MEP.1.3 Normal Operation Light Twin

Question 1

MEP1.3.1 Pre-Flight Preparation

Answer 1

Workload in cockpit is higher

Have documentation ready

Systems of the aircraft studied

Prepare your flight

Conclude with an early and a comprehensive briefing about the flight

Question 2

MEP.1.3.2 Pre-Flight Inspection

Answer 2

Note:

• Props and their direction of rotaiton
• Cowl flaps
• Baggage compartments
• Fuel filler caps
• Drain points
• Engine compartments
• Ask about turbochargers, alternators and fire extinguishers

Question 3

MEP.1.3.3 Cockpit Checks

Answer 3

Confirm operation of:

• Fuel selectors
• Cowl flaps
• Emergency undercarriage extension
• Position your seat and, if available, adjust it vertically to the design eye point
• Ensure you can apply full rudder deflection and that the seat is securely locked

Carry out recommended pre-start checks for your aircraft

• If only one entry door on the right-hand side, leave it partly open for the start of the left engine, and then be doubly sure that it is securely closed for the start of the right engine

Question 4

MEP.1.3.4 Starting the Engine

Answer 4

Usual to start one engine at a time - even if you have external electrical power

If possible

• Start left engine first

If you only have 1 alternator on the right engine

• you may need its electrical power to start the left engine

Nav Lights or beacon light should be turned ON - but not strobe lights

Ensure area is clear, shout clear prop! And start left engine

You may start on battery

When starting the second engine:

• Make sure you have the correct starter engage switch selected and that the magneto switch is on.
• Close and lock the right-hand door and start the right engine

Question 5

MEP.1.3.5 Taxiing

Answer 5

You will require more thrust to get moving.

Don’t be harsh or hurried

Look for smaller aircraft and people behind

Move both throttles as one and as the acft starts to move, reduce the thrust and check the brakes

Requires some extra attention because of the increased wingspan

Excellent forward view

Acft will tend to sway over bumps and around corners as there is more mass in the wings due to the engine nacelles and fuel tanks

Softer ride for the same reason

Less vibration, less engine noise

Prop clearance is some twins is marginal so be cautions about bumps and soft or uneven ground, particularly when braking

Cross ground at 90º to minimise possibility of a prop strike

Question 6

MEP.1.3.5.1 Taxiing in High Winds - Differential Thrust

Answer 6

Use differential thrust on the engines so that the acft taxies straight in a crosswind

Reduces significantly the need for differential braking

Avoid using thrust against partial braking, hot brakes lose their effectiveness and they may be needed for an aborted take-off

Question 7

MEP.1.3.5.2 Manoeuvring in Tight Spaces

Answer 7

Differential thrust offers significant improvements in the ability to manoeuvre in a tight space

Especially effective with a touch of brake as the thrust line has a longer moment arm - but don’t stop the inned wheel

If you have already applied full rudder deflection and perhaps some differential braking be careful not to place too great a side load on the nosewheel strut

Question 8

MEP.1.3.5.3 Emergency Stop

Answer 8

In some acft park brake applied full and immediate pressure to both brakes

Shut down engines if there is the slightest risk of collision

Question 9

MEP.1.3.6 Run-Up and Pre-Take-Off Checks

Answer 9

In run-up area:

• Stop acft and apply park brake
• Do not rush or abbreviate run-up checks as they are crucial
• There will be a check of:
  • Engine
  • Systems
    Comprehensive check of:
  • Crossfeed system
  • Feathering of propellers

Make sure fuel selectors are returned to ON as take-off is generally prohibited with crossfeed selected.

Hence, carry out run-up checks before and separate from pre-take-off vital actions

Run-up the engines individually

Do not fly an acft with a magneto drop that is out of limits

Similarly, if there is any significant difference in MAP, fuel pressure or throttle position for the same RPM, have it checked.

Preferrable to do Run-up pointing into wind if your airfield procedures allow it

In crosswinds, there will be considerable side loads and out-of-balance focers placed on an engine and propeller.

You can actually hear and feel it.

Run forward sufficiently to straighten the nosewheel before stopping

Don’t forget that you may have now three trims to check

Previous of the Run-Up Departure, normally on the stand, but can be performed after Run-Up is the time for the Take-Off Briefing. (Section explained on IFR.2.12)

P

Question 10

MEP.1.3.7 Normal Take-off

Answer 10

Similar to single

Consider both throttles as one

Taxi to centreline and run fwd until nosewheel is straight

Then advance throttles to half “wat” (about 30’ MAP, check both engines are indicating normally and the same)

Then release brakes and advance throttles to 35’ in the MAP

Keep your hand over all levers but ready to close both throttles to abort if necessary

Look at the centre of the far end of the rwy and keep straight

40 Kts AIS alive, engine parameters in green

Vr, pull smoothly but firmly and start the rotation of the acft

Positive climb (altimeter increasing and variometer indicates a positive climb), and no rwy available, raise the Gear UP, while we fly the aircraft to obtain 100 kts

At 400ft, do the first reduction to 25’ MAP and RPM 25’, with the aircraft stabilised on climb, read the After Take Off Checklist

Question 11

MEP.1.3.7.1 Crosswind Take-off

Answer 11

Use into the wind airleron during the ground roll

Positively rotate at VR and allow acft to weather cock into wind

Maintain wings level, continue as for the normal take-off

You could use differential thrust as you start to roll but make sure full power is set on both as soon as the rudder is effective

Question 12

MEP.1.3.7.2 Short Field Take Off

Answer 12

Only used when absolutely necessary essential for obstacle clearance

Acft is very vulnerable during the period it is climbing at Vx

Acft is marginally above the stall and obstacles usually have associated turbulence

Engine failure during this phase requires lowering the nose and reducing power on the live engine to maintain control. Hence, the obstacle clearance will be non-existent

Question 13

MEP.1.3.8 Climb

Answer 13

After take-off and established in the climb attitude with climb power set

Focus on navigation while acft is climbing

You must only monitor the parameters, fly, navigate and communicate properly

Question 14

MEP.1.3.9 Cruise

Answer 14

Do not attempt to fly performance instruments

Set an attitude, hold it, trim the acft and then check the instruments

As you’ll be generally flying at higher altitudes, there will be a need to manage mixture controls.

Once normal cruise is set, cowl flaps can be retracted

Question 15

MEP.1.3.9.1 Engine and Propeller Synchronization

Answer 15

If props are out of sync:
Beat or variation sounds like
Wowowowowowo
Wwowwowwo
Wowwwwwwowwwowwwwwo

To synchronize the engines manually, set both engines to the desired throttle and rpm settings by reference to the instruments

Then slowly advance the right throttle and note whether there is a harmonic oscillating sound and whether the frequency gets faster or slower.

If faster, move the throttle slowly back and monitor the sound

After a while, you should detect when the oscillation smooths to a continuous hum and then the engines are in sync

Question 16

MEP.1.3.9.2 Three Axis Trimming

Answer 16

Correct sequence for trimming:

Maintain a constant attitude and trim in pitch (hold the attitude constant while using the elevator trim wheel to remove any residual push or pull force)

Maintain wings level with aileron and balance the acft with rudder

Then use the rudder trim to cancel out any foot forces

Lastly, use the aileron trim to remove any residual lateral force

To be precise with attitude:

• change
• check
  -hold
  -adjust
  -trim

Question 17

MEP1.3.10 General Handling

Answer 17

Twin has higher inertial in roll, it is reluctant to start rolling and when it does, it is reluctant to stop

The greater the wingspan the greater wing area causes a more marked effect or roll due to yawning but there is also an initial hesitation due to the inertia in roll

Acft accelerates considerably faster as soon as the nose is lowered

Question 18

MEP.1.3.10.1 High Speed Flight

Answer 18

From level cruise

• Set full power, notice the difference in acceleration compared to a single
• There will be the usual nose-up pitching moment due to the thrust and increasing airspeed, but there will be little or no yawning.

Question 19

MEP.1.3.10.2 Steep Turn and Spirals

Answer 19

Dange: twin can accelerate to Vno and beyond very quickly then the nose is allowed to drop

Steep turns need to be flown with a firm control attitude

Any tendency for the nose to drop should be immediately corrected if necessary, by momentarily reducing the bank angle

Question 20

MEP.1.3.10.3 Low Speed Flight

Answer 20

In level flight:

Close throttles and allow acft to decelerate while maintaining altitude

Nose down pitching moment due to the power reduction and also due to reducing airspeed

There will be little or no yaw if throttles are retarded simultaneously

Acft will feel more stable than a small single

It will feel heavier/slower in roll

Question 21

MEP.1.3.11 Stalling

Answer 21

Close throttles from straight and level flight

Nose down pitching moment and acft decelerates

Raising the nose to maintain level flight will require increasing back pressure on the control column

Airflow noise will be reduced and reduced control power due to the reduced airflow and propeller slipstream

There will be a pronounced nose-high attitude before the stall

Control column will require a high pull force and the displacement to the rear will be noticeable - in the pit of your stomach

Note this force and position

They are both valuable cues to an approaching stall

Question 22

MEP.1.3.12 Cruise Descent

Answer 22

Passenger comfort is provided by descending from an early enough point where you can maintain 500ft per minute rate of descent until you reach the arrival point

Plan to maintain Vno in smooth air if you are in a hurry but watch the rate of descent

In case of turbulence:

Reduce to Va
Compromise: 20 Knots below Vno as normal descent speed

In calm condicions:

Increase to Vno to increase rate of descent or distance travelled or, if there is any turbulence, reduce to Va

Check your flight manual: Va changes with weight

On IFR.2.13 you will find the method for calculating the Top of Descent in Flyschool

Question 23

MEP.1.3.13 Visual Circuit

Answer 23

It is professional to arrive in the circuit at the correct altitude, heading and speed

Joining the circuit is routine, but allow extra time and distance to decelerate to Vlo

Complete pre-landing checks early so that you can concentrate on the circuit entry and other traffic

Question 24

MEP.1.3.14 Approach and Normal Landing

Answer 24

Allow further lateral displacement on downwind than your single

Establish downwind spacing so that the wingtip is tracking down the centreline of the runway

Check surface wind

Complete pre-landing checks early

With a retractable undercarriage select down then wait for the three greens

Don’t continue pre-landing checks until you have 3 greens.

It is usual to lower partial flap abeam the touchdown point, before reaching base

Important to set attitudes and power around the circuit. If you do, the accuracy of your flying will improve and at the same time, the workload will be low

When you set Flaps 2, you can commmence to turn base (45º from Rwy Centreline Threshold

Reduce power to the recommended setting, holding the attitude level as you enter the turn

Don’t allow airspeed to come below Vyse until you are ready to lower full flap on final, and committed to land and are certain to reach the threshold.

Turn right through the base leg heading to allow for wind and set the straight descent attitude

Monitor centreline and turn early rather than late - especially if you have any tailwind component on base

Remember to trim the acft when the attitude is set. Imagine the centreline extended

Adjust bank in the final turn, but at the same time, be conscious of the pitch attitude. It is very easy to allow the nose to drop during the base to final turn

When acft is on final, select Final Flap position for landing, props full fine, mixture rich, carb heat off and then retrim.

Complete final checks including 3 greens. Reduce to Vref

Question 25

MEP.1.3.14 Approach and Normal Landing

In pictures

Answer 25

Approaching Traffic Pattern

• Descent checklist
• Reduce to traffic pattern airspeed and altitude

Downwind:

• Flaps-approach position
• Gear Down
• Before landing checklist

Base Leg

• Gear-check down
• Check for conflicting traffic

Final

• Gear-check down
• Flaps-landing position

Airspeed

• 1.3Vso or manufacturers recommended

Headwind Component on Base Leg:

• Delay the turn to final
• If undershooting final: easy off the bank angle
• Crab into the wind

Tailwind Componen on Base Leg
- Begin the turn to final earlier
- Ideally 20º bank
- Caution to overshoot
- If overshooting centreline: Steepen to a maximum of 30º bank angle - no steep turns
- Crab into the wind

Question 26

MEP.1.3.14.1 Aim Points

Answer 26

Where your eyes would impact the runway if you didn’t flare

Then aim for the numbers on the rwy beyond the piano keys or even the 300-metre fixed distance marker if you are using a longer rwy with VASIS or PAPI

Refine aim point and make small continuous corrections to fly your eyes to impact the aim point

Attitude and heading may be varying and the aim point will not necessarily be in a constant position in the windscreen

Control flightpath with the flight controls and the airspeed with the throttles

Monitor airspeed, attitude and aim point

There will be a tendency to over adjust the power to correct airspeed changes

If you monitor the airspeed trend and rate of change as well as the actual reading and make small but early changes, then the accuracy will improve

Make lateral adjustment with aileron, coordinated with rudder

Rudder input significantly improves the directional response at low airspeed

There are several reasons not to close the throttle before the falre. Closing the throttle causes:

• Loss of lift due to loss of slipstream
• Nose-Down pitching moment
• Loss of slipstream and threfore download from the tailplane
• Reduced elevator power due to loss of slipstream
• Loss of thrust

Question 27

MEP.1.3.14.2 Toch and Go Landing

Answer 27

Identify the flap for the takeoff or up setting and reapply power

Be careful to not select the undercarriage

You may need to retrim

Be careful not to look inside the cockpit for long

Try to feel and reach the controls and only look as a quick check

For retrimming, is it valuable to practise and to remember how much wheel movement approximately to reset the trim from landing to takeoff

Reintroduce full power and be careful to balance the power levers and to keep straight as you do so.

Continue for abnormal takeoff and be ready for an engine failure

Question 28

MEP.1.3.14.3 Short Field Landing

Answer 28

Short field landing is when LDA is marginal, but acceptable. Where you wish to stop short of patches of water or gravel or turn off early to allow following traffic to land

Circuit will be normal, approach will be normal, approach angle is normal

However, aim point is critical

For a shortfield landing you have to:

• Accept an increased risk of undershooting by using an aim point at or close to the threshold
• Minimise the float and ground roll

Question 29

MEP.1.3.14.4 Crosswind Landing

Answer 29

As there is greater span and higher inertia in roll, use the crab technique on final and through the flare.

In the flare:
- Lower into-wind wing to prevent drift

Don’t adjust the Vref for windspeed but for gust factor.

As a general rule, add half the gust factor to Vref.

Question 30

MEP.1.3.15 Go Around

Answer 30

When decision about Go-Around is made:

• Advance throttles for takeoff power

With adequate airspeed:
- Airplane should be placed in a climb pitch attitude

• Accomplish these actions simultaneously:
  • Arrest sink rate
  • Place acft in proper attitude for transition to a climb

Initial target airspeed is Vy or Vx if obstructions are present

With sufficient airspeed:

• Flaps should be retracted from full to an intermediate position and the landing gear retracted when there is a positive rate of climb and no chance of rwy contact.
• Then remaining flaps should be retracted

If Go-around was initiated due to conflicting traffic on the ground or aloft:

• Maneuver to the side so as to keep the conflicting traffic in sight
• May involve shallow bank turn to offset and then parallel the rwy/landing area

If acft was in trim for the landing approach when the go-around was commenced:

• It soon requires a great deal of forward elevator/stabilator pressure as the acft accelerates away in a climb
• Apply appropriate forward pressure to maintain the desired pitch attitude
• Trim should be commenced immediately
• Balked Landing Checklist should be reviewed as work load permits

Flaps should be retracted before the landing gear for two reasons:

• Full flaps produce more drag than the extended landing gear
• Acft tends to settle somewhat with flap retraction, and landing gear should be down in the event of an inadvertent, momentary touchdown

If go-around was initiated from a low airspeed:

• initial pitch up to a climb attitude must be tempered with the necessity of maintaining adequate flying speed throughout the maneuver

Examples:
- landing round out or recovery from a bad bounce
- inadvertent approach to stall

Priority is always:
Maintain control
- Obtain adequate flying speed
A few moments of level or near level flight may be required as the airplane accelerates up to climb speed

Question 31

MEP.1.3.15 Go-Around

In pictures

Answer 31

• Timely decision to make go-around
• Apply max power, adjust pitch attitude to arrest sink rate
• Flaps to intermediate
• Positive rate of climb, retract gear, climb at Vy
• Retract remaining flaps
• 500’ Cruise Climb

Question 32

MEP.1.3.16 Shutdown and Post-Flight Inspection

Answer 32

Before shutdown:

• Run engine at fast idle for at least a minute to stabilise the temperatures - especially the turbos

Carry out a post-flight inspection especially for stone or bird damage and for leaks (fuel, oil struts on brakes)

Question 33

MEP.1.4.1 Forces and Moments at Work - Normal Flight

1- How is the flightpath in symmetrical level flight at constant airspeed?

2-How’re the forces and moments if the acft is in trim?

3- How are the pitching moments balanced?

4- What are the small rolling or yawing moments in balanced flight?

5- What does the acft have to balance these moments?

Answer 33

1- Straight, level and stabilised

2- Balanced

3- By the tailplane and elevator trim

4- Small fuel imbalances or minor variations in thrust from each engine

5- rudder trim, and in many cases, aileron trim

Question 34

MEP.1.4.2 Engine Failure

1- What is the immediate consequence of having an engine failure in flight?

2- What is the impact on balance?

3- What happens with the loss of thrust?

4- What happens to lift and what happens when it is combined with a reducing airspeed?

5- What happens with a descending flightpath plus a loss of slipstream over the tailplane in most twins?

6- What is the consequence of having a difference between thrust and drag?

7- What does the yaw cause?

8- How is the stabilising force at high or low airspeed?

9- What happens on the side of the failed engine?

10- What happens as the yaw rate develops?

11- What happens with acft descent? What does it enter into? Will it recover?

Answer 34

1- Reduction of thrust and an increase in drag on the side of the failed engine

2-Balance between total thrust and drag is affected and therefore the acft will immediately decelrate

3- Nose drops and airspeed decays

4- There is a loss of total lift, and the reducing airspeed will cause the acft to descend

5- Causes a nose down pitching moment

6- Immediate yawing moment towards the dead engine

7- Yaw causes immediate sideslip and the fin and keel surfaces battle to keep the acft pointing into the relative airflow

8- The stabilizing force in high speed is powerful, whereas at low airspeed it is overwhelmed by the yaw due to asymmetric thrust

9- There is an immediate reduction in lift due to the reduced slipstream and thus there is a rolling towards the dead engine

10- The roll due to yaw combined with the roll due to sideslip, now causes a pronounced roll towards the failed engine

11- Acft descends more rapidly. It enters what is effectively a steepening spiral dive with asymmetric thrust, drag and lift overcoming the natural stability. It will not recover unaided.

Question 35

MEP.1.4.2.1 Flight Sequence - Uncorrected Engine Failure

1. What would happen if at the instant of failure, the pilot did nothing?
2. What if the acft is allowed to yaw?
3. What happens in the latter stage when the yaw rate is allowed to develop and further rolling is induced?
4. How can control be regained at this stage?

Answer 35

1. The acft wants to yaw and roll towards the dead engine and decelerate and descend.
2. The rolling moment due to yaw causes further roll and sideslip. The acft will enter a steepening, descending spiral.

Yaw——rolls——hesitates——yaws——rolls——departs

Nose will continue to drop, airspeed will start to increase due to the steepening descent path

3. It can lead to loss of control
4. By closing the throttle of the live engine and recovering from the dive - altitude permitting

Question 36

MEP.1.4.2.2 Control After Engine Failure

1. What is the most vital task on engine failure?
2. What if you cannot stop the yaw with full rudder?
3. What may you even have to accept in order to do this?

Answer 36

1. STOP THE YAW
2. You can only control the acft by reducing thrust on the live engine
3. A severe performance loss as a result

Question 37

MEP.1.4.2B.1 Refinements/Finesse

1. What are we looking for during an engine failure?
2. In what ways is it possible?
3. Why is the first option not viable practice?

Answer 37

1. Control with the least loss of performance

• Bank towards live engine - no rudder
• Rudder to stop yaw, wings level
• Rudder to stop yaw, slight bank

3. Because it is too dangerous and offers the greatest loss of performance

Question 38

MEP.1.4.2B.2 Option One: Bank Towards the Live Engine - No Rudder

1. What would happen if we allowed directional stability to stop the yaw?
2. What are the consequences of this?
3. What do you note about this?
4. How can you summarize it?
5. What’s another risk for the structure?
6. What would happen if the fin stalled?
7. What happens if the sideslip is allowed to develop and then full rudder is applied?

Answer 38

1. We would also have to stop the roll and the acft would be flying sideways
2. Enormous drag due to increased frontal area that is presented to the relative airflow and due to the need for a higher angle of attack to compensate for the reduced vertical component of lift.
3. Dreadful imbalance
   • Acft has a very high angle of sideslip
   • Relatively high angle of bank
   • Grossly increased frontal area
   • Large aileron deflection and a relative blanketed area of the wing
4. Excess bank toward operating engine, no rudder input.
   - Results:
   
   • large sideslip toward operating engine
   • Greatly reduced climb performance
5. Structural damage

Fin is an aerofoil and at 16º of sideslip, it will stall.

6. Not enough directional stability to stop the yaw. Control will be lost
7. Immediate fin stall

Question 39

MEP.1.4.2B.3 Option Two: Rudder to Stop Yaw - Wings Level

1. What do we do to prevent yaw?
2. How is this called?
3. Why would this method not make the best use of our control power?
4. What are the advantages of this technique?
5. What are some disadvantages?
6. What’s the compromise of this method?
7. What’s the relatively small performance loss exchanged for?
8. Why do instructors recommend having the wings level method for all situations except in engine failure on take-off?
9. What do you do when you are in doubt of which engine has failed?
10. Can you summarize this point?

Answer 39

1. Use rudder and maintain wings level with aileron
2. Wings-level method
3. Because rudder is having to fight against the directional stability
4. Easy to fly because wings are level and skid ball is centered

5.
- Extra drag due to sideslip, therefore reduced performance
- Although used for control in cruise, it does not offer the absolute best performance for critical situations such as engine failure after take-off

6. Compromise between orientation and performance.
7. Powerful visual references, external and internal to ensure that body’s sensations can be orientated.
   • Wings are level as well as balance ball and turn indicator are also centered
8. In a turn or in IMC and during approach in crosswind conditions, the balance ball centered or wings level provide a useful reference.

In addition, the human body can get confused between bank, balance, sideslip and yaw. It could become so confused that it is not sure which engine has failed.

9. Center the ball with rudder and work it out from there

10.

• Wings level
• Ball centered
• Acft slips toward dead engine

Results

• High drag
• Large control surface deflections required
• Rudder and fin in opposition due to sideslip

Question 40

MEP.1.4.2B.4 Option Three: Rudder to Stop Yaw, Slight Bank

1. How is this method called?
2. What does it offer?
3. Can you summarize it?
4. What’s the maximum recommended bank?
5. What can you do when the 3-5º bank towards the live engine displaces the balance ball slightly and it becomes a vague reference in IMC or in turbulence and you are in doubt?

Answer 40

1. Angle of bank method
2. Best performance

3.

• Bank toward operating engine, no sideslip

Results

• Much lower drag and small control surface deflections

4. 5º
5. Level wings with aileron, center the ball with rudder. Then reapply bank towards the live engine to restore best climb performance.

Question 41

MEP.1.4.3 Factors Affecting Controllability

1. What are the factors that affect controllability?

Answer 41

1. Those which affect the yawing and rolling moments and the power of the flight contrls to balance these moments:
   • Thrust on live engine
   • Altitude
   • Drag from the dead engine and propeller
   • P Factor
   • Torque Reaction
   • Difference in lift due to slipstream
   • CG Position
   • Airspeed (the most important)

Question 42

MEP.1.4.3.1 Thrust on the Live Engine

1. What happens when there is more thrust on the live engine?

Answer 42

1. The yawing moment from the live engine will be greater

Thrust is greatest at low speed

Question 43

MEP.1.4.3.2 Altitude

1. What happens as we increase altitude?
2. What’s the worst case scenario for engine failure?

Answer 43

1. Thrust reduces
2. At lowest altitude

Question 44

MEP.1.4.3.3 Drag from the Dead Engine

1. To what does drag from the Dead Engine directly contribute?
2. What will alter the total drag and yawing moment from this engine?
3. What if the failure is partial? What is the ultimate measure of controllability?
4. How is the drag in a windmilling propeller? How does it work?
5. What’s the outcome of feathering a propeller?

Answer 44

1. Yawing moment
2. Whether propeller is stopped, windmilling or feathered
3. Propeller may be delivering some thrust, controllability is ultimately measured by whether the pilot can maintain directional control
4. High.

Windmilling prop works in reverse, it is being driven. Reacts to relative airflow and generates both lift and drag, components of the total reaction.

5. Reduces drag and generates no torque (which produces itself induced drag)

Question 45

MEP.1.4.3.4 Torque Reaction

1. What happens when the engine turns the propeller?
2. How is the torque reaction in a twin with clockwise rotating engines?
3. What if the left engine fails?
4. What happens with counterrotating engines?

Answer 45

1. Reaction tries to turn the engines in the opposite directions
2. Torque reaction wants to roll acft to the left
3. Failure of the left engine is compounded as the torque reaction now adds to all of the other rolling moments
4. If left engine fails, right engine will rotate anticlockwise, and the reaction will be to roll the acf to the right against the other forces and moments.
   • Both P factor and torque reaction are minimized

There is no longer a critical engine

Question 46

MEP.1.4.3.5 Difference in Lift

1. What’s the result of an engine failure on one side?
2. What can we do to counteract this situation?

Answer 46

• Loss of propeller-induced lift on that side
• Reduction in total lift
• Tendency to descend
• Rolling moment towards the failed engine

2.

Feathering the propeller minimises the disruption to the airflow

Question 47

MEP.1.4.3.6 Position of the Centre of Gravity (CG)
1. Which position of CG offers the greatest stabilising moments and which one offers the least?

Answer 47

1. When CG is at its forward limit, distance to tail surfaces is at a maximum and the stabilizing moments are greatest.

The contrary happens when the CG is at its aft limit. Thus it will offer the least stable position and the least rudder power.

Question 48

MEP.1.4.3.7 Turbulence

1. What does turbulence do?
2. How does it affect control?

Answer 48

• Increases drag
• Demands control inputs, which in turn further increases drag

2. Makes it more difficult and demanding.

• Affects accuracy and symptoms and cues are masked

Question 49

MEP.1.4.3.8 Airspeed

1. On what does aerodynamic power of all the pilot’s controls depend?
2. What happens when there is more airspeed?
3. On what does the stabilizing moments of keel surfaces and the fin depend?
4. What happens when we increase altitude and airspeed?
5. What happens to a dead engine when we increase speed?
6. What happens to controllability with increasing speed?

Answer 49

1. Airspeed
2. More control power
3. Indicated Airspeed

4.

• Thrust reduces
• Yawing moment is reduced

5.

• Drag from failed engine also increases, but not as significantly in comparison with other elements

6. Significan improvement

Question 50

MEP.1.4.4 Minimum Control Airspeed

1. What happens if airspeed is reduced with maximum thrust set on the live engine?
2. What is this condition? What if you go below this speed?
3. Is the instructor allowed to shut down an engine and feather the propeller?
4. What about below this specified minimum altitude?
5. What about engine failure after take-off?

Answer 50

1. Full rudder will be required to prevent yaw
2. Minimum control speed, below which power on the live engine has to be reduced
3. Only above a specified minimum altitude
4. Engine failure is simulated by closing the throttle and then setting zero thrust
5. Only practiced in this way, and permission is required from tower at some aerodromes to practice asymmetric circuits and simulated engine failure after take-off (EFATO)

Question 51

MEP.1.4.5 VMCA

1. What is the difference between minimum control speed and Vmca?
2. How is VMCA measured?
3. What are the specific factors for the determination of Vmca by the test pilot?
4. What does VMCA take into account?

Answer 51

1. VMCA is a dynamic case. It represents sudden and complete engine failure
2. Under very stringent test conditions

• Critical engine suddenly failed with the propeller in the fine pitch position and windmilling
• Maximum thrust on the live engine
• No more than 5º of bank towards the live engine
• Undercarriage retracted
• Flaps in the take-off position
• CG at the AFT limit for take-off
• Maximum take-off weight
• Sea level ISA

4.

• Pilot skill
• Reaction time
• Strength
• Assumes full rudder is available
• Acft is allowed to deviate up to 20º in heading before the pilot regains control

Question 52

MEP.1.4.5.1 Factors Affecting VMCA

Answer 52

MEP1.4.5A.1 Effect of Bank

• Banking towards live engine:
  
  • Reduces rudder deflection required
  • Allows a lower VMCA
  • Only use a small amount of bank
• If a large amount of bank is used:
  
  • Significant reduction in the vertical component of lift
  • Requires a higher angle of attack to maintain altitude
  • More induced drag
  • Significant performance loss
  • Possible fin stall

MEP.1.4.5B.2 Effect of CG Position

• Directly affects the length of the tail moment arm and thus the power of the rudder and fin to maintain directional stability and control
• Destabilizing surfaces ahead of the CG are maximized at aft CG and minimized at forward CG

MEP1.4.5C.3 Effect of Flap

• It affects
  
  • Total lift and drag
  • Nose down pitching moment
  • Stalling speed
• In asymmetric conditions:
  
  • Lowering flaps:
    
    • Reduces climb performance
    • Increases margin above stall but does not directly affect VMCA
  • If take-off flap is set:
    
    • Difference in lift between the two wings due to the propeller slipstream is further increased
    • Rolling moment is increased
    • Requires increased aileron deflection
    • Indirectly affects VMCA

MEP1.4.5D.4 Effect of Cowl Flaps

• Directly increase drag, but can be retracted individually
  -When we open the cowl flap of the live engine:
  
  • for cooling
  • Increases the drag on the live side
• Close the cowl flap of failed engine:
  
  • Reduces drag on the dead side
• Both factors are favourable and would have a marginal effect on reducing VMCA

MEP.1.4.5E.5 Effect of Undercarriage

• Increases drag and thus directly affect performance but not control
• Does not significantly affect VMCA
• Extended undercarriage:
  
  • Decreases directional stability because of the greater surface area ahead of the CG when gear is extended
• Thus, the fin and rudder are opposed in sideslip in sideslip and this will slightly increase VMCA

MEP.1.4.5F.6 Conclusion

• Minimum speed at any time during practice should be Vsse or if a climb performance is a factor, Vyse (blue line)
• Additional unquantifiable factors
  • pilot skill and currency

Question 53

MEP.1.4.6 Performance After Engine Failure

1. How is performance determined?
2. What’s our first priority upon an engine failure counting that VMCA and V2 do not take into account any effect on performance?
3. What must we consider about the performance consequences once we’ve regained control?

Answer 53

• Thrust available versus thrust required
• Power available versus power required

Both depend on airspeed

2. Control of the aircraft

3.

• Establish control and carry out the immediate actions
• Accelerate towards the recommended speed for the flight condition and direction for best terrain clearance
• Clean up the aircraft as you do so
• When safely under control and clear of the ground tell someone
• Look after the good engine

Question 54

MEP.1.4.6.1 Summary

1. What are the only two practicable options for control in the event of engine failure?
2. What’s vital during an engine failure?

Answer 54

1.

• Wings-level method
  • It has advantages clear of the ground
• Angle of bank method which gives the maximum performance under the circumstances

2. Correctly identify the failed engine and feather the propller

Airspeed is everything