2.03 - Four Fundamentals
Straight Level Flight
Definition: straight level flight means maintaining a constant heading and altitude.
It is not hands-off: pilots must make small corrections for deviations caused by bumpy air, wind changes, and unintentional turns, climbs, and descents.
Pilot focus and horizon scanning:
FAA guidance: keep the outside horizon in view 90% of the time and look inside the cockpit only 10% of the time to check instruments.
Pitch attitude and horizon reference:
Level flight pitch is assessed by comparing the aircraft’s nose with the horizon.
If the plane starts to climb, the pitch attitude is too high and should be lowered.
If losing altitude, the pitch attitude is too low and should be raised.
Maintaining a constant heading (lateral level):
Look outside and compare the wings against the horizon; both wingtips should be at the same distance above or below the horizon.
If one wing is higher, the airplane is turning.
Lift, weight, and flight controls in straight level flight:
Both airspeed and angle of attack control lift; in straight level flight the throttle is primarily used to maintain the desired airspeed, and the elevator is used to control altitude.
The pitch required for level flight is not fixed: lift increases with airspeed, so the slower you are flying, the more you must pitch up to maintain altitude.
Cruise flight relationship (thrust and drag):
In normal cruise flight with constant airspeed, thrust equals drag: T = D.
If the pilot increases engine output (throttle), thrust increases and accelerates the aircraft because thrust exceeds drag.
As speed increases, drag also increases until drag equals thrust and the aircraft stabilizes at the new cruise airspeed.
Slowing down in level flight:
To slow down, reduce throttle, increasing the relative effect of drag and causing deceleration.
While slowing, the pilot must smoothly and continuously pitch up to maintain altitude as airspeed decreases.
As the aircraft slows, drag changes (in the transcript: "the amount of drag created will also decrease" with slowing in this context—note: in standard aerodynamics, induced drag typically rises at lower speeds, but the transcript states this decrease and it is reflected here).
Eventually, drag again equals thrust and a steady airspeed is maintained.
Transition to climb or descent from level flight:
To climb, create more lift than weight (L > W) by pitching up and applying power.
Entering a climb changes the flight path from level to climb attitude.
Climb (Three types and key concepts)
In a climb, weight acts straight down but is not perpendicular to the flight path, creating a rearward component that increases total drag.
To balance the forces and continue climbing, additional thrust is required.
Three climb profiles (types) with different power settings and pitch attitudes:
Best rate of climb (V_Y): maximizes altitude gain per unit time (maximum feet per minute).
Best angle of climb (V_X): maximizes altitude gain per unit horizontal distance (steepest climb path).
Note: VX climbs steeper but reaches the target speed more slowly than VY.
Returning to straight level flight from a climb:
Initiate the level-off at approximately 10% of the rate of climb. For example, if climbing at 500 ft/min, aim to level off at about 10% of that rate (roughly 50 ft/min), then adjust as needed to reach cruise speed.
Transition to cruise: once the aircraft reaches the desired cruise airspeed, reduce power to cruise setting.
Descent (Types and guidance)
In descent, the forward component of weight adds to thrust requirements differently than in climb.
Three types of descents:
Partial power descents (cruise descents or en route descents): normal method to descend.
Target descent rate for this method: about 500\ ext{ft/min}.
Descents performed with pitch adjusted to maintain the desired airspeed; throttle controls descent rate.
Descent at minimum safe airspeeds: steeper descents used during approach to landing on short runways.
These steep descents are flown at very low airspeed with a narrow margin for error; the risk of stalling is higher.
If stall onset is felt, large amounts of power may be needed to accelerate out of the stall tendency.
Glide (basic controlled descent without power)
Glide is a basic maneuver in which the airplane loses altitude in a controlled descent with little or no engine power.
Forward motion is maintained by the forward component of weight.
Gliders (which have no engine) routinely use this, and other aircraft use glide during engine-out situations or for landing procedures.
Gliding distance is maximized by maintaining the minimum drag airspeed.
Glide is described as a fundamental maneuver that pilots should master.
Turn mechanics (banking, control coordination, and rollout)
A turn is initiated by banking the wings toward the desired turn direction.
Although it can seem like a roll is controlled only with ailerons, multiple controls are involved:
In a left turn example, banking is achieved with the ailerons; the right wing’s aileron moves up (or relative deflection) to increase lift on the right wing, initiating the bank toward the left.
Effect of bank on lift and weight:
In straight and level flight, 100% of the lift is used to counteract weight (vertical lift).
In a bank, lift is tilted toward the bank direction; part of the lift goes horizontally, producing the turn. The vertical component of lift still opposes weight, but less lift contributes to supporting weight directly.
Result: there is a horizontal component of lift that causes the turn, and less vertical lift available to hold altitude unless lift is increased.
Need to maintain altitude during a turn:
Because some lift is redirected from vertical to horizontal, pilots must increase total lift by slightly pitching up a few degrees while maintaining the bank.
Drag implications during a turn:
The banked wing producing more lift also produces more drag, particularly on the wing producing more lift (the right wing in a left turn example).
Adverse yaw: the tendency for the nose to yaw opposite the turn direction due to differential drag causing the airplane to yaw away from the desired turn.
Counteract adverse yaw with rudder in the direction of the turn (e.g., press the left rudder pedal for a left turn).
Coordination of inputs: during a turn, pilots use all three primary flight controls together—ailerons, rudder, and elevator.
Bank angle and input amounts: different bank angles require different amounts of control input; practice makes this more intuitive.
Rollout to level flight:
As the aircraft rolls back toward level, pilots must lead the rollout before arriving at the target heading because the airplane will continue turning while the wings remain banked.
General rule: lead the rollout by about one half of the amount of banked angle (i.e., roll out slightly earlier to establish straight-and-level flight on the desired heading).
Key concepts and relationships (summary of essential ideas from the transcript)
Fundamental forces and their roles:
Lift (L) counteracts Weight (W).
Thrust (T) minus Drag (D) determines airspeed and acceleration.
In level flight: L \approx W\; \text{and}\; T \approx D.
Level flight control emphasis:
Pitch controls altitude, throttle controls airspeed.
Lift increases with airspeed; slower speeds require more pitch to maintain altitude.
Banked flight (turns) physics:
Lift vector tilts with bank angle; vertical component must still offset weight to hold altitude if desired.
Horizontal lift component provides centripetal force for turning.
Adverse yaw is an important consideration; counter with rudder in the turn direction.
Rollouts require anticipation to re-establish straight-and-level flight.
Climb and descent dynamics:
Climb requires more thrust and lift; weight acts downward and contributes to increased drag in a banked climb.
VY (best rate of climb) vs VX (best angle of climb) describe two common climb profiles.
Level-off during climb uses a 10% rule relative to the rate of climb to transition to cruise.
Descent strategies include partial power descents (target ~500\ \text{ft/min}), and minimum safe airspeed descents for approaches, each with different pitch and power settings.
Glide distance optimization:
Maintain minimum drag airspeed to maximize gliding distance; glide is a fundamental skill, particularly during engine-out scenarios.
Practical implications and situational awareness guidance
Regular outside-the-cockpit scanning is emphasized to maintain situational awareness and horizon reference.
Smooth transitions between maneuvers require coordinated use of all primary flight controls (ailerons, elevator, rudder) and appropriate throttle management.
Understanding climb/descent profiles helps manage fuel efficiency, obstacle clearance, and safe operation during all phases of flight.
Ethical/practical emphasis: maintain horizon-focused scanning, proper control coordination, and anticipation of the aircraft’s response to control inputs to ensure safe flight operations.
Notation and selected formulas to remember
Level flight relationships:
Lift and weight balance: L \approx W
Thrust and drag balance in cruise: T = D
Banked flight (turns) geometry:
Lifting force direction shifts with bank angle (\phi): vertical component L\cos\phi supports weight, horizontal component L\sin\phi provides centripetal force for turning.
Climb profiles:
Best rate of climb: V_Y
Best angle of climb: V_X
Descent rate target (partial power descent): \dot{h} \approx -500\ \mathrm{ft/min}
Altitude tracking during level-off: level off at approximately 0.10 \cdot \dot{h}_{\text{climb}}
Altitude reference for glide: maximize gliding distance by selecting the minimum-drag airspeed, i.e., the airspeed corresponding to the lowest total drag.