OEI PRINCIPLES OF FLIGHTS & AERODYNAMICS Flashcards
Induced flow
- props of the wing create an accelerated flow of air over the wings called induced flow
Turning tendencies & counter-rotating props
- counter-rotating props combat torque & P-factor tendencies
- cancel each other out
YAW - engine failure
- asymmetrical thrust will cause the a/c to yaw around the CG towards the inoperative engine
ROLL - engine failure
- wing of the operating engine will move faster through the air
- creates more lift & roll towards the inoperative engine
ROLL (Induced flow) - engine failure
- accelerated slipstream over the wing from the operating engine & lack of induced flow on the inop. engine causes asymmetrical lift on the wings
- roll towards the inop. engine
Critical engine
- is the engine that if it were to fail, most adversely affect performance or handling characteristics
- no critical engine on our a/c
What determines a critical engine? (PAST)
LEFT-ENGINE CRITICAL
P-FACTOR: asymmetrical thrust, descending blade producing greater thrust than the ascending blade, descending blade on the right engine has a longer moment arm than the left, left engine will result in more asymmetrical thrust
ACCELERATED SLIPSTREAM (ROLL & PITCH): longer moment arm to the center of thrust on the right engine, center of lift is farther out on the right wing, greater roll tendency with the loss of a left engine
SPIRALING SLIPSTREAM (YAW): spinning prop produces a spiraling wind pattern that rotates in the same direction as the props rotation, left engines slipstream hits the vertical stabilizer and counteracts yaw from a right engine failure, right engines slipstream does not reach the vertical stabilizer & will not counteract yaw from a left engine failure
TORQUE (ROLL): for every action there is an equal or opposite reaction, a/c will roll to the failed engine regardless of which one failed, held the prop it will spin in the opposite direction
VMC Definition
- minimum controllable airspeed w/ critical engine inop.
- minimum speed at which directional control can be maintained under specific circumstances
- calibrated airspeed, critical engine is suddenly made inoperative, it is possible to maintain control of the a/c with that engine still inoperative & maintain straight flight w/ an angle of bank of no more than 5 degrees
VMC Directional Control
- directional control is lost when full rudder deflection is applied towards operating engine
SMACFUMA
STANDARD DAY @ SEA LEVEL
MAXIMUM AVAILABLE T/O POWER ON EACH ENGINE
AFT CG
CRITICAL ENGINE WINDMILLING
FLAPS/GEAR & TRIM IN T/O POSITION
UP TO 5 DEGREES BANK TOWARD OPERATING ENIGNE
MOST UNFAVORABLE WEIGHT
AIRBORNE OUT OF GROUND EFFECT
Recognizing & recovering from VMC
- loss of directional control (rudder pedal depressed to its fullest)
- stall warning horn
- buffeting before stall
- rapid decay of control effectiveness
Recovery from VMC
- reduce power on operating engine
- pitch down to blue line
VMC & Density Alt.
- density altitude increase, VMC decreases
- density alt. increase, engine power decreases
- less asymmetrical thrust
- stall speed remains constant
Factors affecting VMC
- Power: more power on the operating engine, more rudder is needed to stop the resulting yaw
- Density Alt.: performance decreases when density alt. increases, less thrust means less rudder needed, VMC decreases
- CG location: changes the length of the arm to the rudder, the longer the arm the more effective the rudder, CG moves aft CG increases
- Flaps: flaps down create more lift and drag
Performance vs Control
- control refers to the pilot’s direct manipulation of the aircraft’s flight controls (like the yoke, rudder, and throttle) to achieve desired attitudes and power settings, while
- performance describes the resulting effects of those control inputs, such as airspeed, altitude, and climb rate
High risk phases of flight OEI
- T/O & initial climb (reduced climb performance, obstacle clearance, climb gradient)
- approach & landing (go-around, maintaining airspeed, maneuverability)
