C172 circuit flying - Am i doing it right?/Questions

[zenrael]

This will be my first post here, so hi! I'm really enjoying the C172. I'm no PPL, but i would like to change that in the coming years, and so i've been focusing on developing proper flying technique as opposed to jumping in and hitting the autopilot from VOR to VOR. The trouble is, with no instructor sat next to me i'm unsure as to whether i'm developing bad habits or simply developing consistent - yet incorrect - methods.

With that in mind, i'd really appreciate it if someone could offer some comments on the 'numbers' i'm using for circuit flying. I also have a couple of questions about the circuit itself, but first i'll outline what i'm doing now...

• I take off from Liverpool (EGGP) usually on runway 27. The charts say the VFR circuit is no greater than 1500 AGL and to be flown over the river, which happens to be a left hand circuit for RWY 27.
  
  I power down the runway with flaps at 10, trim set for TO and rotate at around 55kts. This puts me into quite a steep climb initially. Once i pass around 200ft i retract the flaps and pitch down for a gentler climb usually around 60-70kts. There's plenty of runway below me at this point so i'll usually trim to the climb attitude before commencing turn to crosswind at around 400-500ft.
  
  On the crosswind leg i reduce power to around 2000rpm and first pitch and then trim for around 100kts cruise. Once stable i'll turn to downwind.
  
  On the downwind leg i maintain a cruise of 100kts. Once abeam the numbers i keep an eye out for landmarks that i've learned to be around 45 degrees to threshold. This is when i turn to base.
  
  After the turn to base i immediately throttle down to around 1500rpm, keeping the nose level and adding 10 deg flaps. I trim for 80kts which usually gives a sink rate just in excess of 500fpm. Once trimmed i add another notch of flaps and no longer touch the trim wheel. I keep airspeed around 70kts, give or take, and adjust power to reduce the descent if necessary.
  
  At this point i turn to final. I haven't quite mastered when to do this. I look for the runway and just before passing abeam i make the turn. Invariably i'll either overshoot or be too short and have to turn to meet centre line. I add the final notch of flaps and usually have to reduce to 1400rpm or lower to maintain 55-65kts. My flare and landings are actually pretty smooth - i'm just a little concerned about the rest.

Okay... so if you're still with me, my questions are as follows:

• 1) Is the steep climb upon take off normal? Should i be pitching down and flying the runway or should i let her climb as she wants to in take off trim until a couple hundred feet?
  
  2) Is 100kts a reasonable cruise speed for the circuit? Should I be slower or faster, or does it even matter? If i were entering the circuit downwind, what sort of cruise should i be aiming at before joining the downwind?
  
  3) At what point should i be adding the first 10 deg of flaps. Downwind or on base? At first i added them downwind, and trimmed to level flight, but having seen other pilots do it on the base leg i started to do that instead.
  
  4) After adding 10 deg flaps, i usually trim for 80kts before going any further. I seem to have pulled this number from the air, or at the very least i don't recall where i read it. What airspeed should i be aiming for before adding the next notch?
  
  5) I always miss centreline on the turn to final. I'm either too deep or too short. Can anybody give advice on this? I know its not likely to be perfect for anybody, but i'm usually a fair bit off track. I'm not sure what i'm doing wrong here, or what i'm missing.
  
  6) As well as being off course, i'm either too low or too high on the glideslope. Am i right in thinking its better to meet the glideslope low? I'm usually around 500ft on turn to final, which strikes me as a little dangerously low given the distance to threshold.
  
  7) Finally, all of my turns are coordinated (as well as i can!) 2 minute turns. Is this right? Should i be banking steeper? Can i bank steeper with flaps set to 20?

And that's it! I realise there's a lot of questions, and even more waffle, so i really do appreciate anyone who takes the time to sift through my nonsense. The A2A simulations are just so damned immersive and true to life (from all accounts) that i'm determined to take it seriously and hopefully build up some simulator experience before embarking on a PPL course sometime next year (maybe... hopefully! haha).

Cheers all,

John

[Oracle427]

1) Is the steep climb upon take off normal? Should i be pitching down and flying the runway or should i let her climb as she wants to in take off trim until a couple hundred feet?

Your initial climb should either be at Vx or Vy. the attitude you need to maintain the appropriate V speed is whatever it needs to be. Don't wander between 60 to 70 Kias as that is the range between Vx and Vy. get comfortable with Vy at first and learn to hold the attitude. Keep that climb speed as you retract flaps all the way until you are up to pattern altitude of remaining in the circuit. You will climb fastest at this speed and you want to get altitude quickly on takeoff for safety.

2) Is 100kts a reasonable cruise speed for the circuit? Should I be slower or faster, or does it even matter? If i were entering the circuit downwind, what sort of cruise should i be aiming at before joining the downwind?

90 to 110 is fine for a 172, but there is no harm being on the slower end as you learn. Not sure about your region, but entering downwind is not recommended in the US to avoid traffic conflicts. We generally enter on a 45 to downwind and very important to be at pattern altitude a bit before entering for visibility.

3) At what point should i be adding the first 10 deg of flaps. Downwind or on base? At first i added them downwind, and trimmed to level flight, but having seen other pilots do it on the base leg i started to do that instead.

10 abeam your touchdown point, note that point. 20 on base, 30 when reaching the runway is assured at idle on short final.


4) After adding 10 deg flaps, i usually trim for 80kts before going any further. I seem to have pulled this number from the air, or at the very least i don't recall where i read it. What airspeed should i be aiming for before adding the next notch?

Remain at patten altitude after adding in flaps and let the airspeed bleed off as you reduce power. My instructor liked to have me go to 1500 RPM right before I added flaps and then reduce the power to idle shortly thereafter as I settled into a stable descent at about 70 to 75.

Now don't get into the habit of flying too far away from the runway on downwind nor making all your turns based on landmarks. You should be able to glide in and land if the engine fails.a good rule of thumb is that the runway should be halfway up the wing strut on downwind.

Pay attention to the wind as s strong headwind will require that you turn base early. A crosswind will require that you crab and make steeper or shallower turns into each leg to keep the pattern rectangular. The 45 degree to turn base guideline works well in calm winds, but not as useful in other conditions.

5) I always miss centreline on the turn to final. I'm either too deep or too short. Can anybody give advice on this? I know its not likely to be perfect for anybody, but i'm usually a fair bit off track. I'm not sure what i'm doing wrong here, or what i'm missing.

Winds will change this picture a little. It is better to turn a little early than too late. Keeping turns to no more than 20 degrees of bank is considered normal. Keep practicing and watch the runway.

6) As well as being off course, i'm either too low or too high on the glideslope. Am i right in thinking its better to meet the glideslope low? I'm usually around 500ft on turn to final, which strikes me as a little dangerously low given the distance to threshold.

There is no glideslope when learning. Learn go keep the runway numbers fixed on the windshield using pitch and power as you keep approaching at a steady speed. Use the approach speed for the type of approach you are doing. You will get a feel for this, but remember that the airplane will fly into the point on the ground that is stationary in the windshield. You just need to fly a stable approach to that area and then start your glide break and flare. Personally I like to fly approaches at idle from the time I am abesm all the way to touchdown. I only give the engine a little power once or twice during the descent to make sure it is still responding just in case I need it.

If I come in too low then I go around. I hate to drag in approaches low and depending on power. If I'm to high I can always slip aggressively to lose altitude. Resist the urge to dive and build up speed.


7) Finally, all of my turns are coordinated (as well as i can!) 2 minute turns. Is this right? Should i be banking steeper? Can i bank steeper with flaps set to 20?

No more than 20 degrees of bank is considered normal. Always coordinate your turns unless you are slipping to scrub of excess altitude.

I find this all much easier with trackir.not sure if you use that or some other view management system that allows you to move your head about and keep the runway in sight and keep a traffic scan going.

Do not concern yourself with the instruments. Quick glances to confirm airspeed and altitude are all the info you really need In this phase. learn the keep the eyes OUTSIDE the airplane. You want to be able to fly with precision with the habit of looking outside for traffic with brief butrelay glances inside when you go for your real training.

[Marcus_02]

If I may, I would like to add two points:

If there is enough Rwy available and if there are no significant obstacles in the climb path, make aour Takeoff without Flaps retracted (no Flaps).
The Takeoff Flap Settings are either 0° or 10° and as there is no reason for 10°, let them at 0°.
Why make yourself unnecessary workload?

At 55Kts, you rotate.
That means, that you only pull the yoke as much as you need to get the nose wheel from the ground.
The aircraft now will takeoff by itself.
Right after the aircraft is airborne, hold an airspeed of 70kts (as said, assuming that there are no obstacles)
Don't stay at 55 Kts during the inital climb ...

If you have the right attitude for 70 Kts trim the aircraft, so that it stays at that speed.
In that attitude at full power, you will nearly see the horizon close to the top edge of your glare shield (depending of your sight-settings).

As Oracle wrote, there is no Glideslope when learning.
Ignore it.

The Glideslope is made for a 3° approach.
That means, that any aircraft has the same angle to come in.
As a student pilot. I'Ve learned first to approach with a constant airspeed (mainly 70kts) and a descent of 500ft/min.

At a 3° apporach, the descent rate depends on the airspeed.
If you really want to fly the slope (I either wouldn't recommend that for the beginning) there is a simple rule of thunp for the approach:
Airspeed *5 igves the descent rate in ft/min.
Means: At 100kts Kias, your rate of descent will be 500 ft/min.
At an airspeed of 70kts, your rate of descent will be 350 ft/min (70*5 =350)

But remember:
Reduce your workload, especially at the beginning.
For the approach, ignore the glideslope, trim your speed to 70-75kts and use the power to set the descent rate of about 500ft/min.

Like Oracle, I too have learned to set flaps on the downwind abeam to the touchdown point.
I either reduce power to about 1500rpm (depends on weight, differs between 1500 to 1700).
Flaps to 10° can be set below 110kts, I do it usually at 100.
Turn to base and when below 85kts, set Flaps to 20° and hold the altutude.
You'll notice, that the aircraft will now slow down and at 70 kts, take the Nose down and hold the 70kts.
Now you'll see a nice descent at about 350ft/min.
Use the power to set the rate of descent and hold the airspeed with yoke and trim.
This will give you a stable descent with as less workload as possible ... hopefully

At the final approach, there are only two things important:
Airspeed an Aimpoint.
Keep your speed stable and hold the Aimpoint (the numbers on the rwy) at a fixed position on the window.

Always happy landings
Marcus

[stephan.cote.1]

I might be wrong but I was told to wait for 1000 ft agl before turning crosswind... Can someone confirm or infirm this for me?


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[Great Ozzie]

I might be wrong but I was told to wait for 1000 ft agl before turning crosswind... Can someone confirm or infirm this for me?

If you have a good instructor from the local area who says don't make the turn until 1000' agl - I'd hate to contradict that as there may be a very good reason.

That said (normally) I don't start the turn until a minimum 400' agl and beyond the departure end of the runway. The Aeronautical Information Manual (U.S.) states If remaining in the traffic pattern, commence turn to crosswind leg beyond the departure end of the runway within 300 feet of pattern altitude.

[jacenbourne]

I might be wrong but I was told to wait for 1000 ft agl before turning crosswind... Can someone confirm or infirm this for me?


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This isn't a hard and fast rule, generally it's more dependent upon your pattern distance. I usually turn on to crosswind after TO at about 500ft AGL in my 172. I continue to climb at Vy, and turn on to downwind when I'm far enough out from the runway (general rule of thumb - the runway should be sitting in the middle of the wing strut) and either continue climbing to 1000ft AGL (or 800ft, both are acceptable by the FAA) or if I'm already there, reduce power and trim nose-down. My only thoughts on climbing to 1000 AGL on Upwind is that, depending on your load, this can put you pretty far away from the runway, so you'll be flying a much wider pattern. 500 AGL is what I've stuck with, or in the case of the local strip I fly out of (pattern altitude IS 500 ft AGL), I start my crosswind turn at 2-300 AGL. Altitude does play a part in it, but so does area familiarity. For example, when I'm taking-off and landing on 35L at my local airport, there's a lake off towards the west. I'll turn towards that lake on crosswind, and then right when I'm getting over it, turn on downwind.

At the local strip I fly out of, there's a parallel dirt road that I should be over on downwind. There's a water-tower at the end of the road as well that I can line myself up with (helps when coming in from a distance too!).

At an airport you're not familiar with, you can do it by the numbers, but there's also an element of you picking out landmarks that consistently work for the pattern.

[Oracle427]

Before taking the runway have a plan for what to do if something isn't right. Maybe you aren't getting getting to rotation airspeed by halfway down the runway or the engine isn't making full RPM. Best to plan to have enough runway to stop.

Another thing about local airfields and the pattern altitude. Always check the published procedures for your local field as the pattern may not use the standard 1000 AGL or may not be shaped like a rectangle. In some cases that may be because of noise abatements. In other cases it may be due to being under the approach path for another airport.

Always pay attention to obstacles and the surrounding landscape. If you try to make a turn to left crosswind at 300AGL out of 24 at 4N1, you might become a permanent part of the landscape.

These are things you'll learn in time when you go for the RL training.

Marcus_02,

I actually like using 10 degrees of flaps on takeoff because many fields around here are short with rising terrain or obstacles. It helps to climb up at Vx with those flaps and then lower the nose a bit to reach Vy and then flap retraction. Yes, it is a bit more workload, but not a bad skill to develop.

[Great Ozzie]

either continue climbing to 1000ft AGL (or 800ft, both are acceptable by the FAA)

I am going to just copy and paste (again) from the AIM:

At most airports and military air bases, traffic pattern altitudes for propeller−driven aircraft generally extend from 600 feet to as high as 1,500 feet above the ground. Also, traffic pattern altitudes for military turbojet aircraft sometimes extend up to 2,500 feet above the ground.

The standard / recommended altitude is 1000'agl. Turboprops / Jets typically (afaik) 1500'agl. The way to find out for a specific airport is to look it up in the Airport / Facility Directory. For example, if one searches KHFY (Greenwood Municipal) the second lines shows "TPA—1622(800)". So flying the C172, there's a reason to deviate from the recommended 1000' agl pattern (to use 1622'msl / 800'agl).

500 AGL is what I've stuck with, or in the case of the local strip I fly out of (pattern altitude IS 500 ft AGL)

That sounds awfully low. That's like... circling minima (for an instrument approach). I'm curious where that would be - sounds more like something for an ultralight etc.

[Marcus_02]

At my Homebase (EDXF in Germany), we have a little Viallage close behind Rwy 29 and flying above is to avoid.

That's not a problem at all, because it's enaugh distance, but it's mostly not enaugh to reach 1000ft.
That of course depends on the power fot he aircraft, temperature and weight.
In winter at low altitude with only me in the plane and half of fuel, the C172 goes up at more than 1000 ft/min.
On a hot summer day with full weight, that's logically a total different ballgame.
But either way, we have to stay distant from that village, so that sometimes the turn begins at 500 oder 700ft and sometimes I reach 1000ft prior to the Turn.

I've been teached, that flying a Pattern is not necessarely a thing of flying altitude numbers, but flying according to the VFR-Chart if available for the specific airfield.

There was a time, as we had a military airfield close to ours and if the Tornados were departing or approaching, our Pattern Altitude was temporary changed from 1000' to 700' ...
It's fascinating btw. how visual different this was.

Marcus_02,

I actually like using 10 degrees of flaps on takeoff because many fields around here are short with rising terrain or obstacles. It helps to climb up at Vx with those flaps and then lower the nose a bit to reach Vy and then flap retraction. Yes, it is a bit more workload, but not a bad skill to develop.

Yes, I agree.
The 172-manuel gives us the freedom to decide, both settings are ok.
Here in the very north of germany, we too have some (very) short fields, especially at some islands of the north- and balitc-sea, so we've been teached for short landings too (and as we live near the sea, with strong winds).

I agree, that it could be a good decision to do it as a matter of routine (is that the right term?), because that gives the pilot some kind of additionally safety, ... if I do it automatically, I couldn't forget it .
It was just a suggestion especially for the very beginning but of course I agree to you .

Best regards
Marcus

[jacenbourne]

500 AGL is what I've stuck with, or in the case of the local strip I fly out of (pattern altitude IS 500 ft AGL)

That sounds awfully low. That's like... circling minima (for an instrument approach). I'm curious where that would be - sounds more like something for an ultralight etc.

Haha, you're telling me! I'm flying out of 82TS, Elmdale Airpark if you want to airnav it. It's a privately owned strip, 30x2990 ft (like landing on a pinhead, I swear), pattern alt is 2300ft MSL, about 500ft AGL. Everything is fast and furious and you don't have a lot of room for error. It's why I prefer going over to KABI to do pattern work, since their pattern alt is 2800 MSL, 1000ft AGL and their runways are 150x7000ft. But as my CFI has drilled into me a dozen times, if you can land at Elmdale, you can land pretty much anywhere. Landing at Regional seems like a piece of cake after I've done a half-dozen touch and goes at Elmdale.

[jacenbourne]

TheGreatOzzie, here's the FAA info for KABI: http://aeronav.faa.gov/afd/30apr2015/sc ... PR2015.pdf

You'll see on the Airport Remarks section: AIRPORT REMARKS: Attended continuously. Uncontrolled arpt 2 NM NE of
arpt pattern altitude 2300´.

That uncontrolled airport is where I'm flying out of, 82TS.

[Great Ozzie]

TheGreatOzzie, here's the FAA info for KABI: http://aeronav.faa.gov/afd/30apr2015/sc ... PR2015.pdf

Thanks very much! Excellent example of knowing why such and such TPA (right out of the A/FD).

I understand what you mean about "landing on a pinhead". There's a similar sized airport near me - 6I4, Boone County (3600X30). Long, but wow... did it always feel *so* narrow (if the wings don't fit, why am I landing here? ).

[Great Ozzie]

I power down the runway with flaps at 10, trim set for TO and rotate at around 55kts.

I saw the word "rotate" in there, and it reminded me of something funny I read by John Deakin in an AVweb article - Climb Faster.

A word (or two) about the word “Rotate.” This word was first used after we began flying swept-wing jet transports, and is a highly-defined term of certification which covers the technique of accelerating down the runway in a minimum-drag attitude to V1 (go/no go speed), Vr (rotate), with a precisely timed change in deck angle, which places the aircraft at a speed above Vmu (Unstick), and in an attitude which produces V2 at an altitude of 35 feet with an engine out, OR V2+10 with all engines operating. This “rotation” can cover a time period of up to 15 seconds. This produces maximum performance, and minimum runway used. Varying from this precise technique can have catastrophic consequences – in swept wing jets!

When young CFIs began using this term in Cessna 150s and the like, I thought it was a complete affectation and it made me want to throw up. It still does, but now everyone uses it! I don’t bother making the correction anymore, but deep down inside, it still produces the same feeling as chalk pushed across a blackboard. It’s “just plain wrong!”

My own oft-stated technique with any GA airplane is to allow the airplane to assume a takeoff attitude and let it fly when it wants to, just above the stall. What is the takeoff attitude? With a high-wing, it can be judged by the angle of the lower surface of the wing against the horizon. With a Bonanza, the nose gear oleo strut can be extended, a position that’s very easy to feel. This works very well with any nose-dragger, but calls for a tiny bit (say two tries) of experience with the tailwheel on the proper end. “Slightly tail-up” is about the best I know to say it.

The idea is to have enough airspeed to lift off gracefully, not so slow that you are danger of stalling, and not so fast that you’ll unnecessarily beat up the landing gear and structure.

So, there it is... The idea is to have enough airspeed to lift off gracefully, not so slow that you are danger of stalling, and not so fast that you’ll unnecessarily beat up the landing gear and structure. And that usually requires just a bit a back-pressure (training loading) to let the airplane do its thing when it is ready.

Deakin makes some other interesting points in that article - worth checking out...

Once i pass around 200ft i retract the flaps

No point in leaving the flaps down once clearing obstacles and gaining sufficient airspeed. The Cessna 172 POH spells it out perfectly: If 10° wing flaps are used for takeoff, they should be left down until all obstacles are cleared and a safe flap retraction speed of 60 KIAS is reached.

Once airborne and established in the climb (clear of obstacles) just use the appropriate pressure on the yoke to put the nose where you will accelerate to Vy - for me (and if clear of obstacles, I pitch to Vy) that appears (roughly) where the horizon cuts just across the top of the dash - and trim out that control pressure.

6) As well as being off course, i'm either too low or too high on the glideslope.

(Again) as Oracle mentioned, no glideslope, but there is a glidepath. Always want to be in a position to make the runway if the engine quit. I can remember my first instructor hammering this point home - "no excuse for not being able to make the field if the engine quits" - so I like to hammer that home myself now . But (ordinarily) one doesn't want to be "too high" and have a resulting steep approach - that can cause trouble in the flare.

So you constantly evaluate if too high / too low. Definitely one of those Goldilocks things (looking for "just right") which comes with practice. Abeam point of intended landing is when I pull throttle to descend (roughly 1400-1500 rpm) start trimming off pressure as the airplane slows and add a notch / 10° of flaps. You can certainly add 10° flaps sooner (as long as below Vfe). Instrument approach, one certainly can be configured that way (from the IAF or so - that's well outside the traffic pattern).

I'm personally used to e.g. in a Warrior - Abeam 80kias/one notch, Base 70kias/two notches, Final 63kias/3rd notch. Nice, gentle descent should occur - Marcus pointed out specifics based on airspeed (tho I don't pay much attention to descent rate - no real need). Last notch/30° of flaps based on altitude - no need to add more drag if you realize atm you are low. So I take that procedure to other airplanes. We're just trying to transition from cruise, or thereabouts, to get the airplane slowed up/configured, and into a position on final where we are in a stablized condition, where we can flare and stick it on the pavement without much fanfare.

One other thing you might want to have a look at John... things slightly different in the UK compared to U.S. procedure. Checkout this "GA Safety Poster: Standard Overhead Join" from the CAA. I like the UK method for pattern entry - I don't think our method will ever change. Topic for another day.

At the final approach, there are only two things important:
Airspeed an Aimpoint.

Aaaa Marcus... I think I would term it "Airspeed and Glidepath". I want to be "On Airspeed and On Glidepath" thruout the approach. But yes, certainly watching the aimpoint in the windscreen - and it will certainly let one know if the rate of descent is off.

-Rob

[Marcus_02]

Hi Rob,

Aaaa Marcus... I think I would term it "Airspeed and Glidepath". I want to be "On Airspeed and On Glidepath" thruout the approach. But yes, certainly watching the aimpoint in the windscreen - and it will certainly let one know if the rate of descent is off.

Yep, you're right of course.
But indeed, I have that phrase "Airspeed and Aimpoint" of one of my instructors to this day in my ears .
He was an old Military-Tornado Pilot and I have to admit, that I have given a little too much attention to the instruments in the phase of final approach.
Yes, what he wanted to say was, that I had to pay attention only to Airspeed and Glidepath, to hold the Rwy at a fixed point on the windscreen, what result in a stable Glidepath.

However it worked ... at every approach, even now in the Sim (unfortunately I' actually grounded because I lost my medical two years ago, the A2A 172 btw is a really great tool to kepp the skills ) I remember his words and keep my eyes outside and hold the approach stable
But the right term is certainly "Airspeed and Gliedepath".
Sorry for the confusion.

[jacenbourne]

TheGreatOzzie, here's the FAA info for KABI: http://aeronav.faa.gov/afd/30apr2015/sc ... PR2015.pdf

Thanks very much! Excellent example of knowing why such and such TPA (right out of the A/FD).

I understand what you mean about "landing on a pinhead". There's a similar sized airport near me - 6I4, Boone County (3600X30). Long, but wow... did it always feel *so* narrow (if the wings don't fit, why am I landing here? ).

My thoughts exactly! The 172M has a wingspan of 38', my plane is wider than the damn runway!