Chapter 1-7 Aviation Fundamentals - Vocabulary Flashcards

Key aviation terms from the lecture notes, focusing on PIC, certifications, aircraft categories/classes, lift/drag, airfoils, flight controls, and common flight concepts.

PIC (Pilot in Command)

The pilot legally designated with ultimate authority and final responsibility for the safe operation of an aircraft during flight. This includes all decisions and actions; when flying solo, the pilot is the PIC; with an instructor, the instructor is the PIC during training.

Airman Certificate Category

The broad classification of operating privileges granted by a pilot certificate, such as 'Airplane', 'Rotorcraft', 'Glider', or 'Lighter-than-air'. This should not be confused with the 'Aircraft Category' (e.g., normal, transport) or 'Aircraft Class' (e.g., single-engine land).

Aircraft Category (FAA)

Designations established by the FAA to classify aircraft based on intended use or operating limitations, which in turn determines their airworthiness requirements and allowed operations. Common examples include 'Normal', 'Utility', 'Transport', 'Aerobatic', 'Restricted', and 'Experimental'.

Aircraft Class

A more specific subcategory within an Aircraft Category, further defining the aircraft's characteristics for certification purposes. Examples include 'Single-Engine Land', 'Multi-Engine Land', 'Single-Engine Sea', and 'Multi-Engine Sea'. The Cessna Skyhawk, for instance, falls under 'Single-Engine Land'.

Single-Engine Land (SEL)

An airplane classification for aircraft equipped with a single engine and designed with wheels for operation from land-based runways.

Multi-Engine Land (MEL)

An airplane classification for aircraft that feature two or more engines and are equipped with wheels for operation from land-based runways.

Part 121 Air Carrier

Refers to the Federal Aviation Regulations (FAR Part 121) governing commercial air carrier operations, typically for major airlines. This regulation generally applies to transport-category aircraft with 19 or more passenger seats and a Maximum Takeoff Weight (MTOW) exceeding 19,000 pounds, imposing stringent safety and operational requirements.

Cessna Skyhawk 172

A widely used and recognized model of training aircraft, often referenced as a standard example of an airplane that falls under the normal utility category due to its design and operational capabilities.

Four Forces of Flight

The four fundamental aerodynamic and gravitational forces that continuously act upon an aircraft during flight: Lift (the upward force generated by the wings), Weight (the downward force due to gravity), Thrust (the forward force generated by the engine), and Drag (the rearward force opposing motion). For stable flight, these forces must be in balance or controlled imbalance.

Lift

The upward aerodynamic force that opposes the weight of an aircraft and is essential for flight. It is primarily generated by the airflow over and under the wing (airfoil), a process explained by both Bernoulli's Principle and Newton's Third Law of Motion.

Weight

The cumulative downward force exerted by gravity on the aircraft, including its structure, fuel, payload, and occupants. This force is measured in pounds in U.S. customary units and is continuously opposed by lift during flight.

Thrust

The forward-acting force produced by the aircraft's engine and propeller (or jet propulsion) that overcomes drag and propels the aircraft through the air, allowing for acceleration and sustained flight.

Drag

The rearward-acting force that opposes an aircraft's forward motion through the air. It is a necessary consequence of generating lift and moving through the air, and consists of two main components: parasitic drag and induced drag.

Parasitic Drag

The portion of total drag caused by non-lift-producing components of the aircraft as it moves through the air. It increases with airspeed and includes form drag (due to shape), skin friction drag (due to surface roughness), and interference drag (from airflow interaction between components).

Form Drag

A component of parasitic drag caused by the shape of the aircraft and its various components (e.g., fuselage, landing gear, antennas) disrupting the smooth flow of air, creating pressure differentials and resistance.

Skin Friction Drag

A component of parasitic drag resulting from the friction between the air flowing over the aircraft's surfaces and the microscopic roughness of the airframe, even on highly polished surfaces.

Interference Drag

A component of parasitic drag that arises from the aerodynamic interaction of airflow between different parts of the aircraft where they join, such as the wing-fuselage junctions or where struts connect to the main structure.

Induced Drag

The portion of drag that is an unavoidable consequence and byproduct of generating lift. It is created by the wingtip vortices and the downward deflection of air; induced drag is inversely proportional to airspeed and increases significantly at higher angles of attack.

Angle of Attack (AOA)

The acute angle measured between the chord line of an airfoil (wing) and the direction of the relative wind. AOA is a critical factor in determining the amount of lift and induced drag produced by the wing.

Airfoil

Any surface, such as a wing or propeller blade, designed to produce a useful aerodynamic force (primarily lift) when air flows over and around it. Airfoils typically have a specific cross-sectional shape engineered for this purpose.

Leading Edge

The front-most part of an airfoil (wing), propeller blade, or other aerodynamic surface that first contacts the oncoming airflow.

Camber

The characteristic curvature or arch of an airfoil's upper and lower surfaces. The degree and shape of camber significantly influence the airfoil's aerodynamic properties, particularly its lift generation capabilities.

Upper Camber

The curvature of the top surface of an airfoil, which is generally more pronounced than the lower camber. This greater curvature typically forces air to travel a longer distance over the top, contributing significantly to the generation of lift according to Bernoulli's Principle.

Lower Camber

The curvature of the bottom surface of an airfoil. While often less curved than the upper camber, its shape also plays a role in directing airflow and contributing to lift, especially at higher angles of attack.

Trailing Edge

The rear-most part of an airfoil, propeller blade, or other aerodynamic surface where the airflow separates and rejoins after passing over the upper and lower surfaces.

Cord Line (Chord)

An imaginary straight line extending from the leading edge to the trailing edge of an airfoil. This line serves as a reference for measuring the angle of attack and analyzing airfoil characteristics.

Wingspan

The linear distance measured from one wingtip to the opposite wingtip of an aircraft, often a key dimension in determining an aircraft's aerodynamic efficiency and performance.

Aspect Ratio

A measure of a wing's shape, calculated by dividing the wingspan by the mean (average) chord of the wing (\text{Wingspan}^2 / \text{Wing Area}). Wings with a higher aspect ratio are typically long and slender, generally indicating better aerodynamic efficiency and gliding performance.

Planform Area

The total surface area of a wing as seen from above. The Cessna Skyhawk, for example, is described as having a wing planform that is a mix between rectangular and tapered, influencing its stall characteristics and handling.

Stall

An aerodynamic condition where there is a sudden and significant loss of lift due to the airflow separating from the wing's upper surface, typically caused by exceeding the critical angle of attack. For the Skyhawk, initial stall often begins at the wing root before progressing outwards.

Stall Recovery

The corrective actions taken by a pilot to exit a stall, primarily involving immediately reducing the angle of attack (by pitching down) and adding power to regain sufficient airspeed and airflow over the wings to restore lift.

Wake Turbulence

Turbulent air that is shed behind an aircraft, primarily from the wingtips as powerful, rotating vortices (wake vortices). These vortices are particularly strong behind heavier, slower aircraft and pose a significant hazard to following lighter aircraft.

Ground Effect

An aerodynamic phenomenon that occurs when an aircraft operates very close to the ground (typically within one wingspan distance), resulting in increased lift and significantly reduced induced drag. This effect is often utilized in soft-field takeoffs to achieve liftoff at lower airspeeds and reduce runway distance.

Soft-Field Takeoff

A specific takeoff technique designed for operations from soft, rough, or extremely short runways (e.g., grass, gravel). It involves leveraging ground effect by keeping the aircraft in ground effect after initial liftoff to accelerate to a safe climb speed with reduced drag.

Left Turning Tendencies

A collective term describing the various aerodynamic and mechanical forces that cause a single-engine propeller aircraft to yaw or turn to the left, particularly during high-power, low-airspeed conditions. These include P-factor, torque, spiraling slipstream, and gyroscopic precession.

P-Factor

Also known as asymmetric thrust, P-factor is one of the left-turning tendencies caused by the propeller blades' angle of attack relative to the relative wind. At high angles of attack (e.g., climb), the downward-moving blade has a greater angle of attack and produces more thrust than the upward-moving blade, resulting in a left yawing moment that requires right rudder input to counteract.

Torque

One of the left-turning tendencies where the engine's rotation of the propeller in one direction (e.g., clockwise) creates an equal and opposite reactive force (torque) that tries to rotate the aircraft's fuselage in the opposite direction (e.g., counter-clockwise or left yaw). This effect is most noticeable during high engine power settings and is countered with rudder input.

Spiraling Slipstream

One of the left-turning tendencies caused by the propeller's slipstream (propwash) spiraling rearward around the fuselage. This spiraling air strikes the left side of the vertical stabilizer and rudder, creating a pressure differential that pushes the tail to the right and causes a left yaw, which requires right rudder input to correct.

Gyroscopic Precession

One of the left-turning tendencies, particularly relevant for tailwheel aircraft during takeoff. A spinning propeller acts like a gyroscope; a force applied to its rim (e.g., tail hitting the ground) will be felt 90 degrees in the direction of rotation. This can cause a yawing moment, which must be countered with timely rudder input.

Propeller as a Wing

Describes how a propeller blade functions aerodynamically much like an aircraft wing, generating 'lift' in the form of thrust by moving through the air. Each section of the propeller blade is an airfoil, producing aerodynamic forces that contribute to the aircraft's propulsion and can also introduce torque effects.

Wake Turbulence Avoidance

Procedures pilots follow to prevent encountering hazardous wake turbulence, especially when operating near heavier aircraft. This typically involves delaying takeoff or landing behind a heavier aircraft, taking off/landing before its rotation point, or remaining above its flight path.

Ground Effect Bubble

A less technical term describing the cushion of air (the region of increased lift and reduced induced drag) that forms beneath an aircraft's wings when it is flying very close to the ground, typically within one wingspan of the surface.

Fuel Tank Venting

A system on aircraft like the Skyhawk (which often use gravity-fed fuel systems) to ensure proper fuel flow by allowing air to enter the fuel tanks as fuel is consumed. This prevents a vacuum from forming and ensures consistent pressure for fuel delivery to the engine.

Rudder Trim

A flight control trim tab or system that allows the pilot to adjust the aerodynamic forces on the rudder to counteract persistent yawing tendencies (such as left-turning tendencies) without needing to apply continuous rudder pedal pressure. Sometimes, the trim tab is permanently 'bent' for initial aerodynamic optimization.

Elevator Trim

A flight control trim tab or system that allows the pilot to relieve continuous control pressure on the elevator. It is used to maintain a desired pitch attitude, especially during changes in airspeed, power settings, or aircraft configuration, reducing pilot workload.

Trim

An adjustable aerodynamic device or system (often a trim wheel or trim tab) that allows the pilot to neutralize control forces and hold a desired aircraft attitude (pitch, roll, or yaw) without requiring constant manual input on the primary flight controls, thereby reducing pilot fatigue.

Aileron

Primary flight control surfaces located on the outboard trailing edges of the wings. Ailerons move differentially (one up, one down) to control the aircraft's roll (banking) motion around its longitudinal axis.

Elevator

The primary flight control surface located on the horizontal stabilizer at the tail of the aircraft. The elevator controls the aircraft's pitch (nose up or down) motion around its lateral axis.

Rudder

The primary flight control surface located on the vertical stabilizer at the tail of the aircraft. The rudder controls the aircraft's yaw (nose left or right) motion around its vertical axis.

Axis of Flight – Longitudinal

An imaginary straight line extending from the nose to the tail of the aircraft, passing through its center of gravity. Movement around this axis is known as roll and is controlled by the ailerons.

Axis of Flight – Lateral

An imaginary straight line extending from wingtip to wingtip, passing through the aircraft's center of gravity. Movement around this axis is known as pitch and is controlled by the elevator.

Axis of Flight – Vertical

An imaginary straight line extending vertically through the aircraft's center of gravity, from its top to its bottom. Movement around this axis is known as yaw and is controlled by the rudder.

Bernoulli's Principle

A fundamental principle of fluid dynamics stating that an increase in the speed of a fluid occurs simultaneously with a decrease in its static pressure. In aviation, this principle explains a significant portion of lift generation: as air flows faster over the curved upper surface of an airfoil, the pressure above the wing decreases, creating an upward force.

Newton's Third Law

A fundamental law of physics stating that for every action, there is an equal and opposite reaction. In aviation, this means that as the airfoil pushes air downwards, the air pushes back on the airfoil with an equal and opposite upward force, contributing significantly to the generation of lift.