuel flow during rapid maneuvers and rough air conditions.
Mixture Control
What happens to the fuel-air mixture as altitude increases?
Air density decreases while fuel density remains constant, creating a richer mixture.
Mixture Control
What problems can a rich fuel-air mixture cause?
- Engine roughness: Due to spark plug fouling from excessive carbon buildup.
- Power loss: Resulting from incomplete combustion.
Mixture Control
Why does carbon buildup occur in a rich mixture?
Lower cylinder temperatures inhibit complete fuel combustion, leading to carbon deposits.
Mixture Control
How is the mixture adjusted at higher altitudes?
Leaning the mixture: Reduces fuel flow to compensate for decreased air density.
Mixture Control
What happens if the mixture becomes too lean?
May cause detonation, leading to rough engine operation, overheating, or power loss.
Mixture Control
What should be monitored to maintain proper fuel-air mixture?
Engine temperature and adjustments using an Exhaust Gas Temperature (EGT) gauge.
Mixture Control
Why is the mixture enriched during descent from high altitude?
To prevent the mixture from becoming too lean as air density increases.
Mixture Control
Where should you refer for specific mixture adjustment procedures?
The Airplane Flight Manual (AFM) or Pilot’s Operating Handbook (POH).
Carburetor Icing
What causes carburetor icing?
Fuel vaporization and air pressure drop in the venturi reduce temperature, potentially freezing water vapor inside the carburetor.
Carburetor Icing
Where does carburetor ice typically form?
Around the throttle valve and in the venturi throat.
Carburetor Icing
What are the ideal conditions for carburetor icing?
Temperatures below 70°F (21°C) and relative humidity above 80%, but it can occur at temperatures as high as 100°F (38°C) with humidity as low as 50%.
Carburetor Icing
How much can the temperature drop in a carburetor?
As much as 60 to 70°F (33 to 39°C) due to pressure and vaporization effects.
Carburetor Icing
What is the first sign of carburetor icing in an aircraft with a fixed-pitch propeller?
A decrease in engine RPM, possibly followed by engine roughness.
Carburetor Icing
What indicates carburetor icing in a constant-speed propeller aircraft?
A decrease in manifold pressure with no change in RPM.
Carburetor Icing
When is carburetor icing most dangerous?
During reduced power operations, such as a descent, when ice may build unnoticed until power is added.
Carburetor Icing
How is carburetor icing mitigated?
Using a carburetor heat system to prevent or melt ice formation.
Carburetor Heat
What is the purpose of carburetor heat?
It preheats air entering the carburetor to prevent or melt carburetor ice.
Carburetor Heat
When should carburetor heat be used?
In conditions conducive to carburetor icing or as an alternate air source if the intake filter clogs.
Carburetor Heat
What happens to engine power when carburetor heat is applied?
Engine power decreases (up to 15%) because heated air is less dense, enriching the mixture.
Carburetor Heat
What is the correct response if carburetor ice is detected?
Apply full carburetor heat immediately and keep it on until all ice is removed.
Carburetor Heat
How can you check for carburetor ice in a fixed-pitch propeller aircraft?
Look for an initial decrease in RPM followed by a gradual increase as the ice melts.
Carburetor Heat
How does carburetor ice affect constant-speed propeller aircraft?
Ice causes a decrease in manifold pressure, followed by a gradual increase as ice melts.
Carburetor Heat
Why should carburetor heat not be used during takeoff or normal operations?
It reduces engine power and increases operating temperature, which is not ideal for full-power scenarios.
Carburetor Heat
What should a pilot do if power loss and engine roughness occur due to carburetor icing?
Apply full carburetor heat and wait for normal power to return, even if roughness occurs temporarily.
Carburetor Heat
Why is periodic throttle opening recommended during closed-throttle operations?
To keep the engine warm and ensure the carburetor heater provides enough heat to prevent icing.
Carburetor Heat
What should a pilot monitor during carburetor heat application in icing conditions?
Watch for RPM or manifold pressure changes, smoother engine operation, and recovery of power.
Carburetor Air Temperature Gauge
What is the purpose of a carburetor air temperature gauge?
To detect potential icing conditions in the carburetor.
Carburetor Air Temperature Gauge
How is the gauge calibrated?
In degrees Celsius, with a yellow arc indicating temperatures where icing may occur.
Carburetor Air Temperature Gauge
What is the typical range of the yellow arc?
Between –15 °C and +5 °C (5 °F to 41 °F).
Carburetor Air Temperature Gauge
What should a pilot do if the gauge indicates a yellow arc and icing conditions are possible?
Use carburetor heat to keep the indicator outside the yellow arc.
Carburetor Air Temperature Gauge
What does a red radial on some gauges indicate?
The maximum permissible carburetor inlet air temperature recommended by the engine manufacturer.
Carburetor Air Temperature Gauge
What does a green arc on the gauge signify?
The normal operating range for the carburetor inlet air temperature.
Outside Air Temperature Gauge
What is the purpose of the Outside Air Temperature (OAT) gauge?
To measure the outside or ambient air temperature.
Outside Air Temperature Gauge
How is the OAT gauge calibrated?
In both degrees Celsius and Fahrenheit.
Outside Air Temperature Gauge
What are two primary uses of the OAT gauge?
Calculating true airspeed and detecting potential icing conditions.
Fuel Injection Systems
What does a fuel injection system do?
Injects fuel directly into the cylinders or just ahead of the intake valve.
Fuel Injection Systems
What is the purpose of the alternate air source in a fuel injection system?
To provide air if the external air source is obstructed.
Fuel Injection Systems
What are the six basic components of a fuel injection system?
- Engine-driven fuel pump
- Fuel-air control unit
- Fuel manifold (distributor)
- Discharge nozzles
- Auxiliary fuel pump
- Fuel pressure/flow indicators.
Fuel Injection Systems
How does the fuel injection system work?
The engine-driven fuel pump supplies fuel to the fuel-air control unit, which meters and sends it to the fuel manifold valve. The valve distributes the fuel to discharge nozzles in each cylinder.
Fuel Injection Systems
What type of icing can affect fuel injection systems?
Impact icing, caused by ice forming on the aircraft’s exterior and blocking openings like the air intake.
Fuel Injection Systems
What are six advantages of fuel injection systems?
- Reduction in evaporative icing
- Better fuel flow
- Faster throttle response
- Precise mixture control
- Better fuel distribution
- Easier cold weather starts
Fuel Injection Systems
What are three disadvantages of fuel injection systems?
- Difficulty starting a hot engine
- Vapor lock during ground operations on hot days
- Problems restarting after fuel starvation
Superchargers and Turbosuperchargers
What is the purpose of supercharger and turbosupercharger systems?
To compress intake air, increasing its density and engine horsepower.
Superchargers and Turbosuperchargers
What is the key difference between a supercharger and a turbosupercharger?
- Supercharger: Powered by an engine-driven air pump or compressor.
- Turbosupercharger: Powered by the exhaust stream driving a turbine that spins the compressor.
Superchargers and Turbosuperchargers
What instrument is used to monitor manifold pressure in these systems?
A manifold pressure gauge (MAP).
Superchargers and Turbosuperchargers
What does the manifold pressure gauge indicate on a standard day at sea level with the engine off?
29.92 “Hg, the ambient absolute air pressure.
Superchargers and Turbosuperchargers
How does atmospheric pressure change with altitude?
Atmospheric pressure decreases approximately 1 “Hg per 1,000 feet of altitude.
Superchargers and Turbosuperchargers
What is the service ceiling of an aircraft?
The altitude where manifold pressure becomes insufficient for normal climb.
Superchargers and Turbosuperchargers
How do superchargers and turbosuperchargers affect service ceiling?
They increase induction air pressure, allowing the aircraft to reach higher altitudes and benefit from higher true airspeeds and weather circumnavigation.
Superchargers
What is a supercharger?
An engine-driven air pump or compressor that increases the pressure of the induction air to boost engine power.
Superchargers
How does a supercharger increase engine power?
It compresses the air to a higher density, allowing the engine to produce more power by increasing manifold pressure.
Superchargers
What is the advantage of a supercharger at high altitudes?
It maintains manifold pressure similar to sea level, enabling the engine to produce the same power at higher altitudes.
Superchargers
What is a single-stage, single-speed supercharger?
A supercharger with a single gear-driven impeller that boosts engine power but decreases effectiveness with altitude.
Superchargers
What are two-speed superchargers?
Superchargers with an impeller that operates at low and high speeds, adjusted using an oil-operated clutch controlled from the flight deck.
Superchargers
What are the terms for the two speeds of a two-speed supercharger?
Low blower (low speed) and high blower (high speed).
Superchargers
When is a supercharger’s high blower setting typically used?
After reaching a specified altitude, where power is reduced, and the setting is switched to high blower to maintain desired performance.
Superchargers
What is an altitude engine?
An engine equipped with a supercharger designed to maintain performance at higher altitudes.
Superchargers
What process does the supercharger use to compress the fuel-air mixture?
It accelerates the mixture through an impeller and diffuser, trading velocity for pressure energy before directing it to the cylinders.
Turbosuperchargers
What is a turbosupercharger?
A system that uses exhaust gases to drive a turbine, compressing intake air to boost engine power, especially at higher altitudes.
Turbosuperchargers
How does a turbosupercharger differ from a supercharger?
A supercharger is engine-driven, while a turbosupercharger is powered by exhaust gases.
Turbosuperchargers
What are the two main components of a turbosupercharger?
The compressor (increases air pressure) and the turbine (driven by exhaust gases).
Turbosuperchargers
What is the critical altitude of a turbosupercharged engine?
The maximum altitude where the engine can produce rated horsepower before power begins to decrease.
Turbosuperchargers
What is the role of the waste gate in a turbocharger system?
It controls the amount of exhaust gas flowing into the turbine, regulating the level of boost.
Turbosuperchargers
What happens when the waste gate is fully closed?
Most exhaust gases are directed through the turbine to maximize boost pressure.
Turbosuperchargers
Why is an intercooler used in some turbocharged engines?
To cool the compressed induction air and reduce the risk of detonation.
Turbosuperchargers
What is overboosting?
A condition where manifold pressure exceeds engine limits, potentially causing detonation or damage.
Turbosuperchargers
How can overboosting occur in a turbocharged engine?
By leaving the waste gate closed during descent or applying takeoff power with cold engine oil.
Turbosuperchargers
Why should a turbocharger be allowed to cool down before engine shutdown?
To prevent oil from boiling and forming carbon deposits on the bearings and shaft.
Turbosuperchargers
What is the function of the automatic waste gate?
It adjusts waste gate position automatically to maintain the desired manifold pressure.
Turbosuperchargers
What should a pilot do if manifold pressure decreases before reaching critical altitude?
Have the turbocharging system inspected by a qualified AMT.
Turbosuperchargers
What are the benefits of a turbocharger?
It recovers lost exhaust energy, provides higher true airspeeds, and enables flight at higher altitudes.
Turbosuperchargers
What precautions should be taken with turbochargers during high-power operations?
Ensure the oil temperature is in the normal operating range before applying high throttle settings.
Ignition System
What is the purpose of the ignition system in a spark ignition engine?
To provide a spark that ignites the fuel-air mixture in the cylinders.
Ignition System
What are the main components of an ignition system?
- Magnetos
- Spark plugs
- High-tension leads
- Ignition switch
Ignition System
How does a magneto work?
It uses a permanent magnet to generate an electrical current independent of the aircraft’s electrical system.
Ignition System
What is the advantage of a dual ignition system?
It improves reliability and ensures continued engine operation if one magneto or spark plug fails.
Ignition System
How does the dual ignition system improve engine performance?
By firing two spark plugs per cylinder, it ensures better combustion and slightly higher power output.
Ignition System
What are the five positions of the ignition switch?
- OFF
- R (Right)
- L (Left)
- BOTH
- START
Ignition System
What happens during a pretakeoff ignition system check?
A small decrease in rpm is observed when switching from BOTH to RIGHT or LEFT.
Ignition System
What indicates a malfunction during the ignition system check?
An rpm drop exceeding limits, engine stopping on one magneto, or no rpm drop.
Ignition System
Why is the ignition switch turned OFF after engine shutdown?
To prevent accidental engine start since the magneto requires no external power and can fire if the propeller is moved.
Ignition System
What can happen if the ground wire to the magneto is disconnected or broken?
The engine could accidentally start if the propeller is moved due to residual fuel in the cylinders.
Ignition System
What should you do if the engine starts unexpectedly due to a broken ground wire?
Move the mixture lever to the idle cutoff position to stop the engine and have the system checked by a qualified AMT.
Oil Systems
What are five primary functions of the engine oil system?
- Lubricates moving parts
- Cools the engine
- Removes heat from cylinders
- Provides a seal between cylinder walls and pistons
- Carries away contaminants
Oil Systems
What are the two types of oil systems used in reciprocating engines?
Wet-sump and dry-sump systems.
Oil Systems
Where is oil stored in a wet-sump system?
In a sump that is an integral part of the engine.
Oil Systems
Where is oil stored in a dry-sump system?
In a separate oil tank external to the engine.
Oil Systems
How is oil circulated in a wet-sump system?
The oil pump draws oil from the sump, routes it through the engine, and returns it to the sump.
Oil Systems
What additional feature does a dry-sump system have for oil circulation?
Scavenge pumps return oil from the engine to the external oil tank.
Oil Systems
What are the advantages of a dry-sump system?
Allows for a greater oil volume and is suitable for large reciprocating engines.
Oil Systems
What does the oil pressure gauge indicate?
The pressure (in psi) of oil supplied to the engine. The green area indicates normal pressure; the red line shows minimum and maximum limits.
Oil Systems
What does the oil temperature gauge indicate?
The temperature of the oil. The green area indicates the normal range, and the red line shows the maximum allowable temperature.
Oil Systems
What might high oil temperature indicate?
A plugged oil line, low oil quantity, blocked oil cooler, or a defective temperature gauge.
Oil Systems
What might low oil temperature indicate?
Improper oil viscosity during cold weather operations.
Oil Systems
Where can the oil filler cap and dipstick usually be accessed?
Through a panel in the engine cowling.
Oil Systems
What should you consult to determine the correct oil type, weight, and quantity?
The AFM/POH or placards near the access panel.
Engine Cooling Systems
Why is engine cooling necessary?
To prevent overheating, which can cause loss of power, excessive oil consumption, detonation, and engine damage.
Engine Cooling Systems
How is most engine heat expelled?
Through the exhaust system.
Engine Cooling Systems
What are the two types of engine cooling systems?
Air cooling and liquid cooling.
Engine Cooling Systems
How does air cooling work?
Air flows into the engine compartment, over baffles and fins on the engine cylinders, absorbing heat, and exits through openings in the engine cowling.
Engine Cooling Systems
When is air cooling less effective?
During ground operations, takeoffs, go-arounds, and other high-power, low-airspeed situations.
Engine Cooling Systems
What is shock cooling, and when can it occur?
Shock cooling happens during high-speed descents, where abrupt temperature drops subject the engine to thermal stress.
Engine Cooling Systems
What damage can high engine temperatures cause? (4)
- Cylinder scoring
- Piston and ring damage
- Valve warping
- Excessive oil consumption.
Engine Cooling Systems
What instruments help monitor engine temperature?
Oil temperature gauge and cylinder-head temperature (CHT) gauge.
Engine Cooling Systems
How does the oil temperature gauge indicate engine temperature?
Indirectly and with delay, showing overall engine temperature trends.
Engine Cooling Systems
What is a cylinder-head temperature (CHT) gauge, and how is it calibrated?
A CHT gauge shows direct and immediate cylinder temperature changes; calibrated in degrees Celsius or Fahrenheit with a green arc (normal range) and red line (maximum allowable).
Engine Cooling Systems
How can high engine temperatures be reduced? (3)
- Increasing airspeed
- Enriching the fuel-air mixture
- Reducing power
Engine Cooling Systems
What are cowl flaps, and how do they help control temperature?
Cowl flaps are hinged covers that control airflow. Open to decrease temperature by increasing airflow; close to increase temperature by restricting airflow.
Exhaust Systems
What are the primary functions of the exhaust system?
Vents burned gases, provides cabin heat, and defrosts the windscreen.
Exhaust Systems
What components are included in an exhaust system? (3)
- Exhaust piping
- Muffler
- Muffler shroud
Exhaust Systems
How is cabin heat generated?
Outside air is ducted through a shroud around the muffler, where it is heated by exhaust gases and then sent to the cabin.
Exhaust Systems
What is a key safety concern with exhaust systems?
Exhaust gases contain carbon monoxide (odorless, colorless, deadly). The system must be free of cracks to prevent leaks.
Exhaust Systems
What does an Exhaust Gas Temperature (EGT) gauge measure?
The temperature of gases at the exhaust manifold.
Exhaust Systems
How is EGT used in flight?
To adjust the fuel-air mixture for optimal performance and reduced fuel consumption.
Exhaust Systems
What should be referenced for proper leaning procedures?
The manufacturer’s recommendations in the aircraft manual.
Starting System
What type of starter system is commonly used in small aircraft?
A direct-cranking electric starter system.
Starting System
What are the components of the starter system? (5)
- Source of electricity
- Wiring
- Switches
- Solenoids
- Starter motor
Starting System
How does the starter engage the engine?
The starter engages the flywheel, rotating the engine to start and maintain operation.
Starting System
What powers the starter system?
Typically powered by an onboard battery or external power through a receptacle.
Starting System
What prevents the starter motor from being driven by the engine?
A clutch in the starter drive allows the engine to run faster than the starter motor.
Starting System
What safety measures should be taken before starting an engine? (3)
- Ensure no one is near the propeller
- Chock the wheels
- Set the brakes.
Starting System
Where should the aircraft be positioned when starting?
In an area where the propeller will not stir up gravel or dust to prevent damage.
Combustion
What occurs during normal combustion?
The fuel-air mixture burns in a controlled and predictable manner, ensuring maximum force to the piston at the right time in the power stroke.
Combustion
What is detonation?
An uncontrolled, explosive ignition of the fuel-air mixture, causing excessive temperatures and pressures that can damage engine components.
Combustion
What are four common causes of detonation?
- Using a lower fuel grade
- High manifold pressure with low rpm
- High power settings with an excessively lean mixture
- Reduced cooling during extended ground operations or steep climbs
Combustion
How can detonation be avoided? (5)
- Use the proper fuel grade
- Keep cowl flaps open during ground operations
- Use an enriched fuel mixture
- Avoid extended high-power steep climbs
- Monitor engine instruments
Combustion
What is preignition?
Premature ignition of the fuel-air mixture, usually caused by a hot spot in the combustion chamber, such as a carbon deposit or damaged spark plug.
Combustion
What are the effects of preignition? (3)
- Loss of power
- High operating temperature
- Excessive pressure on the piston during the compression stroke, potentially causing severe damage.
Combustion
How can detonation and preignition be reduced? (2)
- Use the recommended fuel grade
- Operate the engine within its proper temperature, pressure, and rpm ranges
Combustion
What is the relationship between detonation and preignition?
They can occur simultaneously, with one potentially causing the other, and both result in high temperatures and reduced engine performance.
FADEC
What does FADEC stand for?
Full Authority Digital Engine Control
FADEC
What is FADEC?
A system consisting of a digital computer and ancillary components that control an aircraft’s engine and propeller, initially used in turbine-powered aircraft and now in piston-powered aircraft.
FADEC
How does FADEC work in spark-ignition engines?
It uses speed, temperature, and pressure sensors to monitor each cylinder, calculates ideal injector pulses, and adjusts ignition timing for optimal performance.
FADEC
How does FADEC differ in compression-ignition engines as opposed to spark-ignition engines?
It performs similar functions but excludes processes specific to spark ignition.
FADEC
What systems does FADEC eliminate?
Magnetos, carburetor heat, mixture controls, and engine priming.
FADEC
What is a key characteristic of a FADEC-equipped aircraft?
A single throttle lever that the pilot uses to select detents like start, idle, cruise power, or max power, with the FADEC adjusting engine and propeller settings automatically.
FADEC
What does FADEC control during aircraft starting?
It primes cylinders, adjusts the mixture, and positions the throttle based on engine temperature and ambient pressure.
FADEC
What are FADEC’s benefits during cruise flight?
FADEC monitors and adjusts fuel flow and ignition timing for each cylinder, leading to decreased fuel consumption and increased horsepower.
FADEC
What powers the FADEC system?
It can be powered by the aircraft’s main electrical system or a separate generator connected to the engine, with a backup electrical source for redundancy.
FADEC
What redundancy is built into FADEC systems?
Two separate and identical digital channels, each capable of performing all engine and propeller functions independently.
Turbine Engines
What are the five main components of an aircraft turbine engine?
- Air inlet
- Compressor
- Combustion chambers
- Turbine section
- Exhaust
Turbine Engines
How is thrust produced in a turbine engine?
By increasing the velocity of air flowing through the engine.
Turbine Engines
What are the key advantages of turbine engines?
Smooth operation, high power-to-weight ratio, and use of readily available jet fuel.
Turbine Engines
Why were turbine engines previously less common in small aircraft?
High costs due to material limitations, engine design, and manufacturing processes.
Turbine Engines
What has made turbine engines more accessible for small/light aircraft?
Advances in materials, engine design, and manufacturing have reduced costs.
Turbine Engines
What are very light jets (VLJs) or microjets?
Smaller turbine-powered aircraft that seat between three and seven passengers.
Types of Turbine Engines
How are turbine engines classified?
By the type of compressor they use:
* Centrifugal flow
* Axial flow
* Centrifugal-axial flow
Types of Turbine Engines
How does a centrifugal flow compressor work?
It accelerates air outward perpendicular to the engine’s longitudinal axis.
Types of Turbine Engines
How does an axial flow compressor work?
It compresses air using rotating and stationary airfoils to move air parallel to the longitudinal axis.
Types of Turbine Engines
What is a centrifugal-axial flow compressor?
A compressor design combining centrifugal and axial flow for desired compression.
Types of Turbine Engines
What determines the type of turbine engine?
The airflow path through the engine and how power is produced.
Types of Turbine Engines
What are the four types of aircraft turbine engines?
- Turbojet
- Turboprop
- Turbofan
- Turboshaft
Types of Turbine Engines: Turbojet
What are the four main sections of a turbojet engine?
- Compressor
- Combustion chamber
- Turbine section
- Exhaust
Types of Turbine Engines: Turbojet
What is the function of the compressor in a turbojet engine?
It passes inlet air at a high rate of speed to the combustion chamber.
Types of Turbine Engines: Turbojet
What happens in the combustion chamber of a turbojet engine?
It contains the fuel inlet and igniter, where the fuel-air mixture is burned.
Types of Turbine Engines: Turbojet
How does the turbine section contribute to engine operation?
The expanding air drives a turbine, which is connected by a shaft to the compressor to sustain engine operation.
Types of Turbine Engines: Turbojet
How is thrust produced in a turbojet engine?
By the accelerated exhaust gases exiting the engine.
Types of Turbine Engines: Turbojet
What are the limitations of turbojet engines?
Limited range and endurance; slow response to throttle applications at low compressor speeds.
Types of Turbine Engines: Turboprop
What is a turboprop engine?
A turbine engine that drives a propeller through a reduction gear.
Types of Turbine Engines: Turboprop
Why is reduction gearing necessary in turboprop engines?
Because optimum propeller performance occurs at slower speeds than the engine’s operating rpm.
Types of Turbine Engines: Turboprop
How does a turboprop engine operate?
Exhaust gases drive a power turbine, which is connected by a shaft to the reduction gear assembly.
Types of Turbine Engines: Turboprop
What is the efficiency range for turboprop engines?
Most efficient at speeds of 250–400 mph and altitudes between 18,000 and 30,000 feet.
Types of Turbine Engines: Turboprop
What altitude range offers minimum specific fuel consumption for turboprop engines?
Normally between 25,000 feet and the tropopause.
Types of Turbine Engines: Turboprop
How do turboprop engines compare to turbojet engines?
They are a compromise between turbojets and reciprocating powerplants, offering fuel efficiency and good performance at slow airspeeds for takeoff and landing.
Types of Turbine Engines: Turbofan
What is a turbofan engine?
A turbine engine that creates additional thrust by diverting a secondary airflow around the combustion chamber.
Types of Turbine Engines: Turbofan
What are the benefits of the bypass airflow in a turbofan engine?
Generates increased thrust, cools the engine, and aids in exhaust noise suppression.
Types of Turbine Engines: Turbofan
What type of performance do turbofan engines offer?
Turbojet-type cruise speed with lower fuel consumption.
Types of Turbine Engines: Turbofan
How is inlet air divided in a turbofan engine?
One stream passes through the engine core, while a second stream bypasses the core.
Types of Turbine Engines: Turbofan
What does the bypass ratio of a turbofan engine indicate?
The ratio of mass airflow bypassing the core to the mass airflow passing through the core.
Types of Turbine Engines: Turboshaft
What is a turboshaft engine?
A jet engine that delivers power to a shaft to drive something other than a propeller.
Types of Turbine Engines: Turboshaft
How does a turboshaft engine differ from a turbojet engine?
A turboshaft engine uses most of its energy to drive a turbine, whereas a turbojet engine uses it to produce thrust.
Types of Turbine Engines: Turboshaft
What are common uses of turboshaft engines?
Powering helicopters and serving as auxiliary power units (APUs) on large aircraft.
Types of Turbine Engines: Turboshaft
What is the primary function of the turbine in a turboshaft engine?
To convert expanding gases into mechanical energy to drive a shaft.
Turbine Engine Instruments
What five engine instruments are common to both turbine and reciprocating engines?
- Oil pressure
- Oil temperature
- Engine speed
- Exhaust gas temperature (EGT)
- Fuel flow
Turbine Engine Instruments
What three instruments are unique to turbine engines?
- Engine pressure ratio (EPR)
- Turbine discharge pressure
- Torque indicators
Turbine Engine Instruments
What do thermocouples in turbine engines measure?
They provide temperature readings in and around the turbine section.
Turbine Engine Instruments
Why are turbine engine instruments important?
They monitor critical parameters to ensure safe and efficient engine operation.
Turbine Engine Instruments: EPR
What does EPR stand for?
Engine Pressure Ratio
Turbine Engine Instruments: EPR
What does an EPR gauge measure?
The power output of a turbojet/turbofan engine.
Turbine Engine Instruments: EPR
How is EPR calculated?
As the ratio of turbine discharge pressure to compressor inlet pressure.
Turbine Engine Instruments: EPR
Where are pressure measurements taken for EPR?
By probes in the engine inlet and at the exhaust.
Turbine Engine Instruments: EPR
How is EPR data displayed?
Through a differential pressure transducer indicated on a flight deck EPR gauge.
Turbine Engine Instruments: EPR
Does EPR compensate for airspeed and altitude?
Yes, the system automatically compensates for airspeed and altitude.
Turbine Engine Instruments: EPR
What must be adjusted for ambient temperature changes in EPR?
Corrections must be applied to ensure accurate power settings.
Turbine Engine Instruments: EGT
What does EGT stand for?
Exhaust Gas Temperature
Turbine Engine Instruments: EGT
What does an EGT gauge monitor?
The temperature of the turbine section to prevent overheating.
Turbine Engine Instruments: EGT
Why is monitoring turbine temperature important?
To protect turbine blades and exhaust section components from damage.
Turbine Engine Instruments: EGT
What does EGT indicate?
Overall engine operating conditions and limits.
Turbine Engine Instruments: EGT
What are four common variations of EGT systems?
- Turbine Inlet Temperature (TIT)
- Turbine Outlet Temperature (TOT)
- Interstage Turbine Temperature (ITT)
- Turbine Gas Temperature (TGT)
Turbine Engine Instruments: EGT
What determines the name of the EGT system?
The location of the temperature sensors within the turbine section.
Turbine Engine Instruments: Torquemeter
What does a torquemeter measure?
The torque (twisting force) applied to a shaft.
Turbine Engine Instruments: Torquemeter
What types of engines use a torquemeter?
Turboprop and turboshaft engines.
Turbine Engine Instruments: Torquemeter
Why is torque measurement important in turboprop/turboshaft engines?
These engines are designed to produce torque for driving a propeller.
Turbine Engine Instruments: Torquemeter
How is torque displayed on a torquemeter?
It is calibrated in percentage units, foot-pounds, or psi.
Turbine Engine Instruments: N1 Indicator
What does N1 represent?
The rotational speed of the low-pressure compressor.
Turbine Engine Instruments: N1 Indicator
How is N1 displayed on the indicator?
As a percentage of design rpm.
Turbine Engine Instruments: N1 Indicator
What governs the speed of the low-pressure compressor after start?
The N1 turbine wheel
Turbine Engine Instruments: N1 Indicator
How is the N1 turbine wheel connected to the low-pressure compressor?
Through a concentric shaft.
Turbine Engine Instruments: N2 Indicator
What does N2 represent?
The rotational speed of the high-pressure compressor.
Turbine Engine Instruments: N2 Indicator
How is N2 displayed on the indicator?
As a percentage of design rpm.
Turbine Engine Instruments: N2 Indicator
What governs the speed of the high-pressure compressor?
The N2 turbine wheel.
Turbine Engine Instruments: N2 Indicator
How is the N2 turbine wheel connected to the high-pressure compressor?
Through a concentric shaft.
Turbine Engine Operational Considerations
What are five common turbine engine operational considerations?
- Engine temperature limits
- Foreign object damage (FOD)
- Hot starts
- Compressor stalls
- Flameouts.
Turbine Engine Operational Considerations
What is the highest temperature in a turbine engine?
The turbine inlet temperature (TIT).
Turbine Engine Operational Considerations
Why does turbine engine thrust decrease with altitude?
Due to decreased air density.
Turbine Engine Operational Considerations
What does FOD stand for?
Foreign Object Damage
Turbine Engine Operational Considerations
What causes FOD?
Ingestion of debris (e.g., small objects, bird strikes, or ice).
Turbine Engine Operational Considerations
How can FOD be prevented?
Using vortex dissipaters, screens, deflectors, and preflight inspections.
Turbine Engine Operational Considerations
What causes a hot start in a turbine engine?
Excessive fuel entering the combustion chamber or insufficient turbine RPM.
Turbine Engine Operational Considerations
What is a hung start?
Failure of the engine to reach proper idle RPM after ignition.
Turbine Engine Operational Considerations
What causes a compressor stall?
Compressor blade’s angle of attack (AOA) exceeding the critical AOA.
Turbine Engine Operational Considerations
What are the symptoms of a compressor stall?
- Transient stalls: Intermittent “bang” sound.
- Steady stalls: Strong vibrations, loud roar, fluctuating RPM, and increased EGT.
Turbine Engine Operational Considerations
How can a compressor stall be recovered?
Reduce power, decrease aircraft AOA, and increase airspeed.
Turbine Engine Operational Considerations
What is a flameout?
Unintentional extinguishing of the engine flame.
Turbine Engine Operational Considerations
What are common causes of flameouts?
- Rich flameout: Excessive fuel during rapid acceleration.
- Lean flameout: Insufficient airflow or fuel pressure, often at high altitudes
Turbine Engine Operational Considerations
How can a flameout be addressed?
Attempt an airstart following procedures in the AFM/POH.
Performance Comparison
What is BHP?
Horsepower delivered to the output shaft; actual usable horsepower.
Performance Comparison
What does BHP stand for?
Brake Horsepower
Performance Comparison
What is Net Thrust?
Thrust produced by a turbojet or turbofan engine.
Performance Comparison
What does THP stand for?
Thrust Horsepower
Performance Comparison
What is THP?
Horsepower equivalent of the thrust produced by a turbojet or turbofan engine.
Performance Comparison
What does ESHP stand for?
Equivalent Shaft Horsepower
Performance Comparison
What is ESHP?
For turboprop engines, the sum of Shaft Horsepower (SHP) delivered to the propeller and THP produced by exhaust gases.
Performance Comparison
What does SHP stand for?
Shaft Horsepower
Performance Comparison
Which engine type allows the highest maximum aircraft speed?
Turbojet
Performance Comparison
Which engine type has a higher maximum speed than a turboprop or reciprocating powerplant?
Turbofan
Fuel Systems
What is the purpose of the fuel system?
To provide an uninterrupted flow of clean fuel from the fuel tanks to the engine under all operating conditions.
Fuel Systems
What conditions must the fuel system operate under?
All engine power levels, altitudes, attitudes, and approved flight maneuvers.
Fuel Systems
What are the two common classifications of fuel systems in small aircraft?
Gravity-feed systems and fuel-pump systems.
Fuel Systems: Gravity-Feed System
What is a gravity-feed fuel system?
A system that uses gravity to transfer fuel from the tanks to the engine.
Fuel Systems: Gravity-Feed System
Where are fuel tanks typically located in gravity-feed systems?
In the wings, above the carburetor, such as in high-wing airplanes.
Fuel Systems: Gravity-Feed System
What happens if gravity cannot transfer fuel effectively?
Fuel pumps are installed, as in low-wing airplanes where the fuel tanks are below the carburetor.
Fuel Systems: Fuel-Pump System
What is a fuel-pump system?
A fuel system that uses pumps to transfer fuel from the tanks to the engine.
Fuel Systems: Fuel-Pump System
How many fuel pumps are typically in a fuel-pump system?
Two: an engine-driven main pump and an electrically-driven auxiliary (boost) pump.
Fuel Systems: Fuel-Pump System
What is the purpose of the auxiliary pump?
To assist in engine starting and provide reliability if the engine pump fails.
Fuel Systems: Fuel-Pump System
How is the auxiliary pump operated?
It is controlled by a switch in the flight deck.
Fuel Systems: Fuel Primer
What is the purpose of a fuel primer?
To draw fuel from the tanks and vaporize it directly into the cylinders to aid in starting the engine.
Fuel Systems: Fuel Primer
When is a fuel primer especially useful?
During cold weather when insufficient heat is available to vaporize fuel in the carburetor
Fuel Systems: Fuel Primer
What should be done with the primer knob after use?
Lock it in place to prevent it from vibrating out of position during flight.
Fuel Systems: Fuel Primer
What issue can occur if the primer knob is not locked?
It may cause an excessively rich fuel-air mixture.
Fuel Systems: Fuel Primer
How can overpriming be avoided?
Follow the aircraft’s specific priming instructions.
Fuel Systems: Fuel Tanks
Where are the fuel tanks typically located in an airplane?
Inside the wings.
Fuel Systems: Fuel Tanks
How are the fuel tanks filled?
Through a filler opening on top of the wing, covered by a filler cap.
Fuel Systems: Fuel Tanks
Why are fuel tanks vented?
To maintain atmospheric pressure inside the tank.
Fuel Systems: Fuel Tanks
How can fuel tanks be vented?
Through the filler cap or a tube extending through the surface of the wing.
Fuel Systems: Fuel Tanks
What is the purpose of the overflow drain?
To allow fuel to expand with temperature increases without damaging the tank.
Fuel Systems: Fuel Tanks
What might happen if fuel tanks are filled on a hot day?
Fuel may come out of the overflow drain due to expansion
Fuel Systems: Fuel Gauges
What do fuel quantity gauges measure?
The amount of fuel in each tank, displayed in gallons or pounds.
Fuel Systems: Fuel Gauges
When are fuel gauges required to be accurate?
Only when they read “empty.”
Fuel Systems: Fuel Gauges
What should you do to verify fuel quantity?
Visually check the fuel level during the preflight inspection and compare it to the gauge reading.
Fuel Systems: Fuel Gauges
What does a fuel pressure gauge indicate if installed?
The pressure in the fuel lines.
Fuel Systems: Fuel Gauges
Where can normal operating pressure be found?
In the AFM/POH or on the gauge via color coding.
Fuel Systems: Fuel Selectors
What is the purpose of the fuel selector valve?
It allows selection of fuel from various tanks.
Fuel Systems: Fuel Selectors
What are the common positions of a fuel selector valve?
- LEFT
- RIGHT
- BOTH
- OFF
Fuel Systems: Fuel Selectors
Why would you select LEFT or RIGHT on the fuel selector?
To feed fuel from a specific tank or balance fuel remaining in the tanks.
Fuel Systems: Fuel Selectors
What does the BOTH position do?
It feeds fuel from both tanks simultaneously.
Fuel Systems: Fuel Selectors
What should you avoid doing with fuel tanks?
Running a tank completely dry, as it can introduce air into the fuel system and cause vapor lock.
Fuel Systems: Fuel Selectors
What are fuel placards used for?
To indicate limitations such as “level flight only” or “both” for specific phases of flight, like landings and takeoffs.
Fuel Systems: Fuel Strainers, Sumps, and Drains
What is the purpose of a fuel strainer?
It removes moisture and sediments from the fuel system.
Fuel Systems: Fuel Strainers, Sumps, and Drains
What is a sump in the fuel system?
A low point where contaminants and water settle.
Fuel Systems: Fuel Strainers, Sumps, and Drains
What three components may be collocated in the fuel system?
- Sump
- Fuel strainer
- Fuel tank drains
Fuel Systems: Fuel Strainers, Sumps, and Drains
When should the fuel strainer be drained?
Before each flight.
Fuel Systems: Fuel Strainers, Sumps, and Drains
What should you check for when draining fuel samples?
Water and other contaminants.
Fuel Systems: Fuel Strainers, Sumps, and Drains
Why is water in the sump hazardous?
It can freeze in cold weather and block fuel lines or flow into the carburetor and stop the engine.
Fuel Systems: Fuel Strainers, Sumps, and Drains
What should be done if water is found in the sump?
Drain the fuel tanks until no evidence of water remains.
Fuel Systems: Fuel Strainers, Sumps, and Drains
What resource should you consult for specific fuel system procedures?
The Aircraft Flight Manual (AFM) or Pilot’s Operating Handbook (POH).
Fuel Systems: Fuel Grades
What does the grade of AVGAS indicate?
The octane or performance number representing the antiknock value or resistance to detonation.
Fuel Systems: Fuel Grades
How do higher and lower grades of AVGAS differ?
Higher grades withstand more pressure without detonating and are used in higher-compression engines; lower grades ignite at lower temperatures and are used in lower-compression engines.
Fuel Systems: Fuel Grades
What should you do if the proper fuel grade is unavailable?
Use the next higher grade, never a lower grade.
Fuel Systems: Fuel Grades
What are the common grades of AVGAS?
AVGAS 80, 100, and 100LL.
Fuel Systems: Fuel Grades
What does “LL” in AVGAS 100LL stand for?
Low lead content.
Fuel Systems: Fuel Grades
What is 100VLL, and how does it compare to 100LL?
100VLL is a reduced-lead AVGAS (19% less lead) that meets the same performance requirements as 100LL.
Fuel Systems: Fuel Grades
What are the classifications of turbine engine fuel?
- JET A
- JET A-1
- JET B
Fuel Systems: Fuel Grades
What is the main component of jet fuel?
Kerosene
Fuel Systems: Fuel Grades
What is the color of AVGAS 80, 100, and 100LL?
- AVGAS 80: Red
- AVGAS 100: Green
- AVGAS 100LL: Blue
Fuel Systems: Fuel Grades
How are AVGAS and jet fuel visually identified?
- AVGAS: White letters on a red background.
- Jet fuel: White letters on a black background.
Fuel Systems: Fuel Grades
Can automobile gas be used in aircraft engines?
Only if the aircraft has been modified with an FAA-issued Supplemental Type Certificate (STC).
Fuel Systems: Fuel Contamination
What are four common causes of fuel contamination?
- Inadequate preflight inspection.
- Using improperly filtered fuel.
- Storing aircraft with partially filled tanks.
- Lack of proper maintenance.
Fuel Systems: Fuel Contamination
Why should fuel be drained from the fuel strainer and tank sumps?
To check for dirt and water contaminants.
Fuel Systems: Fuel Contamination
How do you identify water in the fuel?
By its cloudy appearance or clear separation from colored fuel after settling.
Fuel Systems: Fuel Contamination
What should you do if contaminants are found in the first fuel sample?
Continue draining and sampling until no trace of contaminants remains.
Fuel Systems: Fuel Contamination
Where does water in fuel tanks typically settle?
At the bottom of the tank
Fuel Systems: Fuel Contamination
What is the best way to prevent moisture condensation in fuel tanks?
Fill the tanks after each flight or at the end of the day.
Fuel Systems: Fuel Contamination
Why is refueling from cans and drums discouraged?
It increases the risk of fuel contamination.
Fuel Systems: Fuel Contamination
Can a chamois filter ensure decontaminated fuel?
No, especially if the chamois is worn, wet, or imitation.
Fuel Systems: Fuel Contamination
When should fuel sumps be drained?
Before every flight during the preflight inspection.
Fuel Systems: Fuel Contamination
What should you do in remote areas if using unfiltered fuel sources?
Use a chamois and funnel cautiously but note they may not guarantee water-free fuel.
Fuel Systems: Fuel System Icing
What causes ice formation in the aircraft fuel system?
The presence of water in the fuel system, either undissolved or dissolved.
Fuel Systems: Fuel System Icing
What is entrained water?
Minute water particles suspended in the fuel due to mechanical agitation or temperature reduction.
Fuel Systems: Fuel System Icing
What is free water?
Water that collects at the bottom of fuel tanks, often introduced through refueling or settling of entrained water.
Fuel Systems: Fuel System Icing
What happens when free water freezes in fuel tanks or reservoirs?
It can render water drains useless and may later melt, causing engine malfunctions or stoppage.
Fuel Systems: Fuel System Icing
How does entrained water behave when frozen?
It forms ice crystals that may block fuel screens, strainers, and filters.
Fuel Systems: Fuel System Icing
What additional problems can frozen entrained water cause in carbureted engines?
It can lead to carburetor metering component icing, even under conditions not otherwise conducive to icing.
Fuel Systems: Fuel System Icing
How can free water be removed from fuel tanks?
Through sump drains specifically designed for that purpose.
Fuel Systems: Fuel System Icing
What is a sign of entrained water in the fuel?
Slight haziness in the fuel under extreme conditions.
Fuel Systems: Fuel System Icing
Why is it difficult to remove entrained water under field conditions?
Settling depends on temperature, quiescence, droplet size, and other factors.
Fuel Systems: Fuel System Icing
How can frozen free water in reservoirs be addressed?
By placing the aircraft in a warm hangar to thaw the water and draining all sumps and reservoirs before flight.
Fuel Systems: Fuel System Icing
What are three approved anti-icing additives for preventing fuel system icing?
- Hexylene glycol
- Certain methanol derivatives
- Ethylene glycol monomethyl ether (EGME)
Fuel Systems: Fuel System Icing
What is the maximum concentration of EGME for effective icing prevention?
0.15 percent by volume.
Fuel Systems: Fuel System Icing
What happens if the concentration of anti-icing additives is incorrect?
Too little or too much additive can result in marked deterioration of its effectiveness.
Fuel Systems: Fuel System Icing
Can anti-icing additives replace carburetor heat?
No, anti-icing additives are not a substitute for carburetor heat.
Fuel Systems: Fuel System Icing
What should pilots do when operating under atmospheric conditions conducive to icing?
Adhere to aircraft operating instructions involving the use of carburetor heat.
Refueling Procedures
What generates static electricity during refueling?
Friction from air passing over the aircraft and fuel flowing through the hose and nozzle.
Refueling Procedures
Why is grounding critical before refueling?
To prevent static electricity from igniting fuel fumes.
Refueling Procedures
What must be attached to the aircraft before removing the fuel cap?
A ground wire.
Refueling Procedures
What does bonding achieve during refueling?
Equalizes the static differential charge between the aircraft and refueling equipment.
Refueling Procedures
What is the sequence for grounding and bonding when using fuel drums?
- Drum to ground
- Ground to aircraft
- Drum to aircraft or nozzle to aircraft before removing the fuel cap
Refueling Procedures
What is the sequence for disonnecting grounding and bonding when using fuel drums?
Disconnect in reverse order.
1. Drum to aircraft or nozzle to aircraft before removing the fuel cap
2. Ground to aircraft
3. Drum to ground
Refueling Procedures
Why should plastic or nonconductive containers not be used during refueling?
They cannot bond or ground, increasing the risk of static discharge.
Refueling Procedures
What increases the static electricity charge during fuel transfer?
Fuel passing through a chamois filter.
Refueling Procedures
What components must be bonded during refueling?
- The nozzle
- Chamois filter
- Funnel
- Aircraft
Heating System
Why is it important to understand the heating system in an aircraft?
Different systems have unique repair, inspection, and operational criteria.
Heating System
What should always be referenced for specific heating system operations?
The aircraft operator’s manual.
Heating System: Fuel-Fired Heaters
What powers a fuel-fired heater?
The aircraft’s fuel system or a separate fuel tank.
Heating System: Fuel-Fired Heaters
What prevents fuel from flowing unless the fan is operational?
A built-in safety switch.
Heating System: Fuel-Fired Heaters
What is a potential risk of improperly maintained fuel-fired heaters?
Exposure to carbon monoxide and other combustion byproducts.
Heating System: Exhaust Heating Systems
How does an exhaust heating system provide cabin heat?
By routing air over exhaust pipes to transfer heat into the cabin.
Heating System: Exhaust Heating Systems
What are risks associated with defective exhaust heating systems?
Carbon monoxide poisoning, reduced engine performance, and fire hazards.
Heating System: Combustion Heater Systems
How does a combustion heater work?
Fuel burns in a sealed chamber, and air passing over the chamber is heated and ducted to the cabin.
Heating System: Combustion Heater Systems
What ensures safety in combustion heaters?
Overheat switches shut off fuel if a malfunction occurs.
Heating System: Combustion Heater Systems
Why is carbon monoxide poisoning less likely with combustion heaters?
Higher external air pressure prevents leaks into the cabin, venting carbon monoxide outside the aircraft.
Heating System: Bleed Air Heating Systems
Which aircraft use bleed air heating systems?
Turbine-engine aircraft.
Heating System: Bleed Air Heating Systems
How is air temperature controlled in bleed air systems?
Hot compressor bleed air is mixed with cooler ambient or re-circulated air.
Heating System: Bleed Air Heating Systems
What safety features are included in bleed air systems?
Temperature sensors, check valves, and engine sensors to prevent excessive heat or loss of compressor bleed air.
Aircraft Electrical System
What voltage do most small aircraft electrical systems use?
Either 14 volts or 28 volts DC.
Aircraft Electrical System
What are the eight primary components of an aircraft electrical system?
- Alternator/generator
- Battery
- Master/battery switch
- Alternator/generator switch
- Bus bar, fuses, and circuit breakers
- Voltage regulator
- Ammeter/loadmeter
- Associated wiring
Aircraft Electrical System
What does the alternator/generator do?
Supplies current to the electrical system and charges the battery.
Aircraft Electrical System
What is the role of the aircraft battery?
Provides power for engine starting and acts as a backup if the alternator/generator fails.
Aircraft Electrical System
Why are alternators preferred over generators?
They produce sufficient current at lower engine speeds and provide a more constant output.
Aircraft Electrical System
What is a GPU, and when is it used?
A ground power unit provides external electrical energy for starting, especially useful in cold weather.
Aircraft Electrical System
What does the master switch control?
It turns on/off the electrical system except for the ignition.
Aircraft Electrical System
What does the alternator switch do?
Excludes the alternator from the electrical system in case of alternator failure.
Aircraft Electrical System
What is a bus bar?
A terminal that connects the electrical system to various components, simplifying wiring.
Aircraft Electrical System
What is the purpose of fuses and circuit breakers?
To protect the electrical system from overload. Circuit breakers can be reset, while fuses must be replaced.
Aircraft Electrical System
What does an ammeter indicate?
The performance of the electrical system, showing battery charging/discharging and alternator/generator output.
Aircraft Electrical System
What does a loadmeter measure?
The load placed on the alternator/generator, showing the percentage of generating capacity in use.
Aircraft Electrical System
What is the role of a voltage regulator?
Stabilizes generator/alternator output and controls the rate of battery charging.
Aircraft Electrical System
What should the generator/alternator voltage be compared to the battery voltage?
Slightly higher to keep the battery charged (e.g., 14 volts for a 12-volt battery system)
Aircraft Electrical System
What are thirteen peices of equipment that commonly uses the electrical system for their source of energy includes?
- Position lights
- Anticollision lights
- Landing lights
- Taxi lights
- Interior cabin lights
- Instrument lights
- Radio equipment
- Turn indicator
- Fuel gauges
- Electric fuel pump
- Stall warning system
- Pitot heat
- Starting motor
Hydraulic Systems
What are three common applications of hydraulic systems in small aircraft?
- Wheel brakes
- Retractable landing gear
- Constant-speed propellers
Hydraulic Systems
What are three common applications of hydraulic systems in large aircraft?
- Flight control surfaces
- Wing flaps
- Spoilers
Hydraulic Systems
What are the six basic components of a hydraulic system?
- Reservoir
- Pump (hand, electric, or engine-driven)
- Filter
- Selector valve
- Relief valve
- Actuator or servo
Hydraulic Systems
What does a servo do in a hydraulic system?
Converts fluid power into mechanical work to move an aircraft system or control surface.
Hydraulic Systems
What type of hydraulic fluid is commonly used in small aircraft?
Mineral-based hydraulic fluid, a kerosene-like petroleum product with additives to inhibit foaming and corrosion.
Hydraulic Systems: Landing Gear
What are the primary types of landing gear configurations?
Conventional landing gear (tailwheel) and tricycle landing gear (nosewheel).
Hydraulic Systems: Landing Gear
What are three advantages of tricycle landing gear?
- Allows more forceful braking
- Better forward visibility
- Greater directional stability, preventing ground looping
Hydraulic Systems: Landing Gear
How is a steerable nosewheel controlled?
Linked to the rudder pedals via cables or rods.
Hydraulic Systems: Landing Gear
What is the main disadvantage of tailwheel landing gear?
More difficult directional control due to the center of gravity (CG) being behind the main wheels, making it prone to ground looping.
Hydraulic Systems: Landing Gear
What are the two main types of landing gear based on retraction?
- Fixed landing gear: Always extended; simple and low maintenance.
- Retractable landing gear: Stows inside the structure for improved aerodynamics.
Hydraulic Systems: Brakes
Where are airplane brakes located, and how are they operated?
Located on the main wheels; operated by hand controls or foot pedals.
Hydraulic Systems: Brakes
What is differential braking, and why is it used?
Independent operation of left and right brakes, used for tight turns and supplementing nosewheel or tailwheel steering during ground operations
Pressurized Aircraft
Why are aircraft flown at high altitudes?
To improve fuel efficiency and avoid bad weather and turbulence.
Pressurized Aircraft
How is pressurization achieved in turbine- and piston-powered aircraft?
- Turbine-powered: Bleed air from the engine compressor section.
- Piston-powered: Air from the engine turbocharger via a sonic venturi (flow limiter).
Pressurized Aircraft
What is the typical cabin pressure altitude maintained in pressurized aircraft?
Approximately 8,000 feet at maximum cruising altitude.
Pressurized Aircraft
What is differential pressure?
The difference between cabin pressure and ambient atmospheric pressure.
Pressurized Aircraft
What are the primary functions of the pressurization control system?
Cabin pressure regulation, pressure relief, vacuum relief, and cabin pressure dumping.
Pressurized Aircraft
What does the cabin pressure regulator do?
Controls cabin pressure and prevents it from exceeding maximum differential pressure.
Pressurized Aircraft
What is the purpose of the outflow valve?
Regulates air exit to maintain consistent cabin pressure.
Pressurized Aircraft
What are the functions of the safety valve?
Acts as a pressure relief, vacuum relief, and dump valve.
Pressurized Aircraft
What instruments monitor pressurization?
Cabin differential pressure gauge, cabin altimeter, and cabin rate-of-climb gauge.
Pressurized Aircraft
What is explosive decompression?
A rapid pressure change faster than the lungs can decompress, occurring in less than 0.5 seconds.
Pressurized Aircraft
What is rapid decompression?
A pressure change where the lungs decompress faster than the cabin.
Pressurized Aircraft
What happens during decompression?
Noise, fog, and potential lung damage; reduction in useful consciousness due to rapid oxygen loss.
Pressurized Aircraft
What is hypoxia?
A state of oxygen deficiency in the body, posing a primary danger during decompression.
Pressurized Aircraft
What precautions should be taken at high altitudes?
Use oxygen masks and ensure proper oxygen regulator settings (e.g., 100% oxygen for demand systems).
Pressurized Aircraft
What is decompression sickness?
Formation of nitrogen bubbles in the body due to pressure drops, causing adverse effects.
Pressurized Aircraft
What structural risks are associated with decompression?
Individuals may be blown out of the aircraft near openings; seatbelts and harnesses are crucial.
Pressurized Aircraft
What should pilots do after decompression?
Initiate a rapid descent to lower altitudes to minimize hypoxia and decompression sickness risks.
Pressurized Aircraft
What safety features are included in pressurized aircraft?
Automatic visual and aural warning systems for decompression alerts.
Aircraft Oxygen Systems
When is supplemental oxygen required for flight crews?
- After 30 minutes at cabin altitudes between 12,500 and 14,000 feet.
- Immediately above 14,000 feet.
Aircraft Oxygen Systems
When must all passengers have access to supplemental oxygen?
Above 15,000 feet cabin pressure altitude.
Aircraft Oxygen Systems
At what altitudes is oxygen recommended for enhanced safety?
Above 10,000 feet during the day and above 5,000 feet at night.
Aircraft Oxygen Systems
What is the typical pressure range for stored aviation oxygen?
1,800 to 2,200 psi
Aircraft Oxygen Systems
What type of oxygen should be used in aircraft systems?
Aviator’s Breathing Oxygen meeting SAE AS8010 standards.
Aircraft Oxygen Systems
How does temperature affect oxygen cylinder pressure?
Pressure decreases with lower temperatures, which may mimic depletion.
Aircraft Oxygen Systems
What is a cannula, and where is it suitable?
A plastic tubing system that fits under the nose; effective below 18,000 feet.
Aircraft Oxygen Systems
What is a diluter-demand system, and its altitude limit?
Supplies oxygen when inhaled, mixing with cabin air or 100% oxygen; usable up to 40,000 feet.
Aircraft Oxygen Systems
What is a pressure-demand system, and its altitude limit?
Supplies pressurized oxygen to the mask; safe above 40,000 feet.
Aircraft Oxygen Systems
What is a continuous-flow system, and who typically uses it?
Provides constant oxygen flow, usually for passengers with reservoir bags.
Aircraft Oxygen Systems
What is an electrical pulse-demand system?
Delivers oxygen only during inhalation, reducing oxygen waste by 50–85%.
Aircraft Oxygen Systems
What precautions are necessary for oxygen masks?
Ensure compatibility with the oxygen system. Clean regularly with mild soap and disinfect.
Aircraft Oxygen Systems
What risks are associated with oil and grease near oxygen systems?
These materials can ignite spontaneously under high oxygen pressure.
Aircraft Oxygen Systems
What is a pulse oximeter, and how is it used?
A device measuring blood oxygen saturation and heart rate, useful for monitoring hypoxia risks.
Aircraft Oxygen Systems
What are the risks of using oxygen improperly?
Increased fire risk; materials that are fireproof in air may ignite in oxygen.
Aircraft Oxygen Systems
What preflight inspections should be conducted for oxygen systems?
Check oxygen supply, mask condition, tubing, regulator settings, and ensure all components are functioning.
Aircraft Oxygen Systems
Why should oxygen servicing be performed outside the hangar?
To minimize fire risks from ignition sources.
Aircraft Oxygen Systems
What is the procedure for cleaning hands and tools before working with oxygen systems?
Ensure all are free of oil, grease, and dirt to prevent ignition.
Aircraft Oxygen Systems
What should pilots do during an oxygen emergency?
Don masks immediately, verify system functionality, and descend to a safer altitude if needed.
Aircraft Oxygen Systems
What should not be done during oxygen system servicing?
Avoid servicing during fueling operations or while passengers are on board.
Aircraft Oxygen Systems
What is hypoxia?
A state of oxygen deficiency in the body sufficient to impair functions of the brain and other organs.
Anti-Ice and Deice Systems
What is the difference between anti-icing and deicing systems?
- Anti-icing prevents ice formation.
- Deicing removes ice once it has formed.
Anti-Ice and Deice Systems
What six parts of an aircraft are typically protected by anti-ice and deice systems?
Leading edges of wings and tail surfaces
Pitot and static ports
Fuel tank vents
Stall warning devices
Windshields
Propeller blades
Anti-Ice and Deice Systems
What should non-certified aircraft do if they encounter icing conditions?
Exit icing conditions immediately.
Anti-Ice and Deice Systems: Airfoil Systems
How do inflatable deicing boots work?
Engine-driven pneumatic pumps inflate rubber boots on the leading edge to crack and remove ice.
Anti-Ice and Deice Systems: Airfoil Systems
What is thermal anti-ice, and how does it work?
Heat (often from engine bleed air) is applied to leading edge surfaces to prevent ice formation.
Anti-Ice and Deice Systems: Airfoil Systems
What is a “weeping wing”?
A system that pumps antifreeze solution through small holes in the leading edge to prevent or break ice.
Anti-Ice and Deice Systems: Windscreen Systems
What are the two main types of windscreen anti-icing systems?
Alcohol spray systems and electrically heated windscreens.
Anti-Ice and Deice Systems: Windscreen Systems
Why should heated windscreens not be used during ground operations?
They can overheat and damage the windscreen.
Anti-Ice and Deice Systems: Propeller Systems
How is alcohol used for propeller anti-icing?
Discharged from nozzles at the blade root and spread by centrifugal force along the leading edge.
Anti-Ice and Deice Systems: Propeller Systems
What are propeller boots, and how do they function?
Electrically heated elements embedded in the propeller to prevent ice formation.
Anti-Ice and Deice Systems: Propeller Systems
How can the operation of the propeller anti-ice system be monitored?
By checking the prop anti-ice ammeter.
Anti-Ice and Deice Systems: Additional Systems
What other three components are protected by electrical heating elements?
- Pitot and static ports
- Fuel vents
- Stall warning sensors
Anti-Ice and Deice Systems: Additional Systems
Why are operational checks of anti-ice and deice systems important before flight?
To ensure proper functioning before encountering icing conditions.
Anti-Ice and Deice Systems: Best Practices
Can anti-icing and deicing systems sustain prolonged flight in icing conditions?
No, they are designed for temporary protection, and immediate action should be taken to exit icing conditions.
Anti-Ice and Deice Systems: Best Practices
What is the myth of ice “bridging” with deicing boots?
It was believed that early activation expanded rather than removed ice. Modern boots do not cause this issue, and activation should occur as soon as ice is detected.
