Circling Approach

[zekeigo]

If you are planning to do a circling approach from an ILS approach what should be the MDA/DH selected, the minimums of the ILS procedure or the Circling minimums?
Where can I find the official statement for this question?
Thanks

[No_Speed_Restriction]

A. circling.
B. circling minima is %99.9 always higher then an ILS minima.
C. circling at 200' requires a spare set of underpants for most pilots.:{

[BOAC]

zekeigo - I think logic alone will suffice? I'm sure it is written somewhere, however.

Let's say the ILS minimum is 200'AAL, while the circling minimum is 800'. With a cloudbase of 400' you could certainly fly the ILS and become visual, but you would then have to climb back into cloud to 'circle'! Not a lot of point. Remember the minima for the ILS depend on your being in the approach and g/a area for that ILS (ie lined up with that runway), whereas the circling minima allow you to be within about 2 miles of the field, subject to any circling sector limitations.

[Tinstaafl]

The answer is in your question:

...to do a circling approach ....... the Circling minimums?

(My emphasis)



If you don't think the circling minimum is appropriate for circling then why else is it there?

[plt_aeroeng]

I personally have only needed to perform circling approaches in anger a few times. Each time, I came to the opinion that unless the circling minima are near to VFR, they are an invitation to disorientation. (particularly at night) In fact, I only felt comfortable circling at familiar airfields.

Typically, the visibility is sufficiently limited that it is difficult to retain sight of the runway environment unless vigorous manoeuvring is employed. The latter is discomforting at low speed with a need to maintain instrument reference due to lack of a horizon while trying to keep contact with the airfield.

Circling minima, after all are such that obstacle clearance is maintained within a reasonable radius of the runway environment. One is never sure what "reasonable radius" really is, so one is motivated to keep it tight.

Mind you, all my circling experience was in jets and larger aircraft. It may be much more comfortable in a Cessna 172.

I would never push the limits for a circling approach. I would also carefully preplan my flight path before starting the approach, to reduce uncertainty in a relatively unstable and uncontrolled environment.

[alf5071h]

From my notes on PANS-OPS: Caution they may be out of date:
The OCA/H for circling shall not be less than the OCA/H calculated for the instrument approach procedure leading to the circling manoeuvre.
There are further two separate requirements to be fulfilled: Both requirements are coupled to aircraft category.

Minimum obstacle clearance, MOC (ft)
A 295
B 295
C 394
D 394
Lowest permissible OCH (ft)
A 394
B 492
C 591
D 689

For TERPS: - The circling MDA must not be above the FAF altitude or below the straight-in MDA. The minimum values are:-
Aircraft Cat / lowest height above airfield / Vis
A 350 ft 1 nm
B 400 ft 1 nm
C 500 ft 1.25 nm
D 550 ft 2 nm

Don’t forget to correct all altitudes for temperature error.

Note the significant differences in the circling protected area defined by arcs centered on each runway threshold.
PANS-OPS Cat / nm / max speed / TERPS / nm
A 1.68 / 100 / 1.3
B 2.66 / 135 / 1.5
C 4.2 / 180 / 1.7
D 5.28 / 205 / 2.3
If you use the incorrect area i.e. TERPS vs PANS-OPS (5.28 nm vs 2.3 nm) then see the BUSAN (http://uk.geocities.com/[email protected]/alf5071h.htm) accident report.
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Unless specifically authorized everything else is forbidden.

[zekeigo]

Wonderful commentaries from alf5071h, plt_aeroeng, thanks. About the others sorry if you guys don’t have enough experience or didn't understand the question to discuss this subject. What I mean is, I’ve been doing circling approach in Jets and Larger Acft in places like Pusan, South Korea for years, the same place where a China Airlines Jet hit the elevations a few years ago. In most of the cases you have to do an ILS with a strong tail-wind and them circle to land in wind conditions not so favorable. What we use to do is a briefing on the ILS approach procedure followed by a circling at the published circling minimums, or any other minimums determined by the company’s SOP, set the ILS approach minimums on the EFIS MDA/DH, and when reaching the minimums for circling, two cases: you reach visual, press the ALT HOLD on the MCP and start your circling procedures or: No visual and you start the published ILS missed approach procedure from the circling minimums altitude. Back to my initial question, I’m just looking for where it is written what should be set on the EFIS panel as MDA/DH, the ILS minimums eg: MDA 215 DH 200 or Circle to Land 1200 or it is SOP police?

[Stan Woolley]

If you are planning to fly a circling approach you set the circling minima.

It should be in your ops manual but if its not I would suggest that you can set what you like but .........why?

You don't set ILS minima if you're flying a VOR or NDB approach so circling is no different.

Keep it simple.

[batty]

Why would you set the ILS minima since if you are planning to do a circling approach? You will never reach the ILS minima since it is lower than the circling minima and it could lead to ambiguity and a possible error in actualy busting the circling minima in poor weather.

We set the circling minima for a circling approach and the ILS minima for an ILS approach, the fact that we are following the ILS initialy doesnt make it an ILS it is still a circle to land. In fact we round the circling minima UP to the next hundred feet i.e 820 would become 900 etc etc

[JantinusDaling]

According to JAR OPS an ILS approach with a circle to land is a non precision approach.
The MDA for a circle to land is based upon 1.3Vs0, also the threshold speed. For CAT A: MDA Loc only (non precision) +200'.
Vs0 is the stall speed in landing configuration.

The maximum approach speeds and speeds for circling are: CAT A/90 B/120 c/140 D/165.
Countries are allowed to make adjustments in speeds and circling altitudes.
Every category aircraft has its own radius of the circle based upon the speed. Therefor the minima in visibility increases with increasing category (as you fly a further distance from the runway).
The larger MDA per CAT is based upon the loss of altitude during go-around and the increasing MOCA with distance from the airfield.
Los off sight of the runway due to clouds or visibility means go around.
This is funny because how are you going to execute a go around in a circle to land?
The rule is (i spend lot of time to find this out):
During approach a go around should be executed on the approach track. If you level of and start circling the go around should be executed on the intended landing track. (Opposite of the approach track so the first thing I would do is contact ATC)
Hope to have helped you!

[qwertyuiop]

Jantinus.

I'm not sure you are correct about the go around once circling has commenced. I believe the go around is always based on the initial approach.

[OzExpat]

I'm sure that you thought it would be self-evident alf, but just in case there are others who didn't get the true picture... in Pans Ops, Circling MDA is not allowed to be lower than straight-in landing MDA. This isn't usually much of a problem with an ILS approach, but is often very relevant in a non-precision approach.

I believe the go around is always based on the initial approach.
The missed approach starts at the Missed Approach Point (or DA) for the specific procedure. If you have already started circling before losing visual reference, all bets are off. Regardless of anything else, every missed approach is based on a point (fix or DA) at the end of the final segment of the approach procedure.

There's far too many possible variations in scenario as to the point at which you might lose visual reference during a circling procedure for me to try to detail any possible escape routes. And, of course, terrain (and/or other traffic) will always be a mitigating factor. The short answer can only be that, if in doubt upon reaching the MAPt., don't circle at all - go around.

You might be able to do better than that at an airport you know, but you are betting the lives of all on board.

There are LOTS of circling procedures in this country - they are, in fact, in the majority because a runway-aligned approach is often precluded by terrain. We also have many airports where circling is restricted to one side of the runway. It works here because everyone gets accustomed to it and develops a certain amount of rat-cunning that keeps everyone alive.

If your airline's training (and Sim refershers) does not place a lot of emphasis on circling, I'd suggest that you need to be sure that the existing weather will allow you to see all the obstacles so that you can circle safely - and comfortably.

[batty]

The go around on a circle to land is based upon the inital approach, ie in this case the ILS that got you down to the circling minima, regardless of the position you are at in the circling procedure when you go around.

Think about it...if you were half way around the procedure and went around why on earth would you go around into the oncoming traffic on the ILS!!!!

People asking these kind of questions I hope are never doing the circling procedures!!!! Mind at least they are asking so thats a good start....:ok:

[alf5071h]

I agree in principle with Stan Woolley – keep it simple. Unfortunately, life and flying are not always simple; I would not advocate setting the Alt Sel to the circling minima.

To combat the continuing risk of approach accidents / CFIT on non-precision approaches, the industry is promoting CANPA, which should include the procedure of using MDA as a DH / DA i.e. nothing seen then fly a missed approach. Thus for this operation, it is more appropriate to set the Alt Sel to the climb-out missed approach altitude; it discourages level flight at MDA (or even lower – never set the airfield alt on the Alt Sel).

For a circling approach, it would be appropriate to use the Alt Hold mode to circle. This is not quite as described by zekeigo, the Alt Sel should still be set for a missed approach. The concept of an Alt Sel is that the value is an altitude at which the aircraft will level off at and maintain; this does not apply to a precision DH or MDA under CANPA.

The missed approach from a circling procedure is always based on the approach. If visual references are lost during the circling procedure, then commence a turn towards the airfield and then establish the missed approach procedure. In some situations this may require a turn / orbit overhead the field, but always turning towards the safe side of the procedure

Another aspect of circling is that in some aircraft the circling manoeuvre is flown in an intermediate configuration, thus flying the correct airspeed is an important factor in staying within the safe area. If local authorities change the circling speed, the assumptions / safe area should be published on the chart with the speed restriction, but beware!

Evidence from accidents shows that approaches go wrong very early in the approach; many due to a poor brief. As NPA’s and circling procedures are flown less frequently then it is more important to brief them as something ‘non-normal’ and that they are different. Start with a mind-set that that circling is unique and that all landings are ‘an approach without a go around’.

[Tinstaafl]

About the others sorry if you guys don’t have enough experience or didn't understand the question to discuss this subject.



Hmm.....but then we're not the ones who phrased his/her question in such a way that the question indicates a lack of understanding about the applicability of a circling approach minima or a runway/landing approach minima to a circling approach. You were the one who seemed to have the misapprension that the straight in/runway/landing approach minima had anything at all to do with the circling approach.

The question was understood perfectly well by most, if not all of us, even if that wasn't the meaning you intended.

[reynoldsno1]

Re: the Busan accident. I understand the Koreans are gearing themselves up to move from TERPS to PANS-OPS. This will certainly affect circling approaches, and many missed approaches.

[OzExpat]

That's good news reynoldsno1. Last time I was talking to Korean procedure designers, toward the end of last year, they were using Pans Ops at some airports and TERPs at others. I've always thought that was a recipe for trouble.

[pinny]

We encountered this same question on RAAF pilots' course just this year...

definitely circling minima, remembering that if is shaded on the plate to subtract your 100' for accurate QNH or adding 50' if you are on an Area QNH. If you're on a TAF leave it as published.

[mythic]

In the discussion about a go-around from a circling approach, here's another view.
If visual reference is not achieved at the MDA then the go-around is that of the instrument approach just flown - easy enough so far. If the visual reference is lost in the circling procedure - same thing applies. This would probably be on one of those marginal kind of days we all just love!
However, and here's the difficult one, think about what you would do if the landing was baulked at a late stage, then the option to enter a visual circuit may well be the best you can hope for, traffic/ATC permitting.
All these eventualities of course were covered in your relevant and interactive briefing with your colleague!
Good preparation and planning are the keys to success for this tricky manoeuvre!

[reynoldsno1]

If the visual reference is lost in the circling procedure - same thing applies
Not really - once you depart the final approach track and commence your visual manoeuvre you essentially throw away the published missed approach and the protection built into it. That's the rub with circling - and why they are not to be encouraged, IMHO.
With visual reference lost you have to make a best guess to turn towards the centre of the landing area and get your self back on the MAPt/missed approach track - the grey area in more ways than one.
A balked landing actually may put you in a better position than losing reference whilst farther away from the runway. At least you have a better idea of your position relative to the airfield...
Be careful out there

[Tinstaafl]

A problem with conducting a missed approach after a baulked landing is that you're starting from a height somewhat less than what was considered in the missed approach obstacle clearance gradient.

[fireflybob]

Having watched a fair number of circling approaches in the simulator where it often starts to go wrong is a lack of wind correction when on the outbound part of the instrument approach.

This is simply because we are not used to applying corrections in this sense since the instrument approach is usually into wind. But wait a minute - WHY are we circling? Too much tailwind for landing straight in.

This coupled with the fact the airspeed for the approach is higher (given reduced config for circling) AND we have a tailwind makes everything quite different - different pitch attitude and thrust settings (to what is the "norm").

All this can combine to make the whole circling manoevre a rushed exercise. Great care needs to be applied to the outbound part of the procedure and attention to full and comprehensive briefing for what is, for many, an "unusual" approach.

As regards the thread topic then circling minima should be bugged but your ops manual should spell this out.