PDA

View Full Version : LVO's


EYZ
10th Aug 2012, 06:45
G'day All,

If you conducting a Cat IIIA approach to 50'/200m minima, what's the minimum RVR you require for the mid point and stop end?
Let's assume everything is working, such as roll out guidance etc

I thought you required 200 for all the segments, but now I'm told it's only 125 for the mid point and 75m for the stop end!!

Thoughts!

Wizofoz
10th Aug 2012, 07:18
LVOs are an individual state/operator authorization, so there will be variations.

For instance, the minimum CatIIIA minima my company operate to are 200M Touchdown, 125 midpoint, and Captains discretion as to whether a stop end RVR is even required, but with a minimum of 75m if he judges it is.

The 200m is required so that, from the 50' DH, enough of the runway can be seen to provide lateral guidance (3 consecutive runway lights) as roll out guidance is not guaranteed with CatIIIA..

Once on the runway, 125m is sufficient to keep straight (it is, after all, the same as the minimum CatC takeoff minima), and the assumption is you will be at low speed and only needing turn off guidance at the stop end (as you would if you were CatIIb, which has an absolute minima of 75m)

Yes, it's called "Minima" for a reason! It's JUST enough, but you can operate to it.

As to "I'm told", and "Thoughts", are you actually in an LVO authorised operation? if so, it sholud be in your manuals- no "Thinking' required!!

Sonny Hammond
10th Aug 2012, 07:42
Good description Wiz.

9.G
10th Aug 2012, 10:39
MID 125 is only required if manual rollout is intended or redundancy for rollout system isn't warranted CAT III SINGLE for the bus otherwise MID and ROLLOUT can be 75 provided CAT III DUAL is on FMA, for the bus. Mind you this is only applicable for EU OPS operators conducting LVO OPS in EU. USA, CANADA, OZZ is different.

as roll out guidance is not guaranteed with CatIIIA.. That's absolute bollocks Wiz. CAT III A can be conducted with NO DH. CAT III definitely guaranties rollout guidance. CAT II doesn't. :ok:

Wizofoz
10th Aug 2012, 10:45
CAT III definitely guaranties rollout guidance.


no, THAT'S Bollocks.

I have operated to CatIIIa with no rollout guidence (B737-300/700 specifically-the CatIIa options don't even have a rudder channel)

That's why you require the 200m vis- to establish lateral guidence.

Though in theory a it can have no DHnever seen a CatIIIa operation with a DH less than 50', To do so you must have an aircraft certified as Fail- operational- in other words any aircraft capable of CatIIIa No DH is basically capable of CatIIb.

From the Royal Aeronautical society:-

For Cat 3a operations involving the use of fail-passive automatic landing equipment, the minimum RVR which is
normally acceptable for operations with small or medium size aircraft is 300 metres. If the aircraft system
demonstrates an in-service record of high reliability, such that the probability of a system failure during the early part
of the landing flare can be shown to be very low, consideration may be given to a reduction in the RVR.

For Cat 3a operations using fail-operational automatic landing equipment which does not include automatic roll-out
control or guidance, the minimum RVR is 200 metres.

For Cat 3a operations using fail-operational automatic landing equipment, with fail-passive roll-out control or
guidance, the minimum RVR is 150 metres.


My bolding.

nitpicker330
10th Aug 2012, 11:03
In our outfit

CAT 2 requires a minimum DH of 100'
CAT 3A requires a minimum DH of 50'
CAT 3B requires a minimum DH of 0' ( ie no DH )

These are regulatory minimums and will vary between Airports as required.

For CAT 2 and CAT 3A touchdown and midpoint RVR's are controlling ( there are allowed exceptions for system failures )

For CAT 3B all 3 RVR zones are controlling ( this can be reduced to 2 in some circumstances as well )

9.G
10th Aug 2012, 11:04
I have operated to CatIIIa with no rollout guidence (B737-300/700 specifically-the CatIIa options don't even have a rudder channel) That's aircraft's feature Wiz, we're talking bout ILS CAT III ground facility.
ILS CAT III ground facility does provide rollout guidance otherwise NO DH OPS would't be allowed on it. Yet it's common all over US to fly CAT III A with NO DH.

Though in theory a it can have no DH never seen a CatIIIa operation with a DH less than 50', Well, check out the definition of CAT III A.:ok:

Wizofoz
10th Aug 2012, 11:07
No, YOU might have been talking about ground facilities, everyone else was talking the specifics of Aircraft operation.

I repeat and am correct- ROLLOUT GUIDENCE IS NOT A REQUIREMENT FOR AN AIRCRAFT TO BE CATIIIA.

Interesting that you claim to have only been talking ground equipment, while simultaniously banging on about the features of tha Airbus.....

Yet it's common all over US to fly CAT III A with NO DH.


Not in 737s it aint....

9.G
10th Aug 2012, 11:33
Wiz, The 200m is required so that, from the 50' DH, enough of the runway can be seen to provide lateral guidance (3 consecutive runway lights) as roll out guidance is not guaranteed with CatIIIA.. There's no reference to the aircraft whatsoever. Never mind, CAT III A ground facility does guaranty rollout guidance. CAT III A certified aircraft under EU OPS doesn't require rollout guidance, that's correct. Other than EU OPS CAT III A with NO DH rollout guidance is required for obvious reasons. RVR requirements are different as well. Just pointing out that EU OPS is different from ICAO and FAA. :ok:

john_tullamarine
10th Aug 2012, 11:47
We're getting into willy waving territory, methinks.

Perhaps better just to make your point and then retire from the argument if it starts to go around and around ?

If the point proposed is a matter of fact rather than opinion then, as one poster has done, it is simpler to cite an authoritative reference .. preferably with a link to an appropriate URL.

9.G
10th Aug 2012, 12:06
If you conducting a Cat IIIA approach to 50'/200m minima, what's the minimum RVR you require for the mid point and stop end?
Let's assume everything is working, such as roll out guidance etc

Under EU OPS, if the aircraft has rollout guidance and redundancy is provided then MID, ROLL OUT RVR can be as low as 75 m. Without Rollout guidance and redundancy given RVR MID has to be 125 for the manual rollout.

reference EU OPS commencement and continuation of approach. The touchdown zone RVR is always controlling. If reported and relevant, the mid-point and stop-end RVR are also controlling. The minimum RVR for the mid-point is 125m or the RVR required for the touchdown zone if less. The minimum RVR for the stop-end is 75m. For aircraft equipped with a roll-out guidance or control system, the minimum RVR value for the mid-point is 75m.

Table 14 CAT III OPS depicts required RVR dependable on type of approach and rollout guidance system installed. All straight forward. :ok:

Wizofoz
10th Aug 2012, 12:50
Under EU OPS, if the aircraft has rollout guidance and redundancy is provided then MID, ROLL OUT RVR can be as low as 75 m. Without Rollout guidance and redundancy given RVR MID has to be 125 for the manual rollout.


I fly a 777 which obviously DOES have roll our guidence, yet the minimum CatIIIa vis we operate to is 200,125,75 with a 50' DH.

Why? Because the only time we are likely to be restricted to CatIIIa is if we carry an MEL or have an equipment failure which leaves us Fail Passive or without roll-out guidence- in which case the 50'/200m applies.

The OP specified 200,125,75 m and I gave the rationale for those figures in an Aircraft that does not have roll out guidence.

Perhaps I should have been more explicit for the sake of the pedants, but that doesn't make what I said Bollocks, and you, 9G, might consider your tone when addressing others.

9.G
10th Aug 2012, 13:16
I fly a 777 which obviously DOES have roll our guidence, yet the minimum CatIIIa vis we operate to is 200,125,75 with a 50' DH. Well, Wiz, I can't force you to take advantage of the current regs. I already quoted it for you, if you are fail operational even on CAT III A with DH 50 your MID RVR can be 75 M. No need to be cocky here Wiz, nothing posted by me is directed against you personally.

Why? Because the only time we are likely to be restricted to CatIIIa is if we carry an MEL or have an equipment failure which leaves us Fail Passive or without roll-out guidence- in which case the 50'/200m applies. So I take it you don't fly to CAT III A only certified airdromes then? When we speak LVO it involves Aircraft, Crew, Airdrome, Operators Specs.:ok:

Wizofoz
10th Aug 2012, 13:57
Well, Wiz, I can't force you to take advantage of the current regs. I already quoted it for you, if you are fail operational even on CAT III A with DH 50 your MID RVR can be 75 M

Only with specific approval. Ours is as I have stated.

need to be cocky here Wiz, nothing posted by me is directed against you personally.

Perhaps you meant "Utter Bollocks" in some new, polite way?

I take it you don't fly to CAT III A only certified airdromes then?

ALOMST certain the answer to that is no, and we fly to some 125 destinations.

When we speak LVO it involves Aircraft, Crew, Airdrome, Operators Specs.

Precisly so, yet you keep stating the absolute minimums as if they are unoversal.

Checkboard
10th Aug 2012, 14:03
http://www.freesmileys.org/smileys/smiley-basic/popcorn.gif

8che
10th Aug 2012, 14:55
Wizofoz,

9.G is absolutely spot on with everything he says.

Cat 3a does not require 125m mid (as the ground based system assures rollout). Only if your aircraft has a degradation do you need to apply 125m instead of 75m.

I also fly the B777 for a EU-OPS compliant carrier and I think you need check again your airports. There are plenty of Cat3a only runways both in Europe and outside. Try Hannover 27R for starters. So when mid drops to <125m you divert while we land ? Commercially your company should look at this again,

9.G
10th Aug 2012, 19:43
Wiz, I'm sure EK has thought it's OPS specs well through. Usually the confused ones are either upgrade candidates or management folks. No offense intended just a mere observation. As you pointed out EK flies to 125 destinations worldwide. So next time you fly to MEL have a look at your plates for ILS 16 X CAT II & III approach chart. You can convince me with 2 pints on CAT III A min 200/125/75 theory there. :ok:

Wizofoz
10th Aug 2012, 21:00
8ache,

I didn't say he was wrong.

Just that I wasn't either.

9

Our MEL approach plates (Lido) say "Cat 3b Company".

Our CCI LVO pages then give Cat3b 0', 75,75, Capts discrection and Cat3a 50', 200m, 125m, Capts discretion.

I accept no offence was intended, but understand that "Utter Bollocks" is not the most polite way to voice disagreement.

Yes, everything you have said is correct, but it was still a pretty abrupt input when all I was doing was explaining the rationale to the OP, who specified 200,125,75, as is usual when roll-out guidence is not available.

9.G
10th Aug 2012, 21:18
aren't we talking CAT III A here? CAT III A for MEL states 175 M, doesn't it? Just trying to make you aware of the differences. Now you tell me, what are the requirements for MID and ROLLOUT on CAT III A in MEL RWY 16? :ok:

Wizofoz
10th Aug 2012, 21:27
I just told you- Our minimas for MEL RWY 16, CAtIIIa are a 50' DH, with 200m TDZ, 125m MID and Captains Discretion down to 75m RWY end.

Would you like me to email you the chart?

We also have CatIIIb there, 0'DH, 75,75,75.

Lido charts don't state anything about CatIIIa if CatIIIb is available- they just refer you to company minima.

COULD IT BE we have different approved minima than what you were aware of??

Wizofoz
10th Aug 2012, 21:41
Oh, and 8, I looked at Hanover, 27r, which we carry as an alternate- we have CatIIIb 0',75m on that runway, so I guess it's US landing while YOU divert?

Maybe just your company that's restricted to CatIIIa there?

9.G
10th Aug 2012, 22:21
Wiz, I'm referring to Jeppesen published mins. Jepp depicts 175 M for CAT III A RWY 16 in MEL and for a good reason. CAT III A is classified as follows:

ILS CATEGORIES (ICAO) same for Ozz regs btw.
a.
ILS Category I An ILS approach procedure which provides for an approach to a decision height not lower than 60m (200ft) and a visibility not less than 800m (2400ft) or a runway visual range not less than 550m (1800ft).

b.
ILS Category II (Special authorization required) An ILS approach procedure which provides for an approach to a decision height lower than 60m (200ft) but not lower than 30m (100ft) and a runway visual range not less than 300m (1000ft) for aircraft categories A, B, C (D with auto landing), and not less than 350m (1200ft) for aircraft category D without auto landing.

c.
ILS Category III (Special authorization required)

1.
IIIA An ILS approach procedure which provides for approach with either a decision height lower than 30m (100ft) or with no decision height and with a runway visual range of not less than 175m (574ft).

2.
IIIB An ILS approach procedure which provides for approach with either a decision height lower than 15m (50ft) or with no decision height and with a runway visual range of less than 175m (574ft) but not less than 50m (150ft).

3.
IIIC An ILS approach procedure which provides for approach with no decision height and no runway visual range limitations.

Well, EK got this CASA EX83/12 - Exemption - from standard take-off and landing minima - Emirates (http://www.comlaw.gov.au/Details/F2012L01124) which explains the difference. Others can shoot CAT III A in MEL with TDZ 175, MID 175 and ROLLOUT 100 which can be ignored if ALD is within TDZ and MID. Auto land and rollout is required in this case however only fail passive. :ok:

If EK has managed to keep the mins uniform throughout the network by getting authorizations from different authorities then, it's the best option. I personally prefer EU OPS one.

Wizofoz
10th Aug 2012, 22:28
It also explains why we don't use 175, 75, 75 for CatIIIa. We HAVE CatIIIb when everything is working, and only need CatIIIa when we have to downgrade.

I may have mentioned that??

Why would I quote Jepperson when we don't use them?

9.G
10th Aug 2012, 22:34
coz it's not about specific operator here wiz, it's about rules and regs. Of course different operators will have different mins etc all depends on how much cash they're willing to spend. The intent of this thread is to clarify applicable regs let it be EU OPS, FAA or Ozzie ones. If you wanna talk specifically EK there's a thread dedicated to EK. This is for general public. :ok:

Wizofoz
10th Aug 2012, 22:40
coz it's not about specific operator here wiz, it's about rules and regs.

Jepperson are not a statutory authority, they are a commercial provider, as is LIDO.



And that's the interpretation YOU'VE decided to put on the thread so you can amaze us with your knowledge.

The thread was started by a newbie who wanted to know about CatIIA operations with minima of 50', 200m,125m,75m. Try reading the OP for reference.

Again, none of the information you've provided is wrong- but you presume to dictate what the topic of discussion is when it was actually about the rationale behind a particular set of minima in particular circumstances.

Checkboard
10th Aug 2012, 23:12
http://www.freesmileys.org/smileys/smiley-basic/popcorn.gif

:}

Wizofoz
11th Aug 2012, 05:04
Glad to provide you with some light entertainment, Checkie!!!

9.G has provided good, accurate information here and, I will certainly admit, shown me some things I didn't know.

My entire exposure to LVOs has been the 737 in Europe (which did not have roll-out guidence), and now the 777 in which we retain the 50', 200m minimum for CatIIIa for reasons I've outlined.

I DIDN'T realise 0'DH and 75m mid field was possible CIIIa.

Just a shane he can't present information without insulting perjoratives like "Utter Bollocks" attached!

Checkboard
11th Aug 2012, 09:27
Both entertaining AND informative, Wiz.

But for your error in writing "guaranteed" when you meant "required" I was with you all the way. :)

My only experience of CatIII ops has been here in Europe, as I left Oz before CatIII was available there. European ops have always specified Cat IIIa as having a decision height of at least 50 feet, so I wasn't aware of no decision height Cat IIIa ops (min vis 175m) in other places around the world either.

Wizofoz
11th Aug 2012, 10:03
No, I MEANT Guarenteed- I was just WRONG!!

It is interesting that people have mentioned there being "Many" CatIIIa only runways.

I've looked, and we seem to have none- CatIIIb or straight to CatII or I.

8che
11th Aug 2012, 10:24
Ok Wiz,

Try looking at Frankfurt Hahn. (for the B777F)

Wizofoz
11th Aug 2012, 10:42
8che

On the LIDO chart, yep, best available is CatIIIa BUT- we don't have LVO approval there, so are restricted to CatI.

9.G
11th Aug 2012, 10:53
Wiz, I wrote absolute bollocks not utter bollocks. It kinda makes it academical in a way but point taken. Sandpit takes it's toll, I guess. You're right I'm a pedant as the devil is always in the details.
Jepperson are not a statutory authority, they are a commercial provider, as is LIDO. that however doesn't absolve any of them from complying with the following:

Publication of minimums does not constitute authority for their use by all operators. Each individual operator must obtain appropriate approval for their use.

GENERAL

Jeppesen charted minimums are not below any State-provided minimums. Higher existing minimums for FAR 121 operators and those applying U.S. Operations Specifications are footnoted. RVR/CMV/VIS values are shown in measuring units as reported by the governing agency.

In case a operator is willing to pay for, tailored charts can be produced and that's what you fortunately have Wiz. :ok:

Wizofoz
11th Aug 2012, 11:36
No sweat, 9. Perhaps a little more thought into the how as well as the what information is delivered?

As I said, educational, and yes I had a mistaken impression, so please don't stop making factually correct posts.

9.G
11th Aug 2012, 11:55
12 CAT III OPERATIONS (EU-OPS 1)

CAT III operations are subdivided as follows:

a.
CAT IIIA: decision height lower than 100ft and RVR not less than 200m,

b.
CAT IIIB: decision height lower than 100ft or no decision height and RVR less than 200m but not less than 75m.

DECISION HEIGHT

For operations in which a decision height is used, an operator must ensure that the decision height is not lower than:


the minimum decision height specified in the Aircraft Flight Manual or equivalent documents,


the minimum height to which the precision approach aid can be used without the required visual reference,


the decision height to which the flight crew is authorized to operate.

Operations with no decision height may only be conducted if:


the operation with no decision height is authorized in the Aircraft Flight Manual,


the approach aid and aerodrome facilities can support such operations,


the operator has an approval for CAT III operations with no decision height.

NOTE: In the case of a CAT III runway it may be assumed that operations with no decision height can be supported unless specifically restricted as published in the AIP or by NOTAM.

Whether an aerodrome is CAT III A or B mainly depends on the lightning system installed in particular taxi lights with red stop bars etc. That's why many aerodromes chose CAT III A certification only as it's cheaper yet still allows a fully automated approach, landing and rollout even with NO DH. Taxi is another story.:ok: