Circuit Ground School

Flying Hours Today 0:00, Total 7:35

The weather over the Pennines looked good this morning at 0800hrs. This was quite unexpected as the forecast for this weekend - and next week - are of doom and gloom and the early onset of winter.

I set off to the flying school with blue sky in sight - today was turning out to be a great day for flying. As I approach Leeds through Bradford the cloud was looking distinctly darker and lower. The blue sky had disappeared, the wind had picked up and this was confirmed by the windsock at the airfield as I passed it before going under the main runway through the road tunnel.

My journey wouldn't be wasted though, as I was planning to sit the air law examination today so I would at least be able to get that under my belt. I'd also be able to get in some last minute revision to go over a few of the points that I had not quite fully understood and had come to light when doing my mammoth 156 question mock test in the PPL confuser.

The Standard Circuit

"To maintain some form of safe and orderly flow of traffic at an aerodrome, and to allow easy and safe access to the active runway, aircraft are flown in a standard circuit pattern. For good operational reasons, the preferred direction of take-off and landing is into wind, hence the same direction will generally be used by aircraft both taking off and landing."

From Trevor Thom's The Air Pilot's Manual 1 My concerns about the weather were well founded. The instructor deemed that the weather was too changeable and that it wouldn't be worth going up today - yet another cancellation to add to my long list of disappointments. However we decided to do the ground school for circuits and to prep before next week's anticipated lesson.

In the end this turned out to be a very good move. Rather than rushing the circuit brief we went through the whole thing in great detail. Lots of questions and answers, discussions, and some off tangent discussion of other points of aviation that came to me during the briefing. As the later lessons, and other students, had been cancelled we had ample time to sit and discuss circuits until we had exhausted the subject.

I still recall the briefing was so long and involved, it was probably the toughest part of my whole flight training. I've broken the briefings into bite-sized chunks below to make the whole thing more digestible. The briefing went something like this...

Take Off

Starting on the runway, cleared for take off, do your line up checks.

• Are the compass, runway and heading all in alignment? You don't want to be heading down the runway the wrong way. As well as being potentially very dangerous you will not win any friends in a busy ATZ.
• Set your transponder as required. Note that you set the transponder when in Standby mode so as not to inadvertently respond with the wrong setting, or even to respond with a 7500, 7600, 7700 code by accident. Once set, put it into Alt mode if available (Alt is Mode Charlie - Mode C) and indicates altitude with the squawk. The On setting will only respond with the identifier.
• Note the time, this is a legal requirement so must be done. You may choose to use local time but the ATC will also make a record and will be using Zulu time.
• Check your T's and P's

So now we are ready to go. Push the throttle forward and note the RPM rise. In the Piper you are looking for it to pass 2300 at least, it may not go much higher as the engine is doing an awful lot of work. Check the T's and P's again, and that the ASI indicates an increase in speed.

Apply back pressure and at around 55-60kts you will be airborne. Go into the standard climb attitude looking for a 70kts airspeed when the attitude is correct. This will be aiming for the best rate of climb for the aircraft (Vy) but best angle of climb (Vx) could be used where necessary. Refer to the manufacturers operating handbook for the target Vx and Vy speeds, and remember that they refer to the MAUW (Maximum All Up Weight).

At 200ft do the next set of checks:

• Flaps are up
• T's and P's in the green
• FERAF - Flaps, Engine T's and P's, Radio (ready to change frequency), Altimeter, Fuel
• Landing light is off
• Climbing now at 80kts with the right attitude
• Tracking in the same direction as the runway centre line

Crosswind Leg

At 500ft make a 15 degree angle of bank turn so that we are at 90 degrees to the runway. In a left hand circuit this will be a left hand turn. Note that as we are still climbing we go no further than a 15 degree angle in the turn.

Keep climbing to 1000ft - note that your circuits will be done on QFE so it will be much easier to view your height with a quick scan of the instruments. Power will be at 2300rpm and you will be in trim.

Level out at 1000ft, make a 30 degree angle of bank turn left by 90 degrees. At this point you will be tracking with the runway but in the opposite direction. You are now entering the downwind leg.

Downwind Leg

So we are now on the downwind leg and it is time to start on your pre-landing checks:

• Brakes on, pressure up, brakes off
• Undercarriage down and locked (n/a here)
• Mixture rich
• Carburettor Heat ON
• Magnetos both on
• Primer in and locked
• Fuel pump on - in general it is good airmanship to have the fuel pump on when within 1000ft of the ground
• Check fuel tank in use - or set to both
• Check fuel levels and switch if appropriate
• Check T's and P's
• Check hatches and harnesses are secure
• Carburettor Heat OFF - during the checks the hot air will have melted any ice. It is good to take the heat off for the remainder of the downwind leg as it will reduce power and so you will find your altitude dropping and will have to compensate - work that you don't really need to be doing.

When abeam of the runway - i.e. if you look directly to the left or the right you will be in line with the runway - make your call to ATC or the Air / Ground radio.

It is as simple as "G-XX Downwind" and you may choose to add "To Land" or "To Touch and Go" if you feel it is appropriate. Don't make the call too early as others joining the circuit from overhead will be joining opposite the far runway threshold and will expect you to already be ahead of them once the call is made.

The downwind call gives the controller the opportunity to place you in the appropriate landing slot. If the radio chatter is particularly busy and you miss the chance to place the call when you are abeam of the runway you have to state this when you get to make your call: "G-XX LATE Downwind".

You may now have 20 seconds or so to enjoy the view. Be aware of the runway position over your left shoulder. When it is 45 degrees behind you (at the 7:30 clock position) it is time to turn left on to the base leg.

Base Leg

Turn on to the base leg with a tight turn of 30, 45 or even 60 degrees angle of bank through 90 degrees. The tighter this turn the better as you will have more time and distance to begin your descent. If the wind is stong you may want to turn early so you won't be blown too far from the runway, also if you have flap failure you will want to turn a few hundred yards later than usual so that you have a longer final approach in order to lose air speed.

Once establised on the base leg, there are more checks to complete:

• Carburettor Heat ON
• Power to 1600rpm - hold the nose up to maintain the attitude
• Check Vfe and engage 2 stages of flap - hold the nose down to counter the flaps
• Assume the powered descent attitude with airspeed of 80kts
• Trim - at around 75-80kts at the correct descent attitude there shouldn't be much need to change the trim setting that was in place for the downwind leg of 100kts at 2300rpm.

If everything has gone to plan you should now be approaching 600ft.

Final Approach

At 600ft make a 30 degree angle of bank turn to line up with the runway. Don't make this turn any steeper as you may stall due to low speed. If you do all this correctly and with no wind to interfere with your flight track you should be lined up with the runway. If you are not in line with the runway then keep turning until it comes back in line then bank right to align correctly.

You will now be 1 to 1.5 miles from the threshold and on your final approach. Time for more checks at 500ft:

• Flaps to full
• Airspeed at 70kts
• Trim - then hand back on the throttle
• R/T call: "G-XX Final, Runway 27" - a final check to the controller to ensure that you are where they expect you to be.

Your perspective of the runway should now remain constant. If it deviates then don't chase back to the original perspective, but ensure that it doesn't deviate further.

Use power to control height and attitude to control air speed. In a light aircraft your approach will be a 5 or 6 degree slope. If PAPI lights are installed at the airfield they will be set for 3 degrees and so are not to be used for this approach.

A 5 or 6 degree slope ensures that you have enough height to glide to the runway, with flaps retracted if there is an engine failure. Larger aircraft can use 3 degrees as they have more than one engine to rely on!

At 300ft carburettor heat OFF in readiness for any urgent requirement for full power. Then approach your target point on the runway, just before touching down flare the aircraft to then gentle drop the aircraft on the surface.

Congratulations, you have completed the circuit.

If you are to do a touch and go then maintain the current control settings and stick pressure and prepare to apply power and do it all again. This time you will need to have a positive rate of climb before retracting the flaps.

Simply isn't it? All the above brings together everything I've been learning about and practising over the past months - it all seems quite logical and simple when written down - but in the air it is time to prepare for information overload.

All of the above will be executed over about 6 minutes! But once it is mastered - it is time to go solo.