CAT 3A minima in Melbourne

[longobard]

Ozzies please illuminate me...

Where the hell the 175m RVR minima for ILS 16 CAT 3A in Melbourne comes from?

[Checkboard]

I don't know - where did YOU find it?

[9.G]

Aussie CAA is guilty as charged, it's nearest value to 600 ft.

[longobard]

checkboard....approach plates?

9.G Cat 3A minima is 700ft

[Capn Bloggs]

Approach Chart:

http://www.airservicesaustralia.com/...MLII04-129.pdf

[9.G]

longobard, if you're so certain why ask then? in imperial system it's 600 ft converted to metric system equal to 182,88 meters. Given the 25 meters steps as per AWO prescription nearest value to 200 M RVR is 175 M. Check US plates or Canadian CAT II/III plates. Funny enough UK is the only country among common wealth ones using metric system.

[Capn Bloggs]

Originally Posted by 9.G

Funny enough UK is the only country among common wealth ones using metric system.

Geez, I thought that Australian "175m" was metric...

[9.G]

Geez, I thought that Australian "175m" was metric...

it's a metric conversion of imperial 600 ft in the wake of harmonization between FAA and EASA. Same story goes with US specs. In imperial system, RVR for CAT III A is 600 ft. Now imagine a Italian dude shooting an approach in MEL and given RVR 600 ft whereas his OM A says CAT III A RVR should be 200 M. I'd give a beer to see that face. Which one is to be applied here?

[longobard]

FAA CAT3A minima RVR is 700ft (AIM), please 9.g please give me some reference to the "imperial" (i suppose CAP) specs referring to rvr 600ft, i only know ICAO annexes and EASA, FAA regulations..sorry

thanks for the plate Capn Bloggs

[9.G]

VOLUME 4 AIRCRAFT EQUIPMENT AND OPERATIONAL AUTHORIZATION CHAPTER 2 ALL-WEATHER TERMINAL AREA OPERATIONS Section 7 Category III Operations:

4-348 ESTABLISHING CAT III OPERATING MINIMA

1) The RVR 1000 level is normally used for initial CAT IIIa operations for an
aircraft new to an operator, unless that operator has received operational credit for using the
Special Process for Minima Reduction. Operators receiving this special operational credit may conduct initial CAT IIIa operations with RVR 700 minima.
2) The RVR 700 level is the basic level for CAT IIIa operations. This level is the
lowest minimum that can be authorized for fail passive operations. RVR 700 is also the lowest minimum that can be authorized for operations with fail operational landing systems, which do not have a rollout control capability. Additionally, operations at runways which have ILS localizer restrictions (such as localizer unusable for rollout) are limited to the RVR 700 minimum.
3) The RVR 600 level is the current (2005) standard level for CAT III operations in the U.S. due to RVR reporting limitations, limitations to taxiway centerline lighting, and ground movement and control limitations. The RVR 600 level is also the lowest minimum that can be authorized at any airport for fail operational landing systems, which do not have at least a fail passive rollout control system.
4) The RVR 300 level is the lowest minimum that can be currently
authorized (2005) for operations by U.S. operators at any airport. This limitation is due to major limitations associated with the ground movement of aircraft and vehicles and the provision of timely crash, fire, and rescue facilities and services when operating in seeing-conditions less than
those equivalent to RVR 300. Operations below RVR 300 are not foreseen until all of these limitations are resolved.
5) RVR 150 level operations are not foreseen in the near future. Operations at this level are not foreseen until the aircraft and essential ground vehicles can be reliably maneuvered on the airport without relying on normal external visual references (for example, forward looking infrared sensors).

Lack of knowledge doesn't absolve of responsibility

[9.G]

For info Aussies along with ICAO have implemented following changes:

Precision Approach and Landing Operations: Instrument approaches and landings using precision azimuth and glide path guidance with minima as determined by the category of operation. Categories of Precision Approach and Landing Operations are:

1.
---- Effective thru 01 Jun 2011: ----
Category I (CAT I) operation. A precision instrument approach and landing with a decision height not lower than 200 ft and a visibility not less than 800m, or a RVR less than 550m.

------------------------------
---- Effective 02 Jun 2011: ----
Category I (CAT I) operation. A precision instrument approach and landing with a decision height not lower than 200 ft and either a visibility not less than 800m or a runway visual range not less than 550m.

------------------------------
2.
---- Effective thru 01 Jun 2011: ----
Category II (CAT II) operation. A precision instrument approach and landing with a decision height lower than 200 ft but not lower than 100 ft, and a runway visual range not less than 350m.

------------------------------
---- Effective 02 Jun 2011: ----
Category II (CAT II) operation. A precision instrument approach and landing with a decision height lower than 200 ft but not lower than 100 ft, and a runway visual range not less than 300m.

------------------------------
3.
---- Effective thru 01 Jun 2011: ----
Category IIIA (CAT IIIA) operation. A precision instrument approach and landing with a decision height lower than 100 ft, or no decision height and a runway visual range not less than 200m.

------------------------------
---- Effective 02 Jun 2011: ----
Category IIIA (CAT IIIA) operation. A precision instrument approach and landing with a decision height lower than 100 ft, or no decision height, and a runway visual range not less than 175m.

------------------------------
4.
---- Effective thru 01 Jun 2011: ----
Category IIIB (CAT IIIB) operation. A precision instrument approach and landing with a decision height lower than 50 ft, or no decision height and a runway visual range not less than 50m.

------------------------------
---- Effective 02 Jun 2011: ----
Category IIIB (CAT IIIB) operation. A precision instrument approach and landing with a decision height lower than 50 ft, or no decision height, and a runway visual range less than 175m but not less than 50m.

------------------------------
5.
Category IIIC (CAT IIIC) operation. A precision instrument approach and landing with no decision height no runway visual range limitations.

EU OPS however maintains CAT III A RVR of 200 M. Well, nobody said it's gonna be easy to persuade Europeans of a way rest of the world follows.

[8che]

The Europeans also believe in a published decision height (min 50ft). According to the above post the Australians seem happy to shoot a 3A with no requirement to see the runway !

So why bother with 175 m ??

[aterpster]

So why bother with 175 m ??

To see to do the landing roll out and to taxi.

[safetypee]

9.G; “EU OPS however maintains CAT III A RVR of 200 M. Well, nobody said it's gonna be easy to persuade Europeans of a way rest of the world follows.”

This is not entirely correct. EU OPS does allow Cat3A, 50ft, 150m RVR for specific aircraft / systems certification [EU OPS-1430 table 8]. The operation is normally based on a GA below DH if the autoland system fails, but the requirements are for a highly reliable system [EU AWO 321(b)3].

Any apparent disjoint between the Australian chart minima and what is allowed by aircraft / operational approval should be governed by the chart note (1), but as no specific restrictions are provided, this can be interpreted as a generic Cat3A instruction. I do not know how the Australian authorities interpret the EU certification requirements or relate them to EU-OPS, if at all.

[9.G]

st, table 8 deals in the new appendix deals with CAT III B, we're talking CAT III A here. Both old and new ones are yet maintaining CAT III A RVR requirement of 200 M. for TDZ.

I do not know how the Australian authorities interpret the EU certification requirements or relate them to EU-OPS, if at all.

They don't, they simply apply ICAO. Yet the question of which minima for a EU OPS certified operator shooting a CAT III A approach in MEL applies, remains unanswered, at least here.

[8che]

Aterpster.

175m does not deal with landing roll. Thats why you have the 50m requirement for the Cat3B.

Therefore I ask again why bother with 175m if no DH with Cat 3A ? I simply dont see how you can do a Cat3A with no decision height as this could be a fail passive approach and as such has no redundancy for the autoland.

The question of which minima to use comes initially from the individual OPS-SPEC granted to each company when approval to operate in that country/state is given. Many EU operators may wish to stay with EU minima for ease of use.

[aterpster]

175m does not deal with landing roll. Thats why you have the 50m requirement for the Cat3B.

I should have parsed my statement better. As someone stated earlier the real limiting issue is movement of ground equipment such as fire fighters.

I was qualified in the sim for RVR 300 feet on the 767 in 1985. But, it hasn't happened yet.

[9.G]

8, 175 is directly related to rollout in manual mode. You seem to confuse auto land with rollout. CAT III A requires autoland with an option of exceptionally completing the landing in manual mode only with DH 50ft and RVR 200 in EU OPS. No such option for FAA or ICAO as TDZ RVR 175 isn't sufficient to accomplish landing manually. However it doesn't preclude a manual rollout which in turn requires a min RVR. 175 is very conservative figure whereas EU OPS is happy with 125. On the other hand EU OPS asks for 75 M to be able to taxi and for emergency services whereas ICAO goes as low as 50m. It's directly related to fail operational concept for both autoland and optional manual rollout. As a consequence one ought to insert DH of 50 ft in case being fail passive on CAT III A resulting in a requirement for a visual segment at DH and NO visual cues requirements at AH in case of fail operational. Now auto land and rollout are cohesive, aren't they? You can't have fail passive autoland and fail operational rollout system at the same time, can you? Thus 175 M is for CAT III A with fail passive auto rollout system.

[longobard]

thanks for exaustive reference 9.G, I was not updated

[8che]

9.G

Confusion certainly does exist. You can operate a Cat 3A with fail passive and still only need 75m midpoint (EU-OPS) as fail passive does not imply rollout guidance is lost. The 125 requirement is for midpoint only and is only applied if you already know you dont have rollout (through technical/ice covered runway etc). It has nothing to do with whether you are passive or operational.

So I return once again to the question of why no Cat 3A DH ? You correctly describe why 175m is insufficient for a DH to manual. Australia must therefore require a CAT 3A to be flown only with a fail operational system. Do they ? The FAA do.
Thus if your operating no DH then you have no requirement to see the runway to land so you must therefore be fail operational correct ? So no need for the 175m !

p.s we apply standard EU-OPs minima to Melbourne. US is a little more complicated.