Circling Minima
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You have gone way outside it whilst on base
You will note that I mentioned...no more than two miles on final...normally it is about 1.8 miles, with the possibility of landing flaps selected whilst in base, and the descent begun at that point.
Is this allowed?
Yes.
The FAA requires very accurate flying, and it certainly can be done.
Is TERPs limiting?
Yup, sure is.
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on base you remained within 2 nm of threshold and you were wings level on finals at about 1.8 nm...?
Early descent from MDA is not allowed, nor are high rates of decent.
A demanding maneuver, to be sure.
I expect this is the reason many airlines have eliminated (or severely restricted) circling from their normal operations.
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The reason that most airlines have removed the circle is driven by one, safety and two economics. The circle takes up a lot of sim time that can better be used for other maneuvers and in the case of our Capt. 411A, it uses up a lot of fuel as well.
Not so sure about 411 comment regarding going to full flaps on base to final (if that's what I understood), as a best practice is to go to final flaps before you turn base, thus keeping the turn radius to a minimum.
What ever works
Not so sure about 411 comment regarding going to full flaps on base to final (if that's what I understood), as a best practice is to go to final flaps before you turn base, thus keeping the turn radius to a minimum.
What ever works
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Not so sure about 411 comment regarding going to full flaps on base to final (if that's what I understood), as a best practice is to go to final flaps before you turn base, thus keeping the turn radius to a minimum.
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as a best practice is to go to final flaps before you turn base, thus keeping the turn radius to a minimum
One aspect of the circling approach often unheeded, is the tendency to commence descent on base in order to fit the landing profile. You should ask yourself - where is the controlling obstacle? You probably wouldn't have a clue because it isn't shown on the chart. Maybe it is on late downwind - maybe on base leg. The aerodrome chart will not necessarily display this spot height. That means once you opt to descend below the published circling MDA for whatever reason, the captain is entirely responsible for his own obstacle clearance. Easy enough by day - but by night where you cannot see the ground directly below you, a different thing altogether.
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Tee Emm, to appease your critics, those aerodromes with critical terrain profile usually impose restrictions for circle to land at night or require additional training.
Other than that as it's been said different strokes for different folks, don't do it if not comfortable. In the end that's what it is a VISUAL flight maneuver. You're fully accountable and responsible for the successful outcome of the mission "impossible"
Other than that as it's been said different strokes for different folks, don't do it if not comfortable. In the end that's what it is a VISUAL flight maneuver. You're fully accountable and responsible for the successful outcome of the mission "impossible"
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The first thing that comes to mind regarding GCTS is that the VOR is SW of the aerodrome.
It is possible to reduce the circling area (exclude a portion of the total area) in order the acheive lower minima. This has been done at GCTS.
However, when this is done the area in which obstacle clearance is provided has to include those parts of the final approach and missed approach that are in the total circling area.
With the VOR a distance from the runway, the final approach area and missed approach area will splay outward i.e. get bigger as one moves from the VOR towards the runway.
The ILS however, will have the area reducing in width as one gets closer to the runway.
Thus it is possible that the circling area in which obstacles have to be considdered is different for the VOR and the ILS.
However, for me the biggest clue could lie in the fact that the ILS charts refered to are some years older then the other approach charts.
Therefore, until I had the situation clarified, I would use the higher minima as published on the later charts.
It is possible to reduce the circling area (exclude a portion of the total area) in order the acheive lower minima. This has been done at GCTS.
However, when this is done the area in which obstacle clearance is provided has to include those parts of the final approach and missed approach that are in the total circling area.
With the VOR a distance from the runway, the final approach area and missed approach area will splay outward i.e. get bigger as one moves from the VOR towards the runway.
The ILS however, will have the area reducing in width as one gets closer to the runway.
Thus it is possible that the circling area in which obstacles have to be considdered is different for the VOR and the ILS.
However, for me the biggest clue could lie in the fact that the ILS charts refered to are some years older then the other approach charts.
Therefore, until I had the situation clarified, I would use the higher minima as published on the later charts.
Thus it is possible that the circling area in which obstacles have to be considered is different for the VOR and the ILS.
The charts show the same circling limitations (066-->264deg) for all approaches.At GCTS, the ILS & VOR approaches are both aligned with the runway and at a MDA of 1,350' on 08 you're only about 2.5nm outbound from the VOR - 5deg track error is c.0.2nm laterally at this range. As pointed out, the dates on the charts range from 2001-->2008...
For those who are heroic enough to be able to circle at 200 knots, or thereabouts, within 1.7 NM, I say more power to your elbow!
My airline still authorises circling approaches but fairly recently raised the minima to at least 1,000'AAL. We do train for this type of approach but to be frank, most sims are crap in this regard as you don't have a proper visual reference for a lot of the "visual" segment so are reduced to watching the map - not exactly good practice.
It does cross my mind that the most likely time (for us) to have to do one of these approaches would be into some hick airfield on an ETOPS diversion in the middle of winter. Personally it would have to be one hell of a cross/tail wind to persuade me not to use the instrument runway! BGSF comes to mind here...
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But as the circling area is defined as distances from the airfield (a sort of convex hull around radii projected from the respective thresholds), either you're inside the area or not... 
The charts show the same circling limitations (066-->264deg) for all approaches.
The charts show the same circling limitations (066-->264deg) for all approaches.The area to be excluded is clearly defined as you say. However, if the final approach area and missed approach area for the VOR overlies part of this area, then obstacles in this overlap will still have to be taken into account despite the fact that overflight is not permitted by the restriction.
Even if the restriction was simply no circling north of 08/26, obstacles north of the centerlines of each runway contained within the annex 14 approach areas and the final approach and missed approach areas for the procedure which are north of the centerline and within the total circling area have to be included.
In simple terms you have to be safe in terms of obstacles flying just inside the most northerly boundary of the final approach area and missed approach area which are contained within the circling area.
While pilots are thinking in terms of being 5 degrees off to the north from overhead the VOR, the final approach area will be a certain width at the VOR and diverge at 8 degrees. Thus really being only 5 degrees off after passing exactly over the VOR would not be at the northern boundary of the approach area in which obstacles are considdered.
There is the posibility of a pilot at the circling MDA being well north of the final approach track but still being contained within the final approach area for the VOR.
Remember that the VOR final approach area is expanding as one moves away from the VOR but the LOC final approach area is getting smaller.
Sit back and do a few simple math calculations based on the following principles for CAT C (ICAO);
1. Circling minimum obstacle clearance is 394ft with a lower limit of 591ft above the aerodrome elevation
2. The final approach obstacle clearance for the VOR final approach area is 246ft as it is for LOC
Missed approach obstacle clearance is a minimum of 98ft and then 164ft
You can play with the figures and come up with a best guess as to what the obstacle is causing and then look at the chart.
My guess is that the slopes of the hill NW of the airport are the dominant obstacle.
However, all that is simply guess work and I would be more inclined to err on the side of safety and use the more recent higher minima for all circling operations.
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As for TERPS, circling area is defined in "miles" and is much smaller than icao but the speeds are different and the minimum obstacle clearance is less. So not really the same thing at all.
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ICAO circling is based on 20 deg aver age bank or rate 1 whichever requries less bank and for cat C a TAS of 180Kt and wind of 25Kt giving an overall speed of 215 Kt combined with 20 degrees AOB for calculation of turn radius.
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Personally it would have to be one hell of a cross/tail wind to persuade me not to use the instrument runway!
DFC,
Thanks for the info. I can see why you might have to raise the circling minima because of obstacle/missed approach requirements pertinent to the approach you actually use to get to circling MDA and will also use in the event of a missed approach. What I don't understand in this case is that the original approach minima are not as restrictive, e.g. 1,060' for the VOR...
Yes, but in that case he'd be OK* for terrain etc. down to the VOR limit: 1,060'. If he didn't get the required visual references at circling MDA, some 300-600' above the VOR MDA then he'd have to fly a missed approach. Even the lower of the two possible circling MDAs more than compensates for the increase in required clearances between circling & NPA?
* Not trying to imply he could mix'n'match with the two approaches: below the circling minimum he can only complete a VOR approach or go-around.
You and me both!
No, but there does seem to be a VOR onto RW33 @ CIA - it's classed as circling although as it's <30deg off the RW and <400'/nm it could technically be called a straight-in...
And why would you want to circle at BEG when there's an ILS at both ends? 
Thanks for the info. I can see why you might have to raise the circling minima because of obstacle/missed approach requirements pertinent to the approach you actually use to get to circling MDA and will also use in the event of a missed approach. What I don't understand in this case is that the original approach minima are not as restrictive, e.g. 1,060' for the VOR...
There is the posibility of a pilot at the circling MDA being well north of the final approach track but still being contained within the final approach area for the VOR.
* Not trying to imply he could mix'n'match with the two approaches: below the circling minimum he can only complete a VOR approach or go-around.
I would be more inclined to err on the side of safety and use the more recent higher minima for all circling operations.
I guess you haven't flown many time to CIA or BEG.
And why would you want to circle at BEG when there's an ILS at both ends?
My opinion on circling approaches is that if I was down to one engine on a dark night, they would be the absolute last thing I'd want to do, especially at a terrain-constrained airfield. I would consider an out-of-wind but better served runway as a lower risk endeavour, as long as performance criteria were met. Autoland first choice, RNAV second & circling last.
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A circling approach, when properly briefed, and executed as briefed, is a non-event. It does not take “Maverick” or “Chuck Yeager” to perform circling maneuvers. Personally, I along with competent airmen have performed the maneuver in actual conditions, to published minima without any squawks. As for myself, I have be performing circling maneuvers all over the world since the mid ‘70s in all types of aircraft from singles up to and including the wide bodies.
Is the circling maneuver the choice procedure to perform under adverse situations??? no… at least not mine. But if you have to do it, you do it. It’s no big deal. If during the maneuver you don’t like what you see… well… execute the published missed approach.
Circling maneuvers come with the job. Proficiency is demonstrated in the simulator 2 times a year, and sometimes during an actual line check. At the end of the day, if one has trepidations about performing such a maneuver, which is approved under their carrier’s Ops Specs, then perhaps another airline that prohibits such maneuvers is the carrier of choice to be employed. There are carriers that do prohibit such procedures if weather is less than 1,000’ ceiling, and 3 miles of visibility, unless category D minima are greater.
Perhaps performing circling maneuvers in actual IFR in a twin, with an instructor in the right seat may help allay one’s fears too.
Is the circling maneuver the choice procedure to perform under adverse situations??? no… at least not mine. But if you have to do it, you do it. It’s no big deal. If during the maneuver you don’t like what you see… well… execute the published missed approach.
Circling maneuvers come with the job. Proficiency is demonstrated in the simulator 2 times a year, and sometimes during an actual line check. At the end of the day, if one has trepidations about performing such a maneuver, which is approved under their carrier’s Ops Specs, then perhaps another airline that prohibits such maneuvers is the carrier of choice to be employed. There are carriers that do prohibit such procedures if weather is less than 1,000’ ceiling, and 3 miles of visibility, unless category D minima are greater.
Perhaps performing circling maneuvers in actual IFR in a twin, with an instructor in the right seat may help allay one’s fears too.
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OK FW sorry my apologies it's BGY not BEG.
To tackle the 200 Kts issue once and for all. As I said the requirement to perform a landing on a clean wing for the initial type check ride is as per FAR. Who is the world lands on a clean wing on daily basis? The answer is those having troubles getting out the flaps, isn't it? Hence the situation is abnormal not to say resembling kinda emergency, certainly the case if only circling is left as an option, all the norms are down the drain. Mayday and the sky is yours or do you wanna maintain that in case of a dual engine failure you care bout boundaries or obstacle clearance? Specially if the weather is CAVOK and you can see miles away. Well so much to Malevich loving brothers who love to paint it all black regardless of the forms or contents.
Back to CIA. Your have chosen your words wisely my friend it only SEEMS indeed. Nothing even close to a straight in it's circling VOR 33 thus it's a circling approach using a prescribed track. Remember we were talking bout circling so forget the once coming from LAT or FRS. as you can see only ROM DME is required to shoot it, isn't it? So you're coming over ROM for a circling VOR 33, aren't you? Do you still have 4,2 NM obstacle clearance in this case? What is your primary means of navigation? Finally what's he applicable weather minimum?
Have fun
To tackle the 200 Kts issue once and for all. As I said the requirement to perform a landing on a clean wing for the initial type check ride is as per FAR. Who is the world lands on a clean wing on daily basis? The answer is those having troubles getting out the flaps, isn't it? Hence the situation is abnormal not to say resembling kinda emergency, certainly the case if only circling is left as an option, all the norms are down the drain. Mayday and the sky is yours or do you wanna maintain that in case of a dual engine failure you care bout boundaries or obstacle clearance? Specially if the weather is CAVOK and you can see miles away. Well so much to Malevich loving brothers who love to paint it all black regardless of the forms or contents.
Back to CIA. Your have chosen your words wisely my friend it only SEEMS indeed. Nothing even close to a straight in it's circling VOR 33 thus it's a circling approach using a prescribed track. Remember we were talking bout circling so forget the once coming from LAT or FRS. as you can see only ROM DME is required to shoot it, isn't it? So you're coming over ROM for a circling VOR 33, aren't you? Do you still have 4,2 NM obstacle clearance in this case? What is your primary means of navigation? Finally what's he applicable weather minimum?
Have fun
Per Ardua ad Astraeus
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I didn’t realize you were the appointed spokes person for the posters on PPRuNe.
I'm getting a warm, fuzzy feeling... 
Thanks, BOAC
9.G, I totally agree about emergencies and rulebooks, etc. However, if you're stuck in clean config, you're not dead yet and it would be a shame to risk piling in short (not implying you would, of course!) when good manners dictate that you should crash on the runway, or at least the airfield. CAVOK means do what you think's best - after all, they're minima not maxima: an appropriately sized visual circuit would seem to fit the bill?
I've never been there so I was just looking at the approach plates (pdf, 3.6MB: Googled from an Italian sim. site but look like genuine ENAV ones) with RW33 being the last in the sequence. It looks like you can go ROM outbound, complete the base turn, join the FAT inbound to ROM, breaking off at 4d to align with the runway if you are visual. The limits appear to be lower for this approach than circling from the other end, so I'd have thought it would be better if the wx was poo? I know it's called a circling approach on the plate but to me it reads more like an offset VOR, albeit with a few more criteria to fulfil when visual... Anyway, I'm not trying to start an argument (that's room 12a) as I readily admit I don't get much practice at circling, apart from the odd bit in the Caribbean and it's rare to be near the minima, so any advice is gratefully received!
Sorry to bore everyone - please feel free not to read this post if you don't want to.
Thanks, BOAC
9.G, I totally agree about emergencies and rulebooks, etc. However, if you're stuck in clean config, you're not dead yet and it would be a shame to risk piling in short (not implying you would, of course!) when good manners dictate that you should crash on the runway, or at least the airfield. CAVOK means do what you think's best - after all, they're minima not maxima: an appropriately sized visual circuit would seem to fit the bill?
Back to CIA. Your have chosen your words wisely my friend it only SEEMS indeed. Nothing even close to a straight in it's circling VOR 33 thus it's a circling approach using a prescribed track. Remember we were talking bout circling so forget the once coming from LAT or FRS. as you can see only ROM DME is required to shoot it, isn't it? So you're coming over ROM for a circling VOR 33, aren't you? Do you still have 4,2 NM obstacle clearance in this case? What is your primary means of navigation? Finally what's he applicable weather minimum?
Sorry to bore everyone - please feel free not to read this post if you don't want to.
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This thread reminds me of an interesting discussion I heard about circling procedures.
Imagine a circling approach for a random aerodrome with a MDA of 650' AGL, and minimum ceiling 700'.
Now, this means that if the pilot has visual conditions and constant visual contact with the runway at 700', he can make a visual landing.
Isn't a circling approach a pseudo standard traffic pattern?
But wait, why is the standard visual traffic pattern at 1000' then?
And why is the minimum ceiling for a visual operation on an aerodrome 1500', or 1000' Special VFR?
If there is a published procedure for visually circling, approaching and landing at 700' AGL or less, why can't VFR aircrafts use this ceiling as well?
Just interested in what you have to say.
Cheers.
Imagine a circling approach for a random aerodrome with a MDA of 650' AGL, and minimum ceiling 700'.
Now, this means that if the pilot has visual conditions and constant visual contact with the runway at 700', he can make a visual landing.
Isn't a circling approach a pseudo standard traffic pattern?
But wait, why is the standard visual traffic pattern at 1000' then?
And why is the minimum ceiling for a visual operation on an aerodrome 1500', or 1000' Special VFR?
If there is a published procedure for visually circling, approaching and landing at 700' AGL or less, why can't VFR aircrafts use this ceiling as well?
Just interested in what you have to say.
Cheers.