OCF Flashcards
(38 cards)
Stall + Yaw =
OCF - The moment in time when unexpected results occur from normal control inputs
Static Directional Stability
Can be positive, neutral or negative tendency to return to equilibrium after disturbance in horizontal plane
The 5 phases of OCF are?
Stall Departure Post-Departure Gyrations Incipient Phase of Spin Steady-State Spin
A stall occurs when?
When an increase in AOA produces a reduction in lift and an increase in drag.
Wing stalls when boundary layer separates from upper surface of wing.
Clean Stall Indications
Warning at 21.5 units / 10kts prior
Buffet at 25 units / 1-2kts prior
Stall at 26 units / 0kts prior
Takeoff Configuration Stall Indications
Warning at 21.5 units
Buffet onset at 26-27 units
Stall at 29-30 units
Approach Stall Indications
Warning at 21.5 units / 10kts prior
Buffet at 28 units / 1kt prior
Stall at 29-30 units / 0kts prior
Emergency Flap Stall Indications (stall airspeed 9-11kts greater than approach stall)
Warning at 21.5 units
No stall warning
Stall at 23-25 units
**Very disorienting, abrupt roll-off
Departure Definition
Departure is when aircraft transitions from controlled to uncontrolled flight or the moment when normal control inputs stop working or airspeed <85kts
CNATRA definition: Any time aircraft rolls uncommanded through 90°AOB following stall
Post Departure Gyration
Random/uncontrolled motions of aircraft about any axis after departure but before incipient phase
Incipient Phase
Initial phase characterized by: Stalled AOA Rotation in direction of spin Varying roll, yaw and pitch rates Average rotation rate slower than steady state
Steady State Spin
Final phase (self-sustaining spin) characterized by: Sustained auto-rotation Stalled AOA
Symptoms of impending departure
Mushy flight controls
Unresponsiveness to control inputs
Buffeting and buffet noise
Wing walk
Signs you have departed
Excessive yaw rate
Spinning or tumbling
Decaying airspeed and uncontrollable altitude loss
4 instruments to scan
Altimeter – time available
AOA – upright or inverted, type of recovery
Airspeed – stable indicates steady state spin
Turn needle – pegged in direction of spin
Upright Spin: Aircraft rolls and yaws in the same direction
Upright spin = stalled AOA + yaw
Inverted Spin: Aircraft rolls and yaws in opposite directions
Inverted spin = negative stalled AOA + yaw
Recovery occurs in exact opposite order of OCF progression. Use anti-spin controls to bring you from steady state spin to:
Incipient spin (AOA/needle pegged, speed oscillating)
Post-stall gyrations (AOA/needle/speed oscillating)
Departure (No response to control inputs)
Stall (AOA above stall)
Recovery (Controls neutral)
2 steps to recover
Reduce yaw rate
Reduce angle of attack
Progressive Spin: Occurs when aircraft enters second spin immediately following recovery from first spin.
Direction of rotation normally opposite original spin
May result from holding in anti-spin inputs after rotation stops, holding in aft stick during recovery, or initiating recovery pullout with insufficient airspeed or excessive AOA
High Speed Spiral: Not a spin. Characterized by…
Nose low attitude High roll rates Minor yaw rates AOA not pegged Airspeed increasing Turn needle in direction of roll/yaw
Pilot factors in OCF
Time distortion: perceived to be passing 5x faster than it really is
G-force distortion: unreliable “seat of pants” cues. You must disregard perceived G forces and trust your instruments
Control inputs: You must position all controls deliberately and visually check all controls for correct position
The two most important procedures to remember are?
NEUTRALIZE – IDLE
Accelerated Stall
Stalls entered with load factor >1G