Multi-Engine과정.

Multi-Engine과정

Ch1.Multi Engine Introduction

Multi Engine 장단점 장 점 (Advantages) 단 점 (Disadvantages) Performance
- Climb - Cruise - Ceiling Useful Load Safety - Two Engines - Redundant Systems Complexity - Dual Systems - Avionics Single Engine Operations Cost Efficiency측면 - Parasite Drag - Fuel Consumption Maintenance측면 - Two engines - Complex System

Theory Critical Performance is rate of climb in the event of an Engine Failure Misconception: 50% loss of Power would result in 50% loss in climb performance Truth: 50% in loss of horsepower, and reduction of more than 80% climb performance Must consider all the drag and weight on dead engine

Planning Consideration (W&B)
Maximum ramp Weight : Maximum weight of the airplane at maximum takeoff weight plus fuel for taxi and run-up Maximum Zero Fuel Weight: Maximum weight of the loaded airplane with zero fuel. Maximum Landing Weight: Less than Maximum takeoff weight and must not be exceeded except in emergency FT=(MTOW-MLW)/5*FF FT= flight time MTOW = max takeoff weight MLW = maximum landing weight FF = Fuel flow

Planning Consideration (Cont’d)
Accelerated/Stop Distance : Total distance required to accelerated to Vr experience an engine failure and bring the airplane to a complete stop Accelerated/Go Distance: total distance required to continue the takeoff and climb to 50 feet, assuming an engine failure at Vr or lift-off speed.

Planning Consideration (Cont’d)
Single Engine Best Rate of Climb Speed (Vyse): Best rate of climb speed with one engine inoperative – Blue Radial Line Single Engine Best Angle of Climb (Vxse): Best angle of climb with one engine inop Minimum Control Speed (Vmc): minimum control speed with the critical engine inoperative. Marked with red radial line.(약80kts) Single engine service ceiling: Density altitude at which single engine rate of climb reduces to 50 feet per minute Single Engine Absolute Ceiling: Density altitude at which airplane cannot climb anymore. Graphic line where Vyse and Vxse meets. Single Engine Drift Down: When operating above single engine absolute ceiling, drift down to the single engine absolute ceiling. – blue line will minimize sink rate

Ch2.Multi-Engine Aerodynamics
Basic Theory

Induced Airflow The LIFT generated from the accelerated slipstream being created by the propellers. Significant to multi-engine propeller driven aircraft more than single-engine aircraft due to what? How and why does this happen? Causes a ROLLING moment Refer to Figure 3-8

Turning Tendencies Conventional vs. Counter-Rotating
Three major factors: 1) Accelerated Slipstream 2) Torque 3) P-Factor

Accelerated Slipstream
Lift produced by wing surface only Combined lift produced by induced airflow from engine and wing surface

Torque For every action; there is an equal and opposite reaction.
This reaction causes an unbalanced moment from the operating engine, which causes another ROLLING moment.

Torque cont. Engine Rotation Torque Effect

P-Factor Due to the thrust vector of the descending blades being further from the aircraft centerline. Multi-engine airplanes have greater left-turning tendencies than singles due to both engines, rather than one, causing the aircraft to yaw.

P-Factor cont.

Multi-Engine Ceilings
Single-Engine aircraft ceilings still apply i.e. absolute ceiling and service ceiling. In addition, we have Single-Engine Absolute Ceiling and Single-Engine Service Ceiling.

Multi-Engine Ceilings cont.
Single-Engine Absolute Ceiling: No further climb is possible with one engine feathered. Single-Engine Service Ceiling: A 50ft per minute climb is possible with one engine feathered.

Multi-Engine V-Speeds
Vmc- Minimum control speed with one engine inoperative; the speed at which when one engine is suddenly made inoperative, it is possible to regain control with either zero yaw or up to five degrees and no more than 150 pounds of rudder force at the discretion of the applicant. Why do we need to know this? Why do we have the limitations?

Vsse- Intentional one engine inoperative airspeed. This airspeed is developed by the manufacturer as the minimum airspeed for intentionally rendering one engine inoperative for the purposes of training. Roughly 10 knots above Vmc. Vxse- Best single-engine angle of climb airspeed. Used for obstruction clearance with one engine inoperative. This airspeed provides the best altitude gain over a given distance. Vyse- Best single-engine rate of climb. This airspeed gives the greatest gain in altitude in a given time period.

You cannot forget about the complex aircraft airspeeds! Vlo- Landing gear operating speed. This airspeed often varies depending on gear extension and retraction. Vle- The maximum airspeed at which the landing can be extended. Please do not forget about Flap airspeeds.

Ch2.Multi Engine Aerodynamics
Critical Engine

Critical Engine - Definition
The engine whose failure most adversely affects the performance and handling characteristics of the aircraft.

Airplanes with Conventional or Co-rotating props have a “Critical Engine”

Critical Engine - Co-rotating / Conventional props
P-Factor and Critical Engine As angle of attack increases P-Factor becomes more pronounced. (Descending prop blades produce greater thrust than the ascending blades.) Angle of attack Cruise (level flight) Unbalanced Forces of Thrust P-Factor Note: Co-rotating Engine airplane shown (C-340)

P-Factor and Critical Engine As angle of attack increases P-Factor becomes more pronounced. (Descending prop blades produce greater thrust than the ascending blades.) Cruise climb Angle of attack Unbalanced Forces of Thrust P-Factor Note: Co-rotating Engine airplane shown (C-340)

P-Factor and Critical Engine As angle of attack increases P-Factor becomes more pronounced. (Descending prop blades produce greater thrust than the ascending blades.) Climb Angle of attack Unbalanced Forces of Thrust P-Factor Note: Co-rotating Engine airplane shown (C-340)

Y1 Y2 Y1 = Y2 P-Factor and Critical Engine As a result of P-Factor, the right engine produces thrust which is further from the airplane’s longitudinal axis, at positive angles of attack. Critical Engine Unbalanced Forces of Thrust Note: Co-rotating Engine airplane shown (C-340)

Y1 P-Factor and Critical Engine Not because of this arm… Critical Engine Unbalanced Forces of Thrust Note: Co-rotating Engine airplane shown (C-340)

Y2 Critical Engine Failure Results in Greater Moment P-Factor and Critical Engine Because of this arm… Critical Engine Critical Engine Unbalanced Forces of Thrust Note: Co-rotating Engine airplane shown (C-340)

Multi-engine aircraft whose engines rotate in the same direction (co-rotating propellers) have a “critical engine”. An airplane with co-rotating propellers produces greater amounts of roll if the Critical Engine has failed. Torque and Critical Engine Direction of Propeller Rotation Note: Co-rotating Engine airplane shown (C-340)

Accelerated Slipstream & Critical Engine An airplane with co-rotating propellers produces greater amounts of roll if the Critical Engine has failed. Critical Engine Y1 Y2 Y1 = Y2 Note: Co-rotating Engine airplane shown (C-340)

Accelerated Slipstream & Critical Engine Lift Lift An airplane with co-rotating propellers produces greater amounts of roll if the Critical Engine has failed. Y1 = Y2 Y2 Y1 Critical Engine Unbalanced Forces of Lift Note: Co-rotating Engine airplane shown (C-340)

Engine Inoperative Flight Co-rotating / Conventional props
Left Engine Failed Right Engine Failed P-Factor Large Left Yaw Medium Right Yaw Induced Lift Left (CCW) Roll Right (CW) Roll Torque Most forces acting in one direction creates the critical engine

Airplanes with Counter-rotating props do not have a Critical Engine.

Airplanes with Counter-rotating props have no Critical Engine
P-Factor and Critical Engine As angle of attack increases P-Factor becomes more pronounced. (Descending prop blades produce greater thrust than the ascending blades.) Angle of attack Cruise (level flight) Unbalanced Forces of Thrust P-Factor Note: Co-rotating Engine airplane shown (C-340)

P-Factor and Critical Engine As angle of attack increases P-Factor becomes more pronounced. (Descending prop blades produce greater thrust than the ascending blades.) Cruise climb Angle of attack Unbalanced Forces of Thrust P-Factor Note: Co-rotating Engine airplane shown (C-340)

P-Factor and Critical Engine As angle of attack increases P-Factor becomes more pronounced. (Descending prop blades produce greater thrust than the ascending blades.) Climb Angle of attack Unbalanced Forces of Thrust P-Factor Note: Co-rotating Engine airplane shown (C-340)

Y1 Y2 P-Factor Y1 = Y2 An Aircraft with Counter-Rotating Propellers produces the same amount of yaw regardless of which engine has failed. Note: Counter-rotating Engine airplane shown (PA-44)

Multi-engine aircraft whose engines rotate in opposite directions (counter rotating propellers) do not have a “critical engine”. Torque An Aircraft with Counter-Rotating Propellers produces equal amounts of roll regardless of which engine has failed. Direction of Propeller Rotation Balanced Forces of Torque Note: Counter-rotating Engine airplane shown (PA-44)

The rolling moment is always toward the operating engine with counter-rotating props with one engine failed. Induced Lift Torque helps counter induced lift and maintain control with one engine failed. Dead Engine Note: Counter-rotating Engine airplane shown (PA-44)

Multi-engine aircraft whose engines rotate in opposite directions (counter rotating propellers) do not have a “critical engine”. Accelerated Slipstream / Induced Lift Multi-engine airplanes with counter-rotating propellers have accelerated slipstreams which are symmetrically located relative to the longitudinal axis. Y1 Y2 Y1 = Y2 Note: Counter-rotating Engine airplane shown (PA-44)

Multi-engine aircraft whose engines rotate in opposite directions (counter rotating propellers) do not have a “critical engine”. Accelerated Slipstream / Induced Lift Multi-engine airplanes with counter-rotating propellers have accelerated slipstreams which are symmetrically located relative to the longitudinal axis. Lift Lift Y1 = Y2 Y2 Y1 Note: Counter-rotating Engine airplane shown (PA-44)

Engine Inoperative Flight Counter-rotating props
Right Engine Failed Left Engine Failed P-Factor Medium Left Yaw Medium Right Yaw Induced Lift Left (CCW) Roll Right (CW) Roll Torque Engine inoperative performance similar regardless of which engine has failed

Ch2.Multi-Engine Aerodynamics
Engine Inoperative Aerodynamics VMCA

Vmc- Minimum control speed with one engine inoperative

FAR 23.149 § 23.149 Minimum control speed.
(a) VMC is the calibrated airspeed at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine still inoperative, and thereafter maintain straight flight at the same speed with an angle of bank of not more than 5 degrees. The method used to simulate critical engine failure must represent the most critical mode of powerplant failure expected in service with respect to controllability. (b) VMC for takeoff must not exceed 1.2 VS1, where VS1 is determined at the maximum takeoff weight. VMC must be determined with the most unfavorable weight and center of gravity position and with the airplane airborne and the ground effect negligible, for the takeoff configuration(s) with -- (1) Maximum available takeoff power initially on each engine; (2) The airplane trimmed for takeoff; (3) Flaps in the takeoff position(s); (4) Landing gear retracted; and (5) All propeller controls in the recommended takeoff position throughout.

FAR Summary VMC (for airplanes weighing 6,000 pounds or less) is defined as the calibrated airspeed, when critical engine suddenly made inoperative, the airplane can be maintained in straight flight at same speed, with maximum bank angle of 5o, a rudder pedal force not exceeding 150 pounds, and the simulated engine failure represents most critical (with respect to controllability) expected in service. VMC must be not exceed 1.2 VS1 where VS1 is determined at the maximum takeoff weight.

FAR Summary Conditions Required for VMC testing & certification Most unfavorable weight Most unfavorable C.G. Ground effect negligible Maximum available power initially on each engine Airplane trimmed for takeoff Flaps in takeoff position Landing gear retracted All propeller controls in the recommended takeoff position throughout

FAR 23.149 – Superceded Takeoff or maximum available power
Most unfavorable C.G. Takeoff trim Maximum sea level takeoff weight Takeoff flaps Landing gear retracted Cowl flaps in normal T/O position Propeller either: windmilling in most probable position for specific design of propeller control feathered if airplane has automatic feathering device Airborne and ground effect negligible The PA-44 was certificated under a previous version FAR These “Nine Factors” of VMC are still commonly referred to in discussions involving VMC.

Published VMC Versus Actual VMC
A manufacturers published VMC is the minimum speed at which aircraft control can be maintained while at specific conditions. An airplane’s actual VMC will almost always be different. Normally slower.

When engine fails, an unbalanced moment occurs.
Vmc - The Problem Yawing Moment Due To Asymmetric Thrust Thrust Y2 The moment is equal to the operating engine’s thrust multiplied by the perpendicular distant from the thrust line to the airplane’s C.G. The unbalanced moment causes the airplane to yaw toward the failed engine. The yawing also results in a roll toward the failed engine. When engine fails, an unbalanced moment occurs.

Part of the Answer for Vmc
Yawing Moment due to Asymmetric Thrust Lift on Vertical Tail due to rudder deflection Yawing Moment due to Lift produced by Vertical Tail Y2 The moment into the failed engine may be balanced by a opposing moment due to lift on the vertical tail. This lift is produced by deflecting the rudder toward the good engine, creating a camber to the vertical tail.

The moment created when the rudder is deflected is equal to the lift produced by the vertical tail multiplied by the perpendicular distance to the airplane’s C.G. Yawing Moment due to Asymmetric Thrust Lift on Vertical Tail due to rudder deflection Yawing Moment due to Lift produced by Vertical Tail Y2 Apply rudder into good engine

More Vmc Problems Loss of Rudder Effectiveness
Addition of thrust & vertical tail’s lift vectors create a resultant force which causes the airplane to sideslip. Sideslip into the dead engine causes lower angle of attack on vertical tail. The lower angle of attack degrades the vertical tail’s ability to produce the horizontal lift which counters the asymmetric thrust. Thrust Resultant Force on Airplane Rudder Effectiveness Degraded Lift on Vertical Tail due to rudder deflection Relative Wind Loss of Rudder Effectiveness

Cause lift to have a horizontal force on aircraft Force causes sideslip into good engine Sideslip into good engine causes higher AoA on V.T. Higher AoA of Vertical Tail creates higher CL and greater horizontal lift At some bank/sideslip angle the vertical tail’s AoA approaches the stall AoA and the vertical tail produces maximum lift. Relative Wind Rudder MORE Effective Horizontal Wing Lift Lift Weight Thrust Dead Engine Bank into good engine Bank helps provide control at lower speed

More Vmc Problems As speed decreases…
the moment (thrust X distance to C.G.) produced by the operating engine remains essentially the same while the moment produced vertical tail (horizontal lift X distance to C.G.) decreases due to decreasing speed. and more and more rudder is needed to increase the vertical tail’s CL. until eventually full rudder is reached and further decreases in speed result in a loss of control. Thrust Less Relative Wind Rudder LESS Effective Horizontal Wing Lift Lift Weight Dead Engine As speed decreases… Control degrades at lower speed

Vmc occurs at the speed where either rudder (or aileron) is insufficient to maintain control of the airplane. To attain control at minimum speed, the airplane must be both banked and slipping toward the operating engine. Less Relative Wind Rudder LESS Effective Horizontal Wing Lift Lift Weight Thrust Dead Engine

More Factors Affecting Actual VMC
Power on operating engine Altitude for normally aspirated engines Throttle/RPM Condition Lever Drag from dead engine and propeller Critical or non-critical engine failed Rudder and aileron positions Sideslip and bank angle Location of C.G. Flap position Landing Gear Position Weight

Density Altitude & VMC VMC decreases with altitude in airplanes with normally aspirated engines. Increased density altitude causes reduced thrust/power (except for supercharged engines) Stall speed (KCAS) is relatively constant as density altitude increases If sea level Vmc is greater than stall speed, it will equal stall speed at some higher altitude. Dangerous!

Effect of Bank/Sideslip Angle on VMC
Actual Vmc achieved when bank toward operating engine (5o is certification limit) slip toward operating engine ball significantly toward operating engine Rule of thumb Vmc increases 3 KCAS for each degree of bank off the bank used for maximum Vertical Tail lift Best climb performance occurs with less bank no sideslip ball slightly toward operating engine higher speed

Effects of C.G. Location on Vmc
Dead Engine X1 Y1 Thrust Aft C.G. Dead Engine X2 Y2 Thrust Forward C.G.

Dead Engine X1 Y1 Thrust Aft C.G. Rudder Moment Arm is Decreased Rudder Effectiveness Degraded Dead Engine X2 Y2 Thrust Forward C.G. Rudder Moment Arm is Increased Rudder Effectiveness Improved

Rudder Moment Arm is Decreased Rudder Effectiveness Degraded Dead Engine X1 Y1 More Rudder Force Required to Maintain Control Thrust Aft C.G. Dead Engine X2 Y2 Less Rudder Force Required to Maintain Control Thrust Forward C.G. X2 > X1 VMC increases as C.G. moves aft Rudder Moment Arm is Increased Rudder Effectiveness Improved

Rudder Moment Arm is Decreased Rudder Effectiveness Degraded Dead Engine X1 Y1 More Rudder Force Required to Maintain Control Thrust Aft C.G. BAD Rudder Moment Arm is Increased Rudder Effectiveness Improved Dead Engine X2 Y2 Less Rudder Force Required to Maintain Control Thrust Forward C.G. GOOD

Effect of Flap Position on Actual Vmc
Airplane specific with flaps more lift on operating engine’s wing requires aileron deflection adverse yaw associated with increased aileron adds to yawing moment with flaps, more drag on operating engine’s wing counters yawing moment with flaps, decreased AoA adds to or reduces yawing moment depending on engine which failed Remember, the lift on the wings must be equal or airplane will roll

Effect of Gear Position on Actual Vmc
Airplane specific Landing gear which increase drag in front of the airplane’s C.G. will degrade directional stability, increasing the demand on the rudder. Landing gear which increase drag behind the airplane’s C.G. will increase directional stability, decreasing the demand on the rudder. Airplane side area above the C.G. causes airplane to roll opposite to sideslip, increasing demands on ailerons.

Effect of Weight on Actual Vmc
Factors to be considered: A light airplane will produce less horizontal component of lift at any given bank angle. HOWEVER, the bank required for the sideslip that will produce maximum Vertical Tail lift is not limited (5 degrees is only for certification). A light airplane will fly at a lower AOA for any given airspeed. This affects P-Factor depending on which engine fails. A lighter airplane will require less thrust at any given airspeed.

Engine Inoperative Flight In-Flight Forces
Roll Asymmetric Lift Asymmetric Torque Yaw Asymmetric Thrust (P-Factor) Asymmetric Drag

Engine Inoperative Flight - Roll due to Induced Lift
When an engine fails a ROLLING moment occurs. Induced airflow over wing from operating engine Lack of induced airflow over wing from inoperative engine Dead Engine Induced Lift

Note: Counter-rotating Engine
Engine Inoperative Flight - Roll due to Asymmetric Torque (Counter Rotating Props) When an engine fails a ROLLING moment occurs. Torque moment is produced from operating engine Dead Engine Note: Counter-rotating Engine airplane shown (PA-44) Engine Rotation Torque Effect

Note: Co-rotating Engine
Engine Inoperative Flight - Roll due to Asymmetric Torque (Co-rotating Props) When an engine fails a ROLLING moment occurs. Torque moment is produced from operating engine Engine Rotation Torque Effect Dead Engine Note: Co-rotating Engine airplane shown (C-340)

Engine Inoperative Flight - Yaw due to Asymmetric Thrust
Dead Engine Yaw When an engine fails an asymmetric yawing moment occurs. This moment is equal to the operating engine’s thrust multiplied by the perpendicular distance from the thrust line to the airplane’s C.G. (Y1) The asymmetrical moment causes the airplane to YAW toward the failed engine. Yawing moment resulting from Asymmetric Thrust is greatest when an airplane is in a climb.

Engine Inoperative Flight - Yaw due to Asymmetric Drag
When an engine fails an asymmetric yawing moment occurs. This moment is equal to the drag produced by the dead engine’s wind milling propeller, multiplied by the perpendicular distant from the dead engine to the airplane’s C.G. (Y1) The asymmetric moment causes the airplane to YAW toward the failed engine. Drag Dead Engine Y1 Yaw Yawing moment resulting from Asymmetric Drag is the same in an airplane regardless of co-rotating or counter-rotating engines

Loss of Directional Control
How it might occur & pilot inputs to correct it. As airspeed is decreased the rudder will become less effective and therefore more rudder deflection will be required to maintain directional control. An airspeed will eventually be reached where full rudder deflection will be required to maintain directional control. Any further decrease in airspeed will lead to loss of control. Control can be regained by lowering the nose (increasing airspeed) and a sufficient reduction of power.

Engine Inoperative Flight Decreased Rudder Effectiveness
Unbalanced vertical tail lift vectors produces a sideslip toward the inoperative engine. The lower angle of attack (at the vertical tail) degrades the vertical tail’s capacity to produce horizontal lift which counters the YAW moment. Direction of Flight Relative Wind Thrust Vertical Tail Lift Sideslip Angle Slide illustrates a condition where pilot has made a rudder input to cancel yawing moment and maintains wings level with aileron.

Engine Inoperative Flight Decreased Rudder Effectiveness
Relative Wind Chord Line Less lift from Vertical tail Sideslip Condition Relative Wind More lift from Vertical tail Chord Line Zero Sideslip Condition Sideslip into dead engine causes lower angle of attack on vertical tail. Therefore rudder effectiveness is decreased.

Engine Inoperative Flight
As airspeed decreases: the moment (thrust X distance to C.G.) produced by the operating engine remains essentially the same while the moment produced by the vertical tail (horizontal lift X distance to C.G.) decreases due to decreasing speed. Less Relative Wind Less Horizontal Lift Horizontal Wing Lift Thrust Dead Engine X1

Engine Inoperative Flight
Horizontal Wing Lift Lift Weight As airspeed decreases: more and more rudder is needed to increase the vertical tail’s lift coefficient. eventually full rudder is reached and further decreases in speed result in a loss of control.

Loss of Directional Control - other potential causes
Partial Power Loss Manifold pressures above ambient are not available, otherwise normal Power loss sometimes proceeded by oil loss. Rough Running Aux fuel pump on high during normal operations Mixture over lean Power reduction when engines are hot. Fluctuating RPM Faulty Prop Governor Low oil quantity. Low Oil Pressure Check oil temp. Check annunciator High Oil Temperature Compare with CHT Check EGT and mixture setting Check cowl flap position High Cylinder Head Temperature Compare with oil temperature Check EGT and mixture setting.

Loss of Directional Control
Remember: Control can be regained by lowering the nose (increasing airspeed) and reducing power as needed.

The Three Primary Rules
Fly the airplane

Ch3.General Systems

Constant Speed Propellers
Characteristics of the PA-34 Propellers Three Blades on each Hub Constant Speed - Hydraulically Actuated Full Feathering

Fixed Pitch vs. Constant Speed

Operating Principle #1 Blade Angle (Pitch) controlled by oil pressure flowing to and from Propeller Hub Oil Pressure TO the Hub = Low Pitch High RPM Oil Pressure FROM the Hub = High Pitch Low RPM

Prop Governor Oil Pressure To and From Hub is regulated by Propeller Governor Governor is adjusted using Prop Levers

Operating Principle #2 Three sets of “Balanced Forces” in equilibrium until they are “upset” by an external force or input Set #1 - Propeller Blades Counterweights / Aerodynamic Twisting Force Set #2 - Propeller Hub Nitrogen & Spring Pressure / Oil Pressure Set #3 - Propeller Governor Flyweights / Speeder Spring

Three sets of “Balanced Forces”
Set #1 – Propeller Blades Aerodynamic Twisting Force Counterweights Set #2 – Propeller Hub Nitrogen (N2) Pressure Spring Pressure Oil Pressure Set #3 – Propeller Governor Flyweights Speeder Spring

Set #1 – Propeller Blades
Counterweights Aerodynamic Twisting Force Low Pitch High RPM Aerodynamic twisting moment tries to decrease the blade angle.

Aerodynamic Twisting Force Counterweights High Pitch Low RPM Propeller counterweights assist in moving the blades to increase the blade angle.

Aerodynamic Twisting Force Counterweights The result is a “Balanced Force”.

Propeller Blades Oil pressure to and from the hub moves the piston (and therefore blades) to high and low pitch with the same effort. Counterweight Aerodynamic Twisting Force

Set #2 – Propeller Hub Nitrogen (N2) Pressure Spring Pressure Oil Pressure Oil pressure from the governor is used to balance N2 & Spring pressure

Set #2 – Propeller Hub Nitrogen (N2) Pressure Spring Pressure High Pitch Low RPM Oil Pressure When oil pressure from the governor is reduced, the N2 & Spring pressure move the piston and blades to High Pitch & Low RPM

Set #2 – Propeller Hub Oil Pressure Nitrogen (N2) Pressure Spring Pressure Low Pitch High RPM When oil pressure from the governor is increased, it overpowers the N2 & Spring to move the piston and blades to Low Pitch & High RPM

Constant speed propeller
1. High pressure oil enters the cylinder through the center of the propeller shaft and piston rod. The propeller control regulates the flow of high pressure oil from the governor.

2. A hydraulic piston in the hub of the propeller is connected to each blade by a piston rod. The rod is attached to forks that slide over the pitch-change pin mounted at the blade root.

3. The oil pressure moves the piston toward the front of the cylinder, moving the piston rod and forks forward.

4. The forks push the pitch-change pin of each blade toward the front of the hub, causing the blades to twist toward the low pitch position.

5. A nitrogen pressure charge or mechanical spring in the front of the hub opposes the oil pressure, and causes the propeller to move toward high-pitch.

6. Counterweights also cause the blades to move toward the high pitch and feather positions. The counterweights counteract the aerodynamic twisting force that tries to move the blades toward a low-pitch angle.

Prop Governor Unfeathering Accumulator Propeller Governor

Prop Governor – Description
Tension on the speeder spring is adjusted by using the prop levers.

Based on this tension, the pilot valve is allowed to move up or down.

Flyweights are used to create either an “overspeed” or “underspeed” condition - allowing oil pressure to either enter or exit the prop hub.

This occurs continuously in order to maintain a “constant speed.”

If the propeller is in the governing range and the propeller control lever is adjusted for a specific RPM, the governor maintains the blade pitch by varying the amount of oil pressure in the propeller hub.

For speed control, the governor uses flyweights and speeder spring to position a pilot valve, which controls oil pressure in the propeller hub. Inside the governor, an engine-driven shaft causes the flyweights to rotate in conjunction with engine speed.

As rotational speed increases, centrifugal force causes the flyweights to pivot outward, opposing the pressure applied by the speeder spring. When the flyweights move outward, they lift the pilot valve, allowing oil to flow out of the propeller hub and thereby allowing the propeller blade pitch to increase.

As the blade pitch increases, the engine and governor flyweight rotational speeds decrease. At the slower speed, speeder spring pressure overcomes the centrifugal force acting on the flyweights, causing them to move inward. The flyweight movement repositions the pilot valve to allow oil to flow into the propeller hub, thereby decreasing the propeller blade-pitch, which causes the engine speed to increase.

By balancing the pressure exerted by the centrifugal force acting on the flyweights and the speeder spring, the governor maintains a constant RPM. To select a desired RPM for the governor to maintain, you adjust the propeller control lever, which simply changes the pressure exerted by the speeder spring.

Windmilling Propeller
Relative Wind Blade Angle

Feathered Propeller Relative Wind Blade Angle

Propeller Feathering Feathering is accomplished following an engine failure to reduce the drag of a windmilling propeller.

Propeller Feathering Feathering is achieved by allowing the nitrogen charge and spring pressure to overcome the force of the engine oil pressure.

Power Application and Reduction
Operating an aircraft with constant speed propellers requires careful use of power. When increasing power, move levers from the right to the left Mixtures, Props, Throttles When reducing power, move levers from left to right Throttles, Props, Mixtures

Propeller Synchronization
Manually accomplished through the prop levers. Power is set, and then one prop lever is finely tuned to match the other. Thus eliminating the “Wah-Wahs.” Necessary for two reasons Improve passenger comfort Osculation noise produces fatigue

Propeller Synchronization

ENGINES -2 four cylinder -Lycoming fuel injected engines
-Each rated 200 HP at 2700 RPM -Left engine rotates in a clockwise direction -Right engine rotates counterclockwise direction when viewed from the cockpit

PROPELLER - Constant speed - Controllable pitch
- Full feathering Hartzell propellers - Operated by oil and nitrogen pressure - Oil pressure sends the propeller toward the high RPM or unfeather position - Nitrogen pressure sends the propeller toward the low RPM or feather position - A governor supplies oil through the propeller shaft to maintain constant RPM settings - A feathering lock, operated by centrifugal force, prevents feathering during engine shut down when speed is less than 800 RPM

LANDING GEAR - Electrically actuated and hydraulically operated
- Landing gear is held up by hydraulic pressure - Landing gear is held down and in locked position by spring assisted down lock hooks - Electrical ‘pressure switch’ stops the hydraulic pump motor when the hydraulic pressure reaches 1800PSIduring retracting - Electrical ‘limit switches’ stop the hydraulic pump motor when the gear is completely down and locked - Gear horn and red light will activate when …One of the throttles touches 14”MP position Gear selector is up on the ground Landing gear is traveling between up/down limit switches Flap extended more than 25 degree(2 notch) without gear down -One squat switch on the left main gear prevents gear retraction on the ground

Landing Gear-Abnormal
-Three green lights indicate the landing gear is down and locked When the gear selector is down and one or two green lights do not illuminated, possible conditions might exist……. a. The gear is not locked down b. The light bulb is burned out (may pull out other bulb to check) c. There is a malfunction in the indication system EMERGENCY GEAR EXTENSION PROCEDURE (USE DO CHECKLIST) 1. Reduce power – maintain airspeed below 100 MPH 2. Gear selector switch to “DOWN” position 3. Pull emergency gear extension knob 4. Check for 3 green lights

FLIGHT CONTROLS - Cable systems are used between the controls and the surfaces - Flaps are extended and retracted manually - Flaps have 3 extended positions 10° (160mph), 25° (140mph), 40° (125mph)

FUEL -Two 24.5 gallon tanks in each wing and are interconnected
-Outboard tank fuel flows into the inboard tank -Total 98 gallons and which 5 gallons (2 1/2 gallons on each tank) are unusable -Must use 100 (blue)/130 (green) octane -Engine driven fuel pump is primary way of supplying fuel for each engine -Electric fuel pump is used as back-up in case of engine driven fuel pump fails and for engine start (ONE ON EACH SIDE) -To extend single engine range and to keep fuel weight balance, CROSSFEED system is used to permit an engine to use fuel the opposite fuel tank.

-Fuel selector has three positions ON, OFF, CROSSFEED
-If cross feed is necessary, position the appropriate fuel selector to CROSSFEED to the tank that needs to be cross feed -Do not operate with both fuel selectors on CROSSFEED -Do not takeoff with a selector on CROSSFEED -There are total of 8 fuel drains… gasculator(fuel filter)(2), each fuel tank(4), each cross feed line(2) -Fuel vents – consists of a vent in each bottom of outboard fuel tank

ELECTRICAL -14Volt DC, negative ground electrical system
-1 main DC bus is supplied by…… -Two 60-ampere 14 volt alternators, one on each engine (Alternator makes AC but rectifier converts to DC) -One 35 –ampere-hour 12V lead acid battery (located in the nose section) -Voltage regulators – maintain load share and regulating the bus voltage to 14 volts -over voltage relays – protect equipments from regulator malfunction (red light shows when it is activated) -Alternator has advantage over generator – produce electrical output at low engine speed

-Ammeter – current flowing to or from the battery
-Load meter –shows load amount of current being produced by the alternator *seneca’s ammeter is load meter -Circuit breakers- protects equipments from high current from the main bus Abnormal question: 1. procedure for circuit breaker pop up? 2. how do we know if alternator fails?

VACUUM -1 engine driven vacuum pump on each engine so total of two
Note : vacuum pump is operated by engine power -Operates Heading indicator and Attitude indicators -Turn coordinators are operated by Electric -Regulators maintain a vacuum of 5.0 +/- 0.1 inches of Mg at 2000rpm -Vacuum less than 4.5 indicates possible instrument inaccuracy -When one vacuum fails, the valve automatically closes and vacuum is supplied by one pump -Red vacuum pump malfunction buttons appears on the face of the vacuum gauge -One pump has sufficient capacity to operate a dual set of gyro instruments up to a 12,500ft -Single pump above 12,500ft requires higher RPM to achieve adequate suction

PITOT-STATIC - Pitot pressure operates Airspeed indicator
- Static pressure operates Altimeter, Vertical speed, Airspeed indicator

CH4. Flight Limitation & Procedure

LIMITATION Maximum Gross Weight 4200 lbs
Maximum Landing Weight 4000 lbs Maximum Zero Fuel Weight 4000 lbs Service Ceiling 17,900 ft at 4200 lb Single Engine Service Ceiling 3,650 ft at 4200 lb Absolute Ceiling 19,400 ft at 4200 lb C.G. Range Limit at 4200 lbs Forward 88 in Aft 95 in Fuel Capacity Total 98 gal Usable 93 gal Unusable 5 gal Fuel Consumption (75% power) 20.6 gal Oil Capacity Each Engine 8 qts

DEFINITION Accelerate-Stop Distance Distance necessary to accelerate the airplane from a standing start to liftoff speed assuming the critical engine fails at liftoff speed and come to a full stop when liftoff speed is reached. Accelerate-Go Distance Distance required to continue a takeoff and climb to clear a 50 foot obstacle following engine failure at liftoff speed. Absolute Ceiling The density altitude where no further climb is possible with both engines at maximum power. Single Engine Absolute Ceiling The density altitude where no further climb is possible with one engine feathered. Service Ceiling The density altitude at which the aircraft can climb 100 fpm with both engines at maximum power. Single Engine Service Ceiling The density altitude at which the aircraft can climb 50 fpm with one engine feathered.

V - SPEEDS Vso 69 mph Stall speed in landing configuration
Vs mph Stall speed in cruise(clean) configuration Va mph Maneuvering speed Maximum speed without damaging aircraft structure with full and abrupt control Vno 190 mph Maximum structural cruising speed Should not exceed it except in smooth air Vne 217 mph Never exceed speed Vlo Maximum landing gear operating speed 150 mph Extension 125 mph Retraction Vle 150 mph Maximum landing gear extended speed Vfe 125 mph Maximum flap extended speed 10 degrees (160mph), 25 degrees(140mph), 40 degrees(125mph)

Vx 90 mph Best angle of climb speed
Vxse 90 mph Best angle of climb speed with one engine inoperative Vy mph Best rate of climb speed Vyse 105 mph Best rate of climb speed with one engine inoperative (Blue Radial) Vmc 80 mph Minimum control speed with critical engine inoperative in air The calibrated airspeed, at which, when the critical engine is suddenly made inoperative, it is possible to recover control of the airplane with that engine still inoperative, and maintain straight flight either with zero yaw or back angle no more than five degrees (Red Radial) Vx-max Maximum Crosswind Components: 17 KIAS

Preflight Preparation
Accurate computation of density altitude Single engine service ceiling Combination of high airport elevation and high temperature resulting in higher density Probability of a sustained single-engine climb to a safety circling altitude is very remote. Possibility of controlled descent to forced landing.

Preflight Preparation
Runway Requirement under existing conditions Accelerate-stop distance Distance required to accelerate to a specified speed and assuming an engine fails at exactly that speed, return to a full stop Sometimes double of the takeoff distance Therefore, Primary limiting factor when evaluating airplane runway requirements Obstacle clearance Available alternatives

V-Speeds

Taxiing 3 Methods Least favorable Steerable nosewheel
Differential Braking Differential power Least favorable Differential braking – wear and tear

Takeoff Verify Rotate 5 Kts Above Vmc
Engine instrument GREEN Power indication Manifold Pressure RPM Fuel Flow Oil Pressure/Temperature Airspeed Indicating Rise Rotate 5 Kts Above Vmc Under no condition rotate below Vmc

Takeoff Climb out at Vy Incase of engine failure at or higher than Vyse Clear of the runway, positive rate, insufficient runway – Brake and Gear UP First Power reduction until gear is fully retracted and at safe maneuvering altitude Fuel pump for each engine off individually and each mixture adjusted for climb Prop Synchronization

Climb Cruise climb Vy Vx Slower rate of climb
Decreases total trip time Better forward visibility Engine cooling Passenger comfort Save fuel Vy Faster rate to reach favorable wind aloft Better weather Vx Clear obstructions immediately after takeoff Increase in total trip time due to slower groundspeed Reduction in engine cooling

Landing On Final Approach Gas Checked Under Carriage Mixture Set
Propeller controls at high RPM Power reduction as airplane touchdown in proper landing attitude

Go Around Full Throttle (Mixture Prop already set) Climb (Vy)
Clean (Flaps, Gear) Cool (Cowl Flaps) Call (“Go Around”) Care (Prop, Mixture)

105MPH 120MPH 100MPH l 95MPH 95MPH 105MPH ⑥ ⑦ ④ ⑤ ③ ⑧ ② ① At CRZ ALT
CLB CHK List 수행 18 inHg/24RPM Mixture-Lean Cowl Flap-Close ⑥ ⑦ At Abeam No of RWY MP – 13 inHg Flaps – 10 VSI – 500 FPM 105 MPH 유지 G.U.M.P CHK At Pattern ALT DSN CHK List 수행 Fuel Selector -ON Radio – SET FLT INST- SET At Base Flap 25 VSI – 500 FPM 105 MPH 유지 At Pattern ALT 16 inHg/24RPM-for 120MPH Cowl Flap-Close ④ 105MPH 26 8 120MPH 750ft AGL 유지 At Mid of RWY Gear – Down SPD CHK-B 150MPH CHK 3 GRN Light At 1000FT AGL APP CHK List 수행 L/D LTS - ON FUEL PUMP – ON MIXTURE – RICH At 1000 AGL Climb CHK List수행 Landing light – OFF Fuel Pump – OFF Power 25/25/SYNC Gear-UP/Light off/HYD Pump off E/G Gauge CHK ⑤ 100MPH l 95MPH 500ft AGL 유지 95MPH 105MPH ③ At Final Flap 40 Gas-Fuel Selector ON Under Carriage Mixture – Full Prop – FWD Speed – 95 MPH At 500 AGL MP-25 inHg Prop- 25RPM ⑧ ② PITCH UP FOR 105 MPH Gear Up at Positive Climb Manual Brake apply Check Ammeter ① T/O POWER SET E/G GAUSE CHK AIR SPEED- ALIVE 85MPH -ROTATION Before L/D CHK List 수행 G.U.M.P – CHK L/D Gear Down/3 GRN

POWER OFF STALL INTRODUCE
RECOVERY SPD DECREASE ALT MAINTAIN CLEARING TURN PRE MANEUVER CHK - L/D LTS ON - ELEC FUEL PUMP ON - MIXTURE RICH - 18”/2400RPM - COWL FLAP OPEN 3. MONITOR HDG/ALT 4. 13” MP (INITIAL) 5. B 150MPH L/G DOWN ( Call “ SPD CHK GEAR DOWN) 6. FLAPS ( ) 7. AT 105MPH PROP FWR 8. AT 90 MPH POWER IDLE ① L/D LTS ON ②ELEC FUEL PUMP ON ③ ④18”/2400 ⑤ 주의 : MAINTAIN : SINGLE E/G 일 때와 틀림 HDG & ALT

POWER OFF STALL ⑤ RECOVERY AT FIRST INDICATION SIGNAL
LOWER THE NOSE TO HORIZON FULL POWER FLAP 25° GEAR UP AT POSITIVE CLB FLAP 10° - 0 MAINATAIN VY (105 MPH) UNTIL REACHING ALT RESUME NORMAL CRZ ① L/D LTS OFF ②ELEC FUEL PUMP OFF ③ ④18”/2400 ⑤ POST MANEUVER CHK 1.L/D LTS OFF 2.FUEL PUMP OFF 3.POWER SET/24/SYNC 4.MIXTURE LEAN 5.COWL FLAP CLOSE

VMC DEMO Cleaning Turn Pre Maneuvering CHK Note HDG & ALT
Decrease power – 13 “ MP Prop Full FWD – 105 MPH At 105 MPH- One E/G IDLE, Another E/G slowly Full power Pitch up with 1 KT/Sec until Loss of Directional Control Recovery Power Idle ( Alive E/G Side) Pitch down (For Increase SPD) Pitch UP at 100MPH then Maintain 105 MPH Note HDG 유지 – 가장 중요한 사항 HDG 유지 방법 – 살아 있는 엔진 쪽의 Rudder 를 살며시 밟아주고 Aileron은 방향을 유지하기 위하여 계속해서 돌려 준다 Recovery시 가장 중요한 사항은 Power Idle & increase시 방향 유지를 위해 Rudder Control를 해야 한다.(Ball Center)

S/E OPERATION S/E CONTROL PROCEDURE
① ② ③ 1.CONTROL-BLUE(105MPH) 2.POWER-FWD (M-P-T) 3.G/U,FLAPS UP/PUMP ON 4.DEAD FOOT/DEAD E/G 5.DEAD E/G IDLE

S/E OPERATION S/E CONTROL PROCEDURE
① ② 1.CONTROL-BLUE(105MPH) 2.POWER-FWD (M-P-T) 3.G/U,FLAPS UP/PUMP ON 4.DEAD FOOT/DEAD E/G 5.DEAD E/G IDLE ③ ③ ③

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