TOPIC 5 - AIRCRAFT PERFORMANCE

Takeoff performance

focuses on how far an airplane must travel on the ground and in the air before it is safely airborne.

Takeoff performance

It involves acceleration from rest to liftoff, and it's especially critical when considering engine failure or obstacles ahead.

Ground Roll

Airborne Distance

2 phases of takeoff

Ground Roll

Distance the airplane travels on the runway before it lifts off.

Ground Roll

Starts at zero speed when brakes are released and engines go full power.

Airborne Distance

After liftoff, the airplane continues to fly low over the

ground until it clears a specific obstacle (usually 35 ft for commercial aircraft, 50 ft for military).

Vstall

Vmcg

Vmca

V1

VR

Vmu

VLO

3 key kpeeds during ground roll

Vstall (Stall Speed)

The minimum speed where the wings can start generating enough lift. Below this, flight is impossible.

Vmcg (Minimum Control Speed on Ground)

For multiengine planes, this is the lowest speed where the pilot can still control the airplane on the ground if one engine fails.

Vmca (Minimum Control Speed in Air)

Similar to Vmcg but applies when the airplane is off the ground.

V1 (Decision Speed)

Critical speed where the pilot must decide: If engine fails before V1, abort the takeoff and if engine fails after V1, continue the takeoff—it's still safe.

VR (Rotation Speed)

Speed where the pilot pulls the nose up (rotates the

aircraft) to begin liftoff.

Vmu (Minimum Unstick Speed)

The lowest speed the airplane can actually lift off, assuming maximum safe rotation.

VLO (Liftoff Speed)

The actual speed at which the airplane leaves the ground.

Slightly higher than Vmu for safety and comfort.

Landing Performance

is the study of how much distance an aircraft requires to safely land, from the moment it

clears an obstacle (typically 50 feet above the ground) to the point where it comes to a complete stop on the runway.

TOTAL LANDING DISTANCE

is the entire distance needed to land safely starting from a point 50 feet above the runway down to a full stop on the ground.

APPROACH DISTANCE

is the segment where the aircraft descends from a 50-foot obstacle height toward the runway on a shallow glide path.

FLARE DISTANCE

is the part of the landing where the aircraft transitions from a steady descent to a level attitude just before touchdown.

GROUND ROLL

is the distance an aircraft travels on the ground after touchdown until it comes to a complete stop.

RANGE

refers to the maximum distance an airplane can travel on a single trip without needing to refuel.

RANGE

This distance is typically measured from takeoff to landing, considering factors such as fuel capacity, weight, aerodynamics, and environmental conditions.

Propeller

This aircraft excel in short-range, regional flights with better fuel economy at lower speeds

jet

aircraft built for high-speed, long-distance travel.

Endurance

is the maximum time an aircraft can remain in steady flight using a given amount of fuel.

cruise

During _____, endurance depends on how efficiently the aircraft uses fuel over time and not how far it travels.

low speeds, high L/D ratio

Max endurance happens at minimum fuel flow, usually at ____ and ______.

T

[T or F] Propeller aircraft are typically optimized for endurance over jets.

Jet Endurance Formula

is designed for aircraft flying at higher speeds and altitudes, where thrust is the dominant factor in fuel burn.

Wind Engineering

a vital field in aerospace that studies the relationship between atmospheric winds and aircraft performance.

Wind

defined as the movement of air relative to the Earth's surface, significantly influences aircraft operations during all phases of flight; takeoff, landing, and cruise.

steady, turbulent

Wind is characterized by its speed and direction, which can be __________ or _____

Headwind

Wind blowing opposite to the aircraft's direction of travel, increasing lift and reducing ground speed during takeoff and landing.

Tailwind

Wind blowing in the same direction as the aircraft, decreasing lift and increasing ground speed, which can extend runway requirements.

Crosswind

Wind perpendicular to the aircraft's path, requiring precise control inputs to maintain directional stability, particularly during landing.

Wind Shear

A sudden change in wind speed or direction over a short distance, posing significant hazards during critical flight phases.

Headwinds

[During Takeoff and Landing] help airplanes take off and land in a shorter distance.

Tailwinds

[During Takeoff and Landing] make takeoff and landing longer and riskier.

Crosswinds

[During Takeoff and Landing] require pilots to adjust controls to stay straight on the runway.

Wind Shear

[During Takeoff and Landing] can cause sudden speed changes, making flying harder

Headwinds

[During Cruise Flight] slow the plane down, increasing fuel use.

Tailwinds

[During Cruise Flight] speed the plane up, saving fuel.

Headwind

improves takeoff and landing by increasing airflow over the wings, allowing lift at lower ground speeds.

Headwind

This shortens takeoff and landing distances and enhances control, making headwinds beneficial for safe and efficient aircraft operations.

Lower Groundspeed at Rotation

Headwind increases airflow over the wings, allowing lift-off at a reduced ground speed

Shorter Takeoff Roll

Each knot of headwind reduces takeoff distance by ~1%.

Improved Climb Gradient

Headwind reduces horizontal distance covered during climb,

enhancing obstacle clearance.

Reduced Groundspeed at

Touchdown

Headwind lowers groundspeed, significantly reducing kinetic energy and braking distance.

Shorter Landing Roll

Less runway is needed to stop, improving safety on short or wet runways.

Improved Directional Control

Greater airflow over control surfaces enhances handling and reduces the risk of runway excursions.

Dry

For runway surface condition in Takeoff, ____ runway is assumed

takeoff

Higher temperatures or elevation increase ________ distance during takeoff

T

[T or F] Takeoff performance data assumes current weight; heavier loads require longer distances.

[T or F] Wet or contaminated runways increase landing distance

Tailwinds

during takeoff and landing, it increase the aircraft's groundspeed, leading to longer runway distances and reduced safety margins.

Increased speed on higher ground

Reduced Lift

Higher Takeoff Roll

Reduced Climb Performance

[enumerate] Tailwind - Takeoff

Ground Speed and Touchdown

Increased Landing Distance

Restricted Control

Increased Risk to Emergencies

[enumerate] Tailwind - Landing

Crosswinds

impact takeoff and landing by blowing across the runway, making it more difficult for pilots to keep the aircraft properly aligned.

crosswinds

demand special handling techniques to maintain control and ensure safe flight operations

Increased Takeoff Roll Distance

Directional Control Challenge

Reduced Stability and Control

[enumerate] Crosswind - Take Off Performance

Alignment and Drift Correction

Increased Control Demands

Touchdown and Rollout Stability

Longer Landing Distance

[enumerate] Crosswind - Landing Performance

cruise performance

is the physical characteristics of an aircraft during the cruise phase, which is usually the longest and most efficient phase of a flight.

Range

Range involves consideration of flying distance; under specific circumstances, it is the furthest an aircraft can travel with a full tank of fuel.

Maximum Range

Specific Range

2 main types of Range

Maximum Range

The maximum distance the aircraft can travel at maximum efficiency.

Specific Range

Distance traveled divided by fuel burned.

Endurance

flight refers to the ability of an aircraft to remain airborne for an extended period.

Endurance

It is a critical factor in aircraft design and operation, particularly for long-haul flights, surveillance missions, and search and

rescue operations.

[T or F] endurance. An aircraft with high fuel efficiency can stay airborne longer, while an aerodynamically efficient design reduces drag, resulting in lower fuel consumption.

specific fuel consumption (SFC)

For engines that deliver power to drive a propeller, __________ is

defined as the mass

T

[T or F] For maximum endurance, fly at minimum power required.

thrust-specific fuel consumption (TSFC)

For jet thrust-producing engines, the specific fuel consumption is defined in terms of the engine's thrust or the ___________

Headwind

- Reduces groundspeed (GS = TAS - wind speed)

- Increases flight time for a given distance

Tailwind

- Increases groundspeed (GS = TAS + wind speed)

- Decreases flight time

Crosswind

- Does not directly affect groundspeed

- Requires a heading correction to maintain course

Breguet Range Equation

provides a theoretical estimate of an aircraft's range during steady, level cruise flight in still air conditions.