Ex 1 - Aircraft Familiarisation
This page is a work in progress.
There are not links to ALL the sections yet. I am working on it, please be patient.
Overview: Exercise 1: Aircraft Systems, Checklists & Drills
Chapter 1: The Fuel System
Chapter 2: The Oil System
Chapter 3: Pneumatic Systems
Chapter 4: Electrical System
Chapter 5: Flight and Engine Instruments
Chapter 6: Navigation Instruments
Chapter 7: The Radio
Chapter 8: The Fire Extinguisher
Chapter 9: Hydraulic Systems
Chapter 10: Heating and Ventilation
Chapter 11: Ice and Rain Protection
Chapter 12: The Flight Control System & Engine Control System
Chapter 13: Checklists and Drills
Chapter 14: Exercise 1E - Ground emergency drills
Overview: Exercise 1: Aircraft Systems, Checklists & Drills
In this lesson, I will introduce you to your aircraft, and her different systems as well as the basic checklists you will become familiar with. Most people will do an introductory flight, (lesson 3), before this lesson. Exercise 1 is part of your first serious training, and is particularly long because it is usually taught along with exercises 2 and 4.
As you progress through your training, you can re-visit this lesson as you will not be expected to know everything instantly, but rather just get a basic overview of an aircraft and its systems now.
The details will become knowledge as you progress through the syllabus. You may skim through this exercise for your first visit, and then come back later when you want clarity on specific areas of your aircraft as your knowledge expands.
Everything you are learning now is probably brand new, so don't become disheartened when you begin feeling it is just too much information. Everyone goes through this stage because in the beginning, the learning curve is very steep. Even when you listen to the radio for the first few times it will probably sound like a foreign language to you. This is normal.
When you get your wings, you will know you have truly earned them.
I will be using a Cessna 150 aircraft for the explanations and demonstrations. There are minor differences in training aircraft, but all the concepts remain the same, so even if you will be doing your practical flight training on a different aircraft, the checks and aircraft systems will be very similar if not identical, and the flight principles will be the same.
What is easier to fly... a high wing or a low wing aircraft?
The answer is: the one you trained on is easier. It makes no real difference, and becomes more a personal preference. Each type has its own perks and challenges. With a bit of experience it shouldn't matter to you whether you fly a high wing or a low wing aircraft.
For details on your aircraft, keep the Pilot Operating Handbook, (POH), handy. Don't just look at the book. Open it up and read it cover to cover. You will be doing a Technical Exam on it, so you might as well make it your friend. Don't worry; the "Exam" is usually open book.
First we are going to name all the bits of the aircraft, to be certain you know where everything is. Then we are going to explore the aircraft systems, followed by the control systems, and the checklists you will need to follow.
The C150 Aircraft:
[ insert picture here]
The C150's systems, as with all trainers, are relatively straight forward.
Here are the systems you need to become familiar with: the fuel and oil systems; the pneumatic system; the electrical system; the flight and engine instruments; the handling and use of navigation equipment; the handling and use of radio equipment; fire extinguishing methods; the hydraulic system; the heating and ventilation system; ice and rain protection; flight and engine control systems; checklists and drills. They will be explained in the following chapters.
Chapter 1: The Fuel System
Fuel is stored in the two separate tanks in the left and right wings of the aircraft. They are surprisingly small and do not run the full length of the wing, but are usually inside the wing close to the fuselage, almost up against the wing root. They are vented to each other and the fuel is gravity fed, through a fuel strainer, into the carburetor.
Excess fuel can escape through an exterior vent and will drip or pour out of the vent onto the grass/tar/hangar floor until the fuel is below the vent level. This vent takes care of external temperature changes, mainly for when the fuel expands due to high outside air temperatures. If you park on a slope, especially with full tanks, the fuel will flow through to the lower wing. If the vent is on this side, you could lose a lot of fuel unnecessarily. Have situational awareness. This vent also allows air in/out of the tanks, allowing the flow of fuel to the carburetor. If this were to be blocked, a vacuum would form preventing the fuel from getting to the carburetor.
To illustrate this, dip a straw into your cool drink, close the top of your straw with your thumb, keep it there and lift the straw out the glass... the cool drink is trapped in the straw. Lift your thumb, allowing air in, and the cool drink rushes out the bottom like a mouse from a cat. Allowing air in (fuel overflow vent clear) allows the fuel to flow as gravity dictates.
It may interest you to know that aviation fuels such as Avgas and Jet A1 are treated so that they do not freeze easily.
The basic characteristics of Avgas are:
Physical Form: Liquid
Boiling Point/Range: 75-338°F / 24-170°C
Melting/Freezing Point: <-72°F / <-58°C
Specific Gravity: 0.68-0.74 @ 60ºF (15.6ºC)
Bulk Density: 5.83 lbs/gal
Percent Volatile: 100%
Evaporation Rate (nBuAc=1): >1
Flash Point: <-35°F / <-37°C
Auto ignition Temperature: 824°F / 440°C
You don't need to memorize this, just thought you might be interested. The important part is that when you check it is blue, clear, and smells right.
The carburetor is a bit like a toilet cistern. It has a valve and float that regulates the level of fuel in the carburetor the same way that a toilet cistern's floating ball cuts off the flow of water once it has reached a set level.
The Mixture Control Knob (the RED knob), allows the fuel from the carburetor float chamber to flow through the jets, into the intake manifold, (intake manifold = a pipe that carries the fuel from the carburetor into the engine), and regulates the quantity that may flow through the fuel system jets by adjusting the knob in or out. Pulling it all the way out closes the flow, so the engine will cut out.
The Throttle rotates a butterfly valve in the intake manifold. The butterfly valve looks like a coin that fits tightly into the intake manifold (pipe). It is pinned through the center top and bottom, and can rotate 90° so that it can form a minimum restriction in the "pipe" when turned in-line with the pipe,(throttle OPEN), or bock the "pipe" completely,(throttle CLOSED), or take up any position between the two extremes.
As you open the throttle by pushing it in towards the dash, you are rotating the butterfly valve and opening up the flow of air in the "pipe" which we will now continue to call the intake manifold. Air rushes past the butterfly valve creating a lower pressure as it passes the valve, (Bernoulli's Theory). This lower pressure "sucks" fuel out of the jets that are controlled by the mixture control knob. The stronger the air rushing past the butterfly valve, the more fully open the valve is, the more fuel is sucked through the jets, the more power the engine is able to produce.
The throttle and mixture controls in the fuel system are interrelated. The throttle can only do its job if the mixture control has been set accordingly.
The fuel system for a low wing aircraft will include an engine driven fuel pump, and an auxiliary (electrically driven) fuel pump.
Chapter 2: The Oil System
The main thing you need to know about the oil system in your aircraft is that you need it to lubricate your engine! Check your Pilot Operating Handbook (POH) for the minimum and maximum oil quantities for your aircraft.
Too little oil and your engine will overheat. Too much oil and it will be thrown out through a breather, wasting the oil.
It is very important to check the oil dipstick in the engine compartment to make sure you have enough oil. If the dipstick is secured by screwing it in place, take care that you make it only finger tight, so turn it back a little once you have closed it. C152's tend to have this system, and if you tighten it, when the engine heats up, the two different metals get better acquainted and need He-Man, (or pliers) to undo it to check the oil again. It strips the thread and causes problems. Make sure your oil dip stick is secure, but do not over-tighten if you have a screw-on thread.
Oil Pressure Gauge
Also, check your oil pressure gauge in the cockpit after start. The pressure must come up within 20 to 30 seconds on a day above 0° C. If it does not, SHUT DOWN YOUR ENGINE.
The oil is air cooled. So the faster you go, and the less power you use, the cooler you keep your engine. It is, however, important to note that your engine operates best when quite hot - but not too hot.
Oil lubricates all the moving parts in your engine. Without oil pressure, your engine will overheat rapidly with the intense friction that goes on inside it, parts will begin to buckle, burn and break, and your engine will stop turning that big fan up front, (the propeller), which invariably leads to a sweaty pilot.
If you see your oil temperature climbing, and your oil pressure dropping, you had better find a place to land, quickly.
Most light aircraft have a wet sump. This means that the oil all collects down the bottom of the engine. Whenever you are idling, always set your revs to 1000rpm (or as per your POH), to allow sufficient revs so that the oil can be splashed up into the engine for cooling.
(Aerobatic aircraft have to have a dry sump with a separate oil reservoir otherwise when they turn upside down their aircraft engine would not be sufficiently lubricated.)
There are two main oil varieties you will use:
You will only use straight oil for the first 20 to 50 hours of running in a new or overhauled engine, otherwise you will use ashless dispersant.
If you are topping up the oil, make sure you are using the correct oil and grade.
Chapter 3: Pneumatic Systems
Any system that is operated using air under pressure is called a Pneumatic System.
In the C150, there are usually two pneumatically driven systems.
One is for flight instruments, which will be discussed further under chapter 5; flight and engine instruments.
The second is only partially pneumatic. It is the oleo strut on the main (front) undercarriage. The oleo strut is a shock absorber that takes the pressure when the nose wheel drops to the ground after landing. It is pumped up with a combination of hydraulic fluid and air, and there must always be four fingers of the inner tube of the oleo strut showing in the preflight.
Other trainers, like Pipers, have oleo struts on all three legs of the undercarriage.
Chapter 4: Electrical System
The electrical system not only powers certain electrical items, but also charges the battery using an alternator.
The Master Switch
The Master Switch is usually divided into two sides, the Battery Switch and the Alternator Switch which lie side by side and are often switched on together. To extend the life of the system, switch on the Alternator side of the Master Switch only AFTER you have started the engine. Read this interesting article “Know your charging system” by Robert M.Adkins for more information. ( www.nflite.com/ChargingSystem.html)
When the aircraft engine is not running, switching on the alternator does sweet nothing. The engine has to be running for the alternator to work.
If you switch the Master Switch off after starting the aircraft, the engine will keep running, but all the electrical systems will switch off.
Aircraft Systems that use electricity
Exterior Navigation Lights:
- red in a 110° arc on the port (left) wingtip
- green in a 110° arc on the starboard (right) wingtip
- white in a 140° arc behind the aircraft
[insert pic] - Landing and Taxi Lights on the port (left) wing for the C150.
Red Rotating Beacon Light on the top of the vertical tail plane.
None of these lights are mandatory for flights by day.
Pitot heat, (in case of icing conditions, something you should not experience in SA during training)
Turn and slip indicator - the "Turn" portion is usually electrically operated. The black ball is mechanical.
Transponder, (secondary surveillance radar system so that Air Traffic Control can identify your aircraft)
Radio, (so that you can communicate with Air Traffic Control and other aircraft)
The C150 has a 12 volt battery, which is charged by an alternator. An alternator needs the battery to have some charge before it is able to re-charge the battery. The voltage regulator regulates the voltage that flows from the alternator to the battery, and will control the voltage to about 14V, so that the battery is charged and not depleted by the alternator, since electrical current " flows downhill".
The amount of charge or discharge of the battery can be seen on the ammeter. It is important to look at this little gauge periodically as it will show you whether your battery is charging or discharging and will give you the first warning (besides the alternator/low voltage warning light), that you are soon going to lose your electrical systems.
After start, the first thing you check is the oil pressure.
The second thing you check is the ammeter or load meter, for a positive charge.
Below is a very basic sketch of the electrical system. There are many components missing. This is just to give you an idea of how things are connected. Look in your POH for the electrical schematic for your aircraft.
Chapter 5: Flight and Engine Instruments
Below is a picture of a typical training aircraft cockpit layout.
[ insert pic]
The pilot always sits in the left hand seat. Your instructor will sit in the right seat. The instruments on the pilot side, top row from left to right are as follows:
Air Speed Indicator (ASI); Artificial Horizon, (AH); Altimeter.
The second row pilot side left to right:
Turn and Slip (partially hidden behind the control column); Directional Indicator (DI); Vertical Speed indicator (VSI)
In the centre is the radio stack. On the right, top row, left to right:
Left fuel gauge; Oil Pressure Gauge; Oil Temperature Gauge; Right fuel gauge; Suction Gauge.
Second row left to right:
Rev counter; Ammeter ; Hobbs meter; radio headset jacks.
The description of the instruments in the cockpit follow:
Pressure Operated Flight Instruments:
Airspeed Indicator (ASI)
Vertical Speed Indicator (VSI)
To understand these flight instruments you first need to understand that there are two types of air pressure. Static Pressure and Dynamic Pressure. You also need to understand that air pressure decreases with altitude.
Static pressure is the air pressure that is on us all the time, in other words the 'weight' of the air. We are subjected to this pressure constantly. At sea level, this pressure is maximum. As we climb higher and higher, the pressure becomes less and less. This is why when people climb the Himalayas or other high mountains; they need oxygen - very thin air. So where the air is thicker, it is also heavier and closer together - denser.
[ insert pic]
An interesting point about air density is that when it is humid, as in lots of water molecules in the air, these water molecules push the air molecules out of the way and take up their space. So when the air is humid, it is less dense. When sitting on the coast in humid conditions, there may be just as much air available as if you were sitting half way up a tall mountain.
[ insert pic]
Imagine you are just sitting, relaxing, meditating. Can you feel any pressure? Not really. That's because you are so used to it. There is Static Pressure, the pressure of the atmosphere, pressing on every part of your body.
Now if a strong wind comes up, you will feel a definite pressure on your body. The air is moving, it has speed and direction (velocity). The stronger the wind, the stronger the pressure on your body.
This is Dynamic Pressure. Dynamic Pressure is the pressure exerted on an object by moving air.
The atmosphere is layered with all aviation taking place in the Troposphere up to about 30,000ft. The temperature decreases at the steady rate of about 2° C(1.98° C) per thousand ft of height, up to the top of the troposphere where it stabilizes for a little while at -56.5° C. Atmospheric pressure decreases with height.
About 80% of the "weight" of the atmosphere is in the Troposphere. This layer is where we experience all our weather. The top of the Troposphere and into the Tropopause is the highest that Jets fly, about 30,000ft. As a PPL in a non-pressurised piston aircraft we will fly to a maximum altitude of 12,000ft (in visual, not instrument conditions!). See this site for an excellent diagrammatic representation of the atmosphere: http://earthguide.ucsd.edu/earthguide/diagrams/atmosphere/index.html
Essentially the ASI works by measuring the dynamic pressure of air rammed into a diaphragm through the pitot tube.
Static vents allow the static air to put static pressure the diaphragm that is filled with dynamic and static air pressure, thereby canceling out the static portion of the airflow and allowing the dynamic pressure to be read on an ASI through a series of linkages.
as the static pressures cancel each other out.
The static port is usually found on the airframe out of direct airflow, but can be on the side of the pitot tube, though usually not in light trainers.
The ASI has colour markings under the numbers. These have significance as in the diagram below:
The White Arc is the flap operating range
The Green Arc is the normal operating range
The Yellow Arc is the caution, operate only in calm conditions range
The Red Arc is the Never Exceed Speed. Exceeding this speed caused your aircraft to break apart.
You will use your ASI along with your rev counter to confirm the performance you require from your aircraft.
Below are speeds you need to learn:
VSO - Stall speed in the landing configuration - with flaps and gear extended - bottom of the White Arc.
VS1 - Stall speed with the flaps and gear retracted - bottom of the Green Arc.
VFE - The fastest speed at which flaps may be extended - top of the White Arc
VNO - Maximum structural cruise speed - top of the Green Arc.
VNE - Never exceed speed, past this speed the aircraft breaks apart. The Red line.
The Altimeter in the picture below is indicating an altitude of 1,410ft.
The altimeter tells you how high you are above the ground, the sea, or the standard pressure altitude depending on what you dial in on the adjustable scale in the altimeter setting window.
At airfields you normally set in the QNH. On the ground, with QNH set in the sub-scale, your altimeter will read the airfield elevation, which is the airfield's actual height above sea level. The scale in the altimeter is adjustable because the air pressure at any place can vary from day to day and hour to hour. This adjustable scale in your altimeter allows the instrument to compensate for differing external air pressures so that your altimeter may read your elevation accurately, even if there was a low pressure system at your airfield yesterday, and today there is a high pressure system.
The altimeter uses static pressure. Because static pressure decreases with height, your altimeter is able to show your change in height. You just help it with the starting point by setting your QNH.
The Vertical Speed Indicator uses static pressure to show you your rate of climb or rate of descent in hundreds of feet per minute. It is much like the altimeter, except it shows you the rate of change and the speed at which you are climbing or descending.
Please note that all these instruments lag. This means that your aircraft will perform in a certain way, and then, a few seconds later, your instruments will '"catch up" and confirm your aircraft's performance. So it is important to fly an ATTITUDE with your chosen POWER setting, which will give you your aircraft PERFORMANCE. Do NOT "chase" your instruments, as you will never "catch" them because of this lag. More about this later.
Pneumatically operated flight instruments
Air (Pneumatically) Driven Instrument System
In our training aircraft this system is driven by a vacuum pump, so it "sucks" or "pulls" the air through the gyro instruments before dumping the "used" air through the overboard air line.
In light aircraft, there are usually two instruments driven this way:
The Directional Indicator, (DI) and the
Artificial Horizon, (AH).
There are two types of pneumatic vacuum pumps, wet pumps - which are lubricated by engine oil; and dry pumps, that have graphite vanes inside the pump casing, so they self-lubricate as the pump rotates. Your aircraft can have either as they are inter-changeable with a few modifications. They work the same way.
The pumps create a vacuum by drawing outside air through a filter and pass it through the gyro instruments spinning them up to between 10,000 and 15,000 rpm. "Used" air is then dumped through the overboard air line.
The pump is bolted onto the engine behind one of the magnetos and uses the same gear as the magneto to spin up.
You will know the pump has failed if the suction/pressure gauge indicates outside the normal operating range, and/or if the instrument information is inaccurate or conflicting.
Sometimes it is obvious when the vacuum pump fails, and other times it is not so obvious. This is why it is so important to scan all your instruments. This will be covered in more depth in exercise 19, Instrument Flight.
A proven way to break the pumps is to turn the propeller opposite to the rotation of the engine. Please don’t do this.
It is important for you as the pilot to regularly monitor your engine instruments because they tell you about the health and state of your engine. Something a pilot worth his salt should have a keen interest in and check regularly. Engine instruments you will monitor are:
Oil Pressure Gauge
Engine Temperature Gauge
The Rev Counter - engine revolutions per minute (rpm) increase when you open the throttle (i.e. push the throttle in towards the dash). The rpm reduces when you close the throttle, i.e. pull it away from the dash.
The rev counter is connected to the engine by a small gear that spins an electromagnet, so the message is coded in electrical impulses, then is de-coded in the rpm instrument by wire, where it spins another electromagnet which in turn turns a gear, effectively reversing the process and allowing the Rev Counter to show on a dial how fast the engine is rotating.
The oil pressure gauge tells the pilot about the oil pressure in the engine. If it is cold, the oil pressure will likely read quite high until it warms and thins, then it may drop a little. If the oil pressure continues to drop through the flight after the engine is warm, (which doesn't take very long), then there is possibly an oil leak.
It is possible to have a faulty gauge, so always cross check it with the oil temperature gauge. If the oil temperature is stable and the oil pressure is dropping, it is possibly a faulty gauge. If the oil pressure is dropping and the oil temperature is rising, look for a place to land.
Oil is forced, under pressure, by an engine driven gear pump, and squeezes through small tunnels in the engine casing to cool and lubricate the pistons and other engine parts. Oil is quite viscous, sticky, and creates a thin slippery layer between parts so that they are protected from each other by reducing friction and thereby heat, keeping the engine at an acceptable working temperature.
A small transmitter sends an electrical signal to the Oil Pressure Gauge which gives a reading for the oil pressure.
The Oil Temperature Gauge tells the pilot how warm the engine oil is. On a cold day, the pilot may have to idle the engine for a while until the temperature gauge shows in the green before he/she can do the engine power checks.
If the oil is too cold, it is very thick, and won't be able to be pushed through the thin passages fast enough for effective cooling, so you can damage the engine by applying too much throttle when the oil is still thick and cold.
If the oil level in the aircraft is too low, the oil will get too hot, too thin and will also not be able to cool the engine or reduce friction, so the range that the oil operated in is very important, both temperature and quantity monitoring.
The oil is passed through a small radiator to cool it after it has journeyed through the hot engine. If the oil is still cool, it will bypass the radiator (oil cooler). There is a temperature probe downstream from the cooler where the message about the oil temperature is collected by using a bi-metallic strip which is made from two different metals that expand at different rates, which then signals the oil temperature gauge in the cockpit.
The EGT. Not all training aircraft have an EGT gauge. This is an Exhaust Gas Temperature Gauge, and is used to measure the heat of the burnt fuel. Adjusting the temperature of the EGT is done by leaning or enriching the mixture. The engine must always run on the cooler - richer - side of peak or you risk detonation. Detonation will break your engine into little bits very quickly.
Air cooled engine vs. water cooled engine
Most aircraft are air-cooled. The engines have a large number of fins protruding from it so there is a larger area for the cool air to affect, thereby cooling the engine.
Water cooling is used sometimes, just like in a car, but it is a heavier, more complex system.
Chapter 6: Navigation Instruments
The Magnetic Compass
The Magnetic compass contains a magnet that aligns itself with magnetic north. It rotates freely on a pivot in a housing filled with fluid to dampen out the oscillations. It can move freely in its housing, but is directly affected by the movement of the aircraft, and can be hard to read in even mildly turbulent conditions.
Magnetic Compass Errors
The Magnetic Compass suffers from climbing, turning and acceleration/deceleration errors. If you want to help yourself to get lost during a Navigation exercise then to one of the following things:
--> Adjust the DI to the Compass when in a climb or descent
--> Put something magnetic next to the compass
--> Ignore your gut instinct when the map and compass disagree
WARNING: It is NOT much fun to get lost, so I recommend you do the following instead:
Only align your DI to your Magnetic Compass in straight and level flight.
When climbing or descending, your magnetic compass card tilts in its little prison and the cards' movement becomes restricted, so it cannot move as freely and gets stuck, so it cannot show you the real magnetic direction under these circumstances.
Although the magnetic compass is used as the primary reference in navigation, the Directional Indicator, (DI) is used more by the pilot.
During the Pre-flight Inspection:
Always check that there are no bubbles in the magnetic compass housing.
The DI - Directional Indicator
Because the magnetic compass is not very stable, and bounces around in flight, a DI - Directional Indicator is used. The DI is a gyroscopic instrument.
A gyroscopes' main property is that it has rigidity in space. So once the gyro has "spun up" it becomes rigid. This means that the instrument will stay in one place and the aircraft will rotate around the instrument, (except for where the instrument is tied down). The DI card is aligned with the compass by the pilot. The pilot needs to push in and turn the little knob on the bottom left of the DI until the numbers on the DI card agree with the magnetic compass.
You will notice that the magnetic compass card and the DI card initially cause you a dab of confusion because the numbers on the magnetic compass DECREASE to the right, and on the DI, they INCREASE to the right. Just look carefully when you make the adjustment.
Referring to the DI during navigation is a whole lot easier than referring to the magnetic compass because of its rigidity. The DI is a pneumatic instrument.
he AH - Artificial Horizon
The AH - Artificial Horizon, is also a gyro, and is also a pneumatic instrument. The AH is there for instrument flight, and is not required for visual flying. The AH takes the place of the real horizon when the pilot can no longer see the real horizon due to weather.
To perfect your visual flight it is convenient to use the ° markings on the AH to confirm your bank angle is accurately on 10° , 15° , 30° or 45° as require
Chapter 7: The Radio
The Radio in a light aircraft is quite easy to use as soon as you understand a few of the basics.
All the ab-initio training aircraft I have come across to date have only one.
Switching on and setting the volume
To turn the set on, rotate the second button from the right clockwise. In the picture above, pull the knob out and you will hear background noise. Turn the on/volume knob until the background noise is at a comfortable level, then push the knob back in to stop the background noise. The radio is now set at a comfortable volume level for communication.
On some sets you push this knob to test the volume rather than pull it, but there will be a clue on the panel itself. Look just to the right of the knob, it says "ULL TEST" If you were looking at the real thing you would be able to look past the knob and see it actually says "PULL TEST".
To switch the set off, turn the knob anti-clockwise until it clicks and the numbers on the face disappear.
An aircraft radio has a place for two different frequencies. The frequency on the left is the one you are listening to and will transmit and receive on. The frequency on the right is on standby, ready to be flicked into action with a press of the button in the middle below the two frequencies with the double arrow head <--->.
To change the frequency, turn the knob on the right. This will change the standby frequency on the right hand side of the radio face. The knob is split. The base of the knob changes the number on the left of the decimal point, and the top part of the knob changes the numbers on the right of the decimal point.
If you have more than one radio, you are likely to also have an Audio Panel where you control whether you use Com1 or Com2, and which navigation instruments you listen to.
You will have switches or buttons to select Com 1 or Com 2, and various Navigation Instruments such a VOR, ADF. On older panels, you will also have a knob with which to select the set you want to transmit on. Most likely though, you won't need to worry about this during your ab initio training.
Being able to communicate with your instructor is vital. For you to hear each other over the headphones there must be an intercom. You will either plug your headset into the headphone and mike jack somewhere on the instrument panel or you may plug it into an intercom box. The setup doesn't matter, but it is important to know where the intercom squelch and volume are. Adjust the squelch knob to cut out interference, but be careful with this knob. Turn it too far, and you will cancel out the intercom altogether. The volume knob speaks for itself. You have a TV remote, you know what to do.
You have volume knobs in the following places: your aircraft radio, the intercom system, and on your headset. Find your happy medium.
The two headset jacks are different sizes, so they only connect one way. Put your headset in the Pilot's side. (Your instructor gets the Co-Pilot jacks... feels awesome to be the pilot, don't you think?!)
The push-to-talk is somewhere on your control column, and varies in size from a very small button the size and shape of a large grain of rice, up to a rectangular button about 2cm by 1.5cm big and 0.5cm deep. Whatever the size, when you transmit, push in this button firmly and hold it in until you have finished speaking, then release it. You will see "TX" for transmit appear on a digital display when you do this.
To talk on the intercom, just talk, (master switch on); no need to push any buttons.
Buying your own headset
Should you buy your own headset? In my opinion, yes. Unless you like wearing a headset used by countless other sweaty pilots. To be heard clearly, you also need to be quite intimate with the microphone, so it is bound to pick up a little spit and such. I think of using school headsets as almost but not quite as bad as using someone else’s' underwear. A little too intimate for my liking. You may see it differently.
If you cannot hear the other person, or if you cannot be heard, check that your headset jacks are pushed all the way in.
Check the volume knobs.
Check you have the correct frequency dialed in.
With multiple radios, check the Audio Panel selections are correct.
This will sort out 90% of radiotelephony problems.
Chapter 8: The Fire Extinguisher
Fire extinguishers in light aircraft are usually the dry powder type. This means that when you discharge them, besides sucking all available air out of the near vicinity, (making it very hard to breathe), there will be a fine white powder residue covering everything when you are done.
I know this not because I am mischievous, not because I have ever had to put out a fire in an aircraft, but because I have had to put a fire out in my house, set by my three year old son who had just discovered how to light a match and was completely enchanted with his new skill.
Fortunately we had a (dry powder) extinguisher affixed to the wall in the kitchen. I whipped the 9kg cylinder off the wall as though it was as light as a feather, flew back to the room, calmly pulled out the pin (just after yelling "How does this damn thing work?! about five times), aimed it at the fire, and made the mistake of breathing while I discharged it, followed shortly with spluttering, coughing, and gasping for breath as I dashed into the passage to find some air once the fire was valiantly extinguished. One new mattress, duvet, duvet cover, sheet, pillow and pillow case, some sandpaper and paint, and a thorough clean later, everything was good as new, and I had gained a personal working knowledge of the humble yet heroic fire extinguisher.
Always check that the pressure indicator shows in the green, and that the extinguisher is within its service period. If the gauge pointer is not in the green, assume it will not work and get a working extinguisher in the aircraft before you accept it for flight.
The unit must be serviced annually, or if it has been discharged. This is a legal requirement, but is not in place because the extinguisher service guys need to make an income, but rather to make sure that if you need the extinguisher, it will come through for you.
Inspect the bottle itself. The date it was serviced and the next service date must be clearly displayed somewhere on the bottle, (as well as a few other details).
Mastering the Clasp
The fire extinguisher must be within easy reach in flight, be securely strapped down, but still a cinch to unstrap if the need were to arise. Examine the clasp(s) so you will know how to release them if needed.
Unleash the Powder!
To discharge the extinguisher, you need to pull out a pin, breaking the seal, point the nozzle at the base of the fire, and press the trigger. Remember to hold your breath before pressing the trigger! Look at the fire extinguisher in your training aircraft and familiarize yourself with how to operate it should the need arise.
If you found yourself in a fire emergency situation requiring the extinguisher, you might not be in a calm enough state of mind to read the instructions!
Expect the best, but prepare for the worst.
Chapter 9: Hydraulic Systems
We use hydraulics in three places on a C150... the wheel brakes, the oleo strut (which is partially pneumatic as well), and the shimmy dampener.
Training aircraft are traditionally two to four seaters. They are basic aircraft with simple systems. The need for powerful hydraulically operated systems is therefore minimal.
Based on the principle that pressure exerted on a fluid is distributed equally throughout the fluid, a relatively small force can move a big object a small distance using pressure distribution via incompressible fluids. Because there are "no free lunches", (except in South African politics and the inevitable nepotism), a smaller area has to move a lot in order to move the larger area a little.
Exactly how these systems work is not of any great concern for your PPL training. The part that is important for you to know is what to look out for to be sure things are in proper working order before you accept the aircraft for flight.
The fluid used is normally an interesting colour, like pink or purple, so it cannot be mistaken for oil or fuel. Check the relevant mechanisms for any bleeding. If you find any "blood" aka pink / purple fluid on sat the shimmy dampener, the brake lines or the oleo strut, bring it to your instructor's attention. It shouldn't be there, and needs to be repaired before flying.
A note about the brakes - it has been found that with light Cessna aircraft, if you apply the park brake when everything is still hot, it gets attached to the disks like a clingy woman to her lover. Really hard to shake it off when it is time to go. The general wisdom: do not use the Cessna park brake if it can be helped, use chocks instead.
Chapter 10: Heating and Ventilation
The heating and ventilation systems
Here in South Africa we very seldom use the heating system in our aircraft. There is a knob on the dashboard that you pull out to open the heating vents. These vents direct air that has been run between a shroud and the exhaust manifold (exhaust pipe) directly into the cockpit.
This is a very effective way of heating the air at no cost to the performance of the aircraft. There is just one teensie-weensie potential drawback. If there is a hole in the exhaust somewhere along this system, it will be impossible to see without dismantling they system, and then you will not notice the carbon monoxide poisoning as it insidiously puts you to sleep. The lack of control you will then be able to apply to the aircraft is likely to accelerate your journey into the afterlife somewhat.
So PLEASE! If you are going to use the cabin heat, MAKE SURE you have a serviceable Carbon Monoxide Detector in the cabin, since it is impractical to carry a canary. (Canaries used to be taken into mines to warn miners of poisonous gasses being present). Pilots I train do not die in airplane crashes due to poor decision making, got it?!
Check your POH for the venting system.
In a C150 there are two separate adjustable ventilators near the top of the door close to the front windscreen. They can be manually pulled out and turned to adjust the direction of the airflow. The pilot side one often has the air temperature gauge attached to it.
I prefer to point the flow towards the windscreen and get the cooling air from the bounce back because I find that streaming the vent directly onto my face, refreshing as it is, interferes with the microphone and causes a constant, irritating crackle in my ears through the headset.
Fresh air can be channeled to ventilate the feet by pulling the CABIN AIR knob. This air will mix with the CABIN HEAT knob if it has been pulled out too, just like mixing the water in your bath for that perfect and pleasurable temperature. The CABIN AIR knob also leads air towards the windshield for defrosting if needed.
Chapter 11: Ice and Rain Protection
Ice and rain protection-
As any sensible South African will tell you, the place to be when it is near or just below freezing is under the covers or in front of a warm fire. This is the most effective ice and rain protection!
Sometimes, though, in spite of our most heartfelt prayers, Jack Frost gets bored and decides to torment us here in SA where we are not as prepared for the cold. We do have a little preparation up our sleeves though! Hehehe.
Icing you may come across as a PPL student in South Africa is carburetor icing. Even at outside air temperatures above freezing, carb ice can form. This is because of the airflow speeding up, the pressure drop and fuel evaporation causing temperatures to fall considerably around the throttle butterfly valve, enough to cause icing, especially if the air is humid, i.e. it has a high moisture content. Ice can form around the butterfly valve with outside air temperatures of as much as 13° C!
You will recognise carb icing because the engine begins running very roughly. Carb icing can also prevent you from being able to adjust the throttle. Immediately pull the carb heat leaver all the way out to the carb heat hot position. The first thing that will happen is the engine will sound even worse and run even more roughly. This is a good sign; it means the engine problem probably is carb icing. Both the hot air and the melting ice cause a drop in engine performance. Carb heat must be either fully on or completely off, no half measures here.
Within a few minutes, the icing should clear, and you might consider changing your level or going back to home base until things warm up.
Very Cold Oil
I understand that in colder countries, engines sometimes have to be warmed with an electrical blanket before start so that the oil can be thin enough to circulate through the engine. We just don't have that challenge here, thank goodness! The worst we tend to have regarding starting up is you need to prime more on a cold day with a cold engine, less on a hot day with a cold engine and even less with a hot engine. Read your POH for the starting procedure and check with your instructor.
We don't fly in rain because we prefer to train when we can see clearly, and are in VMC (Visual Meteorological Conditions). Being able to see where you are going is a legal requirement for VFR (Visual Flight Rules) flight. Heavy downpours make this difficult, so as a rule we avoid them.
If you get caught in rain, whatever the reason, the aircraft still flies, and because of your speed, the rain runs off the windscreen quite quickly. Visibility is reduced, but you should manage to get back to the field and land. The air filter in the C150 is right up front, and could get sodden with a long and heavy rain pelting at it and so be ineffective forcing you to use the carb heat as an alternate air source with its corresponding drop in RPM.
An instructor worth his/her salt will not allow you to do ab-initio flight training in poor weather, and if you are not comfortable to fly, say so. Rather fly on a beautiful day. You will learn more, and enjoy it more.
There will be plenty of time to go play in the clouds if and when you have done your instrument rating.
Airframe icing is possible, but only likely at or below zero when flying through visible moisture. It is very unpleasant (read scary) to pick up airframe icing. As a PPL student you should certainly not be flying in any such conditions!
There are all sorts of anti-icing and de-icing fluids and equipment which, once again, are not relevant for our training aircraft. Systems like fluids that prevent icing, de-icing rubber boots on your wing leading edges and heating systems. You will learn about them when it becomes relevant to you.
You may have a pitot heat switch in your training aircraft. This is to warm up your pitot tube if it gets blocked by ice. There are electrical coils in the tube. You can check if your pitot tube heater is working in your pre-flight if you like.
Switch on the pitot heat switch with the master switch on, wait a few seconds, then quickly touch and release the pitot tube to see if it warms up.
In the 10 years I have been instructing I have not experienced airframe icing, or the need to use the pitot heat.
Chapter 12: The Flight Control System & Engine Control System
The Flight Control System
Primary Control Surfaces
You have three main flight controls at your service. These are the Elevator, the Ailerons and the Rudder. Their job is to allow the pilot, (you), to control the aircraft... within certain design limits. These control surfaces are linked via cables, pulleys (and sometimes rods) to your control input devices.
Primary Control Inputs
Your main control input devices are the Control Column and the Rudder Pedals.
The fore and aft movement of the control column moves the Elevator down and up.
The side to side movement of the control column moves the Ailerons up and down. Rotating the Control Column to the left will raise the left aileron and lower the right aileron. Rotating the Control Column to the right will raise the right aileron and lower the left aileron.
The Left Rudder Pedal will move the Rudder surface to the left, and the right Rudder Pedal will move the Rudder Surface to the right.
The Rudder pedals also move the nose wheel on the ground. They are unable to move the nose wheel in the air because once airborne the nose wheel oleo extends fully and locks into position, so you will not get unwanted drag from the nose wheel turning in flight.
Secondary Surfaces Control System
Support systems for your primary control system controls are the Trim Tab and the Flaps. Most light trainers have only one trim tab, and you will find it on the Elevator. Larger heavier aircraft tend to have trim tabs on at least two, but often all three of the major flight control surfaces.
The purpose of a trim tab is to take excess control pressures off the control system inputs, and hence reduce the load on the poor old pilot. So unless you plan on using your aircraft as a muscle building resistance trainer, use the trimmer. You will fly more accurately if you use the trimmer. Aren't aircraft designers just so nice?!
The Trim Tab is adjusted with a trim wheel or handle that you will find on the dash, the floor between the seats or above your head in the middle of the canopy. It is important to note though, that the trim tab is to reduce/eliminate the pressure on the control column, and is NOT designed to control the aircraft in flight.
The Flaps allow the pilot to fly safely at slower speeds and give him/her/you much better visibility out the windscreen for an approach to an airfield. Got to love those clever aircraft designing folk!
The Engine Control System
The Engine control system is just as much fun. There are two main knobs you get to manipulate.
The one you will be busiest with is the "Throttle". It is normally black, and is the control closest to you. Hold the knob in your hand and point your index finger. Let your index finger rest on the base of the Throttle. This will help you judge how far you are pushing or pulling the throttle in or out, and give you some tension so you are able to exert subtle control.
Pushing the throttle forward into the dash opens up that butterfly valve in the intake manifold to increase the fuel drawn out of the mixture jet and increases your RPM, and engine power. YEEEHAAAA!
Pulling it out reduces the flow, decreases the RPM and slows your aircraft down. WOAH BOY!
You will notice a rough-ish ring around the base of the throttle (or a seemingly arbitrary leaver on some aircraft types near the throttle). This is a Throttle Friction Nut. It should be finger tight for normal flight, but you can tighten or loosen it to adjust the amount of force you need to apply to manipulate the throttle. It prevents the throttle from sliding out in a climb or easing in during a descent - both extremely undesirable occurrences.
Please do not play with this in flight! It is the RED knob. You will be taught to adjust it in flight when you get to your Navigation exercise (Ex 18). For now leave it fully rich or as your Instructor instructs.
If you take off or fly with your mixture too lean, you will burn the valves in your engine to a cinder. The ring seats will come loose, and get flung into your engine causing major damage and an engine failure will follow. Engines DO NOT LIKE TO RUN LEAN! That said, they can also cut out if they run too rich, but at least the engine won't break up from the inside.
Fuel burns best at a ratio of 15 parts air to 1 part fuel. 15:1 If the air is less dense, due to altitude or humidity, then you need to reduce the amount of fuel entering the system so that the 15:1 ratio can remain.
Closing the throttle will just slow your aircraft down, so you need to reduce the amount of fuel by adjusting the mixture. The mixture control knob operates a gate that when fully open allows the fuel from the carburetor into the jets unrestricted. When the mixture is pulled out, away from the dash, the "gate” starts sliding over the entrance to the jets restricting the flow of fuel from the carburetor. This restricts the amount of fuel that the throttle can draw out of the jets and in so doing you can restore the 15:1 air:fuel ratio. Exactly how to do this will be explained in the next section, Checklists and Drills.
The Pitch Lever
Although you do not have a pitch lever as a control system in your training aircraft it is worth a mention as it forms part of your checklist.
As soon as you graduate as a PPL and may convert to larger faster aircraft, you will come across the Pitch Lever. This controls the pitch of the Propeller blade so that it is optimum for climb in the climb phase of flight (full fine) and can be adjusted in cruise to give a better speed at a slightly course setting. It is often blue in colour, but sometimes is also black like the throttle. It looks just like the throttle. It is usually found between the Throttle and the Mixture knobs. For now, just know it exists and where it will be positioned. When you have a Variable Pitch or Constant Speed Propeller, you will have a Pitch Lever. Where you have a Pitch Lever, you will also have Cowl Flaps. Cowl Flaps are small flaps under the nose cowling that, when open, assist with cooling the engine.
This is not really a direct engine control, but it does form part of the support system. You will apply the carb heat, (pull the knob out) any time you plan to reduce the throttle RPM below the green arc on the rev counter. When you plan to increase the RPM again, or in preparation for landing, close the carb heat by pushing the knob in.
Carb heat is also used for ice protection.
Chapter 13: Checklists and Drills
Checklists have been devised to make flying safer, both for acceptance of the aircraft as airworthy before flight, and for all the vital actions that need to be performed during the course of the flight.
If you were to see the aircraft bare to the "bones", with all the aluminium cladding that we perceive as so solid peeled back, you might get a little fright and a great amount of marvel, and realise just how important a thorough pre-flight really is. The control cables are no more than thin ordinary cables on pulleys connected to control surfaces, (some aircraft have push rods).
Check-lists for light aircraft are very similar with only a few minor variations aircraft to aircraft. It is easier to complete your checks from a list than paging through your aircraft's Pilots Operating Handbook.
When you first learn to fly, you will be faced with the following lists:
Before Start Checks
After Start Checks
Before Take-off Checks
HASELL Checks/HELL Checks
After a few lessons, roughly when you begin your circuit training, you will be expected to learn few more checks:
After Take-off Checks
After Landing Checks
Shortly followed by your Emergency Drill Checks:
Action in the event of Radio Failure
Engine Fire in the Air
Engine Fire on the Ground
Engine Failure After Take-off
Then when you begin Navigation training, you will learn a few more checks:
Top of Climb Checks
Field Approach Checks
You are expected to use the checklist for all your checks, except for the Emergency Drills, which you must know off by heart, because you won't have time to look for a checklist if you are faced with an emergency in a light aircraft.
You also need to memorise your circuit checks. Why? Because you are too busy in the circuit to worry about scanning a list, and need to instinctively know the drills.
So, memorise the checks in red and blue above, and use the checklist for the others.
Your flying school will provide you with a your very own list of checks for your training with them, but feel free to download and print the preflight, (www.ppl-flight-training.com/support-files/cessna-preflight-checklista5.pdf); start and shut-down, (www.ppl-flight-training.com/support-files/cessnachecklist1a5.pdf);and emergency and other info (www.ppl-flight-training.com/support-files/cessnachecklist2a5.pdf);checklists for a Cessna 150/152/172. Or draw up your own list. Generic lists can also be purchased at Pilot Shops.
Remember, if there are any major discrepancies, your POH (Pilot Operating Handbook) wins! Just in case you haven't figured out what the Pilot Operating Handbook is, it is a manual that comes with the aircraft. This manual tells you all about your aircraft, its checklists and how to operate it. It has to be certified as correct for that aircraft by the relevant Aviation Authority for your country.
The main difference in the checklist between low wing and high wing aircraft is the presence of an auxiliary fuel pump, and a fuel pressure indicator. The auxiliary pump is used when switching tanks, and very often on take off- as per the POH - and is a standby in case the engine-driven pump decides to take the day off. If your fuel cannot reach your carburetor, your engine will be unable to operate! Checking the fuel pressure gauge and the auxiliary fuel pump is a very good plan for pilots who like to keep that big fan up front in perfect working condition.
The fuel pump switch can be found on the panel with the other switches, and looks just like the other switches. Everything is labeled. Did I just hear you say "Thank goodness!"? Sorry friend, you need to fly with your eyes outside the cockpit, and learn to find the correct controls and switches without having to look for them. You can confirm you have located the correct control/switch with a quick glance, but like an experienced typist for whom the location of the letters on the keyboard become instinct, so too must the location of the knobs and switches become to you. Just think of the cockpit as your "keyboard in the sky". You may glance to confirm though!