AVAT11001: Course Outline
1. Aircraft and Terminology
2. Radio Communications
3. Structure, Propulsion, Fuel Systems
4. Electrical, Hydraulic Systems and Instruments
5. Air Law
6. Aerodynamics: Basics
7. Aerodynamics: Performance
8. Human Factors
9. Meteorology
10. Loading
11. Take-off and Landing Performance
12. Navigation
Stuff to read
• Required Reading: BAK Chapter 4, pp. 59105
Questions from the Reading
1. Why does the pilot drain fuel before
every flight?
2. Why have two magnetos?
3. What does the mixture control do?
4. Why is an engine lubricated?
5. What is a chock?
Structures
• An airframe is designed to handle the
loads associated with flight
– Gravity
• Taxi
• Landing
– Air pressure loads
• Level flight
• Manoeuvre loads
– Propulsion loads
• Transmit thrust to the airframe
Types of Loads
Tension: pulling apart
Compression: pushing together
(Can cause buckling)
Torsion: twisting
Shear Stress
Bending Moment
Basic Structural Components
• Most aerospace structures consist of simple light
weight designs
– See Figure 4-9 page 61 and Figure 4-10 page 62
• Ribs and Frames
– Are used to used to define the basic shape
• Spars and Longerons
– Are used to connect ribs and provide extra strength
• Skins and Stringers
– Are used to define the final outer mould lines and
often carry much of the loads
– Stringers are used to connect pieces of skin to each
other and the rest of the airframe
Rigger’s Angle
• Often, the wing is mounted to the fuselage
at an angle, such that the chord line is not
parallel to fuselage centre line
• This is done to provide a desired angle of
attack in cruise conditions with the
fuselage relatively level
– Improves comfort and visibility for pilot
• See Figure 4-12 page 63
Walk Around
• Prior to flight, you will typically walk around
the aircraft to perform a visual inspection
of the structure and to insure the vehicle is
ready for flight
– See Figure 4-21 page 66
• Each aircraft will have a checklist of
specific items that you will inspect
– The checklist of a Cessna 172 is included in
these notes as an example
Cessna 172 Pre Flight Inspection
Checklist
•
Cabin
–
–
–
–
–
–
•
Control Wheel Lock -- REMOVE
Ignition Switch -- OFF.
Master Switch -- ON.
Fuel Quantity Indicators – CHECK QUANTITY
Master Switch -- OFF
Baggage Door – CHECK, lock with key if child’s seat is to be occupied.
Left Wing Trailing Edge
–
•
Aileron - - CHECK for freedom of movement and security.
Left Wing
–
–
–
–
•
Main Wheel Tyre - - CHECK for proper inflation.
Before first flight of the day and after each refueling, use sampler cup and drain small
quantity of fuel from fuel tank sump quick-drain valve to check for water, sediment and
proper fuel grade.
Fuel Quantity - - CHECK VISUALLY for desired level.
Fuel Filler Cap - - SECURE.
Left Wing Leading Edge
–
–
–
Pitot Tube Cover - - REMOVE and check opening for stoppage.
Fuel Tank Vent opening - - CHECK for stoppage.
Stall Warning Opening - - CHECK for stoppage. To check the system, place a clean
handkerchief over the vent opening and apply suction; a sound from the warning horn will
confirm system operation.
Cessna 172 Pre Flight Inspection
Checklist, Continued
•
Nose
–
–
–
–
–
–
–
–
Engine Oil Level – CHECK. Do not operate with less than six quarts.
Fill to eight quarts for extended flight.
Before first flight of the day and after each refueling, pull out strainer
drain knob for about four seconds to clear fuel strainer of possible
water and sediment. Check strainer drain closed. If water is
observed, the fuel system may contain additional water, and further
draining of the system at the strainer, fuel tank sumps, and fuel
selector valve drain plug will be necessary.
Propeller and Spinner - - CHECK for nicks and security.
Landing Light(s) - - CHECK for condition and cleanliness.
Carburetor Air Filter - - CHECK for restrictions by dust or other foreign
matter.
Nose Wheel Strut and Tyre - - CHECK for proper inflation.
Nose Tie-Down - - DISCONNECT.
Flight Instrument Static Source Opening (left side of fuselage) - CHECK for stoppage.
Cessna 172 Pre Flight Inspection
Checklist, Continued
•
Right Wing
–
–
–
–
–
•
Wing Tie-Down – DISCONNECT.
Main Wheel Tire --- CHECK for proper inflation.
Before first flight of the day and after each refueling, use sampler cup
and drain small quantity of fuel from fuel tank sump quick-drain valve
to check for water, sediment, and proper fuel grade.
Fuel Quantity -- CHECK VISUALLY for desired level.
Fuel Filler Cap – SECURE.
Right Wing Trailing Edge
–
•
Aileron – CHECK freedom of movement and security.
Empennage
–
–
–
Rudder Gust Lock – REMOVE
Tail Tie – Down -- DISCONNECT
Control Surfaces – CHECK freedom of movement and security
Engine
• What is an engine? What does it do for an
aircraft?
– The primary purpose of the engine is to
convert chemical energy (fuel) into
mechanical energy (kinetic) to generate
thrust.
• There are 2 main types of engines used in
aircraft
– Piston engines (used to drive propellers)
– Turbine engines
How do piston engines work?
• Piston engines operate on principles that govern
the behaviour of gases
– Charles’ Law, Boyle’s Law, etc
• A spark is used to burn fuel and increase the
temperature of gases in a cylinder
• When the temperature of a gas is raised, the
pressure is increased
• This increase in pressure can be used to do
work
– See Figure 4-27 page 69
Ignition
• In order to get the fuel to combust in a
controlled fashion, it must be lit at the right
time.
• The fuel in the cylinder is ignited by an
electrical spark that is provided by a spark
plug.
• The electrical energy required to cause a
spark is provided by magnetos
• See Figure 4-29 page 70
Dual Ignition Systems
• Most modern aircraft have dual ignition systems
on their piston engines
– Provides safety
– Improves fuel efficiency
• When starting an aircraft it is important to verify
that both ignition systems are working correctly
– See Figures 4-31 and 4-32 page 71
– When a particular magneto is turned off, you should
notice a slight drop in engine RPM
Carburettor
• The carburettor mixes the fuel with air so that
this mixture will burn well in the engine
• Automobile engines have carburettors that are
designed to provide the proper fuel-to-air ratio
on an standard day
• Aircraft engines are exposed to a greater variety
of pressures and densities than automobiles,
and the pilot needs to be able to change the
carburettor to maximize fuel efficiency
Mixture Control
• The amount of air flowing through the
carburettor is a function of the density of the air
outside the aircraft and the engine RPM
• Density, in general, decreases with altitude
• To keep the engine running efficiently, the pilot
will change the amount of fuel being mixed with
the air as the density changes
– See Figure 4-35 page 75
Engine Oil
• 5 Functions of Engine Oil
– Lubrication
– Cooling
– Cleaning
– Sealing
– Protecting
• It is better to run an engine with bad oil
than no oil at all
Propellers
• Propellers generate thrust the same way the wings
generate lift
– They create a pressure differential when they are moved through
the air
• All propellers are very expensive because they are very
precisely manufactured
• There are 2 main types
– Fixed pitch
– Variable pitch
• Fixed pitch propellers are mechanically simple
• Variable pitch propellers involve complex machinery and
are heavier than fixed pitch propellers
– The advantage of a variable pitch propeller is that it can provide
improved fuel efficiency by allowing the engine to operate at a
more efficient RPM
Fuel Systems
• See Figures 4-62 and 4-63 on page 101
• 2 Basic types
– Gravity-feed
– Pressure-feed
• Vents and drain valves are important to check fuel and equalize
pressure in the tanks
• Be aware that fuel gauges are:
– Not very accurate
– Affected by aircraft attitude
• Always visually inspect the tanks before flight
– Proper quantity
– Impurity free
– Condensation check
• Only use the proper grade of fuel
– If you put the wrong type of fuel in, expect something bad to happen
For next week…
• Required Reading: BAK Chapter 4, pp.
106-132