Terminology Flashcards
What is Asymmetric Thrust, and what does it do?
Single engine operations: the functioning engine creating more thrust than the dead engine, causing a roll and a yaw towards the dead engine.
What is your goal for single engine operations?
Maintain directional control: heading and course
How do we maintain directional control?
Rudder authority on the side of the active engine.
What could happen if you lose rudder authority and can’t recover?
Death
Why do we not have counter rotating engines?
Too expensive to manufacture and maintain.
What allows you to have authority over your flight controls?
Airspeed! The more airflow over the control surfaces, the more responsive they are.
What is a Vmc roll?
An uncontrollable roll + yaw into the dead engine.
What is the Critical Engine?
The engine, when lost, has the most adverse effect on controllability and performance.
How do we know which engine is the critical engine?
The engine with the Center of Thrust closer to the center of the aircraft.
Also- PAST acronym
What is PAST?
P-factor: descending prop blade creates more thrust than ascending blade- yaw to the left
Accelerated Slipstream: accelerating air over the wing causes lower pressure- roll
Spiraling Slipstream: slip stream trails off and hit vertical stabilizer on the left side. Yawing the nose to the left
Torque: As the propeller spins clockwise, the airplane experiences a rotating force in the opposite direction.
Engine out flow:
1) maintain directional control! 0 side slip
2) max power both engines!
3) gear up, flaps up - reduce drag
4) identify which engine is dead “dead leg, dead engine”
5) verify - reduce power of dead engine
6) Feather (engine master off)
7) climb power: 100 -> 91 -> 75, trim
8) CHECKLIST
9) Secure the Engine: Alternator Off, Fuel Pumps Off, Fuel Selector Off
10) plan my next move. Continue or declare emergency and land?
Vmc demonstration
Proving you can recover from Vmc roll and how to recover:
Maintain heading +/- 20°, Airspeed +/- 5knots
- Vmc recover at (whichever comes first):
- Vmc 71 knots
- Loss of directional control
- Stall (horn or buffet)
How do you recover from Vmc demonstration ?
Same time:
1) reduce power, near idle, of functioning engine. ( reduces asymmetrical thrust)
2) reduce angle of attack. (Break the stall, regain airflow over the control surfaces.)
3) apply full power of the good engine, climb at Vyse 85k
What is Vmc and how is it determined?
Vmc = 71 knots, but is not always the same. Vmc changes with Density Altitude.
SMACFUM
Define SMACFUM
S: standard day 15°c 29.92”mhg
M: max power in op engine- more power= more asymmetric thrust (lower power=lower Vmc)
A: most aft CG. Forward CG= lower Vmc; Aft CG = higher Vmc
C: Critical Engine windmilling = generating more drag exacerbating asymmetric thrust. More drag= higher Vmc
F: flaps T/O, Gear. Flaps lower Vmc, Gear produces Kiel Effect aiding directional stability (surfboard fins)
U: up to 5° bank- for every 1° of bank, Vmc drops by 3knots- max 15knots
M: most unfavorable weight - lighter AC are easier to push around
