Protecting Missed Approach in NZ

[murdoch_disliker]

Very confusing system in NZ; :confused:
AIP and Jepps state that the controller may protect the missed approach by requiring an aircraft to join the circuit visually in the event of a missed approach off an instrument approach.

When you are cleared for an instrument approach, you are also cleared for the (instrument) missed approach, therefore my take on this is you set the instrument missed approach alt ie usually 3000'. The controller MAY change this to a clearance to join the circuit visually (as long as 8k vis and 2000' clg).

A common perception is that you should set circuit altitude as the missed approach altitude off an instrument approach when the wx is better than 8k vis and 2000' clg. I think this is wrong.

Like to hear some other opinions. :)

[Cloud Cutter]

It is a bit confusing, but it significantly reduces delays when conditions are suitable - it means ATC can launch a departure with an aircraft on short final which saves a significant amount of time. You will notice the delays caused by non-circling aircraft particularly at WLG.

If conditions are above the limit, you are required to join the circuit, so it would make sense to set circuit alt on final, rather than have to quickly change it after a go-around

In practice, if you have to go-around due to runway sep etc joining the circuit gets you on the ground a lot sooner so surely that's a good thing. If you're going around due to weather conditions, it will always be the standard MA anyway.

[murdoch_disliker]

But you are not cleared to join the circuit at that point, seems like its anticipating a clearance which we shouldn't do in aviation??. eg if the transmissions are blocked which is a reasonably realistic scenario...would you join the circuit off an ILS without a clearance. I think its more prudent to follow the clearance that we have at that time which is climb straight ahead to 3000'.

Agree protecting the missed approach has to be done in NZ, just too grey an area..

[waren9]

If ATC want this, they will ask you (at about the time they expect to to come visual) something like "in the event of a missed approach, would you accept a visual circuit?" If, after assessing condx in the circuit area, you agree, they will then respond with that as a requirement.

Plan for and set your alerter to the published MAP altitude until you are cleared for something else.

If you dont agree, the standard MAP will always be available. Contollers especially in WLG use it a bit.

It is your choice, and it was quite simple I thought. Thats how I understand it anyway.

Tarq57 or someone may be able to elaborate further?

[Cloud Cutter]

Actually, on closer inspection I think you're right.

ATC may protect the missed approach by requiring arriving aircraft to circle visually within the aerodrome circuit

So you would prepair for a standard missed approach unless cleared otherwise, and should set the MCP accordingly

[Fruet Mich]

Hmmm, its a really good point. In our company, provided the weather is suitable via the company sops and we haven't advised we are unable to do a harbour circuit, we breif for the harbour circuit unless told to carry out a full missed approach. We still set 3000' however until we are in the go around where we re-set 1500'. As far as I'm aware, we just continue into the circuit 1500' without clearance as it's expected. Have to clarify that one? Good point to bring up with training.

Another confusing ATC instruction is "no speed" on an approach to 16 via Libri. It doesn't actually mean we can fly faster than 170kt at Libri. I always thought that when they referred to "no speed" it meant the full speed restriction on the star? apparently we must get that clearance from the tower to be faster than 170 at Libri. You would think they could liase with one another and make it a little clearer.

[waren9]

Fruet

What category aeroplane are you flying?

From a very distant hazy memory the rules for cat a/b are possibly different to cat c regarding the MAP issue?

[murdoch_disliker]

Actually Warren9, its not that simple. Firstly, you have to tell both approach and tower that you will not be able to accept visual circuit in the event of the missed, so as you say; the "published missed approach is always available", is not correct. You have to accept the circuit if you have not told both these controllers you will not accept it.
Also, I have not heard controllers state the phrase "in the event of a missed app, will you accept the visual circuit?", in the last 12 months. I presume it has been removed from their manual.
I agree with you philosophy on MAP alt in MCP.

Our SOPs state to set the circuit alt for MAP alt if wx conditions suitable.

So seems not so cut and dried as I would have thought.

[Tarq57]

There is a bit of confusion about this, and pretty much always has been.
The confusion seems to have increased in more recent times, with some operators not able to circle under any circumstances, the published minimum in the chart being lower than the accepted industry standard minimum for cat C (at least in Wellington) (1500/8km vs 2000/8km) and the often subjective area of "how much turbulence and windshear exists, and is it likely to make the circuit unacceptable"?

Basically the AIP states that any time a crew cannot accept a circuit, approach control should be informed of that fact. (Don't have the AIP reference, sorry. 1: I'm at home, and 2: That document is counter-intuitive to navigate these days.)
Once approach has been informed, the likely result is that a 175kt speed restriction is placed on the approach, commencing at 10DME final. Reason: Tower is able to provide the protections based on tables issued for each a/c performance category. (These tables can be complicated.) Tower is unable to make a value judgement of this; the separations applied are delegated for use, and it's an approach separation. The distances used have been worked out using the simulator, and where indicated, tweaked over time and real life experience.
You should interpret the "may require an aircraft to enter the circuit.." as "That's quite likely to happen unless you've told us otherwise," and if you'd prefer the MAPP (but don't actually need it) let us know; it may be available.
It should be simple. If the weather was always clear cut, and everyone had a similar performance, and there weren't terrain issues affecting the ability to turn off the MAPP at WN, it would be. Unfortunately, reality all too frequently intrudes.
Where approach has previously advised a speed restriction and then cancels it, it simply means that Tower has no departing traffic to go ahead of the inbound. Where "no speed restriction" is advised, without previous discussion, you can fly at the barbers pole to the threshold, if you want. (The subsequent overshoot would be fun to watch, I'm sure, but you get the idea.)
As stated above, when the arriving a/c is believed to be able to enter the circuit, the required space between it and a preceding departure may be based on visual means, rather than radar (min. 3nm, which means the "gap" can be anything from 4nm to 12nm.)) which increases runway capacity significantly.
There was a recent change in the AIP concerning the ATIS. Up until recently, the ATIS included a phrase like "All aircraft category A and B advise approach on first contact if unable to enter the circuit in the event of an overshoot." Terrible.Wordy. You could die of hunger waiting for the ATIS to cycle. (Anyone dying of hunger here reading this?) Now that requirement is published in the AIP instead, and it is up to the crew to decide based on the reported wx, and up to us to try and report the wx accurately.
There can be several different reasons for speed restrictions on approach generally; the circling status is one of them, so in answer to your question re "no speed via libri", I don't know.
Do you fly a '738, perchance?
Sorry to waffle. I'm like that on the radio, too.;)

[Tarq57]

Hi craka, don't go calling me Tarky on a public forum, mate. You'll wreck my anonymity. :}

[craka]

who called who who

[slamer.]

Its not so unusual, have a look at Jepp USA re entering the circuit in the event of a MAP in VMC.

[haughtney1]

It shouldnt really be a big deal as long as you brief for it..or at the very least have a plan.
Click..Click..get the automatics out (if you've got them) and do some proper aviating:ok:

I wonder what kind of separation are we talking about? is it 2.5 miles? and are we talking about differing types? i.e. A320 on a shortish final..and a ATR about to depart etc.

[always inverted]

Does it not actualy say to advise on first contact if unable to carry out a visual citcuit in the event of a "GO- AROUND" not a MAPP.
The 2 are completely different.

[Tarq57]

I wonder what kind of separation are we talking about? is it 2.5 miles? and are we talking about differing types? i.e. A320 on a shortish final..and a ATR about to depart etc.
Examples: ATR departing straight ahead, A320 on final, ATR must commence roll before the A320 crosses a 7 mile final. Becomes 5 miles if the ATR is on a side SID.
A320 (or Boeing) ahead of another jet on final, the distance is 4 miles. Slow a/c (eg C208) ahead of a jet on final, straight ahead SID, required distance is a whopping 12 miles. We are not permitted to shorten that distance.
The types that regularly operate IFR range from Caravan to A320/B737. On a day when the conditions are below circling for all, delays become substantial.
There's a tabular distance promulgated for all combinations of types/SIDS, and it's different for each runway.
The minimum radar separation is 3 miles.
The whole thing is a bit of a blunt tool, and there is, at times, a lot of wasted airspace. For example, no allowance is made for the fact that a lower performance departure might climb like a rocket. Nor for the fact that, although the speed of approach tested on the sim is 175, most a/c will be 10-30kt slower than that for the last 4 miles of the approach. Ironically, if a departure can accept a visual departure - which is surprisingly often even when below circling conditions exist for cat C - then visual separation may be applied up to the point geographical exists, or (as happens 99% of the time) the arriving a/c has landed.

[Tarq57]

Does it not actualy say to advise on first contact if unable to carry out a visual citcuit in the event of a "GO- AROUND" not a MAPP.
The 2 are completely different.
IIRC the wording in the AIP (and the matching intention) is indeed "go around" or maybe "overshoot".
Thanks for pointing out that the two are completely different.

[murdoch_disliker]

So tarq57, if one was to commence a missed approach from an ILS in WLG and the weather is suitable for circling visually....You would expect us to carry out the ILS missed approach and climb to 3000' unless you cleared us to join the circuit visually. Is that a fair comment.
Thanks

[Tarq57]

I suppose that's the original question.
I'm going to presuppose that when you say if one was to commence a missed approach from an ILS in WLG you mean "if one was to go-around from..." (which might then become a MAPP or a circuit)
The answer is somewhat dependent on the situation.
1) You are still IMC; say, unstable on the approach (or config warning or other problem) and can not safely continue to VMC, then, even without your saying you have an emergency, ATC would treat it as such- at least in regard to other traffic - and pull something out of the bag of tricks to make sure you didn't collide with anything ahead while you are on the missed approach. It's unusual, it happens sometimes, we drop everything else and make it work. (It will work, because in this situation you are likely to be at least a 5nm final when you overshoot.We have time and space.)
2) You've heard the ATIS, and decided in advance you don't want any part of the circuit, and advised approach control accordingly, we expect the MAPP and have planned for it with the appropriate gap for the last departure ahead of you.
3) You are VMC, have to overshoot on short (ish) final for a more mundane reason (cabin not secure, too high/fast etc) we expect you to make the call and then respond to ATC instructions, which would often/usually be to join the circuit. This could vary depending on the traffic. And that's the bit, I think, where the problem lies.
What if you have a comms failure at (3)? (Or tower has a comms failure.I've had two in the past two days.)
I'd expect you to choose a course of action, squawk 7600 (which in theory sounds great, but in a high workload situation like this, I appreciate that it might take you a minute to do that, and either fly the circuit or the full MAPP, and be ready to respond to any TCAS warning.
Obviously in a highly fluid environment the traffic situation is changing. At Wellington it's not unusual to get a windshear. (Someone has to be the first on any one day to experience it.) Some companies have SOP's that say that you don't do a circuit in certain conditions of windshear/turbulence.
(3) would be a very weird occurrence. ATC would definitely treat it as an emergency, in regard to traffic management, and get circuit traffic (or IFR traffic ahead) out of the way ASAP. And hope you had a cell phone on board.
Sorry if that doesn't help much. I'd suggest default #1, if you haven't previously advised approach that the circuit is a no-go, is that you plan on joining the circuit. For us to get a Cessna downwind in VMC out of your way will happen very quickly, once we've realized the necessity. For the radar controller to get a preceding C208 in IMC heading for TY (worst case scenario) out of the way will take longer.Maybe quite a bit longer. There would fairly likely be a loss of separation.

[murdoch_disliker]

Thanks very much for your informative replies Tarq57.

[Tarq57]

You're welcome.
FWIW, wouldn't be at all surprised if one day, maybe in the not too distant future, a circuit in the event of an overshoot is a thing of the past. All departures/arrivals could end up having standard gaps. RNP and all maneuvers programmed into the FMS will be the norm. And I'll have a big dog watching me, just like you. :E

[conflict alert]

All departures/arrivals could end up having standard gaps. RNP and all maneuvers programmed into the FMS will be the norm.

Already in the wind with CAM version 2 Tarq57...enroute will give ETA's at points and there's your gaps...dissappearing very quickly is the art of ATC.

(Must replenish your wine supply one day:))

[conflict alert]

Interesting subject though, as an approach controller, on the sector that I work we only protect the missed approach when weather conditions are marginal or below circling for the cateogory of aircraft flying the approach. Having said that, most of our releases of departures are given to the tower as a "Released your sep" on the inbound so the tower won't clear an aircraft for takeoff until they see the inbound or use a "composite" visual sep. Once they have seen the inbound (obviously now VMC) they can instruct the aircraft to enter the circuit (when the MET criteria is there) if for some reason the aircraft goes round or is instructed to go around by ATC for whatever reason.

I'll investigate all the rules and talk to the man in ATS OPS (Airways policy and rules person) and get back.

[Tarq57]

What I find interesting about the current incarnation of the procedure is: why the change?
(That is, why is the wording now "may require an a/c to enter the circuit...")
This has obviously created some uncertainty.
Is it yet another example of the adoption of ICAO standards dumbing us all down, or a genuine attempt to remove the cumbersome ATIS requirement (yay), perhaps as a result of recommendations made concerning that 777 that failed to notice the reduced rwy length at AA a while back?

[haughtney1]

Examples: ATR departing straight ahead, A320 on final, ATR must commence roll before the A320 crosses a 7 mile final. Becomes 5 miles if the ATR is on a side SID.

Wow, what do you guys do when your busy? seven miles? thats a massive spacing!

The whole thing is a bit of a blunt tool, and there is, at times, a lot of wasted airspace. For example, no allowance is made for the fact that a lower performance departure might climb like a rocket. Nor for the fact that, although the speed of approach tested on the sim is 175, most a/c will be 10-30kt slower than that for the last 4 miles of the approach.

So why is this used? isn't it a bit like boxing with one arm tied behind your back?
Surely SSR radar has the required accuracy to provide proper separation inside the terminal area and on approach to make this process look a bit antiquated?
Using Wellington as the example....how often do you get anything bigger than a 767-300 operating on a regular basis? Even at Max landing weight your approach Vref is still only about 140ish knots..which is well below the 175 you quote....
Whats wrong with 180kts till 8 miles...reducing to 160kts till 4 miles etc...? It works bloody well in Europe, and appears to be gaining traction in the USA as well.
No attempt from me to be crtitcal, I'm just trying to understand the thinking behind what appears to be an ill thought-out procedure.

[The Hill]

Whats wrong with 180kts till 8 miles...reducing to 160kts till 4 miles etc...? It works bloody well in Europe, and appears to be gaining traction in the USA as well.


I think that would be a little too fast for some of the turboprops, unfortunatly the SOPs dont allow some of us to descend on the glideslope clean ie gear down, go down policy

[Tarq57]

Wow, what do you guys do when your busy? seven miles? thats a massive spacing!
When busy, in theory we "type match". So the required distance is 4nm. But since there isn't enough room to have a/c pass each other on the threshold taxiways, (thanks for building the taxiways too close together) it usually falls into the "too hard" basket. By the time it's been organized, the situation that made it seem a good idea is often irrelevant.
When really busy, everything just slows right down. The morning and afternoon rush period lasts longer. It's a PITA.
So why is this used? isn't it a bit like boxing with one arm tied behind your back? Yep. I believe it is referred to as best practice. (http://www.dilbert.com/strips/comic/2008-09-03/)
But seriously, it works in the worst case scenario, and provides a bit of a buffer. Frequently the space provided by the procedure seems excessive, but TWR staff are not approach rated and have no authority to vary it. (If we were, I believe we could possibly make departure rate increases of the order of 10 maybe 20% on many "below circling" days.)
Surely SSR radar has the required accuracy to provide proper separation inside the terminal area and on approach to make this process look a bit antiquated? The minimum radar spacing is 3nm. Shaving it by .5nm won't make a huge difference.
Using Wellington as the example....how often do you get anything bigger than a 767-300 operating on a regular basis? Even at Max landing weight your approach Vref is still only about 140ish knots..which is well below the 175 you quote....
Whats wrong with 180kts till 8 miles...reducing to 160kts till 4 miles etc...? It works bloody well in Europe, and appears to be gaining traction in the USA as well.
Generally the largest sched a/c is a 757 (maybe 3-7X a week.) The bread and butter is 737/A320, lots of DH8's/ATR72/B190, a fair few C208 and light twins.(PA31 etc.) 767+ usually only run through WN if diverting. The arrival of a 777 or 747 etc is rare, maybe a once or twice a year event. (Perhaps needless to say, the poor C208 etc is at the bottom of the food chain when it's like this, and I've seen one of them wait well over an hour for a departure gap at times.)
Partly the reason this seems antiquated is that the wx around here is unusually changeable, can get quite windy, windshear and turbulence is likely, and terrain to the north prevents radar vectoring below 3000'. The procedure is tailored to the worst case scenario, and in that scenario (overshoot likely due wx, preceding climbing poorly due turb, preferred approach airspeed higher rather than lower due w/s) you absolutely would not want to shave it. That it is excessive in a situation of light wind but cloud below the circling minima, where everyone is performing normally, is an unfortunate consequence. I guess alternative and more expeditious procedures are just too hard to dream up and implement. I don't know,but I imagine that such a procedure would have to be nightmarishly complicated to satisfy the regulators' requirement. So in fair weather we have to guard against an event that happens maybe once a fortnight, using procedures that are designed against the worst case scenario. Sad, innit?

[conflict alert]

Controller instuctions according to our Bible - the Manual of Air Traffic Control - with regard to protection of the missed approach.


306 PROTECTION OF THE MISSED APPROACH

Separation shall be applied between an IFR flight on missed approach and other aircraft in accordance with the applicable airspace rules. An aircraft that is unable to establish visual reference by the MAPt is required to carry out the published missed approach procedure. Aircraft may need to carry out a missed approach for other reasons.

When conditions are at or above the published circling minima for an arriving aircraft’s approach category and the type of approach, the missed approach may be protected by instructing the pilot to circle visually within the aerodrome traffic circuit by day or night, except that:


circling instructions shall not be issued where circling is not authorized for the aircraft approach category or type of approach; and

circling instructions shall not be issued to category D aircraft; and

for approach category C aircraft, the known or reported MET conditions shall be equal to, or better than, ceiling 2000 ft and visibility 8 km or the circling minima for the aircraft approach category and the type of approach, whichever is the higher.
Where a higher criteria or other conditions apply, this shall be documented in LUO’s

Note: For all aerodromes:
The pilot may decline circling at any stage during the approach if it is considered unsafe. In this circumstance, separation must be established by the quickest means practicable and essential traffic information given if applicable. Confirmation of ability to circle should be established earlier rather than later.

A controller shall not use this procedure when:


MET conditions such as fluctuating cloud base, severe turbulence or strong cross winds are reported to an aircraft or broadcast on the ATIS; or

It is known or suspected that the pilot is unfamiliar with the aerodrome; or

The pilot advises approach or aerodrome control at any time that they are unable to carry out this procedure.
Phraseology examples:

1) When ATC initiates the procedure:

“FOR SEPARATION, CONTINUE (type) APPROACH. WHEN VISUAL (circuit joining instructions) RUNWAY (number). REMAIN IN THE CIRCUIT [(level details)]. TRAFFIC IS (details)”

2) When a pilot unexpectedly initiates a missed approach and MET conditions are suitable for visual circling:

“FOR SEPARATION, REMAIN IN THE CIRCUIT, RUNWAY (runway), [(circuit joining instructions)] [(level details)]. TRAFFIC IS(DETAILS)”.

Note: the pilot may refuse circling. See previous Note.


306.1 ARRIVING AIRCRAFT REQUESTING A MISSED APPROACH

When a request for a missed approach is received from an arriving aircraft that is not experiencing an emergency, the aircraft may, for separation purposes, be instructed to:


continue the approach down to a level which is separated from other aircraft prior to permitting the missed approach to be carried out; or

carry out a visual circuit, provided that the conditions specified above are met.




All copy right of course.

[murdoch_disliker]

So, after reading all this; when we are on the instrument approach should we preset the published MAP alt OR the circuit alt in the alt preselect window of the autopilot?? Which is the most correct philosophically?? Maybe nit-picking but important for standardisation.
Ta

[conflict alert]

I for one won't even begin to get involved with what you should set within your flight deck etc, that's your choice. What I can tell you is that when the circling conditions are equal to or better than that required for your aircraft cat, then the expectation is that you will get visual and as an approach controller I will NOT protect the missed approach and as a Tower controller, in the event of an overshoot, I would be instructing you to enter the circuit.

So if I were in your shoes, after establishing that conditions are suitable for circling then probably setting the circuit alt would be more appropriate coz that what ATC is going to tell you to do!

When circling conditions are below the criteria for your aircraft type as an approach controller I WILL protect the missed approach and as a Tower controller my only expectation in the event of an overshoot or not going visual at the DA or MAPt is that you will execute the missed approach procedure.

So if I were in your shoes, after establishing that conditions are NOT suitable for circling then setting the Missed Approach alt would be more appropriate.

When conditions are above circling for your aircraft cat but you don't want to circle you should advise ATC that that is your intention as early as possible so that in this case they can protect the missed approach. This is covered in someways by the blurb on some airport ATIS's that ask you to advise ATC if not able to circle.

So if I were in your shoes, after establishing that conditions are suitable for circling but you don't want to in the event that you overshoot, (and advising ATC of this!) then setting the Missed Approach alt would be more appropriate!

Now that you know what our expectations are, you should be able to decide what to select on your altitude preselect yourself. It will just depend on the wx conds at the time of your approach.

Clear as mud!!

[dejapoo]

Dragging up an old one for a kiwi 🥝 determination? 185 KIAS missed approach speed restriction off the ILS is for the climb gradient? How do you effectively manage this at higher weights? Thanks for any local knowledge.

[Tarq57]

The 185 limit is so an a/c on a miss doesn't catch a departure ahead.
If there's doubt you'll make the required gradient at or below that speed, ask the approach controller for an exemption prior to commencing the approach.

[missy]

The 185 limit is so an a/c on a miss doesn't catch a departure ahead.
If there's doubt you'll make the required gradient at or below that speed, ask the approach controller for an exemption prior to commencing the approach.
185K limit in the missed, fascinating. Is this a NZ thing?

[NZScion]

185K limit in the missed, fascinating. Is this a NZ thing?

It’s published on the approach charts for some aerodromes in NZ. From memory, AA and WN have 185kt missed approach speed limits. CH has 210kts.

[missy]

Thanks. It's the first I have ever heard of such a restriction. I haven't been on Pprune as longer as this tread. It makes sense to me, surprised it's not an ICAO / PBN based thing vs a local thing.

[Tarq57]

Thanks. It's the first I have ever heard of such a restriction. I haven't been on Pprune as longer as this tread. It makes sense to me, surprised it's not an ICAO / PBN based thing vs a local thing.
I think possibly that's likely to be because the NZCAA requires a protection in place for an unexpected missed approach. In many (perhaps most) other jurisdictions a miss will result in ATC quickly coming up with something to prevent a collision. Here, we have to have something in place in advance.

[missy]

I think possibly that's likely to be because the NZCAA requires a protection in place for an unexpected missed approach. In many (perhaps most) other jurisdictions a miss will result in ATC quickly coming up with something to prevent a collision. Here, we have to have something in place in advance.
Bravo to NZCAA. 185K would've helped in some of the missed approaches I have seen, either as a participant or a spectator.