Commercial Pilot Ground School Class 1 PDF

COMMERCIAL PILOT GROUND SCHOOL AIRFRAMES, ENGINES, AND SYSTEMS CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 1 Course Outline Class 1: 96 slides Class 3: 72 slides - Methods of constructions - Other Aircraft Systems - Landing Gear...

COMMERCIAL PILOT GROUND SCHOOL AIRFRAMES, ENGINES, AND SYSTEMS CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 1 Course Outline Class 1: 96 slides Class 3: 72 slides - Methods of constructions - Other Aircraft Systems - Landing Gears, Brakes, Flaps - Turbochargers and Superchargers - Jet Engines (Turbines) - Engines - Oxygen and Pressurization - Anti-Ice and De-Ice Systems Class 2: 112 slides - Carburation Class 4: Final Exam and Review - Fuel Injection - EXAM: 50 multiple choice questions. - Electrical System - 1 hour. - Lubrication Systems and Oil - Fuel Properties and Fuel Systems - Review: 1 hour. Same day as final exam. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 2 Important Information – CPL AES Commercial AES is based on all the Requires self-study: previous knowledge you have learned - Review your notes and supplement them with the FTGU textbook and CPL workbook. in PPL ground school. Additionally, we - Great visual explanations are available online will introduce you the systems present (interactive videos). in high-performance aircrafts. Expectations​ Reference material: - Be on time​ - Be in uniform​ - Ground school slides. - Have supplies to take notes​ - From the Ground Up. - If you are not on time and in uniform, you will be - Commercial FTGU workbook. marked absent and asked to leave! - TC CPL Study and Reference Guide Study hall: - Each Wednesday, 1200-1500, in library. FREE! CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 3 Today’s pilot has evolved from a practitioner of skill into a systems manager, requiring an in depth understanding of the equipment being operated. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 4 CPL AES AIRFRAMES CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 5 Methods of Construction Truss Type - Wood or steel tubing - Strong - Non-load bearing skin usually made of fabric or plywood Monocoque Type - Monocoque or stressed skin - Usually composed of aluminum or composite - Light and strong but complex, the skin bears the load - When extra internal bracing is used it is called semi-monocoque CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 6  The stressed skin construction is just that, “stressed”, and the thin skin absorbs all loads. Hence, any damage, however slight, must be examined by an A.M.E. before an aircraft is flown. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 7 Materials Used in Construction Aluminum alloy - Durable - Resists weathering - Light but strong - Ideal for assembly by semi-skilled personnel - Proven technology with lots of design data available. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 8 Materials Used in Construction Wood - Flexible, Light & strong - Was cost effective - Labor intensive and difficult construction. - Difficult to get in good quality and long lengths. - Still a commonly used material when used in combination with modern epoxy resins. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 9 Materials Used in Construction Composites - Made from fiberglass, kevlar, carbon and/or graphite embedded in epoxy resin, vinyester or polyester resin - Light &strong - Expensive - Smooth surfaces - Easy to use for compound curves CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 10 Fiberglass Composite CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 11 Composites Composite construction uses a “sandwich” of high strength skin materials separated by a lightweight core material. The outer skin carries most of the tension and compression loads, while the core transmits loads (mostly shear) from one skin surface to the other. Composites can be tailored to take full advantage of the material properties involved and the aerodynamic and structural requirements needed. Core materials may be PVC foam, extruded Styrofoam, end grain balsa wood, Nomex paper honeycomb, or aluminum honeycomb. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 12 Composite Spar Section CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 13 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 14 OLDER STYLE CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 15 MODERN STYLE CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 16 Modern aircraft do not use a wing tip bow which is a hold over from the days of tube and fabric aircraft. They often have a one piece wingtip (often a fiberglass molded part) for better aerodynamics and ease of maintenance. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 17 CPL AES LANDING GEAR, BRAKES, AND FLAPS CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 18 Wheel arrangement There are 3 types of wheel arrangements commonly found on aircraft - Tail Wheel (conventional gear) - Tricycle ( trike gear ) - Tandem CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 19 Tailwheel Conventional Tail wheel gear. Main wheels ahead of the C of G. Steerable or fixed tail wheel. Tendency to ground loop in crosswinds Ideal for rough fields Difficultly handling in high winds due to high angle of attack on the ground CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 20 Tricycle Gear Most common landing gear configuration. Main wheels behind the C of G Steering through nose wheel Superior in ground handling CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 21 Tandem Gear Seldom found on modern airplanes Wheels are in straight line Wings supported by outrigger wheels This type of gear is used on the U-2 spy plane and Harrier jet CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 22 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 23 The Oleo Used to absorb the shock of landing The shock is absorbed by oil that is forced through a hole Springs or compressed air may be added to provide shock absorption while on the ground taxiing Compressed air is sometimes replaced with nitrogen to prevent corrosion CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 24 Retractable Landing Gear More sophisticated aircraft typically have retractable landing gear, which is selected in the “up” or “down” position by the pilot. There are significant aerodynamic advantages to having the gear retract, but it adds weight, complexity, cost, and there is always the possibility of the pilot landing with the gear up. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 25 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 26 The Brakes Good brakes must be: - Reliable - Able to dissipate heat rapidly There are 2 Major advantages of having brakes on an A/C: - Quick deceleration - Steering on ground (differential) CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 27 Mechanical Brake Actuation Were used on the very earliest of airplanes. Deployed with a hand crank or gravity Generally a poor substitute for hydraulic brakes. Still used on some ultralight aircraft. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 28 Hydraulic Brake Actuation The introduction of the hydraulic system quickly replaced the mechanical system on most modern aircraft Often work in the same manner as hydraulic brakes in a car. Pressure is applied to the system (usually through the rudder pedals) activating a piston that pushes a pad that pinches a disc against a another pad. Its all dependent on the integrity of the system with respect to the hydraulic fluid. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 29 Hydraulic Brake Actuation The hydraulic brake fluid in system is somewhat flammable, and is frequently dyed red in color, so it will be easy to spot any leaks. Many aircraft let you brake each wheel independently, for steering assist. Hydraulic brakes on larger, more sophisticated aircraft may be complicated by pneumatic, hydraulic or electrical boost systems. Some aircraft have anti-skid brake systems(a complex electro-hydraulic device) CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 30 Pneumatic Brake Actuation Pneumatic systems are similar to hydraulic but use air instead of a fluid, and a drum instead of the disc assembly. Usually found on older aircraft CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 31 Electrical Brake Actuation The key to the electrical system is an electrically-driven screw jack that raises and lowers the landing gear. There is a gear reduction system to decrease speed and increase the force of rotation. Still other gears for changing rotary motion into push- pull motion. And, linkage for connecting the push-pull movement to the landing gear strut. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 32 The Disc Brake CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 33 Flap Actuation Many light aircraft are fitted with flaps that have a strictly mechanical flap actuation. The pilot pulls on an actuating lever and thru various pushrods and bell cranks, the flaps are deployed such is the case for the Seminole - The cheapest, and some would say, the best linkage is the pure mechanical one. - Where a mechanical linkage is not feasible due to complexity of linkage or the large aerodynamic forces involved, other methods are used. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 34 Flap Actuation Hydraulic cylinders may be used to actuate the flaps. (hydraulic pump involved may be manually or electrically powered.) In other cases, electric motors drive linkages using the screw jack to provide flap movement…such is the case for the C-172 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 35 Mechanical Flap Linkage CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 36 CPL AES ENGINES CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 37 Engine Cylinder Layouts Horizontally Opposed Radial Engine In-line Engine CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 38 Horizontally Opposed Most popular design. (for light aircraft) Good visibility. Low parasite drag. Comparatively low cost Manufacturing leaders are Lycoming and Continental. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 39 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 40 Radial Engine Very rugged and reliable. Large amount of parasite drag Poor visibility (in single-engine aircraft) No longer produced commercially (except in Russia and Poland) Manufacturing leaders were Pratt & Whitney and Curtis- Wright Multiple rows of Radial engines exist to allow for greater power CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 41 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 42 Inline Engine Good drag and visibility characteristics. Limited in the number of cylinders because of vibration. Popular with British manufacturers, e.g. the “Gypsy Queen” Still manufactured today. May be mounted upside down to allow for better visibility The practical limit for cylinders in a row is six Multiple rows of inline cylinders may be used in the V, X, and H configurations using the same crankshaft for greater power CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 43 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 44 Engine Power Piston engines are rated in horsepower. Power is the rate of doing work. Work is the amount of heat transformed into energy. One horsepower is the amount of work done when 33,000 pounds are raised one foot in one minute. Brake HP- the amount of power available after friction and other losses. Jet engines are rated in pounds of static thrust. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 45 Engine Power Indicated HP is the amount of HP developed within an internal combustion engine. Indicated HP is equal to PLAN÷33,000 where:- - P= The mean cylinder pressure in lbs/sq.in. - L= The length of the stroke in feet - A= The area of the piston in sq. inches - N= the number of impulses ( power strokes) per minute Another important factor is torque which is the twisting moment developed by an engine. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 46 The 4 Stroke Cycle The piston travels 4 times to complete one four-stroke cycle, 2 up and 2 down. The 4 strokes are: - Intake - compression - power - exhaust CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 47 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 48 The Two Stroke Cycle Two-stroke engines are very powerful for their weight. They are considered somewhat unreliable for aircraft use but have improved greatly in the last few years. They are not very fuel efficient. They are often very noisy. Commonly found in such equipment as lawn mowers, snow blowers, motorbikes, etc. In aviation the 2-strokes are used almost exclusively on ultra-light aircraft. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 49 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 50 Valve Overlap Valve overlap appears to defy common sense as both the intake and exhaust valves are open at the same time for a portion of the four-stroke cycle. Due to the inertia of the gases in the combustion chamber the scavenging action of the departing exhaust gasses helps the inlet charge fill the cylinder. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 51 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 52 Methods of Engine Cooling Air Cooled (the most popular today) Oil Cooled through lubrication (the oil cooling helps cool an air-cooled engine) Liquid cooled (water cooled) CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 53 Air Cooling Air cooled engines use a system of fins on the cylinder barrels and cylinder head section of the “jug” or “pot” to provide area for cooling. Air is directed over the fins by a system of baffles within the cowling. In some engines, exhaust augmentor tubes enhance the cooling effect. Oil cooling is a necessary integral component of the air cooled engine. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 54 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 55 Liquid Cooling Some aircraft engines are liquid cooled. These engines have water jackets surrounding the heat producing parts of the engine and the associated complexity of water pump(s) and a radiator(s). This is not very common on present day engines but it does tend to enhance fuel efficiency and make the engine quieter. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 56 The Ignition System The ignition system provides the spark to ignite the fuel/air mixture The Magnetos provides the electrical punch to fire the spark Magneto: Engine driven generator that produces an alternating current Its source of energy: a permanent magnet CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 57 The Ignition System Contains: - Two Magnetos - Two spark plugs in each cylinder - Ignition lead - Magneto switch CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 58 Polarity of a Magnet When something is magnetized - It acquires a “north” and a “south” pole - “Unlike” poles attract. “Like” poles repel The magnetic lines of force in a magnet pass from South to North, then from North to South CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 59 Principles of the Magneto Now, imagine the magnet is around a coil of wires The current is induced on the coil as the magnet and coil are rotating AC current, low tension CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 60 Principles of the Magneto A magneto is an electromagnetic device that can generate electricity The magnetic field created by the magnet generates electricity in the coil of wire. If the conductor is wound into a coil that has many turns of fine wire, a very large amount of electricity will be generated in the coil. This is the basic principle of operation that runs a magneto CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 61 Principles of the Magneto: Types Rotating Armature type magneto - Horseshoe magnet with a rotating iron core, wound with a coil of wire Rotating Magnets type - The core is stationary and the magnets rotate - The principle is the same CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 62 Principles of the Magneto Armature between the magnet poles generate a low tension current in the primary winding (first set of wires) The contact breaker opens, stops the flow of current in primary winding, and makes it collapse The collapse of the magnetic field around the primary winding induces a high voltage in the secondary winding. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 63 Principles of the Magneto Secondary Winding - Coil of wires, lighter than the primary - Wound around the primary in a tighter ratio high tension carried to the distributor rotor by a carbon brush and then to the proper spark plug through the appropriate ignition cable. The ignition switch grounds the primary circuit to stop the magneto from producing sparks when not needed. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 64 The Principles of the Magneto This high voltage is carried to the distributor rotor by a carbon brush and then to the proper spark plug through the appropriate ignition cable. The ignition switch grounds the primary circuit to stop the magneto from producing sparks. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 65 The Magneto Condenser - Prevents current from jumping across gap of contact breaker. Impulse coupling - Facilitates starting - Permits magneto to turn quickly regardless of crankshaft speed - Winds up the armature CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 66 Dual Ignition All aircraft (with very few exceptions) have dual ignition. Usually this is two magnetos per engine Some dual magnetos are driven by a single shaft There are two spark plugs per cylinder. The advantages of this system are: - Safety - Performance ( better combustion, power increased) CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 67 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 68 Full Authority Digital Engine Control Computer controls the engine - Fuel injection - Ignition firing Establishes desired spark, mixture control and parameters Purpose: fuel consumption, HP increase, engine smoothness, engine start capabilities CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 69 FADEC Available for both piston and jet engines Flight crew enters data in FMS which uses this data to calculate power settings for different phases of the flight. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 70 Exhaust Systems The purpose of the exhaust system is to expel spent gases (and deadly carbon monoxide) away from the aircraft. Exhaust systems are usually made of stainless steel for light weight, strength, and corrosion resistance. The typical light plane has a short stack exhaust system, or a simple collector arrangement. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 71 Mufflers Help reduce noise levels. Usually have a heat shroud for ancillary controls. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 72 Exhaust Systems The collector system on a turbo-charged engine is of course more complex. Exhaust Augmentors (augmentor tubes) assist in engine cooling by creating a low pressure near the back of the engine cowl which draws air around the engine. Mufflers help reduce noise levels and usually incorporate a heat shroud to provide hot air for some ancillary controls. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 73 Exhaust Augmentor Cooling System CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 74 Turbo-Charger Exhaust CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 75 Ancillary Controls Carburetor Heat Control Primer Pump Mixture Control Alternate Air Cowl Flaps Environmental Controls - Windshield Defogger - Cabin Heat and Ventilation CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 76 Ancillary Controls Most of the ancillary controls are related to engine management. Primer Pump is a manually operated pump that squirts raw fuel into the intake ports. It aids cold starting. Carb Heat Control provides heated air to the carb and prevents or eliminates carburetor icing. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 77 Ancillary Controls Mixture Control lets the pilot adjust the fuel-air mixture from full rich to full lean to allow for various power requirements and fuel economy. Alternate Air provides a backup inlet air source selectable in case the normal air inlet is blocked for whatever reason (usually icing). CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 78 Ancillary Controls Cowl Flaps are used on some aircraft to let the pilot have an additional measure of control over engine cooling and temperatures. Environmental Controls include a cabin heater and windshield defroster and provision to take in outside air for cabin cooling. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 79 Effects of Density Altitude, Humidity and Power Outside air temperature & altitude will affect the power output of an engine. The more dense the air is, the better the engine performance. (as seen with the turbocharger) Density altitude ( pressure altitude corrected for temperature) gives an indication of your engine performance, important for calculating the safe fuel/payload for take-off. The lower the Density Altitude (MSL), the better the performance. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 80 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 81 Effects of Density Altitude, Humidity and Power Humidity decreases the density of the air. Therefore, humidity decreases engine performance (slightly). Humidity; however, only gives about a 2% change in power output at - 32º Celsius and - 100% relative humidity. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 82 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 83 Limitations and Operations The life of the modern aircraft engine is dependent on good maintenance and good operating procedures. Good operating procedures include: - On take-off open throttle slowly but positively and steady - Once climbing speed is reached reduce power slowly. - Avoid high speed dives with the engine idling. - Avoid long run-ups that overheat the engine. - If the engine is fitted with idle cut-off, this should always be used to stop the engine. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 84 Engine Instruments The engine instruments provide the pilot with valuable information on the performance and “health” of the engine. The most common engine instruments are listed in the following slides: CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 85 Engine Instruments Oil Pressure Gauge - indicates pressure produced by the oil pump - should be checked after start, and indicate pressure within 30 seconds in summer, 1 minute in the winter. - Cold oil may cause higher than normal pressure - hot oil will cause lower than normal pressure. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 86 Engine Instruments Oil Temp Gauge - Measures the temperature of the oil in the oil sump. - Located next to oil pressure gauge. - Gives an indication of what to expect from oil pressure. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 87 Engine Instruments Fuel Pressure Gauge - Shows pressure output by the fuel pump for low wing aircraft. - High wing aircraft low power aircraft typically do not need them as they use a gravity feed system CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 88 Engine Instruments Tachometer - Measures the RPM (revolutions per minute) of the engine. - On fixed pitch props, it’s the only indication of power. - On aircraft with constant speed props, it is used in conjunction with manifold pressure. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 89 Engine Instruments Carburetor Air Temperature - It’s a pilots guide to using the carb heat. - Depending on the installation, indicates the temperature of the fuel air mixture before entering the carb, or after leaving the carb. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 90 Engine Instruments Exhaust Gas Temperature - Found in light aircraft more frequently than in previous years, the exhaust gas temperature gauge uses a thermocouple to measure the actual temperature of the exhaust gases near an exhaust port. - It is very useful in leaning the mixture correctly. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 91 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 92 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 93 Engine Instruments Suction Gauge - Shows the amount of pressure differential in the vacuum system. - Gives an indication if the gyro instruments are operating properly. - Measured in inches of mercury. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 94 Engine Instruments Manifold Pressure Gauge - Indicates, in inches of mercury, the pressure of the fuel air mixture in the intake manifold. - Found on aircraft with controllable pitch or constant speed props. - Power settings are a combination of manifold pressure and RPM. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 95 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 96 CPL AES CARBURATION CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 97 Theory of Operation The carburetor must measure the airflow through the induction system and use this measurement to regulate the amount of fuel which is discharged into the airstream. The carburetor system uses the venturi tube principle as it narrows to increase the fuel/air velocity. Remember Bernoulli? CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 98 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 99 The Carburetor Mixes fuel & air in the proper ratio. - Mixture is based on weight not volume. - Richest mixture 8:1 - Best power mixture 14:1 - Leanest Mixture 20:1 These ratios represent for example, 14 pounds of air to 1 pound of fuel. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 100 The Carburetor: Idling When engine idles, throttle valve is partially closed Insufficient air in venturi to lower pressure Idle jet provides a narrow passage for air to accelerate and drop pressure - Because low pressure is required to draw fuel. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 101 The Carburetor: Acceleration Pump During rapid acceleration - Liquid fuel cannot accelerate as quickly as air - Causes a temporary leanness Acceleration pump draws more fuel at the carburetor - When throttle is opened slowly, valve open, no extra fuel - When throttle is open quickly, valve closes, fuel pumped through discharge needle CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 102 Mixture Control Regulates the amount of fuel supplied to the carburetor. - Can be manual or automatic. In light aircraft it is almost always a manual control. The mixture is adjusted to give best power or best economy for the altitude at which the aircraft is operating. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 103 Mixture Control A general rule is that rich mixtures are for high power settings, and lean mixtures are for cruise power settings. The mixture control may be used to shut down the engine if the Carburetor has an “idle cut-off” provision. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 104 Mixture Control: Idle Cut-off Idle Cut Off - The mixture control is moved full aft to the lean position, the fuel flow is immediately stopped and the engine ceases to operate. - This system makes the aircraft easy to start by leaving the carburetor and fuel lines full. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 105 Leaning the Mixture Leaning the mixture translates into improved economy of fuel consumption which means lower costs of operation and means a smoother running engine. A more efficient engine, gives higher indicated airspeeds and better airplane performance. Excessively rich mixtures make the engine run rough and cause vibrations which might cause damage to engine mounts and engine accessories. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 106 Leaning the Mixture Leaning also extends the range of the airplane at cruise, And there is less spark plug fouling and longer life for spark plugs, And provides a more desirable engine operating temperature, And cleaner combustion chambers and therefore less likelihood of pre-ignition from undesirable deposits. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 107 Leaning the Mixture Improper leaning (worst case scenario) has led to shortened engine life, poor engine performance, and occasionally even engine failure. Improper leaning (best case scenario) has deprived airplane owners of a tremendous amount of fuel economy. The most common misuse of the mixture control by pilots is the selection of too lean a ratio. “Too lean” a mixture, however, causes overheating of the cylinder parts and, in many cases, will lead to complete engine failure and substantial damage. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 108 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 109 Carburetor Ice Simply put, carburetor icing is caused by the cooling effect of the carburetor and moisture in the air. Icing can occur at a temperature range of -6 degrees Celsius up to +32 degrees Celsius. The ultimate hazard can be a total blockage of the intake system and engine failure. Icing can be recognized by a loss of power (or a sudden engine stoppage). CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 110 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 111 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 112 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 113 Carburetor Heat Carburetor heat is an ancillary control in cockpit that should not be used on the ground. Use on the ground will ingest foreign material into the carburetor. Proper use causes a richer mixture, And causes a drop in power (this is normal) Should always be used in the full position, unless coupled with a carb air temperature gauge. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 114 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 115 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 116 CPL AES FUEL INJECTION CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 117 Principle of Operation In a fuel injected engine, fuel is metered to each cylinder. This produces slightly more power and uses less fuel than a carburetor system. Most injected engines have what is known as “port injection”. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 118 Principle of Operation In a port injection engine, a continuous flow of fuel is vaporized into the induction system near the intake valve. This fuel vaporization is sucked into each cylinder on the intake strokes. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 119 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 120 Fuel Injection Icing and Alternate Air As already stated, fuel injected engines cannot have carburetor ice, they can; however, still have inlet tract icing which can be serious. Icing may also form around the air filter, or the throttle butterfly, or the manifold tubes. This type of icing is known as “impact icing”, and it can restrict or completely cut off the air flow, if this happens a source of alternate air is necessary. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 121 Fuel Injection Icing and Alternate Air The alternate air source referred to should not be confused with the alternate “static” source which utilizes cabin air should the static port become clogged with ice or other material. An alternate air source is provided so that if the normal air inlet becomes clogged with impact icing, an air source inside the cowling, out of harms way, is utilized. With this alternate air source inside the cowling warmer air is provided to the environment. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 122 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 123 The Diesel Engine Principle almost identical to gasoline engine Some Significant differences internally: - Fuel air mixture is ignited by heat resulting from compression of air into the top of cylinder - Does not require electric ignition Does not require carburetor CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 124 The Diesel Engine Compression rate is usually from 15:1 to 20:1 Operating temperatures: between 500 and 700 Celsius. Air at such temperature causes ignition of fuel, which is sprayed in the combustion chamber at very high pressure - 500 lbs per square inch CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 125 The Diesel Engine Fewer moving parts Greater power-per-pound of fuel More time between overhaul requirements Develops less power-per-pound of total weight vs gasoline engine More costly Complex dampening of vibrations required CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 126 CPL AES ELECTRICAL SYSTEM CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 127 The Generator The generator is driven by the engine for the purpose of supplying current and to recharge the battery. (some very old airplanes had a wind driven fan that turned the generator) The generator supplies DC (direct current) to the electrical system by means of electromechanical induction. All generators; however, require AC (alternating current) to operate and is supplied by…as the word indicates, the alternator. The generator is heavy and inefficient compared to its modern replacement the alternator. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 128 The Alternator The alternator supplies electric power to the electrical system. It works on a different principle than the generator as it generates AC internally which is converted (by diodes) to give DC. The alternator is more efficient through a range of engine speeds and takes less horsepower to turn. Alternators often weigh less than a comparable generator. The alternator carries the electrical load in flight and recharges the battery. The C-172 has a 60-amp alternator. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 129 The Battery The battery is for starting the engine, which enables the alternator. (it is also a back-up it the alternator goes down) The battery stores the electrical energy that may be required to operate various instruments and equipment. It is important; therefore, it must be fully charged to ensure the electrical system runs properly. Light aircraft batteries are considerably smaller than automobile batteries, so they must be handled with caution and respect. The C-172 (1978) has a 25-volt, 14 amp-hour (or 17) battery. (provides 14 amps for 1 hour, or 7 amps for 2 hours…but the higher the load, the hotter the battery which reduces the efficiency)(28 volt electrical system) CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 130 External Lights Conventional navigation lights located on the wing tips and the top of the rudder. A single landing light or dual landing/taxi lights also are included. A rotating beacon is required and this lighting package may be supplemented by strobe lights. (anti-collision) CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 131 Interior Lights Instrument and control panel lighting provided by flood lighting and post lights. The floodlight may be red to preserve night vision. Engine instruments, radio equipment , and the magnetic compass frequently have their own internal lighting. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 132 Master, Alternator, and Generator Switches Often the master switch is a split rocker type switch labelled MASTER. The right half of the switch, labelled BAT, controls all electrical power to the aircraft. The left half, labelled ALT, controls the alternator. Normally, both sides of the master are used simultaneously; however the BAT side may be turned on to check electrical equipment on the ground. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 133 Master, Alternator, and Generator Switches By turning the ALT to OFF, the alternator is removed from the electrical system and the load is then carried by the battery. Continued operation with the ALT turned off will drain the battery to a point where power will also be removed from the alternator field resulting in being unable to restart the alternator. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 134 Ammeter and Load Meter The ammeter indicates the flow of current, in amperes, from the alternator to the battery. (or from the battery to the aircraft electrical system if the alternator is down) When the engine is operating and the master is turned on, the ammeter indicates the charging rate applied to the battery. Some airplanes are equipped with an automatic over voltage protection system consisting of an over voltage sensor behind the instrument panel and a red warning light. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 135 The Bus Bar The bus bar is a large conductive metal strap to which various electrical terminals are attached. It can be thought of as similar to the service entrance panel in your home. The bus bar receives current produced by the alternator. (or battery) From the bus bar current goes to various circuit breakers and to various electrical circuits connected to electrical components. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 136 Circuit Breakers and Fuses All electrical circuits are protected by circuit breakers or fuses. They are part of the system to protect the components, and wiring, against damage caused by short circuits and excess current. Most circuit breakers are the “push to reset” type, but some aircraft are equipped with a toggle type circuit breaker to protect the avionics package. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 137 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 138 Grounding and Bonding Grounding is a method of providing electrical current paths through the airframe. The negative side of the battery terminal connects to “ground” which provides the complete path for various electrical circuits through the airframe. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 139 Grounding and Bonding Various fixed and moveable components of the aircraft are provided with flexible electrical straps or wires so that the entire airframe is interconnected. The electrical system is “bonded” together. This helps prevent dissimilar charges and electrical “noise” which can affect navaids and radios. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 140 Grounding and Bonding Because the aircraft flies through the air, it can at times build up a considerable static electrical charge. To help prevent this, static discharge wicks are installed at strategic locations on the airframe to help dissipate any static electric charge. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 141 Grounding and Bonding Because the static charge can be high on occasion, it is imperative that when an aircraft is refueled, it is first connected to ground to dissipate any static charge. The action of fueling itself may also build up an electrical charge waiting to discharge and cause a possible fuel fire. The connection to ground is often a clip on a ground wire that is connected to a tie-down ring or other easily grounded component. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 142 Oil Types There are 3 main types of aircraft engine oils: 1. Mineral Oil - commonly used often in new normally aspirated engines during the “break in” period 2. Ashless Dispersant - Very commonly used, it does not have the tendency to form carbon that mineral oil does - Used for the break in on turbocharged engines 3. Synthetic - Ideal for harsh environments and high engine temperatures or cold outside temperatures (very good oil) CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 143 CPL AES LUBRICATION SYSTEMS AND OIL CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 144 Viscosity Viscosity is resistance to flow (stickiness) an oil which flows slowly is viscous or high viscosity. Free flowing oil has a low viscosity. An oil is designated by a viscosity index number by the S.A.E. A high number is a high viscosity. High viscosity means, due to use with varying temperatures, the changes it undergoes is small. High oil pressure will result from using too high a viscosity. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 145 Grades and Seasonal Use Aviation oils are classified numerically with grades typically 50, 60, 80, 100, 120. A “W” in front of the grade number indicates it is suitable for winter use and has that numeric viscosity in winter environments. Newer oils are often multi-grades which enable engine operation under various temperature ranges without the necessity to change the oil. Summer viscosity 120 S.A.E. 60 Fall or Spring viscosity 100 S.A.E. 50 Winter viscosity 80 S.A.E. 40 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 146 Purpose of Oil Cooling- moves heat ( heat transfer) Sealing- helps seal the piston and cylinder Lubrication- reduces friction, and cushions shock loads to bearings Flushing- cleans deposits and keeps particles in suspension and protects against corrosion. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 147 Methods of Lubrication Wet Sump System - The oil drains back into a sump beneath the crankcase and then is sucked up at the oil pickup and is pumped throughout the engine again. Dry Sump System - In a dry sump system the oil goes down to the bottom of the engine but one or more scavenge pumps pick up the oil from wherever it is in the engine and sends it to a separate collector or header tank. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 148 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 149 Methods of Lubrication A dry sump system lets the engine be more compact and ensures that oil is available no matter what the aircraft attitude. Another advantage of this dry sump system is that the engine can be provided with a much larger oil capacity and always have some in reserve. The dry sump system; however, is more complex and expensive. A wet sump system is light and simple. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 150 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 151 Venting Since an engine is basically an air pump, large volumes of gases are flowing during operation. The crankcase of the engine is vented to the atmosphere to allow for “blowby” and pumping losses. This venting is often a simple tube with a baffle (oil / air separator) that directs crankcase vapors out the bottom of the engine compartment. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 152 Oil Dilution Oil Dilution is a system whereby raw gasoline is added to the engine oil just before engine shut-down. The purpose of this is to thin the oil sufficiently to enable a restart when outside temperatures are extremely cold. This thinned oil provides better lubrication at very cold temperatures. When the engine does start, oil temperatures are allowed to climb to normal ranges and the gasoline is vaporized out of the crankcase oil. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 153 Oil Filters Solid contaminants and sludge pumped through the aircraft engine lubrication system can clog oil passages and damage moving parts. The engine does wear somewhat during operation and combustion itself creates harmful by-products that need to be dealt with. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 154 Oil Filters Major Oil Contaminants are - gasoline - moisture - acids - dirt - carbon - metallic particles CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 155 Oil Filters These minute pieces of metal and combustion by- products can damage the internal surfaces of the engine if allowed to circulate freely. It is the job of the oil filter to capture this junk and enable it to be disposed of at the next engine service interval. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 156 Oil Filters Sometimes the Aircraft Maintenance Engineer will use the filter as a diagnostic tool. By cutting the oil filter apart and examining its internal pleated paper folds for evidence of something unusual, the A.M.E. can get another clue as to the health of the engine. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 157 Pressure Relief An engine oil system has provision to dump excess oil by a filter bypass (usually) to prevent undue pressures building up. This might occur when oil temps are too low, engine RPM is high, or oil viscosity is too high for conditions. Without a pressure relief valve, gaskets and seals could fail, or the oil pump may be overloaded and possibly fail. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 158 Oil Cooler A oil cooler is a small radiator that lets hot engine oil cool before it is returned to the oil sump. If engine oil is overheated it may reach the “flash point” where the hot oil vapors can ignite explosively. Overheated engine oil also breaks down and the viscosity changes to a point where lubrication failure can occur. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 159 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 160 FUEL AND FUEL SYSTEMS CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 161 Fuel Types There are several types of fuel used in aircraft engines. Primary fuel in the aircraft we fly is AVGAS, or aviation gasoline. Jet fuel closely related to kerosene or diesel fuel which is not suitable for most piston engines. MOGAS, or automotive gasoline, used with permission in some aircraft engines. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 162 Fuel Types Each fuel is appropriate for a specific engine type, and is formulated for the ideal combination characteristics for that fuel type. Fuel types have specific properties and fall into different grades depending on their characteristics. To aid in identification, fuels of different grades are dyed in specific colors. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 163 Properties of Fuel Good fuels burn slowly and expand evenly. OCTANE - a substance which possesses minimum detonating qualities. HEPTANE - a substance which possesses maximum detonating qualities. The grade of fuel is a ratio of octane to heptane. - ‘80 octane’ is 80% octane & 20% heptane. - Octane #’s go up to 100, then the value is expressed as a performance number. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 164 Grades of Fuel Grades may be indicated by 2 numbers (80/87) The first number is octane at lean mixture The second number is octane at rich mixture Grade 100HL med power green Grade 100LL med power blue Grade 80/87 low power red MOGAS P87-90 green MOGAS P84-87 un-dyed Increased Lead content(Increased lead fouling over time) Jet Fuel kerosene clear/straw CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 165 Weight and Density Fuel weight is determined by density and not volume. (6lbs/US Gallon) - 10 liters of AVGAS weighs 15.8 lbs. - 1 imperial gallon of AVGAS weighs 7.20 lbs. - Jet fuel typically weighs more from 8.01 to 8.39 pounds per imperial gallon. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 166 Additives Water that may be suspended in the fuel may, in very cold weather, change into ice crystals and accumulate in fuel lines in sufficient quantity to block the fuel line and cause an engine stoppage. Anti-icing fuel additives inhibit the formation of these ice crystals. Other special fuel additives have been developed to scavenge lead and reduce lead fouling of spark plugs. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 167 Additives Fuel additives should be used only if approved by the engine manufacturer, and used only in strict compliance with the manufacturers instructions. A typical fuel additive is “Prist” which has anti-icing, anti-microbial agents, and assorted other good stuff in it. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 168 Contamination and Deterioration Fuel can easily be contaminated. This is especially likely when the aircraft is refueled from drums, as condensation and flakes of rust are often present in fuel drums. Also fuel will deteriorate with age as volatile components of the fuel evaporate out, leaving behind the heavier components of the fuel. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 169 Contamination and Deterioration Some Contaminants can include: - Solids such as dirt, or rust - Improper fuel grade - Water - Sludge - Micro-organisms Needless to say none of the above are ideal fuel for aircraft engines. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 170 Contamination and Deterioration Some fuel additives such as “ Prist” will help deal with these fuel contaminants. The responsibility of the PIC to ensure that the aircraft is only fueled with fresh, clean fuel. Old fuel is not to be trusted as it can leave deposits in the fuel system, cause difficult starting, or reduce power significantly. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 171 Tank Location The location, size and shape of fuel tanks vary with the type of airplane in which they are installed. The wing is the ideal tank location for safety and center of gravity effects. Fuel tanks are most often located in the wings of the aircraft, although extra tanks may be located in the cabin area. Wing tip tanks are also fairly common. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 172 Tank Location High wing low powered aircraft typically have wing tanks that let fuel flow by gravity to the engine. Low wing aircraft typically have fuel in the wings but rely on mechanical and electrically driven fuel pumps to get a reliable supply of fuel to the engine. This is the primary requirement of a fuel system, to deliver the proper amount of fuel at the right pressure to meet the engine demands. It must deliver this fuel reliably throughout all phases of flight, including violent maneuvers and sudden acceleration and deceleration. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 173 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 174 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 175 Tank Location In addition to wing tanks, fuel systems may be complicated by the addition of various tip tanks, header tanks, crossfeeds, selector valves, pumps, and so on. Tanks are often made of aluminum, but may be fabricated as a fuel bladder (often known as a fuel cell ) made out of synthetic rubber or nylon impregnated with fuel resistant material. When entire sections of the wing are sealed off to hold the fuel, it is known as a “wet wing”. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 176 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 177 Venting and Baffling Fuel tanks require atmospheric pressure to allow flow of fuel. Venting can be through fuel caps. Venting can also be through a line connected to the tank. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 178 Venting and Baffling Fuel Baffling- Metal plates are placed throughout the tanks to prevent fuel surging from one area of the tanks to another with attitude changes. Fuel baffles act like a maze to give few places for large volumes of fuel to move unimpeded throughout the tank. The problem with big tanks is a possible large change in C of G without baffles. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 179 Venting and Baffling Fuel sloshing in the tank is not a problem when the tank is full since there is no place for the displacement of fuel with change in attitude. Some aircraft (military aircraft) have a special foam filling in the fuel cell, this is for anti-explosion effects, but it also acts as a very efficient fuel baffle. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 180 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 181 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 182 Fuel Lines – Filters and Drains Fuel Lines - constructed of aluminum alloy metal tubing and flexible rubber or Teflon hose. Fuel Filters - located at the lowest point of the system to prevent foreign matter from entering the carburetor and to trap small amounts of water which may be present. Fuel Drains - located at the lowest point of the fuel tank and fuel system. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 183 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 184 The Induction System The induction manifold provides a means of distributing the fuel/air mixture to the cylinders from the carburetor. When the fuel is introduced into the airstream by the carburetor in a liquid form, it must be vaporized by the air, this takes place partly in the induction manifold. The next slide is of a fuel injection system but it shows schematically, the induction manifold. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 185 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 186 Detonation The inability of fuel to burn slowly. It is generally defined as abnormally rapid combustion, replacing or occurring simultaneously with normal combustion. It results in a rapid rise in cylinder pressures and temperatures beyond the structural limitations that the engine was designed for. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 187 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 188 Detonation Detonation is dangerous and costly. It puts a high stress on engine parts and causes overheating, warped valves and piston damage. It is not always easy to detect, but a Cylinder Head Temperatures gauge will offer the best appraisal of the unseen combustion process. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 189 Detonation A rapid increase in cylinder head temperature, unless explained by some other factor, often indicates detonation. Throttle reduction is the most immediate and surest remedy. Detonation may be audible to the pilot if you have a keen ear and know what it sounds like. sometimes colloquially called “spark knock” and may be heard if you are loading the engine too much such as climbing at best angle too long or running low octane gas (80/87) in an engine designed for high octane (100LL). CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 190 Detonation - Cause Caused by: - use of incorrect fuel - overheating (prolonged climb at best angle) - too lean a mixture - too much boost or manifold pressure (more complex aircraft) CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 191 Detonation - Cures Temporary Remedy: - enrich the mixture - reduce power Permanent Remedy: - long term detonation is caused by using a fuel with too low an octane - ALWAYS use the correct octane as listed in the POH, or the next higher. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 192 Pre-Ignition The premature ignition of the fuel/air mixture. (not to be confused with detonation) Pre-Ignition is the ignition of the fuel/air mixture before the timed spark from the magneto occurs. Caused by glowing carbon particles or local hot spots in cylinders. Often experienced when starting a hot engine, and usually results in a “backfire” through the intake manifold. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 193 Pre-Ignition Pre-Ignition can be prevented by good engine maintenance and operating procedures which result in avoiding extremely high temperatures in the cowling. Pre-ignition will cause warped pistons, cracked cylinder heads and other serious damage. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 194 Vapour Lock Vapour Lock occurs when fuel changes from a liquid to a gas state. High temperatures may cause gasoline to vaporize resulting in a blockage in the fuel line preventing the flow of liquid fuel. More common with some types of MOGAS CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 195 Vapour Lock Vapor lock may also be caused by low atmospheric pressures (very high altitudes) or by low fuel pressure. Fuel injected engines may be hard to start when hot because of vapor lock. The use of correct fuel grades (and a fuel boost pump) may help alleviate the problem. Another simple fix for vapor lock starting problems is to open up the cowling and let things cool off before attempting a restart. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 196 Fuel Heater Some aircraft engines incorporate a fuel heater so that water droplets will not ice up and block the fuel filter. The Fuel heater resembles a radiator and may be of one of two types: - Air-to-liquid - Liquid-to-liquid CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 197 Fuel Heater Air-to-liquid uses hot compressor bleed air circulated around fuel lines inside the fuel heater. (turbo-charged or turbine engines) Liquid-to-liquid uses hot engine oil to heat the fuel lines inside the fuel heater. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 198 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 199 Primers The primer pump is an essential aid to starting most aircraft engines. Incorrect use of the primer can lead to problems, such as failure to start, or in worse case scenarios, engine fires. The primer is a small metal hand pump, often located on the instrument panel. The primer draws filtered fuel from the fuel system and injects a fine spray directly into the engine intake ports. This system is useful particularly for cold weather starts when fuel is difficult to vaporize. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 200 Primer Use The primer must be used only as specified in the Aircraft Flight Manual (P.O.H.) Overpriming will increase the possibility of an engine fire during start. Most manual primers are equipped with a lock and after being pushed full in must be rotated either left or right until the pin is past the notch and the knob cannot be pulled out. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 201 Primer Use If the primer is not locked the engine may draw fuel through the priming system, and the enriched fuel/air mixture can result in engine roughness or even engine failure. The fact which should be appreciated is that most engine fires which occur at the time of starting result from improper techniques in the use of the primer (over-priming), throttle accelerator pump (pumping), or other priming devices. It’s usually a “backfire” that starts the fire. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 202 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 203 Fuel Management and Safety Fuel management in the air is very important. 1 in 3 accidents are caused by fuel starvation. Fuel additives should only be used in accordance with the POH. ALWAYS check for fuel contaminants when fueling. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 204 Fuel Management – Air/ Ground Know the accurate amount of fuel. Know fuel consumption per hour. Know max endurance. Lean the mixture properly. Monitor a clock and the Hobbs Meter for switching tanks. Balance fuel burn. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 205 Fuel Handling Ensure correct type and grade of fuel goes in the tanks. Ground the aircraft. Record fuel before or after every flight. Do not start or stop an aircraft when it’s pointing at the fuel pumps or tanks. Be careful of contamination. No smoking. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 206 Grounding and Bonding While the aircraft flies through the air, it can at times build up a considerable static electrical charge. To help prevent this, static discharge wicks may be installed at strategic locations on the airframe to help dissipate any static electric charge. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 207 Grounding and Bonding Because the static charge can be high on occasion, it is imperative that when an aircraft is refueled, it is first connected to a ground wire to dissipate any static charge. The action of fueling itself may also build up an electrical charge waiting to discharge and cause a possible fuel fire. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 208 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 209 CPL AES OTHER AIRCRAFT SYSTEMS CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 210 Turbocharging Turbochargers provide the engine with more dense air at high altitudes, and let an engine develop higher power at lower altitudes. If the turbo provides higher than atmospheric pressure in the inlet manifold this is referred to as “boost”. Boosted engines are very powerful but require appropriate engine management techniques. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 211 Turbocharging A turbo is driven by hot engine exhaust gases which drive a turbine wheel or “impeller”. The turbine wheel is mounted on a shaft along with a centrifugal air compressor. The cool air is compressed making it more dense before being fed to an inlet to the manifold of the engine. Additional power is now produced because of this new fuel:air mixture. Exhaust gas is controlled by a “waste gate” to keep pressures within limits. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 212 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 213 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 214 Leaning a Turbocharged Engine Special consideration and limitations must be made in leaning turbocharged engines. In many turbocharged engines, a rich mixture is required to adequately cool the engine. Care must always be exercised in using the mixture control. Incorrect mixture ratios will cause certain variations in engine performance. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 215 Jet Engines Turbine (jet) engines are more powerful, lighter and far simpler in design than reciprocating engines. Same principle as other aircraft engine: - Accelerating a mass of air rearward - Newton’s second law: Force is equal to mass multiplied by acceleration - Newton’s third law: For every action, there is an equal and opposite reaction CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 216 Jet Propulsion Energy added by burning fuel to raise its temperature and to expand the air Hot expanded air exits the engine Converts thermal energy into velocity Fuel and air must be burned at high pressures Air is compressed prior adding fuel Achieved by the compressor in most engines CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 217 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 218 Jet Principles In the Combustion Chamber fuel is introduced and the fuel air mixture is ignited. (once ignition takes place, combustion remains continuous) Fuel is mixed in and ignition occurs There’s no spark plugs, but rather…a flame. Once lit, the cycle will continue if the fuel/air mixture is uninterrupted CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 219 Jet Principles In the Compressor Section at the front of the engine large volumes of air are drawn in and compressed The intake air is compressed and rammed into the combustion chamber by a compressor, which is driven by a turbine wheel CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 220 Jet Principles In the Exhaust Turbine, hot exhaust gases spin this turbine which is coupled to the inlet section to provide inlet compression. The turbine in turn is driven by the momentum of the hot exhaust gases. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 221 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 222 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 223 Jets Compressors Can have multiple stages of compression Two main types of compressors - Axial Compressor - Centrifugal Compressor CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 224 Jets Compressors - Differences Axial Flow: - More efficient - Greater capacity of air for given frontal area Centrifugal Compressor: - More robust - Tolerant to damage - Easy to design Large engines use axial for high efficiency Small engines use a combination of axial and centrifugal CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 225 Jets Compressors – Axial Requires two types of blades - Rotor blades - Stator blades Rotor blades rotate, accelerates air through engine Stator blades are fixed - Converts air velocity to pressure - Raises the pressure through steps CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 226 Jets Compressors – Axial Air passing through ROTOR accelerates fast, with small increase in pressure Air passes then through stator blades, converts velocity to pressure - Significant increase in pressure - Decrease in velocity Air moves to next set of rotor/stator - 10 stages is common on large jets CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 227 Jets Compressors – Axial Stators also eliminate the spinning motion of airflow Ensures air hits next set or rotors at proper Angle of Attack CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 228 Jets Compressors – Centrifugal Two components - One that Rotates (Impeller) - One that is Stationary (Diffuser) Air forced to rotate by the spinning impeller Flings air outward into diffuser Air enters diffuser, slows it down, converts velocity into pressure Directs it to combustion chamber CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 229 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 230 File:Turboprop T-53.jpg CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 231 Jet Combustion Chambers Double walled chambers 30% of air for combustion 70% through outer walls - Cools inner wall - Steers the flame - Eventually mixes with combustion product, cools it Air to fuel ratio 15:1 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 232 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 233 Jet Combustion Chambers - Types Three types - Can type - Can-Annular type - Annular type CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 234 Jet Combustion Chambers – Can Type Individual chambers Arranged in a ring around the shaft Early design Ease of design Uses a lot of space CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 235 Jet Combustion Chambers – Can Annular Type Similar to can type Common outer wall Reduces weight Better use of space Ease of design CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 236 Jet Combustion Chambers – Annular Type Individual, large combustion chamber Optimal use of space Even combustion Challenging to design CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 237 Jet Turbines Extracts power from exhaust to drive compressors and accessories Usually an axial type - Similar to axial type compressors May be single or multi shaft - One shaft may drive the low pressure compressors, another may drive the high pressure one Built of special alloy as they must withstand very high temperatures Can be cooled CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 238 Thrust and Engine Health Measurement Engine Pressure Ratio (EPR) - Ratio of total pressure of exhaust stream to the total pressure of inlet air N1 - Speed of the low-pressure compressor and turbine N2 - Speed of high-pressure compressor and turbine Fuel Flow - Used as an indication of engine power output CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 239  N2 N2 N1 N1 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 240 Turbine Classification The turbine engine is the engine of choice at speeds of 250 to 450 kts. Turbine-powered engines can be classified various ways, but the more common is by power produced… - Turbojet – simplest but noisy and is hard on fuel - Turboprop – are geared down for props - Turbofan - high fuel efficiency/thrust at lower speed - Turboshaft - similar to the turboprop but geared for helicopter rotors CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 241 Turboprops Propeller driven by turbine - Great majority of energy used to drive propeller Exhaust still generates some thrust - Max 5% of total power output Principle is the same - Shaft speed must be reduced by reduction gear box, to suit propeller speed CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 242 Turboprops – Direct Drive In direct drive the exhaust turbine drives the inlet compressor and the power output shaft directly. - Noisy when on ground, as engine forced to run at high speeds - More demanding on starter (must turn whole engine) - The Garret TPE331 is a commonly used model being found on the Metroliner, Merlin, and Cessna Conquest - The propeller is usually started in the full fine position to allow for an easier start CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 243 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 244 Turboprops – Free turbine In free turbines two separate turbines are used, one to drive the compressor and another to drive the shaft. - Accessory drives can turn at a variety of speeds - Smaller starter, quieter - The Pratt and Whitney Canada PT6 and its variants are very common and can be found on a variety of aircraft - The engine is usually started in the full feather and the turbine can remain running with the propeller stopped CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 245 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 246 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 247 Turbofans Larger mass of air Some air bypasses core Extra compressor: Extra thrust Slows down exhaust velocity - Less noise - Less wasted energy - More efficiency CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 248 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 249 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 250 Reverse Thrust Many jet engines are configured to provide some amount of reverse thrust when selected by the pilot. Two main types: - Clamshell type doors - Turbojets - Cascade type - Turbofans - Combination of the two are possible Reversers are most effective at higher speeds. Use for initial braking CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 251 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 252 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 253 Oxygen Systems The higher flying aircraft make pilots and passengers susceptible to hypoxia - inadequate oxygenation of the tissues caused by anything that interferes with the transfer of oxygen from the air to the tissues. The rule is supplemental oxygen must be available in any unpressurized aircraft that will be flown above 10,000 feet over 30 minutes. As a general rule-of-thumb; however, hypoxia is a possibility above 5,000 feet. (smokers are more susceptible due to carbon monoxide blocking the transfer of oxygen) CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 254 Oxygen Systems Light aircraft can have fairly simple oxygen systems consisting of a portable oxygen bottle, simple regulators, and tubing to connect to oxygen masks. Permanent oxygen systems are more complex with bigger oxygen bottles, (or more than one) sophisticated regulators, controls, and permanent manifolds to hook up oxygen masks to crew and passengers. Pressurized aircraft, which regularly fly at high altitudes, enable the cabin altitude much lower than the aircraft’s actual altitude. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 255 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 256 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 257 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 258 Vacuum Systems Engine Driven Vacuum System A vacuum pump run by the airplane engine creates a partial vacuum in the system. A filtered inlet in the gyros allows air to rush into the system causing the gyro wheel to spin. Requires a suction gauge mounted on the instrument panel which indicates the proper amount of suction ( 4.6 to 5.4 inches of Hg ) This system begins to operate as soon as the engine starts. In the event of an engine failure, all power to the vacuum gyro instruments is lost. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 259 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 260 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 261 Vacuum Systems Venturi Driven Vacuum System A venturi is used in place of a vacuum pump. The venturi tubes are usually mounted on the side of the aircraft in a position to be in the airflow of the propeller. A low pressure is created within the venturi that results in a partial vacuum in the line leading to the gyro instruments. Typically, a venturi may power only the turn and bank instrument although larger ones may power more than one instrument. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 262 Environmental Systems More sophisticated aircraft have cabin heating, air conditioning and, as mentioned, pressurization systems. Pressurization systems, by their very nature result in heated air, hence cooling of the compressed air is usually necessary. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 263 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 264 Pressurization A pressurization system has three primary goals - Automatically maintain a maximum cabin pressure altitude of approximately 8,000 feet up to the aircraft’s maximum designed cruising altitude. - Prevent unwanted, rapid changes of cabin altitude regardless of rate of climb or descent. - Reasonably fast fresh air exchange to eliminate odors and remove stale air. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 265 Pressurization It is normal for smaller pressurized aircraft to have the cabin, flight deck, and baggage area constructed as a single pressure vessel. Pressurization tries to blow up the fuselage like a balloon resulting in significant internal stress placed on the fuselage’s skin. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 266 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 267 Pressurization and Air Conditioning These systems are increasing in sophistication as the demands to meet the needs of the aircraft and human occupants are high - Reliable source of compressed air. - Pressure regulator - Method to prevent over-pressurization - Positive control of cabin temperature - An effective air sealing system CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 268 Pressurization System Pressurization is done by centrifugal superchargers or positive displacement superchargers. Typically turbo jet engines use centrifugal superchargers to pressurize the cabin. The actual pressurization controls work through electronics or pressure feedback. The components of the system include the: - sealed hull - compressor - air cooler - outflow valve - dump (safety) valve. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 269 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 270 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 271 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 272 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 273 Anti-ice and De-ice systems Anti-Icing systems are installed to prevent ice forming and De-Ice systems are designed to remove formed ice. Various methods are employed based on type Fluids – aircraft designed with porous leading edges allow anti-icing fluid to be pumped over the surfaces. Also, this method is very effective when used on propeller blades. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 274 Anti-ice and De-ice Systems Rubber De-Icer Boots - these are rubber membranes attached to leading edges. These pulsate in sequence and crack off accumulated ice. They are powered by air pumps or engine bleed air. CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 275 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 276 Anti-Ice and De-ice Systems Heated Surfaces - These may take the form of electric heating elements embedded on key surfaces or hot air supplied to heat these surfaces. Typically these heated surfaces use engine bleed air and are often noticeable as a silver colored section on wing leading edges, or engine nacelle inlets. These may also be in the form of black heating pads on the inner leading edge of the propellor CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 277 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 278 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 279 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 280 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 281 CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 282 CPL AES END CONFIDENTIAL | © MONCTON FLIGHT COLLEGE | mfctraining.com| 283