So, what exactly is a "Cloudbreak Procedure" ?

[A Squared]

I know what one is generally, I've flown them, but what I'm asking is there a specific technical definition that differentiates a cloud break from an instrument approach Procedure?

The term Cloudbreak doesn't exist in the US. Would this procedure (http://aeronav.faa.gov/d-tpp/1207/06213LDADH.PDF) be termed a "cloudbreak" if it weren't in the US?

For those who don't feel like clicking the link, it's an IAP based on Localizer and DME guidance, but the missed approach is 5 miles from the airport and 4400 feet above it.

[Roger Scramjet]

Cloudbreak is an emergency proceedure for engine out / power loss ops used by RFDS (in PC12). There is no specific plate.

It is basically a steep descent (1000'/nm) to an airfield in IMC. The steep decent is flown clean, near Vne down to 400'agl and the high angle provides terrain clearance. The high speed = inertia at the bottom and therefore more options for a landing if visual.

[Sarcs]

Cloudbreak is an emergency proceedure for engine out / power loss ops used by RFDS (in PC12). There is no specific plate.



Also a lot of fun (although nerve wracking) in training, not sure if I'd be that keen to do it for real and in the gloop! ps RS I thought it was 700'agl not 400'...or have times changed?

[morno]

700 AGL is what I was taught. Assigned Alt to 1,200 AGL, Radalt to 700 AGL.

As Sarcs said, a lot of fun, but you'd be crappin' ya dacks if you had to do one for real!

morno

[megle2]

Whats the procedure if your not visual at cloudbreak and your now just above the deck at near vne - the cloudbreak missed approach is ??

[A Squared]

Cloudbreak is an emergency proceedure for engine out / power loss ops used by RFDS (in PC12). There is no specific plate.

It is basically a steep descent (1000'/nm) to an airfield in IMC. The steep decent is flown clean, near Vne down to 400'agl and the high angle provides terrain clearance. The high speed = inertia at the bottom and therefore more options for a landing if visual.

Interesting. Apparently we're talking about 2 different kinds of cloudbreaks. That does sound like fun to practice, but not so much fun if you're doing it for real.

The cloudbreak procedure I'm asking about are the one's I've seen in PNG and are charted procedures to specific airports. Off the top of my head there's one at Tari and one at Mt Hagen. I had thought that it was an Aussie term, PNG aviation having been strongly influenced by Aussie Aviation. Apparently that was a bad assumption as "cloudreak" means something entirely different in Oz.

[Sarcs]

KYAGB! But really your supposed to use what inertia you have left pitch up and slow to a more survivable speed, get everything hanging out and wait for the crunch!

[MyNameIsIs]

Whats the procedure if your not visual at cloudbreak and your now just above the deck at near vne - the cloudbreak missed approach is ??

To wish you were in a KingAir instead with the ability to climb with 1 inop!

Otherwise, I suppose you can do that real steep descent on an RNAV or other rwy aligned approach and hope you make the runway or at least field? Emergency situation, below minima is ok....

In the aircraft fitted with Proline 21, its not to hard to even plug in a visual approach with a preferred profile that will bring you to the threshold. If it all turns to poo, its another option.

[43Inches]

A Squared, I think what you are refering to is a procedure which is remote from an airfield. Yarrowee near Ballarat, Vic is one that is not located in the vicinity of an airport. It allows an aircraft to descend through cloud and become visual at a nav-aid such as a VOR and then proceed below cloud base in VMC.

The procedure you have initially posted appears to be associated with an airport.

[training wheels]

Yarrowee is often used for IFR training and also Cowes although I think the approach plate for Cowes no longer exists. Cowes was more of a cloudbreak procedure for a VFR approach at the strip at Phillip Island, but most people would use it for IFR training.

[43Inches]

Not sure the Philip Island approach would be the same category as Yarrowee. The approach still had a procedure for tracking from the VOR to the airfield (in IMC) and an IFR circling minima. The MAPt was set at a distance beyond the VOR to take you into the runway circling area so it was still associated with the Philip Island airport.

Yarrowee is just set on the edge of the ranges. I guess the intention was to allow an aircraft to get visual after crossing the hills and then go to any one of the numerous little ALAs in the area beyond in VMC.

[beaver_rotate]

In PNG, A Cloudbreak procedure when I was there is basically a GPS RNAV.

Nothing seems odder than briefing the plate 'Effective 5 Jun, 1995' :D

[prospector]

I do believe the term "Cloud Break Procedure" goes back at least to the 1970"s. It was the term used to describe the let down procedure at McMurdo for the Antarctica sightseeing flights.

[Arm out the window]

One use of the 'cloudbreak' term in miltary radar airspace was 'radar vectors to cloudbreak' - you could request that, and just be vectored down to sector MSA to hopefully get visual and avoid the need to queue up for instrument approaches when a lot of people were out in the training area all wanting to get back at the same time.

There weren't any particular published plates, just vectors from air traffic to wherever the low sector MSAs were and it was expected you'd get visual.

[Tinstaafl]

A cloudbreak procedure is an instrument approach but one not associated with a runway/airfield. Really just a way to get below the cloud base and then proceed where ever you like once in VMC. I recall one that used based on the Bromelton NDB, south of Archerfield, prior to the Laravale VOR being installed around the time the new YBBN runways were built.

A similar one was based on the NDB east of Archerfield, although it terminated at Archerfield after a 5nm visual segment so it could be argued it was an approach, not a cloudbreak.

[compressor stall]

G'Day mate, hope you're enjoying life up there.

As you say, what it is is not in question, so to answer the technical side of the question (the difference), I've had a look through PANSOPS and can't find the term. I have, however, found the following reference for the South African CAA that might have some search terms that you could search for in ICAO type docs



Cloud break procedures may be approved by the
Commissioner for Civil Aviation, when one or more
of the following conditions apply:

Such procedure is conducted outside con-
trolled airspace.
Such procedure is conducted inside con-
trolled airspace.
The runway and/or equipment does not
comply with the ICAO requirements.
The final approach track is not aligned with
the runway.
Local QNH may not be available.



Have you tried e-mailing Ozexpat? :ok:

[Wally Mk2]

A cloud break proc is intended to end in a visual App via the circuit. It is intended to be flown thru cloud on decent expecting to be visual early enough to conduct a visual circuit at 1500' for a jet. Cloud base 2000 ft in this case with no rain in the vicinity of the airfield.
It can also be used to become visual to continue under VMC to yr destination further along yr track/flt plan..
In other words it's basically a DGA Arr using the step down element of that App simply to get clear of cloud & maneuver for landing. The same tracking tolerances apply as any std DGA App.


Wmk2

[sheppey]

Quote:
Cloudbreak is an emergency proceedure for engine out / power loss ops used by RFDS (in PC12). There is no specific plate.
Also a lot of fun (although nerve wracking) in training, not sure if I'd be that keen to do it for real

Lot's of fun, sure. Just like lots of fun practicing engine failure turn-backs by the RFDS in the PC12 which is part of their emergency training. It is a good bet the bloke that introduced that dangerous habit is a former RAAF instructor on the PC9. The turn back manouvre in training killed four pilots in the RAAF until it was banned 25 years ago. Obviously that has been forgotten?

[morno]

Ohhh here we go. :rolleyes:

Sheppey, a turn back procedure in a PC12 is indeed a dangerous procedure..... But so is flying in general.

I have personally done many a turn back in the PC12, and done properly, it is a perfectly acceptable, safe procedure. It's not exclusive to aircraft that an ex RAAF pilot has gotten into. The same procedure is taught as part of Caravan endorsements.

That 'don't turn back' mentality belongs in piston singles being flown by inexperienced pilots. Not in a single engine turboprop which is very capable of doing it.

morno

[compressor stall]

Here we go indeed. Thread drift as well.

Sheepy, would you care to enlighten the dear reader of the respective glide ratios of the pc9 and pc12? Also what heights were the raaf turn backs initiated vs RFDS?

When I did them in the -12, it wasn't very edge of the (aerodynamic) envelope stuff.

[Arm out the window]

The turn back manouvre in training killed four pilots in the RAAF until it was banned 25 years ago. Obviously that has been forgotten?

I don't know where you're getting your information from; your statement about 'banning' just isn't true.

They are a legitimate part of the takeoff safety plan for a PC9 and I wouldn't hesitate to try one if the circumstances were favourable - as Stally says, it's not pushing the envelope in an aircraft like that with suitably chosen height and speed gates.

[43Inches]

They are a legitimate part of the takeoff safety plan for a PC9 and I
wouldn't hesitate to try one if the circumstances were favourable - as Stally
says, it's not pushing the envelope in an aircraft like that with suitably
chosen height and speed gates.


You can also eject if it doesn't work out.

[Arm out the window]

Yes, true, but even for a single-engine, non-ejection seat aircraft with similar climb and glide performance, the option of landing back on the takeoff runway with engine out is a legitimate one.

[roulette]

To summarise all of the above:

Correct, it's not mentioned in PANS-OPS.
It's essentially an instrument approach procedure - most usually to a ground-based navaid such as a NDB or VOR/DME - that essentially can only deliver you to a known location from which you must be visual to circle and land ... and is (usually*) defined by circling minima at lowest.
That is, a cloudbreak is a circling procedure! No straight-in minima published.
Yep, there are GPS (pre use of term GNSS) cloudbreak APCHs in PNG (for more on those, ref OzExpat)
In South Africa, they call them Breakcloud procedures!
* In South Africa, sometimes the minima is defined as "not known, land at pilot discretion" ... or wording to that effect

[A37575]

In USA there is also a manoeuvre called "Sidestep". Typically ILS to one runway then when visual at above a certain safe altitude, you simply slide across a bit to land on the parallel runway. Guam was an example with ILS runway 6L - sidestep to land 6R. I suppose you could also call it a cloud break manoeuvre?

[A Squared]

Interesting variety of responses. It would seem that "cloudbreak" means a number of different things in different contexts.

In the context of the charted procedures used at a number of airports Papua New Guinea, none of the offered suggestions have quite hit the mark, although some are close.

What a cloudbreak is not (in this context):

It's not a procedure *not* associated with an airport. All the ones I know of in PNG are very much associated with a specific airport.

It's not what a GPS approach is called in PNG. Some of the cloudbreaks are based on GPS, others are NDB or NDB and DME. And there are GPS approaches which are called GPS approaches (Moro, for example)

Obviously, a cloudbreak is a procedure that is some combination of too far from the airport/too high above the airfield/not aligned with the runway to be considered an approach. But apparently how far/high/unaligned before it's not an approach is shrouded in mystery.

For what it's worth, we don't have this term in the US, they're all called instrument approach procedures, but to be an approach to a specific runway, the final approach course has to be aligned within 30 degrees of the runway and the MDA low enough for a "normal" descent for landing (No more than 400 ft/NM) Otherwise it's a "circling" approach and some maneuvering is required for landing.

[compressor stall]

Ísafjörður in Iceland has a number of cloud break procedures for its airport published on its approach charts.

[Arm out the window]

:)Ísafjörður

That's easy for you to say!

[A Squared]

ÍsafjörðurThat's easy for you to say!


I'm impressed that he used the correct fonts. Although not particularly surprised.

CS, your suggestion that ozexpat might have the answer was right on.

I found this old thread (http://www.pprune.org/tech-log/51436-cloud-break-procedure.html) in which he says that it's use in PNG is a procedure where the MAP is outside the circling area. That definition seems to be the most consistent with my observations about cloudbreak procedures.