Aircraft Systems Related to IFR Operations Flashcards
What type of engine does your aircraft have?
Propeller?
Engine: Textron Lycoming IO-360-L2A, normally aspirated, direct-drive, air-cooled, horizontally opposed, fuel-injected, 4-cylinder engine with 360 cubic inches of displacement, producing 180 BHP at 2700 RPM.
Propeller: McCauley Propeller Systems, fixed pitch, 76 inches in diameter.
Ref: POH Section 1, Descriptive Data
What does “normally aspirated” mean?
The engine relies on atmospheric pressure to draw air into the cylinders, without the use of turbochargers or superchargers. This limits performance at higher altitudes due to reduced air density.
Ref: General engine
knowledge, POH Section 1
What does the mixture do?
The mixture control adjusts the ratio of fuel to air entering the engine. Leaning reduces fuel for high-altitude or cruise operations, while enriching adds fuel for takeoff, climb, and cold conditions. Proper adjustment ensures engine efficiency and prevents fouling or detonation.
Ref: POH Section 1
What is the fuel capacity of the aircraft?
Usable? Unusable?
Total Fuel Capacity: 56 gallons (28 gallons per tank).
Usable Fuel: 53 gallons.
Unusable Fuel: 3 gallons.
Ref: POH Section 1, Fuel
What type of fuel can you use?
What color is it?
What color are other fuel types?
Approved Fuel: 100LL (blue) or 100 (green).
Other Fuel Types:
Jet A: Clear or straw-colored.
Auto gas (not approved for this aircraft): Clear.
Ref: POH Section 1, Fuel
Why do you sample fuel before every flight?
To check for contamination (water, debris) and verify the correct fuel grade and color. Ensures safety and engine performance.
Ref: POH Section 1, Preflight Procedures
What are the two systems that add fuel to an engine?
What system does your aircraft have?
Two Systems: Carbureted and fuel-injected.
Cessna 172S System: Fuel-injected system for precise fuel delivery, reducing icing risks.
Ref: POH Section 1, Engine
What does a carburetor do?
Mixes fuel with air to create a combustible mixture for the engine. It operates using venturi suction to atomize fuel. Not applicable to the fuel-injected Cessna 172S.
Ref: General knowledge
What is carb ice?
How is it recognized?
When can it take place?
Definition: Ice formation in the carburetor due to rapid cooling of air during fuel vaporization.
Recognition: Loss of RPM (fixed pitch) or manifold pressure (constant speed).
Conditions: Common in high humidity, temperatures between 20°F and 70°F.
Ref: General knowledge (Not applicable to 172S due to fuel injection).
What is induction icing?
Are fuel-injected systems susceptible to it?
Ice forms in the air intake system, reducing airflow to the engine. Fuel-injected systems are less susceptible but not immune, particularly in freezing rain or severe conditions.
Ref: General knowledge
Does your aircraft have any anti-icing or deicing equipment?
Anti-icing: Pitot heat, windshield defrost.
Deicing: Not equipped with airframe deicing systems.
Ref: POH Section 7, Systems Description
What are some limitations to anti-icing and deicing equipment?
Limited effectiveness in severe icing conditions.
May not protect all surfaces (e.g., wings).
Relying solely on anti-icing can lead to dangerous situations in known icing.
Ref: General systems knowledge
Explain the electrical system.
28-volt DC system powered by a 60-amp alternator.
24-volt main battery and 24-volt standby battery for essential systems during alternator failure.
Circuit breakers protect the system from overload.
Ref: POH Section 7, Electrical System
What indications will be displayed during an alternator failure?
Alternator annunciator light illuminates.
Voltage indication drops on the electrical meter.
Essential systems may lose power if the battery depletes.
Ref: POH Section 3, Emergency Procedures
What instruments operate from the pitot-static system?
Airspeed Indicator: Requires both pitot and static pressures.
Altimeter: Uses static pressure to measure altitude.
Vertical Speed Indicator (VSI): Uses static pressure changes to indicate the rate of climb or descent.
Ref: PHAK Chapter 7
Which instruments are connected to the pitot tube?
The static port?
Pitot Tube: Provides ram air pressure to the airspeed indicator.
Static Port: Supplies static pressure to the altimeter, VSI, and airspeed indicator.
Ref: PHAK Chapter 7
How does an altimeter work?
The altimeter uses static pressure to compare the ambient air pressure to a sealed aneroid wafer calibrated to standard atmospheric pressure (29.92 inHg). As the aircraft climbs or descends, changes in static pressure cause the wafers to expand or contract, moving the hands on the altimeter display.
Ref: PHAK Chapter 7
What is the maximum allowable error for an altimeter when used for IFR flight?
Is this recommended or mandated?
The altimeter must be within 75 feet of the field elevation when set to the local altimeter setting. This is a mandated requirement for IFR flight to ensure altitude accuracy.
Ref: FAR 91.411, AIM 7-2-3
Define the following types of altitude:
Indicated Altitude: Read directly from the altimeter when set to the local altimeter setting.
Pressure Altitude: Altitude above the standard datum plane (29.92 inHg). Used for performance calculations.
True Altitude: Actual altitude above mean sea level (MSL). Airports and terrain elevations are expressed in true altitude.
Density Altitude: Pressure altitude corrected for nonstandard temperature. Indicates aircraft performance.
Absolute Altitude: Height above ground level (AGL).
Ref: PHAK Chapter 7
How does the airspeed indicator work?
The airspeed indicator measures the difference between ram air pressure from the pitot tube and static pressure from the static port. The diaphragm inside the instrument expands or contracts as the difference changes, moving the needle to indicate airspeed.
Ref: PHAK Chapter 7
Define the following types of airspeed:
Indicated Airspeed (IAS): Airspeed read directly from the instrument, uncorrected for errors.
Calibrated Airspeed (CAS): IAS corrected for instrument and position errors.
Equivalent Airspeed (EAS): CAS corrected for compressibility effects at high speeds.
True Airspeed (TAS): EAS corrected for altitude and temperature. Represents actual speed through the air.
Groundspeed (GS): TAS adjusted for wind, representing the speed over the ground.
Ref: PHAK Chapter 7
How does the vertical speed indicator (VSI) work?
The VSI measures the rate of change in static pressure. A calibrated leak allows static pressure to change inside the diaphragm and casing at different rates. This difference causes the needle to show climb or descent rates in feet per minute (FPM).
Ref: PHAK Chapter 7
What are some limitations of the VSI?
Lag: A delay of 6-9 seconds to display accurate climb/descent rates due to the calibrated leak.
Errors: Rapid pressure changes (e.g., turbulence) can cause inaccurate readings.
Ref: PHAK Chapter 7
What instruments are affected if the static port freezes over?
What are the instrument errors?
Affected Instruments: Altimeter, VSI, airspeed indicator.
Errors:
Altimeter: Will freeze at the last altitude.
VSI: Will read zero regardless of climb or descent.
Airspeed Indicator: Reads incorrectly—higher than actual during descent and lower during climb.
Ref: PHAK Chapter 7