Standard Visual Circuits
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Standard Visual Circuits
Hi, I wonder if you experts can help me. I’m an ex-military pilot. I have no GA experience, but recently I went to my local flying club, as I wanted to get checked out on a light aircraft. I have flown with two flying instructors. They have left me totally confused about a couple of things; amongst them the ‘standard’ visual circuit. Each seemed to have a different idea about how it should be flown.
In an attempt to clarify things, I’ve been looking up various references, on and off-line, to see how to fly a ‘standard’ powered visual circuit. The first thing that I have discovered is that there does not seem to be any such thing; something which seems to be borne out in the real world! The references are all delightfully vague and contradictory. But further than that, I can find none that actually ‘work’. By work, I mean that the described geometry actually works out.
Let’s take RD Campbell, author of the AOPA Flying Instructor’s Manual, which I understand is often considered an authority.
Campbell suggests climbing at Vx to a minimum of 500 ft, a climbing turn onto the crosswind leg and then levelling at circuit height (800 or 1000 ft). The turn downwind is made level using 30ºAoB ‘when at a suitable distance out from the runway’. He gives no clues what he considers the downwind spacing should be.
He suggests the turn onto base should similarly be made level at 30ºAoB ‘at a suitable distance from the touchdown area’. Elsewhere he mentions that the ideal point to turn is ‘when the intended touch-down point lies at an angle of approximately 45º behind the wing’. Presumably this is in still air conditions.
He then says that ‘the approach will be prepared at some stage along this [the base] leg’. So, at an unspecified point after rolling out on base leg, one should ‘select required power, select flap and adjust the attitude [for the descent].
There is no indication precisely where the finals turn should commence, other than the height should be 500-600 ft. He has already stated that all turns (other than the climbing turn onto crosswind) should be flown at 30ºAoB. After rolling out on finals the approach is flown straight in.
Now, this is my problem with this description. A normal approach is flown at 3º. This means approximately 320 ft per NM travelled. Let’s use a typical light aircraft base leg speed of 75 KT. The rate of descent required to achieve 3º is approx 400 fpm. At 30ºAoB the aircraft has a turn radius of 1860 ft, circumference of 1.92 NM and will take 23 sec to complete a 90º turn, in which time it will have lost about 150 ft. If it started at 500 ft, it will then roll out at 350 ft which equates to 0.875 NM. If the turn were started at 600 ft, the roll-out would be at 450 ft/1.125 NM. So far, so good (ther than the fact that we now have 2 'standard' circuits).
Between commencing descent and start of turn the aircraft must lose 400 or 500 ft, taking it 1 or 1.25 NM. The turn onto base leg and the finals turn will take the aircraft a further 3720 ft or 0.6 NM, plus the unspecified distance travelled after rolling out on base leg to commencing descent. Let’s say that is brief: in 10 seconds the aircraft would travel 0.2 NM. Add that all together and we get a downwind spacing of 1.8 to 2.05 NM. Does that sound right?
Well how about this. Let’s plot out the start of base leg turn point(s). If X is the distance along the extended centreline and Y is the distance in the direction of the downwind leg, then we know that Y is 1.8 or 2.05 NM. As the 2 turns cancel each other out in direction X, then the start of the base leg turn is the same distance from the touchdown point in direction X: 0.875 or 1.125NM. So the angle from the touchdown point to the start of base turn is either 23º or 32º aft of the wing. But wait a minute, didn’t Mr Campbell tell us that it was 45º?
I’ve tried other references. Some day that the downwind spacing should be 0.5 to 0.75 NM (woah, that’s some difference from what Campbell’s works out at). Many agree on 45º being the cue to start the base turn. Some say do a descending base turn. Most agree on about 500 ft being the turn onto finals height. Several suggest rate one turns (specifically argued against by Campbell). However, none are specific; they are all vague about the detail, and the reason is that none of them actually work, when one plots out where the aircraft would actually travel if their descriptions were followed.
Then another can of worms is opened when it comes to how to space from other traffic. I’ve read extend upwind (most would agree with that one), extend crosswind (so presumably have varying downwind spacing and delay descent on base leg by the same amount) and extend downwind (a total no-no for others).
The fact is that (assuming a 1000 ft circuit height) one must travel 3.14 NM from descent to touchdown (2.5 NM for a 800 ft circuit) unless doing a steeper approach. The final approach will account for 300-450 ft of descent, the 2 x 90º turns another 300-400 ft, so the base leg descent must be between 150 and 400 ft, which equates to 0.5 to 1 NM. Added to the turn radius x 2 (0.6NM at 75 KT and 30ºAoB, more at higher speeds/rate one) and you can see that the downwind spacing is a minimum of 1.225 NM (achieved by doing a descending turn with 30ºAoB and commencing the finals turn at 600 ft). Incidentally, this pattern is the closest to 45º from the touchdown point; but it is still a little less (42.5º). Most are considerably more. The only way to achieve closer spacing is a steeper descent or to extend downwind.
So, after all that waffle, my questions: what do you regard as a ‘standard circuit’? What do you use to judge one? What do you teach, and what are your sources?
And what has the esteemed Mr Campbell been doing all these years: dive bombing the runway or flying bomber circuits?
I have to say I’m totally bemused by this approach to aviation. Both in the military and the airline I now work for, standard procedures have been, well, standard. No grey, just black and white! That’s the point; isn’t it?
In an attempt to clarify things, I’ve been looking up various references, on and off-line, to see how to fly a ‘standard’ powered visual circuit. The first thing that I have discovered is that there does not seem to be any such thing; something which seems to be borne out in the real world! The references are all delightfully vague and contradictory. But further than that, I can find none that actually ‘work’. By work, I mean that the described geometry actually works out.
Let’s take RD Campbell, author of the AOPA Flying Instructor’s Manual, which I understand is often considered an authority.
Campbell suggests climbing at Vx to a minimum of 500 ft, a climbing turn onto the crosswind leg and then levelling at circuit height (800 or 1000 ft). The turn downwind is made level using 30ºAoB ‘when at a suitable distance out from the runway’. He gives no clues what he considers the downwind spacing should be.
He suggests the turn onto base should similarly be made level at 30ºAoB ‘at a suitable distance from the touchdown area’. Elsewhere he mentions that the ideal point to turn is ‘when the intended touch-down point lies at an angle of approximately 45º behind the wing’. Presumably this is in still air conditions.
He then says that ‘the approach will be prepared at some stage along this [the base] leg’. So, at an unspecified point after rolling out on base leg, one should ‘select required power, select flap and adjust the attitude [for the descent].
There is no indication precisely where the finals turn should commence, other than the height should be 500-600 ft. He has already stated that all turns (other than the climbing turn onto crosswind) should be flown at 30ºAoB. After rolling out on finals the approach is flown straight in.
Now, this is my problem with this description. A normal approach is flown at 3º. This means approximately 320 ft per NM travelled. Let’s use a typical light aircraft base leg speed of 75 KT. The rate of descent required to achieve 3º is approx 400 fpm. At 30ºAoB the aircraft has a turn radius of 1860 ft, circumference of 1.92 NM and will take 23 sec to complete a 90º turn, in which time it will have lost about 150 ft. If it started at 500 ft, it will then roll out at 350 ft which equates to 0.875 NM. If the turn were started at 600 ft, the roll-out would be at 450 ft/1.125 NM. So far, so good (ther than the fact that we now have 2 'standard' circuits).
Between commencing descent and start of turn the aircraft must lose 400 or 500 ft, taking it 1 or 1.25 NM. The turn onto base leg and the finals turn will take the aircraft a further 3720 ft or 0.6 NM, plus the unspecified distance travelled after rolling out on base leg to commencing descent. Let’s say that is brief: in 10 seconds the aircraft would travel 0.2 NM. Add that all together and we get a downwind spacing of 1.8 to 2.05 NM. Does that sound right?
Well how about this. Let’s plot out the start of base leg turn point(s). If X is the distance along the extended centreline and Y is the distance in the direction of the downwind leg, then we know that Y is 1.8 or 2.05 NM. As the 2 turns cancel each other out in direction X, then the start of the base leg turn is the same distance from the touchdown point in direction X: 0.875 or 1.125NM. So the angle from the touchdown point to the start of base turn is either 23º or 32º aft of the wing. But wait a minute, didn’t Mr Campbell tell us that it was 45º?
I’ve tried other references. Some day that the downwind spacing should be 0.5 to 0.75 NM (woah, that’s some difference from what Campbell’s works out at). Many agree on 45º being the cue to start the base turn. Some say do a descending base turn. Most agree on about 500 ft being the turn onto finals height. Several suggest rate one turns (specifically argued against by Campbell). However, none are specific; they are all vague about the detail, and the reason is that none of them actually work, when one plots out where the aircraft would actually travel if their descriptions were followed.
Then another can of worms is opened when it comes to how to space from other traffic. I’ve read extend upwind (most would agree with that one), extend crosswind (so presumably have varying downwind spacing and delay descent on base leg by the same amount) and extend downwind (a total no-no for others).
The fact is that (assuming a 1000 ft circuit height) one must travel 3.14 NM from descent to touchdown (2.5 NM for a 800 ft circuit) unless doing a steeper approach. The final approach will account for 300-450 ft of descent, the 2 x 90º turns another 300-400 ft, so the base leg descent must be between 150 and 400 ft, which equates to 0.5 to 1 NM. Added to the turn radius x 2 (0.6NM at 75 KT and 30ºAoB, more at higher speeds/rate one) and you can see that the downwind spacing is a minimum of 1.225 NM (achieved by doing a descending turn with 30ºAoB and commencing the finals turn at 600 ft). Incidentally, this pattern is the closest to 45º from the touchdown point; but it is still a little less (42.5º). Most are considerably more. The only way to achieve closer spacing is a steeper descent or to extend downwind.
So, after all that waffle, my questions: what do you regard as a ‘standard circuit’? What do you use to judge one? What do you teach, and what are your sources?
And what has the esteemed Mr Campbell been doing all these years: dive bombing the runway or flying bomber circuits?
I have to say I’m totally bemused by this approach to aviation. Both in the military and the airline I now work for, standard procedures have been, well, standard. No grey, just black and white! That’s the point; isn’t it?
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You are correct that there is no such thing as a standard circuit - as (mostly) the circuit is determined by airspace constraints (vertically and laterally), by noise abatement procedures and by local procedures.
Whilst prepping a student for first solo we fly a standard LH or RH circuit with reference to clock positions (8,4,2 and 10) and back up that with ground tracks. Much of this is confirmed (at home base) by reference to ground features to ensure noise abatement/airspace etc.
The difficulty in GA comes when you start to 'land-away'. What works at your home airfield may not fit in with the procedures at your destination. The generics need to be adjusted to fit what ground tracks and features you can gleen from Pooleys/AFE/AIP information and/or a PPR briefing.
When turning final its a variable feast again. We aim to start the turn at about 500' AGL rolling out about 350' but where the turn begins is obviously a factor of wind with reference to the position of the runway in the side window (vertically as well as laterally). In our SOP's it's a MAX 25degree AOB turn onto final, but thats a minor point. And a 3degree glideslope.... mostly a myth in GA.
I'm sure that you'll appreciate all of that anyhow, but there are far more variables at GA airfields than there are at military - and far more 'standards' being applied. There is, unfortunately, no civilian CFS!
HTH
DD
Whilst prepping a student for first solo we fly a standard LH or RH circuit with reference to clock positions (8,4,2 and 10) and back up that with ground tracks. Much of this is confirmed (at home base) by reference to ground features to ensure noise abatement/airspace etc.
The difficulty in GA comes when you start to 'land-away'. What works at your home airfield may not fit in with the procedures at your destination. The generics need to be adjusted to fit what ground tracks and features you can gleen from Pooleys/AFE/AIP information and/or a PPR briefing.
When turning final its a variable feast again. We aim to start the turn at about 500' AGL rolling out about 350' but where the turn begins is obviously a factor of wind with reference to the position of the runway in the side window (vertically as well as laterally). In our SOP's it's a MAX 25degree AOB turn onto final, but thats a minor point. And a 3degree glideslope.... mostly a myth in GA.
I'm sure that you'll appreciate all of that anyhow, but there are far more variables at GA airfields than there are at military - and far more 'standards' being applied. There is, unfortunately, no civilian CFS!
HTH
DD
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And to throw into the pot a standard visual approach fir a light GA aircraft s not 3 degree either. That's a standard instrument approach.
A visual approach angle for GA is whatever is appropriate for the type and the field.....
A visual approach angle for GA is whatever is appropriate for the type and the field.....
A normal approach is flown at 3º. This means approximately 320 ft per NM travelled.
Ron Campbell brought most of his ideas from the RAF circa 1950s, they have largely been the basis of GA ever since however; with no APs to set things in concrete, there has been a natural drift. Perhaps the largest factor in destroying the Standard Circuit concept has been Noise Abatement, with local circuit patterns that are more concerned with missing some Nimbie's house than flying a safe pattern.
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bemused1812,
I'd say what you need is a good SOP. Most flight schools have this. Normally as a picture of a traffic pattern with comments along side with guidance of what track/speed/configuration to use. Not sure what aircraft you check out on, but I have a traffic pattern profile for C172 if you'd like it sent over. PM me if so. Not sure if it will confuse you even more or point you in the right direction.
The traffic pattern is really easy for someone who knows how to fly, but I agree that without clear instructions HOW TO do it, it can become very confusing. This can be a big problem when a training organisation lack good SOP and standardisation among instructors. There are many ways to skin a cat, none necessarily wrong just different.
I'd say what you need is a good SOP. Most flight schools have this. Normally as a picture of a traffic pattern with comments along side with guidance of what track/speed/configuration to use. Not sure what aircraft you check out on, but I have a traffic pattern profile for C172 if you'd like it sent over. PM me if so. Not sure if it will confuse you even more or point you in the right direction.
The traffic pattern is really easy for someone who knows how to fly, but I agree that without clear instructions HOW TO do it, it can become very confusing. This can be a big problem when a training organisation lack good SOP and standardisation among instructors. There are many ways to skin a cat, none necessarily wrong just different.
Welcome to General Aviation!
I think I could explain this far better with the aid of a whiteboard and a set of coloured markers! However, let's just start with variability...
- Aircraft in a GA airfield circuit may well have downwind speeds from 50-110 knots
- 3 degrees is only an instrument approach. What is normally appropriate depends upon the aircraft, varying from around 5 degrees for something like a PA28, to over 20 degrees for a really slow and draggy microlight like a TST or an XL. The XL and the PA28 may be in the same circuit.
- Circuit height varies also - from 600ft at some microlight airfields, to 1200ft at some places with a lot of irritable neighbours. 800ft or 1000ft is most normal. Some airfields change the circuit height at night.
- Most airfields reference QFE in the circuit, a few reference QNH
- Usually there's a single circuit, sometimes two (higher/faster, lower/slower): for example at Booker or Popham. They are defined geographically (rather than the time defined military circuit).
- As Whopity rightly says, at-least half of all UK GA airfields have a circuit modified for noise abatement.
- Different aircraft types, with different circuit heights, and often different circuit shapes and sizes will inevitably require differences in where you select flap, approach speed, approach power.... And if there are multiple aircraft behind you, select all of them as late as possible to help them keep their spacing. Alternately if you are in a microlight that accelerates for finals, select them as early as possible!
So basically you've correctly put your finger on the fact that there isn't a standard circuit in GA. There is a correct circuit at a given field, modified for your type, modified further to fit in with everybody else.
Strangely, it all makes good sense after a while. I think that some quality time with an FI and a whiteboard will certainly help - on the other hand, some quality time in the right hand seat with some experienced PPLs doing burger runs might help you out in seeing the variations in circuits (and much else, not all of which is quite so healthy
)
G
I think I could explain this far better with the aid of a whiteboard and a set of coloured markers! However, let's just start with variability...
- Aircraft in a GA airfield circuit may well have downwind speeds from 50-110 knots
- 3 degrees is only an instrument approach. What is normally appropriate depends upon the aircraft, varying from around 5 degrees for something like a PA28, to over 20 degrees for a really slow and draggy microlight like a TST or an XL. The XL and the PA28 may be in the same circuit.
- Circuit height varies also - from 600ft at some microlight airfields, to 1200ft at some places with a lot of irritable neighbours. 800ft or 1000ft is most normal. Some airfields change the circuit height at night.
- Most airfields reference QFE in the circuit, a few reference QNH
- Usually there's a single circuit, sometimes two (higher/faster, lower/slower): for example at Booker or Popham. They are defined geographically (rather than the time defined military circuit).
- As Whopity rightly says, at-least half of all UK GA airfields have a circuit modified for noise abatement.
- Different aircraft types, with different circuit heights, and often different circuit shapes and sizes will inevitably require differences in where you select flap, approach speed, approach power.... And if there are multiple aircraft behind you, select all of them as late as possible to help them keep their spacing. Alternately if you are in a microlight that accelerates for finals, select them as early as possible!
So basically you've correctly put your finger on the fact that there isn't a standard circuit in GA. There is a correct circuit at a given field, modified for your type, modified further to fit in with everybody else.
Strangely, it all makes good sense after a while. I think that some quality time with an FI and a whiteboard will certainly help - on the other hand, some quality time in the right hand seat with some experienced PPLs doing burger runs might help you out in seeing the variations in circuits (and much else, not all of which is quite so healthy
)G
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With what has been said above about there being no such thing as a standard circuit I will tell you what I was taught and teach as standard. Climb out at a suitable speed - this can vary depending on type, but for a normal training aircraft I would probably use Vx. Turn crosswind at 500', level at circuit height (1,000' for a standard field) and turn downwind, call downwind abeam the upwind end of the runway (this may be modified dependant on other r/t traffic, but this IS the correct place to call), then do checks. Tracking for most low wing aircraft should have the wingtip just over the far side of the runway - adjust if you have a particularly long/short wingspan. Turn base with the threshold 45 degrees behind the wing (as said - this is nil wind, so adjust as needed). Immediately after the turn, close the throttle, hold attitude, select initial flap and on reaching your initial approach speed, adjust attitude and power so that you start your turn onto final to roll out on final at 500', this should put you about a mile and 1/2 on final - note - steeper than a 3 degree slope, then take final flap and adjust speed. Each leg should be adjusted for driftto track at 90 degrees/parallel to the runway and power on base/final will need to be adjusted to allow for tail (hopefully only on base)/headwind.
As pointed out, this WILL need to be varied because of local procedures and/or how other pilots are flying their circuit ahead (and behind) of you, but IMHO should form the basis if there is nothing written down or been passed by briefing.
As pointed out, this WILL need to be varied because of local procedures and/or how other pilots are flying their circuit ahead (and behind) of you, but IMHO should form the basis if there is nothing written down or been passed by briefing.
Turn crosswind at 500', level at circuit height
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Good point, you do see some very wide downwinds sometimes, outside the ATZ even. I also do tend to climb further upwind myself, say 600', but it does depend which aeroplane I'm flying. You could also continue a climbing turn from crosswind to downwind instead.
All this of course is not really giving the OP what he was looking for, other than the fact that we fly steeper than 3 deg. approaches, which should make his maths work better.
Bemused1812
I think one thing you should do is get one instructor you're comfortable with and stick with them, that'll reduce the variables while you get yourself sorted out. It's a bit disappointing that two FIs at the same school haven't sorted themselves out with some common standards to teach though isn't it.
All this of course is not really giving the OP what he was looking for, other than the fact that we fly steeper than 3 deg. approaches, which should make his maths work better.
Bemused1812
I think one thing you should do is get one instructor you're comfortable with and stick with them, that'll reduce the variables while you get yourself sorted out. It's a bit disappointing that two FIs at the same school haven't sorted themselves out with some common standards to teach though isn't it.
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The problem with this is, with the poor climb performance of a typical trainer, probably at max weight, the crosswind climb from 500' to 1000' followed by the protracted levelling out by the student before turning can position you very wide downwind.
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Thanks
Wow, thanks very much for all the advice. The lack of standardisation is disappointing, mrmum. I am heading towards the opinion that I might have to look elsewhere for a different level of professionalism. But that’s another matter.
I have come across these notes which I believe apply to a PA-28-180. They seem much more like what I was expecting. What do you think?
Climb and Crosswind Turn and Crosswind Leg
Complete the after take-off checks and climb straight ahead (track along the runway centreline) at VY (76 KT) until at least 500 ft (note 1). Lookout to clear the turn as you approach 500 ft. At 500 ft commence climbing turn with 15° AoB. Roll-out to track at 90° to runway (allow drift for wind at circuit height).
Level at 1000 ft. Accelerate to downwind speed (85 KT) and set downwind RPM (2000 RPM).
Downwind Turn and Downwind Leg
Downwind spacing is 1 NM out from the runway. Judge the turn by looking back at the runway and turning when it is relative to part of the aircraft (be aware that the angle looks different when allowing for drift crosswind), and/or by looking for a ground feature on the downwind leg if there is one.
Turn downwind using 20°AoB. Adjust heading to allow for wind at circuit height. Use a ground feature if available to aid accurate downwind spacing. Otherwise use position of the wing relative to the runway, but make sure wings are level when checking, and be aware that the picture is different when drift is applied. Adjust your track if necessary to maintain the correct downwind spacing. When you are abeam the upwind threshold, make the downwind R/T call “[C/S] downwind [intentions]” (note 2). Carry out the pre-landing checks, including selecting 10° flap. Progressively adjust the attitude and trim as the speed reduces towards the base turn speed (75 KT). If it reaches 75 KT before the turn in point be prepared to increase power a little to maintain 75 KT.
Base Turn and Base Leg
If there is a ground feature at 1 NM on the extended centreline, use it to judge when to commence the base turn (turn when abeam); otherwise use the angle to the touchdown point: 45°. If there is a strong headwind, turn early. Turn level using 20°AoB.
Roll-out tracking at 90° to the runways heading; allow drift for wind. As soon as you roll out, select base leg descent RPM (1700 RPM), flap (25°) and lower the nose to achieve 665 fpm rate of descent in still air conditions. The RPM and hence RoD should be adjusted to take account of crosswinds. A tightening crosswind will require a reduced RPM/ increased RoD, and a slackening crosswind will require increased RPM/reduced RoD.
Finals Turn and Short Finals
If there is a ground feature at 1 NM on the extended centreline, use that to judge the finals turn. Otherwise look at the runway and ‘imagine’ the extended centreline. Ideally the turn is commenced at 720 ft, but it is initiated at the right point over the ground rather than height. If you turn over the correct point on the ground and the height differs from 720 ft, you can use that as a check height and adjust the RPM and hence rate of descent to compensate; reduce RPM if high, and increase if low. Use 20°AoB but adjust the AoB as required to roll-out tracking along the extended centreline; use a maximum of 35°AoB. If you need more, consider going around at this point.
In theory, you should roll out at 530 ft and 1 NM from touchdown. This will give you a 5° approach. Adjust the attitude to pick the landing point. Use power as required to maintain 75 KT until you select full flap (40°). The point at which to select full flap depends on the headwind. In still air conditions, it should be at about 300 ft. In any case, you should have stabilised your approach by 300 ft. That means you should be on the centreline, at the correct speed and configuration, and have received clearance; if you have not achieved these criteria, go-around immediately. After selecting flap, allow the aircraft to gradually decelerate towards VAT of 66 KT, trimming as it slows down.
Note 1
Consider extending upwind (beyond 500 ft; even up to, or after levelling at, 1000 ft) if:
• You wish to increase the spacing between you and an aircraft ahead;
• There is a very strong headwind at circuit height which is shortening the time on the downwind leg too much; or
• The aircraft performance is such that it is difficult to achieve circuit height before turning downwind.
If you extend upwind significantly and there are aircraft following you in the circuit, make the information call “[C/S] extending upwind”.
Note 2
If you are unable to make the R/T call in the correct place due to other R/T traffic, do not delay your checks while you wait. If you delay the call for this reason, or forget to make it on time, say “[C/S] late downwind [intentions]” when you make the call.
Spacing
Avoid the temptation to adjust the circuit by widening the downwind leg or extending downwind to adjust your spacing from aircraft ahead; the place to do this is upwind. If you are too close crosswind or downwind, then go around from circuit height and judge the point you re-join the circuit pattern to fit in with other aircraft. Be aware that others will use poor techniques, including flying very wide circuits and extending downwind. Do not compensate by adopting poor techniques yourself, nor get into arguments over the R/T; sort out such problems by discussion on the ground later. One common reason for poor circuit patterns is when pilots attempt to compensate when there there are too many aircraft attempting to fly circuits at the same time. The solution is to fly practice circuits elsewhere or at another time. The two problems arising from widening the pattern are:
• It makes it difficult for other aircraft (and ATC) to spot you if you are not where you should be, and there is a danger of other aircraft turning inside you (deliberately or inadvertently) if you are very wide.
• It makes the judgement of the finals turn and a constant angle approach very difficult if you deviate from standard parameters. The circuit described here will result in a 5° approach path, and the speeds/heights/RPMs are all calculated to help you achieve that without too much thought or judgement. It is far more difficult if you deviate from this standard. Good landings result from good and stabilised approaches.
I have come across these notes which I believe apply to a PA-28-180. They seem much more like what I was expecting. What do you think?
Climb and Crosswind Turn and Crosswind Leg
Complete the after take-off checks and climb straight ahead (track along the runway centreline) at VY (76 KT) until at least 500 ft (note 1). Lookout to clear the turn as you approach 500 ft. At 500 ft commence climbing turn with 15° AoB. Roll-out to track at 90° to runway (allow drift for wind at circuit height).
Level at 1000 ft. Accelerate to downwind speed (85 KT) and set downwind RPM (2000 RPM).
Downwind Turn and Downwind Leg
Downwind spacing is 1 NM out from the runway. Judge the turn by looking back at the runway and turning when it is relative to part of the aircraft (be aware that the angle looks different when allowing for drift crosswind), and/or by looking for a ground feature on the downwind leg if there is one.
Turn downwind using 20°AoB. Adjust heading to allow for wind at circuit height. Use a ground feature if available to aid accurate downwind spacing. Otherwise use position of the wing relative to the runway, but make sure wings are level when checking, and be aware that the picture is different when drift is applied. Adjust your track if necessary to maintain the correct downwind spacing. When you are abeam the upwind threshold, make the downwind R/T call “[C/S] downwind [intentions]” (note 2). Carry out the pre-landing checks, including selecting 10° flap. Progressively adjust the attitude and trim as the speed reduces towards the base turn speed (75 KT). If it reaches 75 KT before the turn in point be prepared to increase power a little to maintain 75 KT.
Base Turn and Base Leg
If there is a ground feature at 1 NM on the extended centreline, use it to judge when to commence the base turn (turn when abeam); otherwise use the angle to the touchdown point: 45°. If there is a strong headwind, turn early. Turn level using 20°AoB.
Roll-out tracking at 90° to the runways heading; allow drift for wind. As soon as you roll out, select base leg descent RPM (1700 RPM), flap (25°) and lower the nose to achieve 665 fpm rate of descent in still air conditions. The RPM and hence RoD should be adjusted to take account of crosswinds. A tightening crosswind will require a reduced RPM/ increased RoD, and a slackening crosswind will require increased RPM/reduced RoD.
Finals Turn and Short Finals
If there is a ground feature at 1 NM on the extended centreline, use that to judge the finals turn. Otherwise look at the runway and ‘imagine’ the extended centreline. Ideally the turn is commenced at 720 ft, but it is initiated at the right point over the ground rather than height. If you turn over the correct point on the ground and the height differs from 720 ft, you can use that as a check height and adjust the RPM and hence rate of descent to compensate; reduce RPM if high, and increase if low. Use 20°AoB but adjust the AoB as required to roll-out tracking along the extended centreline; use a maximum of 35°AoB. If you need more, consider going around at this point.
In theory, you should roll out at 530 ft and 1 NM from touchdown. This will give you a 5° approach. Adjust the attitude to pick the landing point. Use power as required to maintain 75 KT until you select full flap (40°). The point at which to select full flap depends on the headwind. In still air conditions, it should be at about 300 ft. In any case, you should have stabilised your approach by 300 ft. That means you should be on the centreline, at the correct speed and configuration, and have received clearance; if you have not achieved these criteria, go-around immediately. After selecting flap, allow the aircraft to gradually decelerate towards VAT of 66 KT, trimming as it slows down.
Note 1
Consider extending upwind (beyond 500 ft; even up to, or after levelling at, 1000 ft) if:
• You wish to increase the spacing between you and an aircraft ahead;
• There is a very strong headwind at circuit height which is shortening the time on the downwind leg too much; or
• The aircraft performance is such that it is difficult to achieve circuit height before turning downwind.
If you extend upwind significantly and there are aircraft following you in the circuit, make the information call “[C/S] extending upwind”.
Note 2
If you are unable to make the R/T call in the correct place due to other R/T traffic, do not delay your checks while you wait. If you delay the call for this reason, or forget to make it on time, say “[C/S] late downwind [intentions]” when you make the call.
Spacing
Avoid the temptation to adjust the circuit by widening the downwind leg or extending downwind to adjust your spacing from aircraft ahead; the place to do this is upwind. If you are too close crosswind or downwind, then go around from circuit height and judge the point you re-join the circuit pattern to fit in with other aircraft. Be aware that others will use poor techniques, including flying very wide circuits and extending downwind. Do not compensate by adopting poor techniques yourself, nor get into arguments over the R/T; sort out such problems by discussion on the ground later. One common reason for poor circuit patterns is when pilots attempt to compensate when there there are too many aircraft attempting to fly circuits at the same time. The solution is to fly practice circuits elsewhere or at another time. The two problems arising from widening the pattern are:
• It makes it difficult for other aircraft (and ATC) to spot you if you are not where you should be, and there is a danger of other aircraft turning inside you (deliberately or inadvertently) if you are very wide.
• It makes the judgement of the finals turn and a constant angle approach very difficult if you deviate from standard parameters. The circuit described here will result in a 5° approach path, and the speeds/heights/RPMs are all calculated to help you achieve that without too much thought or judgement. It is far more difficult if you deviate from this standard. Good landings result from good and stabilised approaches.
As a starting point in a PA28 I'd agree with most of that. With practice, you'll get used to adjustments, just as I'm sure you did in your military flying.
One thing I disagree with is the proscription against extending downwind. A great many airfields prefer this as a means of ensuring spacing. I do agree however that widening the circuit is a poor practice. Some airfields also prefer orbits for spacing, but those need treating with care because it can just mess everybody up behind you.
It is very "flying by numbers" mind you, which is perhaps appropriate to military training or airline flying, but light GA does both allow and need a bit more flexibility on speeds / power settings / turning points, particularly if e.g. you find yourself sharing a circuit with a couple of microlights and a helicopter, as well as the usual mix of fixed wing traffic which might have downwind speeds from 50-110 knots, requiring care and flexibility from everybody. The pilot insistent on flying an absolutely standard circuit regardless of what's going on around him will make few friends!
G
One thing I disagree with is the proscription against extending downwind. A great many airfields prefer this as a means of ensuring spacing. I do agree however that widening the circuit is a poor practice. Some airfields also prefer orbits for spacing, but those need treating with care because it can just mess everybody up behind you.
It is very "flying by numbers" mind you, which is perhaps appropriate to military training or airline flying, but light GA does both allow and need a bit more flexibility on speeds / power settings / turning points, particularly if e.g. you find yourself sharing a circuit with a couple of microlights and a helicopter, as well as the usual mix of fixed wing traffic which might have downwind speeds from 50-110 knots, requiring care and flexibility from everybody. The pilot insistent on flying an absolutely standard circuit regardless of what's going on around him will make few friends!
G
lower the nose to achieve 665 fpm rate of descent in still air conditions.
I think a slightly more flexible approach is preferable.
I would also add that if incorrectly spaced, orbits on downwind are not a good idea, preferably go around and try again. Of course we all know how to go around from any point in the circuit and not just on final, don't we?
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Doing my training from a large airport I was/am taught not to turn crosswind until past the end of the runway which is often well after climbing through 500' (especially on a go-around) unless OKed by ATC.
ATC also prefer orbits for spacing where I'm based - but its normally due to longer waits for 737s (or larger) to land. They often have some aircraft on rt hand and some on left hand circuits at the same time so harder to judge. They have also asked me to extend downwind on occasion.
Another reason to not fly too far away from the runway is you should be within gliding distance (in case of engine failure) so a 500' circuit would be closer to the runway than a 1000' circuit.
PAPI is set at 3 or so degrees so can be missleading.
For a PA28 we don't use 10° flaps at all (selecting carb heat pretty much reduces speed enough to select 2 stages of flaps) - find what works for you and follow the advice of an instructor.
ATC also prefer orbits for spacing where I'm based - but its normally due to longer waits for 737s (or larger) to land. They often have some aircraft on rt hand and some on left hand circuits at the same time so harder to judge. They have also asked me to extend downwind on occasion.
Another reason to not fly too far away from the runway is you should be within gliding distance (in case of engine failure) so a 500' circuit would be closer to the runway than a 1000' circuit.
PAPI is set at 3 or so degrees so can be missleading.
For a PA28 we don't use 10° flaps at all (selecting carb heat pretty much reduces speed enough to select 2 stages of flaps) - find what works for you and follow the advice of an instructor.
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Thanks again for your thoughts guys.
Bingofuel, is your point not covered by:
"The RPM and hence RoD should be adjusted to take account of crosswinds. A tightening crosswind will require a reduced RPM/ increased RoD, and a slackening crosswind will require increased RPM/reduced RoD."
It would be useful to have some rules of thumb for how much to adjust the power, and rate of descent, mind you.
Genghis, I take your point about flying by numbers, but I guess that cuffing it requires judgement and experience, which is lacking in inexperienced pilots, therefore it's good to give them a framework to hang their hats on. I'd put myself in that category, with regard to this type of flying anyway. I've been a trainee and trainer in several different flying disciplines, and have always found that walking before running is best. Maybe I’m too institutionalised, but I don’t feel right now that I have the experience to make it up as I go along, and really want someone to tell me what I should be aiming for; even if achieving it in the real world is a little challenging.
My instructors seem to think that I don’t need any instructing, probably giving too much credit for my experience in other types of flying. But without that experience, I’d be really bemused right now!
I guess what I really want is a student study guide like we gave to ab-initio pilots in the RAF.
Bingofuel, is your point not covered by:
"The RPM and hence RoD should be adjusted to take account of crosswinds. A tightening crosswind will require a reduced RPM/ increased RoD, and a slackening crosswind will require increased RPM/reduced RoD."
It would be useful to have some rules of thumb for how much to adjust the power, and rate of descent, mind you.
Genghis, I take your point about flying by numbers, but I guess that cuffing it requires judgement and experience, which is lacking in inexperienced pilots, therefore it's good to give them a framework to hang their hats on. I'd put myself in that category, with regard to this type of flying anyway. I've been a trainee and trainer in several different flying disciplines, and have always found that walking before running is best. Maybe I’m too institutionalised, but I don’t feel right now that I have the experience to make it up as I go along, and really want someone to tell me what I should be aiming for; even if achieving it in the real world is a little challenging.
My instructors seem to think that I don’t need any instructing, probably giving too much credit for my experience in other types of flying. But without that experience, I’d be really bemused right now!
I guess what I really want is a student study guide like we gave to ab-initio pilots in the RAF.
My comment was a bit tongue in cheek re the exact fpm quoted.
Difficult o give exact power/rod clues but try 100 rpm will change rod by 100 fpm as a starting point.
I dislike concentrating on flying too much by numbers in a visual circuit when you need your eyes outside because unfortunately circuit discipline can be very poor at some airfields. However if you are learning on a PA28 here are some numbers to try , 2100 rpm downwind, turn base , 1500 rpm/ flaps 25, and it should settle about 75 kts with no trim change required, then on final, full flap should give you about 65kts again with negligible trim change so it helps reduce the workload.
Difficult o give exact power/rod clues but try 100 rpm will change rod by 100 fpm as a starting point.
I dislike concentrating on flying too much by numbers in a visual circuit when you need your eyes outside because unfortunately circuit discipline can be very poor at some airfields. However if you are learning on a PA28 here are some numbers to try , 2100 rpm downwind, turn base , 1500 rpm/ flaps 25, and it should settle about 75 kts with no trim change required, then on final, full flap should give you about 65kts again with negligible trim change so it helps reduce the workload.
I guess what I really want is a student study guide like we gave to ab-initio pilots in the RAF.
However, can I suggest that what you might want to try - as an experienced aviator who can take material in rather faster (one hopes) than most student pilots, you consider acquiring an instructors guide?
The two I have, both excellent in their own ways are and the much more recent Newton and Halstead: http://www.ontrackaviation.com/book.htm. For what you want, I think I'd pick the second.
Ultimately however, I still think you'll find sitting next to an experienced PPL doing a few burger runs will go a long way to helping it make a bit more sense. If you've associated yourself with a club, I'm sure they can recommend some of the good guys who wouldn't mind a passenger, particularly if you offer to chip in something for fuel and lunch.
G
Am I alone in finding a hint of 'disconnect' in the OP's comments?
