Approach procedures

[1Charlie]

As an ATC not a pilot, I have two questions for those IFR gurus lurking.

1.
Eagle, Air NS and NZM have an agreement with Airways that straight in instrument approaches will be flown at CAT C speeds. Once vis drops below CAT C minima one of two things happen. Some aircraft will slow down prior to the ARC and fly CAT B speeds around the ARC, others like to have their cake and eat it too flying 240kt around the ARC then slowing to CAT B speeds by the FAF to take advantage of the lower vis minima.

This can be a problem when the former is first and the latter is last as the second aircraft rockets up No.1s trumpet.

Where in the AIP does it say you can / can't do this? I would have thought if you were going to fly CAT B you'd have to fly CAT B speeds once established on the ARC.

2.
When flying a holding pattern with a limiting distance, should you fly outbound until you hit the limiting distance regardless of the time, or should you turn at the limiting distance / 1min whichever comes first? I would have thought this would make sense. Usually controllers will expect a 4min lap of the holding pattern, but when a low performance ac is flying 2 min outbound legs all the way to the limiting distance and even longer inbound legs it makes it difficult to judge timing if there are following aircraft.

It also says nowhere in the AIP anything about this (again that I can find). I have seen in the Aus AIP, it says to turn at which ever comes first, but thats not to say the rules are the same.

In casual conversation feedback is very mixed.
Cheers

[rennaps]

In answer to 2

I think you can turn in the holding any time before the limiting distance but not after.

[waren9]

In answer to Q1, the following is a straight cut and paste from the AIP

ENR 1.5 - 24 AIP New Zealand

4.10.2 An aircraft may use a higher category speed, or fly a higher
category procedure provided that:
(a) the minima and restrictions for higher category are authorised and
complied with; and
(b) where approach control is provided by a non-radar unit, prior
approval has been obtained from ATC before commencing the
approach.

Ergo, to descend below the cat C minima, you need to be flying a cat B speed. Not aware of any defined point where cat B speed had to be achieved by, other than the cat C minima of course. As an ex Air Nelson Metro pilot, we'd tear round flat out and the normal slow down and configuring would put us back at cat B speeds and so, we'd use that minima. From memory, it was an advantage to all for the higher speeds in non radar airspace to reduce the amount of holding for following traffic. We used to tell the guy in the tower, and nobody really cared too much.

In answer to Q2, another cut and paste

ENR 1.5 - 12 AIP New Zealand

Outbound Timing
3.3.4 Outbound timing begins at the end of the turn onto the outbound
leg or abeam the holding fix, whichever occurs later. The outbound track
must then be flown:
(a) for one minute if at 14,000ft or below, or for one and a half minutes
if above 14,000ft; or
(b) until the appropriate limiting distance is attained, where distance is
specified.
3.3.5 When clearance is received specifying the time of departure from
the holding point, the pilot should adjust his pattern within the limits of the
established holding procedure in order to leave the holding point at the
time specified.

Again, we mostly only ever held when non radar and turned in bound as soon as the preceeding got visual and we were given an approach clearance.

but when a low performance ac is flying 2 min outbound legs all the way to the limiting distance and even longer inbound legs it makes it difficult to judge timing if there are following aircraft.

Its not well written, but my interpretation of that is the lesser of the timing or the limiting distance.

[alexWCD]

I'm now in IFR training, and from my take on things when you are in a hold with a limiting distance you fly to the distance then turn.

For example NZPM VOR/DME 25, the UVISI hold has a 20DME limit on it, and the UVISI w/p is at 14DME. So a 6NM outbound flown at 120kts will take 3 minutes. If the aircraft was to turn in at 1 minute they basically would be missing the whole point of a holding pattern.

However, reading the AIP insert from waren9, if you are cleared to leave the hold at a certain time then you would cut your hold early to make that time if need be.

That's my interpretation of it anyway

[TSIO540]

In Oz re holding: any distance quoted is a limit by which the turn must be commenced (i.e if outbound timing is not yet complete)

[TSIO540]

In Oz re holding: any distance quoted is a limit by which the turn must be commenced (i.e if outbound timing is not yet complete)

[Oktas8]

PANS-Ops, upon which both Australian & NZ procedures are based, has this to say (my bolding):

Where DME is available, the length of the outbound leg may be specified in terms of distance instead of time.
1.5 HOLDING
1.5.1 Still air condition
a) ...
b) It continues outbound:
1) where timing is specified:
i) for one minute if at or below 4 250 m (14 000 ft); or
ii) for one and one-half minutes if above 4 250 m (14 000 ft);
2) where distance is specified until the appropriate limiting DME distance is reached; then

It seems clear that the intent is to obey a timing rule by default, or fly to the limiting distance if specified, but not a mix of both techniques. Australia, but not NZ, has chosen to depart from PANS-Ops in this respect.

Later in the same section of PANS-Ops are instructions for shortening the hold to achieve a nominated onwards time.

I'm not sure why this is a problem for ATC. Does it matter how long an aircraft continues outbound? There will be no-one else following it in the hold or entering at the same altitude. Just give the pilot an onwards time and get on with other tasks.

My preference is for controllers to give an onwards time, or a crossing time, and let me do the job for which I've been trained. Don't second guess how long I'll be flying outbound for.

[Tinstaafl]

The way I read those cut & pastes, is that you use timing *unless* a distance is specified, in which case, you must use the distance. Separately, there are additional options that allow the hold to be shortened irrespective of whether or not the hold is time or distance based.

[1Charlie]

When you fly an approach in procedural airspace, the approach controller will have organised your sequence based on time, calculated from the distance around the arc + final, and the speeds you normally fly. Its fine if you tell the tower, but if you fly the arc at 180 when you'd normally do 240 and don't tell anyone it creates problems behind you.

When trying to organise a sequence in a procedural approach environment it's very usefull to know how long your lap of the hold will take. Not the length of the outbound leg in particular.

I'm not having a go, I'm just pointing out different pilots interpretation of the procedures, and the effect it has on the traffic.

[Ollie Onion]

If a holding distance is published then you fly to that DME/GPS distance before you turn regardless of the timing. PAN-OP's is pretty clear on that and NZ as far as I know obeys that interpretation. Australia doesn't, but then again Australia reinvents the wheel with just about all things aviation.

I don't know how anyone can interpret it any differently to that, it makes no sense to mix timing and distance.

[Oktas8]

Fair enough 1Charlie, and I'm not having a go at you either. But, in my ten years + of flying in NZ's Class D airspace, it was rare for ATC to specify onwards times.

As much as your SOPs allow, please stop second guessing pilots' intentions in a hold. It's a parking lot in the sky - just give them a time to leave the parking lot, don't worry about how they achieve it.

[MakeItHappenCaptain]

Why does there always have to be an answer to a NZ question that contains,"Well the Australian rule is....."

Who cares?:ugh::rolleyes:

[1Charlie]

I'll tell you why controllers in class D rarely give onwards times, it's because they can't be bothered working it out :eek: but if the hold is being used as a parking lot at a class D NZ aerodrome, it doesn't really matter because its usually 'delay not determined' (bad wx most likely). However, if you're using the hold as a sequencing tool it does. Today was a case in point. Three aircraft inbound, BKN010. Aircraft 2 is too close behind 1 to go direct outbound (after holding because he was over his landing weight), then a gap after him is 3. So I work out a time I want 2 to commence the approach and pass him an approach commencement time. This time occurs as he is starting the outbound leg of his second hold. When I asked him his position in the hold, his intentions were to continue that hold then commence the approach (about 4 mins away). Fine, but not today because number 3 is running you down. So I told him to leave the holding pattern and track outbound on the approach. Which they did, and everyone lived happily ever after.

My point is, pilots read these procedures differently. Now if you'd being flying the plane Oktas, you'd have positioned the aircraft to cross the Navaid at the time I'd given you and we'd be away laughing. However I've learn't in my days, that if you want to make a sequence work the way you want it to, you have to drive it! Sometimes that will mean second guessing.

PS you can't tell me you've never second guessed a controller ;-)

[Oktas8]

PS you can't tell me you've never second guessed a controller ;-)

Guilty as charged your honour... :E