Circuits are, by convention, flown at 1000 feet above circuit altitude. This means that if your airfield elevation is 3700 foot, then your circuit altitude is 4700 ft. If your airfield elevation is 100ft, then your circuit altitude is 1100ft. This is true most of the time, but not always!
Sometimes Circuit heights are published in the AIP's that are different from the standard height, eg. Virginia Airports circuit in Durban North, elevation: 20ft - circuit height : 800ft. Richards Bay's circuit, elevation 108ft - circuit height : 1500ft.
Assumptions may be wrong
Before assuming an airfield you are flying to has a standard circuit pattern and or height, it is best to check.
The big boss baddie in the Steven Segal Movie "Under Siege II", said it so well when his goon told him our hero was dead, but that he hadn't seen the body:"Assumption is the mother of all f*$%-ups!" he said. Prophetic words, since they were later all killed by the "dead" cook, Segal.
So, don't be taken by surprise by a "dead cook"; look your destination airfield up in the AIP's Airfields
Directory to discover if it has a standard circuit, or boasts something more challenging. (Or ask your Instructor).
In the circuit, there are certain checks that are mandatory as well as advisable. You are expected to learn these off by heart, unlike your ground checks for which you are expected to use your checklist.
During your training, you will be learning some checks for items that do not exist in your training aircraft. Here's why:
Training aircraft are by their nature very basic. As soon as you have your PPL, you may convert to larger and usually more complex aircraft. If the checks for these more complex aircraft are not already entrenched in you, you are very likely to forget them, which could have disastrous and expensive results. These checks are "gear down", "pitch", "fuel pump on/off", (high wing gravity fed training aircraft don't have fuel pumps, but their low wing counterparts do. It is advisable to have this check in your check list arsenal even if you initially train on high wings).
For the time being, the circuit checks you don't understand are "place-markers" for when you graduate to more complex aircraft.
I find it easiest to think of the
and the Downwind circuit checks of
--> Climb out at your best Rate of Climb (ROC) speed.
--> Final approach, hold a steady glide path. Fly an ATTITUDE. Do not chase the airspeed. If you apply more flap at 300ft, then you will have to lower your nose to maintain speed, AND increase your power to maintain your glide slope.
A gentle reminder to prevent sudden death
Remember, in a climb your speed is already low. When you turn, you INCREASE your stall speed. So say you are climbing at 60kts in a C150, and your flapless stall speed is 48kts. Now you don't notice, but you slow down to 51kts, and start turning steeper towards 25o angle of bank, where your stall speed is 52kts! If you get to 25o angle of bank, you WILL stall a wing tip, resulting in a very sudden wing drop and the first stage of a spin.
At this point you "were" still climbing to circuit altitude, 1000ft agl, now, below this height, you are rapidly spinning to the ground. Will you, in the few seconds it takes you to hit the ground, have the presence of mind to CHECK FORWARD on your control column and LOWER your nose towards the ground which is speedily spinning towards you?! I doubt it.
This technique, applied at low level, has successfully killed quite a few pilots. Please be aware of it, and climb at NO MORE THAN 10o to 15o angle of bank!!! And no slower than your best rate of climb speed!!
You should already have experienced this phenomenon in your "spin avoidance" exercise 11. It is fun to do at a safe altitude, but is deathly to attempt at low altitude. Don't do it.
Look in your POH. As your bank angle INCREASES, so does your STALL SPEED. This means that the greater your angle of bank, the higher/faster your stall speed.
The same danger exists when attempting fancy steep turns onto final approach. At 65kts approach speed, a 60o angle of bank will increase your stall speed to 68kts in a C150. At low level the result will be a spin, followed by death on impact of unyielding terrain.
Be very aware of airspeed and turning, especially in a climb or descent. Climbing/descending turns are
safe, provided you are flying above the stall speed and without any sudden changes in direction which could result in exceeding the critical angle of attack.
It is customary to take off into the wind. This is sensible, since lift is dependent on airflow over the wing from the leading edge flowing over the trailing edge. The wing doesn't care whether the lift is from wind blowing over it, or from the power of the engine moving the aircraft forward.
With the aircraft cowling pointing into say a 10 knot wind, you will have 10 knots of airflow over the wing before you apply any power. This means you will reach your rotate and flying speed a lot sooner, which will reduce your ground roll.
Another advantage is that your angle of climb will be increased, so if you have to clear obstacles, a brisk wind assists you to do so.
The normal take-off:
The take-off is really easy to master. After you have done all your checks,
lined up on the runway and done your
1.release the brakes - heels to the floor,
2.apply full power in about three seconds,(never slam the throttle) and anticipate with right rudder for the slipstream
and gyroscopic effects that try to turn your aircraft off the center-line to the left,
3.check back slightly to keep the nose-wheel light, (this is so that you do not "wheelbarrow" the aircraft with large
weight/pressure on the nose-wheel - wheel-barrowing id not part of the design characteristic of the nose-wheel and will cause
damage),check your revs are full and airspeed is alive(increasing), T's and P's good,
4.rotate at your rotate speed, (in C150 this is 55MPH), and wait for the aircraft to
fly herself off the runway.
5.As soon as you are airborne,release the back pressure a little to build up airspeed to your
best ROC speed, using the ground effect to cushion you, so minus the ground
friction you are able to reach your climb speed a lot faster.
6.When you reach your best ROC speed (Vy), rotate for the climb.
7.By 300ft AGL do your "after take-off checks"
This is the same as for the normal takeoff, except you look at the direction of the wind, and turn your control column slightly into the wind. After lift off, you will roll into the wind. Then you correct and roll your wings level, but you will be facing a little into the wind.
So although you will be at an angle relative to the runway during your climb, your track over the ground will be correct, which is the important part.
Check your aircraft operating manual for the correct procedure for your aircraft.
The usual method, however is:
Similar to the normal takeoff, except:
1.apply 10o of flap
2.pull back slightly to be light on the nose-wheel
3.apply FULL POWER against the brakes
4.Check revs, T's and P's, then release the brakes, heals to the ground.
5.as soon as you are airborne, check forward on the control column as above to increase your speed asap. Rotate for the climb as soon as you have reached your best ROC speed (Vy)
6.By 300ft AGL do your "after take-off checks"
At 500' AGL, (Above Ground Level), you begin a 15° climbing turn onto your crosswind turn. Remember, climbing turns have a nasty little habit of liking to steepen up on you. Your speed is already low, and if you increase your bank angle, you also increase your stall speed, bringing you closer to a potential stall and spin. You also will not climb as well with a steeper bank angle, so there are two good reasons to maintain a 15° bank angle and the correct airspeed.
Turn only until you are flying at a 90° angle to the runway. Keep climbing until you have reached a 45° angle to the runway from your present position. This is when it is time to turn onto your downwind leg.
You may reach your circuit altitude before your turn to downwind, in which case you do a normal medium 30° turn onto downwind.
If you are still climbing to your circuit altitude when it is time to turn onto downwind, then perform a climbing turn as before.
If you reach your circuit altitude during your turn, no problem, just lower your nose attitude to your medium level turn attitude, and increase your bank angle to 30° . Reduce your power to cruise or as required to remain within the white arc on the airspeed indicator in anticipation of needing to lower flaps, and roll out of the turn when parallel to the runway on downwind.
Do your downwind checks and radio call.
Hold off for wind as appropriate throughout the circuit so you fly a nice rectangular pattern over the ground.
Judging your distance
A good rule of thumb so that you know you are about the right distance from the airfield, is that the airfield must appear about 2&frasl3 up your Cessna's strut. If you are in a low wing, then the airfield must be seen about 2&frasl3 up from the wing root .
This puts you at about the right distance from the airfield to easily descend on base.
At the end of your downwind leg, when you once again reach a 45° angle to the runway, do a medium 30° turn onto base.
Now things happen very quickly. You have to initiate the descent and effectively loose 500' from your present position to where you roll out on your final approach.
Carb heat HOT. (You will be bringing your power back out of the green arc on the rev counter, so you need to apply carb heat).
Close/reduce your power, (depending on your aircraft and how quickly she begins to descend). As soon as you reduce/close your power, the aircraft nose will want to drop, (remember your first lesson, exercise 4?!). DO NOT allow this. HOLD the attitude by checking back on the control column as you reduce/close the power.
Apply your next stage of flap (usually 20°) if required.
You will be pretty close if not at your approach speed by this time. Lower your nose attitude by checking forward just a little on your control column, to hold your airspeed and adjust your throttle so that you have a 500' ROD (Rate Of Descent).
You need to look at your approach slope and adjust your throttle as required here so that you will end up at your 500'AGL at the beginning of your final leg. Normally this means you need a 500' ROD on the base leg.
Judge your turn to roll out straight on the final leg. Start too late and you hammerhead to get back to the correct line. Start too early and you cut off a big wedge and usually end up a bit high. Try to get it bang on. A little practice and awareness of how the wind is affecting you goes a long way to make this a source of pride in perfection. It's not too hard. You can do it!
How to land an aircraft (with tricycle undercarriage)
We land into wind for the same reason we take off into wind. At our approach speed, we will have a reduced groundspeed. This will lead to a shorter landing run.
If we had a tailwind on landing, not only will we have a higher groundspeed and ridiculously long landing run but we also risk having our ground distance over the runway extended so much that we might even only touch down past the runway.
I remember having a 3 knot tailwind at a controlled strip 900m long, that caused the C152 to touch-down half way down the runway. Even such an imperceptible breeze can usher you to using a lot more asphalt than you were planning to. Not very comforting.
Exception: There is an exception to every rule. There are some runways that are one way in, one way out, no matter what the wind. There are also some runways on very steep slopes. These might require of the pilot to take off downhill, and land uphill regardless of wind direction. A prudent pilot will always, however, stack the odds in his/her favour. Don't go looking for this type of thrill until you know what you are doing with your aircraft.
You have set up your airspeed and ROD from your base leg. In perfect conditions, you are able to bring the aircraft all the way down to the flare without having to touch the controls.
Most days the conditions do not co-operate so willingly, and you get to feel useful in the cockpit. There are two main points to get your mind around:
1. Your AIRSPEED is controlled by your aircraft ATTITUDE (elevator)
POWER + ATTITUDE = PERFORMANCE
Of course, since everything is inter-related, changing the power setting will affect the airspeed, so a small attitude adjustment would be required as well. Conversely, changing the airspeed will affect the rate of descent, so a power adjustment may be required.
Your aim is to control your airspeed and rate of descent so you fly down a smooth "path" all the way to the runway, at an angle of about 3o.
You want to see the runway numbers 1/3 up from your nose cowling on your windscreen the whole way down, with the slope of the runway looking right. The runway numbers must stay in the same relative position on your windscreen the whole way to the runway, they must just get bigger as you get closer.
Judge the slope by eye-balling the runway it as in the pictures below:
Turning perfectly onto final approach is a judgement based on feeling and your awareness of the wind direction. If you turn past final and have to turn back onto final approach this is called a "hammerhead".
Flying inaccurately is not a sin, it only becomes a sin if you have noticed your error and do nothing to fix it. Fix your slight error as soon as you notice it, and two good things will happen:
PAPI's are "Precision Approach Path Indicators". They are designed for to assist pilots in poor visibility such as Instrument Conditions and for Night landings. They are useful in good weather too...
They are made up of four lights, side by side, and depending on the angle you are approaching at, show you red or white. They appear pink-ish when in transition from red to white or white to red, warning you of a trend. See the diagram below for an explanation of how they work.
When you add flap on final approach, it is usually drag flap. Doing this will slow your aircraft down and increase your rate of descent resulting in a steeper approach and falling short of the runway threshold. To counteract this, you need to lower your nose to keep up your speed, or accept a slower approach speed, and apply power to reduce your rate of descent so you will actually reach the airstrip.
Definition: Flare = bringing the aircraft into a level attitude in preparation for landing, with reduced / no power, then coming all the way back on the control column in stages (which can happen quite rapidly).
You have already practiced landing when you did stalling at altitude. When you did stalling, you were asked to maintain your altitude, and not climb or descend. It is, however, inevitable that you will descend when you stall. You then reduced your angle of attack and recovered.
The procedure is the same for landing, except you do not recover from the stall, but instead allow the ground/runway to break your fall, in other words, you land.
If you have ever watched birds land, you will realise that the procedure is the
same for aeroplanes.
When learning, you will initially get many landings wrong. Don't feel bad, birds mess it up too at first.
Your instructor will gentle you through the process so that you learn from your mistakes, but your mistakes will not be allowed to become dangerous.
So, from a good approach, when coming up over the numbers,
Your two main wheels are your LANDING GEAR. Your nose wheel is just there to balance your aircraft for the taxi. Landing on the nose gear can cause it to collapse, and jam the rudder.
Once you have touched down, keep the control column all the way to your chest and allow the aircraft to drop her own nose to the ground before you release the back pressure.
Things that can go wrong when landing
When flaring for the landing Do NOT check back so far that you climb. This is called ballooning and will result in a very hard landing, possibly with a one or two bounces and is rather uncomfortable unless you "catch" it with a little power and re-flare. Best not to balloon
Flaring too high:
If you flare too high, you will run our of airspeed and still have a little way to the ground. The result: A big bump thump onto the ground, very similar to the end result of an un-corrected balloon landing.
To correct, add a little power to help slow down your rate of descent until you are at the appropriate height.
Flaring too low:
This results, most often, in three point landings with a serious risk of landing nose wheel first. Your nose wheel is NOT landing gear. It is purely to balance your aircraft, and for taxiing purposes. Landing on it will cause damage. You are likely to bounce nose-mains, be sure to pull your control column all the way into your chest and just hold it there until your bucking bronco stops. It can also collapse your oleo strut and jam your rudder pedals and surface. Avoid this please, land on the landing gear, the two MAIN wheels.
With a bit of practice, you will begin to "get the picture". Then landing becomes easier, and you are ready for your next challenges:
Flap improves your view over the nose cowling, AND allows you to fly at a slower speed safely.
Being able to land without flap is an important skill to master for a few reasons: Your flaps could get stuck or the flap motor breaks, or your alternator may give up the ghost and your battery runs flat, so you can't use your electric flaps. Perhaps it is very gusty, or there is a strong crosswind, you choose to land with no or less flap so you don't get bounced around quite as much.
Wind will affect how you plan your approach. If there is very strong wind, you can usually turn onto base from downwind at your normal spot. All checks remain the same, except you don't use flap.
If there is little or no wind, it would be wise to extend your downwind before turning base, so that you have sufficient distance to descend since you can't/are not using the flap that normally assists you to descend over a shorter distance.
Flapless, your approach will be flatter. Instead of seeing the runway numbers 1/3 up your screen, you will have to crane your neck to see the runway edge just under your cowl.
You approach 5KTS/MPH faster than your normal approach speed, since you do not have the flap deployed to fly at a lower speed safely.
When you reach the runway, you are already about in the flared position. Be careful not to check back on the control column too much when you close your power to settle on the runway. You have approached at a faster speed with no extra drag, so inertia will carry the aircraft quite far (Newton 1). Checking back more than necessary to remain level is likely to balloon you and will result in either a hard thump to the ground, a go-around or an application of power and a re-flare.
Very often flapless landings are three-pointers or the nose wheel is only just off the runway when you touch down.
Consult the pilot operating handbook for the approach speed. It is usually about 10 to 15 mph/kts above the stall speed in the landing configuration.
For short field landing, approach at your slowest safe speed in the landing configuration. Approach at your normal angle, or a slightly higher angle, since you have so much drag. This stacks the odds in your favour. The idea is to land at the slowest possible ground speed, which will minimise your ground run. A favourable wind will help you land even shorter. POWER + ATTITUDE (and CONFIGURATION) = PERFORMANCE
Your flare to touch-down is likely to happen a little quicker, and if you dump your flaps once you have touched the ground, you will settle very quickly as you will be below flapless flying speed. NB: TAKE CARE TO NOT TOUCH YOUR UNDERCARRIAGE! Many a pilot has lifted his undercarriage mistaking it for flaps when in a hurry. This is a bit hard to explain to the aircraft owner / insurance.
For a glide approach and landing we usually assume you still have your flap available to you.
Set up your glide at your best ROD speed, and aim 1/3 into the runway. The thinking is that is is better to run off the end of the runway at low speed than not to make the beginning of the runway at a higher speed.
When you are sure you will make the point 1/3 into the runway, you can put down your first stage of flap. As soon as you do this, you need to lower your nose attitude to hold your speed, and your glide distance will be shortened. Your aiming point will move closer to the runway threshold.
Wait until you are sure you can make it 1 3 into the runway again. When you are sure you will, put down your second stage of flap, check forward to maintain best ROD airspeed. Once again your glide distance will be shortened and your aiming point will move closer to the runway threshold.
Wait until you are absolutely sure you will make it a distance into the runway before lowering your final stage of flap, and bringing your landing point to the beginning of the runway.
Flare and touch down as normal.
Sometimes a glide approach requires no flap, sometimes you need to put it down quite quickly. It all depends on your height above ground and the strength of the wind. It is pure judgment. Familiarity with your aircraft, and experience help a lot, but you should be able to manage it okay by the time you go solo.
With this method you approach the runway straight on, with your into-wind wing lower. In other words, you sideslip the aircraft in, but using power to control your rate of descent.
You will be pointing straight down the runway the whole way.Adjust the bank angle and opposite rudder as required to keep pointing straight down the runway.
It is a bit uncomfortable as you are flying out of balance.
To land, reduce the angle of bank, but touch down on the wheel with the wing into wind first. The other wheel will follow and you can help with aileron. Allow the nose wheel to come down relatively soon to assist with directional control.
I personally prefer the crabbing method. For this method you approach the runway slightly side on, but on the correct final approach path. Your aircraft nose is off set, pointing into the wind so that your track over the ground may be straight to the runway threshold.
On your base leg, remember to compensate and begin your descent earlier or more positively if you have a tailwind, and keep a higher power setting if your base leg is into wind.
Use your preferred flap settings for the conditions, approach the normal way, but when you flare, you have to use cross controls to align your aircraft undercarriage with your direction of movement. In other words, to line up with the runway, so you don't tear the tyres off the rims with opposing forces.
Use your rudder to yaw the aircraft about the normal axis in line with the runway. The further effect of yaw (roll) will become apparent unless you do something about it: apply opposite aileron. Enough to keep the wings level. Otherwise flare normally.
I like to aim slightly for the upwind side of the runway, so if I am drifted a little, I will hopefully end up on the center-line, or maybe the other side of it, but not off the runway. Try to flare and touch down quite quickly so that there is not much time to be drifted off the runway. Allow the nose wheel to come down relatively soon to assist with directional control.
A positive aspect of crosswinds is that they are normally more pronounced with stronger winds at altitude, and decrease in strength as you descend to land. Constant adjustments are therefor necessary.
Landing in gusts
Landing in gusty conditions can be tricky. A good rule of thumb is to add half the gust factor to your approach speed to insure that you won't suddenly reach a speed less than the stall speed for your configuration. Eg if the wind is 25G35, the gust speed is 10 knots. Add half (5 knots) to your normal approach speed.
You might also consider an approach with less flap, as less drag will minimise you being bumped around, and at a slightly faster speed you will penetrate through the turbulence a tad better and sooner.
False sense of security... extra speed
There seems to be some sort of belief that there is safety in extra speed. I have seen pilots adding 5 knots for their wife, 5 knots for their Mum, 5 knots for their children.... at the end of the time they have added so much speed to their approach speed that they need a really long runway to bleed it all off. Too much speed when you approach to land is not really your friend, and results in a very long landing roll.
Look at the stall speed in a given configuration for your aircraft (in the POH). This is a maximum all-up weight speed. If you are lighter, the speed is actually lower. Now consider your approach speed, which is worked out like this: 1.3xVS where VS is your stall speed for the landing configuration you have selected.
You will find it is already 10-15knots above your stall speed. You have to bleed off all this speed before your touchdown, since you want your main wheels to land with the stall warning blaring. This will mean you have landed at your slowest possible ground speed.
When training for circuits and landings, you will do "touch and go's". This means that after touchdown you will:
Doing touch-and-go's allows you to do a lot more circuits in an hour than you would if you had to stop and taxi to the holding point each time. You will record every landing you do in a touch-and-go as a full landing.
Because you still have momentum and speed when you land, your takeoff run is relatively short during touch-and-go's.
I have used the call sign "ABC" - Alpha Bravo Charlie - replace this with your own call sign.
The radio work in the circuit is very repetitive with a few minor variations.
After you have done all your initial checks and been given your initial takeoff clearance, which will be something like:
Then continue with the downwind radio call as in the diagram below, then the finals call, repeat process.... until you are ready to finish the training, then call "full stop" instead of "touch and go".
Variations in ATC Instructions:
Tower "ACB, Report finals number 2"
It is very important that you find the other aircraft in the circuit, and report to the tower that you have them, (the other aircraft), visual, so that ATC knows you see each other and won't crash. eg you see them on final approach, then say: ABC I have the traffic on finals visual".
Tower "ABC, extend your Downwind"
Tower ABC, do one Orbit to the left(/right)
Tower ABC, report before turning base
Tower ABC, fly a short Circuit
Radio work for Circuits and Landings : UN-manned procedures
Un-manned radio work in the circuit is a lot busier than in a manned circuit as you need to make a call on almost every leg, as in the diagram below: