Turbocharged SR22 System Description Turbo Limitations Normal - - PowerPoint PPT Presentation

Turbocharged SR22

• System Description
• Turbo Limitations
• Normal Operating

Procedures

• Emergency Operating

Procedures

Turbonormalize vs. Turbocharged

A turbocharged engine has boosted manifold pressure above ambient sea level pressure, increasing the amount of power the engine is capable of producing.

VS

A turbonormalized engine compensates for the loss of ambient sea level pressure as the aircraft’s altitude

• increases. This allows the engine to maintain sea level

rated horsepower up to very high altitudes. It does not increase the amount of horsepower the engine is capable of producing.

Keep in Mind

• The engine always thinks it is at sea level
• The turbo does NOT increase the rated

horsepower of the engine

System Components

Upperdeck

• The portion of the turbo

system that starts after the turbo/compressor and ends at the throttle plate

• The turbo will create and

regulate 33 inches of pressure in the upperdeck before the intercoolers

• Key Upperdeck

components

– Intercooler – Overboost control

Intercooler

• The induction air from

the turbo is warm and pressurized to approximately 33 inches of pressure

• The intercooler cools

the induction air for combustion and reduces pressure to 29.6 inches

Overboost protection

• In the event of an
• verboost condition

excess pressure will be relieved by the overboost poppet valve.

• An overboost could be

cause by:

– Excessive oil pressure due to low oil temperature – Malfunction in the turbo system (absolute pressure control or wastegate)

Turbo

• Turbo- uses accelerated

exhaust gases to spin a compressor which increases the pressure in the upper deck.

• Capable of +100,000 RPM
• Maximum Turbo Inlet

Temperature (TIT) is 1750°F, seen on MFD Engine page

• Turbo is lubricated via the

engine oil system. Compressor Turbo

Turbo…

• A scavenger

pump is added to pull oil through the turbo for cooling and lubrication.

Turbo…

Twin Turbos supply pressure to the upperdeck

Turbo…

• The turbo allows the engine to maintain 100% power up

to 25,000’ MSL.

• The maximum certification altitude of 25,000’ MSL is

lower then the critical altitude.

– Critical altitude is the altitude where the turbo can low longer maintain sea level pressure. Not a factor in the Cirrus

• The amount of pressure produced by the turbo is a

function of exhaust allowed to flow through the turbo.

Wastegate

• The wastegate controls the

amount exhaust that is allowed to flow through the turbo.

• Air will take the path of least

resistance.

• A closed wastegate sends

more exhaust through the turbo.

• An opened wastegate allows

Exhaust to bypass the turbo and be dumped overboard.

• A spring holds the wastegate

in the open position. Oil pressure closes the wastegate.

• Each turbo has an

interconnected wastegate.

Wastegate…

True or False? An open wastegate sends more air through the turbo. FALSE

Wastegate Actuator

Absolute Pressure Control

• Moves the wastegate to

manage the pressure created by the turbo.

• Adjusts the wastegate to

maintain approximately 33 inches of pressure in the upperdeck

• Uses engine oil as

hydraulic fluid to move wastegate.

Absolute Pressure Control…

• Pressure from the

upperdeck is plumbed into the absolute pressure control unit.

• An aneroid inside the

APC will expand and contract based on the pressure in the upperdeck.

• Oil pressure to the

wastegate controller is adjusted by the movement of the aneroid.

• When the upper deck

pressure drops the aneroid expands allowing oil pressure to close the wastegate sending more exhaust through the turbo.

Air Intake

• Induction air

passes through an air filter in the front right cowl.

• The airflow splits

after the air filter to the right and left compressor

Air Intake

• An automatic alternate air source

will open if the air filter becomes clogged (ice, dirt…)

• Magnets hold alternate door
• closed. When the filter clogs the

pressure drops in the intake forcing the door open.

• The door will automatically close

when the resistance is gone.

• A message will appear on the

MFD alerting the pilot when the alternate air door opens or closes.

Fuel Injectors

• GAMI Injectors are

included with the turbo kit.

• Tuned injectors supply

close fuel/air ratios to all cylinders, important for running lean of peak

• Pressure from the

Upperdeck is plumbed to each injector preventing the backflow of fuel through the injector at high altitude.

Engine Driven Fuel Pump

• Upperdeck pressure is plumbed to an aneroid in the

engine driven fuel pump controlling the amount of fuel that goes to the engine or return line.

• High upperdeck pressure will cause the aneroid to

contract and increase the amount of fuel available to the engine.

• Low upperdeck pressure will cause the aneroid to

expanded sending more fuel to the return line.

• Why is this important? What would happen if you ran a

tank dry at high altitude.

Magnetos

• Magnetos receive

pressure from the upperdeck to prevent arcing

• An inline filter removes

contamination and moisture before the air enters the magneto

Environmental

• Warm pressurized air is

taken from Upperdeck before the Intercooler.

• The air is plumbed

through the exhaust to increase temperature.

• The air pressure from

the upper deck is higher then the pressure in the

• exhaust. This reduces

the chance of Carbon Monoxide from entering the cabin from an exhaust leak.

Environmental…

• A valve uses

ambient pressure and upperdeck pressure to control the amount of hot air available for the heater.

Putting it all Together

Engine Idling on the Ground at Sea Level

• Is the

wastegate

• pen or

closed?

• Why?

See speaker notes for the answer.

Full Throttle at Sea Level

• Is the wastegate
• pen or closed?
• Why?
• What could cause

an overboost when adding takeoff power? See speaker notes for the answer.

Departing Denver International (True of False)

• The mixture

should be leaned for takeoff to compensate for the higher altitude

• False!!!

See speaker notes for the answer.

As the Aircraft Climbs Through:

• 5,000MSL
• 10,000MSL
• 15,000MSL
• 20,000MSL
• 25,000MSL
• What happens to

the wastegate?

• Will the wastegate

be fully closed at 25,000MSL? See speaker notes for the answer.

Turbo Limitations

System Limitations

• Operating Limitations

Speed KIAS Remarks Vne up to 17,500 MSL 201 Never Exceed Vne at 25,000 MSL 171 Vne is reduced linearly from 17,500 to 25,000 Vno up to 17,500 MSL 178 Maximum Structural Cruising Speed Vno at 25,000 MSL 152 Vno is reduced linearly from 17,500 to 25,000

Note: Vno and Vne can be interpolated for altitudes between 17,500 and 25,000. The PFD airspeed tape will change with altitude to reflect the difference in Vne / Vno

System Limitations

• Altitude Limits

– Maximum Takeoff Altitude…...………..10,000 MSL – Maximum Operating Altitude................25,000 MSL Note: FAR 91.211 requires the use of oxygen below the maximum operating altitude.

• Environmental Conditions

– Do not operate the aircraft below an outside air temperature of -40°C

System Limitations

• Flap Limitation

– Do not use flaps above………………...17,500 MSL

• Power Plant

– Avoid continuous operation with the fuel flow set between 30gph and 18 gph with the MP above 26’’ MP Warning: Continuous operation with MP above 26’’ and fuel flow set between 30 gph and 18 gph could lead to engine damage and possible failure. Operation in this area can lead to excessively high cylinder head pressures and temperatures.

Normal Operating Procedures

Preflight

• O2 preflight

– O2 quantity, requirements and duration tables – Verify O2 flow to each mask/cannula that will be used

• Pulse Oximeter

– Check saturation levels on the ground and monitor during flight. – Adjust O2 flow to maintain saturation levels above 90%

• Cannulas can not be used

above FL180 as per FAR part

• 23. Masks must be worn

above FL180. Plan accordingly.

O2 Considerations

• Do not use cannulas above FL180
• Passengers should be thoroughly brief on the use of O2

including:

– Proper use of masks/cannulas and flow regulators – Recognition and response to hypoxia – Recognition and response to pilot incapacitation

• If saturation levels decrease below 90%

– Increase to flow of O2 – Increase mask seal around face – Descend to a lower altitude if saturation level can not be maintained above 90%

Normal Procedures

• Engine Start

– No Change

• Taxi

– Lean mixture to the X in miXture

• Before Takeoff

– No Change – Ensure oil temperature is above 100° F before run up

Takeoff

• Full throttle
• Full mixture (for every altitude)
• Boost pump on
• Monitor MP for overboost

– If the MP exceeds 32 inches reduce the throttle below 32 inches of MP

Note: Manifold pressure in the yellow arc (29.6 – 32) is normal with full power and no action is required as long as MP does not exceed 32”

Full Power Climb

• Full power
• Mixture rich for all altitudes
• Boost on
• CHT cooling is a function of airspeed

– CHT’s should be kept within normal operating temperatures

• Cruise climb airspeeds

– Up to 7000 MSL -120 KIAS – After 7000 MSL – 130 KIAS

Lean of Peak Climb

After transitioning to a cruise climb

– Throttle 2700RPM’s / Max MP (full throttle) – Mixture lean to 17.5GPH – Boost pump on – Airspeed 130KIAS Note: CHT’s should be kept below 380° F during lean of peak climbs – CHT cooling is a function of fuel flow and airflow – IF CHT’s exceed 380° F

• Increase airspeed and sacrifice climb performance and/or
• Decrease fuel flow .5GPH at a time. CHT’s do not respond as quickly as
• EGTs. Monitor CHT’s and watch for trends. This will also sacrifice climb

performance.

– If CHT’s can not maintained below 380° F with the fuel flow and or airspeed switch to a full rich climb setting. – Above 18,000 MSL transition to full power / full mixture climb.

Operations Lean of Peak (EGT)

EGT- exhaust gas temp CHT- cylinder head temp ICP- internal cylinder pressure HP- horsepower 1/BSFC- brake specific fuel consumption (efficiency rating comparing HP to fuel flow) Note:

• Close relationship of CHT, ICP, HP
• Order of peaks- HP, ICP, CHT,

EGT

• Curvature of peaks on the rich and

lean side of peak

• Rich of peak

– Leaner increases CHT

• Lean of peak

– Leaner decreases CHT 1 3 4 5 2

Full Power Climb vs. Lean of Peak Climbs

Cruise Altitude (MSL) Fuel Savings LOP (Gallons) Range Increase LOP (NM) 2,000 .5 5 4,000 .9 9 6,000 1.4 14 8,000 1.9 20 10,000 2.5 26 12,000 3.1 33 14,000 3.7 41 16,000 4.4 49 18,000 5.1 58 20,000 5.1 58 22,000 5.0 59 24,000 5.0 60 25,000 4.9 60 The following is a comparison between a lean of peak climb and full power climb from sea level

Full Power Climb vs. Lean of Peak Climbs Consider the following factors when deciding to climb LOP or ROP

• Workload associated with LOP climbs

– Closely monitor CHT’s – Adjusting mixture/airspeed for cooling – Transitioning to ROP @ 18,000MSL…

• Decrease in climb performance
• Significance of fuel savings
• Significance of extra range

Cruise

• Leave power, mixture and boost until aircraft

accelerates to cruise speed

• All cruise power settings will be lean of peak
• Power setting can vary from 85% - 65% for

normal cruise and should be selected considering fuel and time requirements.

• The Max Power Fuel Flow placard will be

replaced with:

– Avoid continuous operation with the fuel flow set between 18 gph and 30 gph with the MP above 26”

Setting Cruise Power

• Throttle to 2500 RPM / Max MP (29.0 – 29.6)
• Adjust mixture to 17.6 – 17.0GPH

– Mixture should be pulled smoothly and promptly to 17.5GPH. Small adjustments can be made once the fuel flow is within the ballpark range – Percent power will be approximately 85%

• Reduce throttle to 75% or 65% as desired
• If CHT’s go above 380° F during level cruise lean the mixture to cool

the CHT’s

– On the lean side of peak approximately .5 gph leaner near 380° F should result in a 15° F decrease in CHT.

• Boost pump off after 30 Min. Why?
• Turning the boost pump off will change fuel flows

– Before turning pump off note fuel flow – Turn boost pump off and readjust mixture to previous fuel flow

Boost Pump Operation

• Pressure affects the temperature required to vaporize

fuel

– Lower pressure = lower vaporization temperature

• Low boost provides extra pressure to keep fuel from

vaporizing at high altitude

• High boost may be necessary above FL180 with warm
• r hot fuel if vapor lock is present
• Vapor lock can be recognized in flight by:

– Fluctuations in normal fuel flow – Rising EGTs and TIT coupled with falling fuel flow – Rising CHTs

Engine Roughness at Lean of Peak

• Unbalanced

fuel/air ratios

• More apparent

during lean of peak operations

• Why?,

Remember the HP curve in relation the fuel/air ratios

40 HP 50 HP 60 HP 65 HP 50 HP 45 HP 310 HP total output

Unbalanced Fuel/Air ratios

Balanced Fuel/Air ratios

Descent

• Descent planning is key when operating at higher

altitudes

– Garmin VNAV – Calculate top of descent (TOD)

• Altitude to loose / 1000fpm = TOD ETE
• Example; 19,000’ to loose / 1000fpm = TOD 19 minute ETE
• Avoid power idle for extended periods
• Maintain CHT’s above 240° F (airspeed/power setting)
• Throttle- reduce as necessary
• Mixture- do not touch
• Boost pump- off

Normal Procedures

• Before Landing

– Power as required – Flaps 100% – Mixture full rich (regardless of field elevation)

• Before FAF or traffic pattern

– Boost pump on – Lights as required

After Landing and Shutdown

• After Landing

– Lean aircraft for taxi

• Shutdown

– No change – Turbo cool down time is not required – Turbo cooling is a function of oil temperature not turbo inlet temperature

True or False?

• Leaning the engine will cause the CHT’s to rise

when operating lean of peak. See speaker notes for answer.

Scenario

During a lean of peak climb while climbing at 130KIAS the CHT’s exceed 380° F

– What is the appropriate response? – What if that does not work? – What if that does not work? See speaker notes for answer

Scenario

After setting cruise power at 85% (2500RPM / Max MP and 17.6 GPS) the CHT’s remain at 395° F.

– What is the appropriate action? See speaker notes for answer

Emergency Procedures

Specific to Turbo Operations

Unexplained Loss of Manifold Pressure

• Cause:

– A leak or rupture somewhere in the induction system. The engine will operate as a normally aspirated

• engine. Problem poses little threat to the system. As

descent from high altitude may be necessary. Or; – A leak in the exhaust system. A significant threat and may lead to engine fire.

• It is very difficult to distinguish between the

possible causes of the problem.

Unexplained Loss of Manifold Pressure

• An unexpected loss of manifold pressure should be

treated as an emergency.

– Power minimum required – Be alert for indications of an engine fire. At the first sign of fire, shut fuel selector off and refer to in flight fire checklist. – Declare emergency – Land as soon as possible

• Post Maintenance Consideration

– To ensure proper connections of the many components, intakes and ducting, etc, a flight to high altitude (17,500-FL250) should be accomplished to ensure proper turbo operation. – Consider completing this flight as soon as possible in case additional maintenance is required by your service center.

Engine Failure

• One cause of engine failure may be from reducing the power to idle

with the mixture set near or at full rich. Altitude and fuel pump

• peration will affect the failure conditions.

Note: The cause of the engine failure is an excessively rich mixture of fuel and air, essentially flooding the engine. Note: If this is not cause of the failure refer to the engine failure in flight checklist procedure.

• First reaction to failure

– Increase throttle control

• If that does not work

– Auxiliary fuel pump off – Throttle ½ inch open – Mixture control lean until engine starts – Throttle, mixture and fuel pump reset for normal operation.

• Richen the mixture slowly after engine start then increase the throttle.

Scenario

Shortly after leveling out at 22,000 you set the cruise power, lean the mixture and turn your boost pump off and your engine fails.

– What do you do? – Why did the engine fail? See speaker notes for answer.