PDA

View Full Version : Low Visibility Ops in US


Airmann
28th Mar 2017, 12:57
In the US the METARS do no not explicitly state 'low visibility procedures in force'. How then should we know when it's safe to go down to CAT II or III minimums?

I read somewhere that the ILS sensitive zone will be protected when RVR is below 2000 feet and/or the cieling is below 200ft (I'm not mistaken). But there is of course other equipment that needs to be functioning for a low vis approach. Is it just assumed that the airport is operational for low vis unless otherwise stated.

B737900er
28th Mar 2017, 16:03
If the airport is below MVFR/VFR and in IFR conditions you can assume its in LVPS's.

No Fly Zone
28th Mar 2017, 19:11
Oh, darn good question, and one nearly difficult to answer. Bottom line is that when you know where you are going and know what the approach should look like (with full qualifications,) perhaps make one approach, to look. If junk prevails, GA, divert and do it now. Bruised SLC and paid freight are not going to make a measurable difference, when properly delivered. Other generic rules do not apply. -NFZ, gratefully retired but not yet a metal cripple.

Gonzo
29th Mar 2017, 12:28
EASA/rest of world and the FAA have tried to harmonise LVPs through AWOHARC but unfortunately it hasn't really worked.

FAA wanted everyone else to move to their system.

Is it really safe to 'assume' the ILS is being protected to CAT III tolerances?

Good question.

BizJetJock
29th Mar 2017, 15:01
Maybe I'm misunderstanding the question, but I've never seen "LVP in force" on a METAR anywhere in the world. ATIS yes, NOTAMs saying not available yes, but METARS purely give you weather.

LookingForAJob
29th Mar 2017, 16:24
As Gonzo says, attempts to harmonize what 'LVP in force' actually means have largely failed. And in reality, the whole topic is one of the least standardized parts of airport operations around the world. The measures put in place to safeguard operations - and what is actually protected - in poor visibility vary hugely and assumptions galore can often get made based on what someone saw at one airport.

And there is rather a lot riding on those assumptions!

And don't forget departures and ground operations. I personally rather like LVP that safeguard these parts of the operation also.....but if you just assume that it is the case, you might be surprised at the reality!

CaptainMongo
29th Mar 2017, 16:47
We are required to advise approach control and tower on initial contact when we plan an auto landing with weather greater than 800/2. ILS critical areas are to be protected with weather less than 800/2. ATIS will advise when SMGCS is in effect - 1200 RVR or less.

Airmann
29th Mar 2017, 20:29
Maybe I'm misunderstanding the question, but I've never seen "LVP in force" on a METAR anywhere in the world. ATIS yes, NOTAMs saying not available yes, but METARS purely give you weather.

Yes I meant ATIS, sorry about that.

And don't forget departures and ground operations. I personally rather like LVP that safeguard these parts of the operation also.....but if you just assume that it is the case, you might be surprised at the reality!

I am surprised at the lack of answers to my question. I thought it would be an open and shut thread. With a clear reference to one of the FAA regulations. In other parts of the world it is clearly stated either in the national regulations or in the airport information section of the charts that once vis/ceiling, goes below X LVP is in force, end of story. No assumptions required. I'm left a little bewildered that there hasn't been any clear replies until now. Come on, someone, where's the clear answer.

Airmann
29th Mar 2017, 21:24
Ok just an update, I have read through FAA Order 8000.94 and it seems to say that LVO/SMGCS and the procedures that an Airport has to meet in order to carry out these operations is at BELOW RVR1200. I assume that this means RVR1200 is not included! RVR1200 is CAT II. So this leads me to believe that US airports need not have a LVO procedure in force unless it is operating at CAT III!

Here's the link for that document:

https://www.faa.gov/documentLibrary/media/Order/8000.94.pdf

4. Scope. This order establishes an FAA interservice agreement that provides for consistent low-visibility (less than RVR 1200) airport operations; establishes requirements for uniform low-visibility airport equipment and enhancements; and implements uniform air traffic control (ATC) and airport operator practices and expectations.
Note: For the purposes of this order, LVO means those airport operations conducted at visibilities of less than RVR 1200.

So does this mean that most US airports have no real extra plans in place when the weather drops to CAT II other than guarding the ILS sensitive area?

a. LVO/SMGCS Operations Less Than RVR 1200. When the LVO/SMGCS plan designated authority reports the RVR for any runway is less than RVR 1200, the FAA considers that the conditions may exist to require LVO/SMGCS operations.

But then there's this from the Rules and regulations of LA Ontario Airport https://www.lawa.org/uploadedFiles/ONT/pdf/ONT%20Appendix%2001%20LVO%20SMGCS.pdf

When any one portion of the Airfield is in a low visibility condition; i.e., visibility (RVR) values are 1200 feet and below, the entire Airfield is considered to be in low visibility conditions and LVO/SMGCS procedures and restrictions are in effect.

These guys seem to include 1200ft. The FAA doesn't

peekay4
29th Mar 2017, 21:29
I am surprised at the lack of answers to my question. I thought it would be an open and shut thread.
CaptainMongo already provided the answer.

In the US, LVO is in effect whenever the RVR is less than 1,200 feet. This is the threshold for an airport to activate their Surface Movement Guidance and Control System (SMGCS) plan. See AC120-57A.

FAA Order 8000.94 requires all Part 139 airports to have an approved LVO/SMGCS plan for ops with RVR less than 1,200 feet.

Airmann
29th Mar 2017, 21:33
Is 1200ft. included?

What happens if the RVR is between 1200-1800ft (both excluded). That's lower than Cat 1 but as per what has been stated LVO would not be in force? Can you go down to CAT 2 minima in the US without LVO being in force?

peekay4
29th Mar 2017, 22:14
Special ground procedures aren't required when the RVR is 1200 ft or above, other than things like ILS protection areas.

The FAA did some studies which concluded that (on the ground) pilots can navigate visually just fine down to something like RVR 500 ft. So LVO level 1 is defined as RVR between 600 and 1200 ft (exclusive). Below RVR 600 ft other restrictions come into play.

By the way this is the same in Canada. LVOP is mandatory for operations below 1200 ft RVR. At or above 1200 ft, a Reduced Visibility Operations Plan (RVOP) is recommended but not mandatory.

Amadis of Gaul
30th Mar 2017, 00:11
Just an FYI, in just over 10 years with 3 airlines, I had whip out a Smigs chart exactly once.

knarfo
12th Feb 2018, 16:06
Still no ohne with a good Answer? At lebst YouTube US should be able, to explain this.

oceancrosser
12th Feb 2018, 20:49
I hear ya, 32 yrs of flying to the US and I have never done a Cat. II/III there. EUR is a very different story.

JammedStab
13th Feb 2018, 20:03
Is 1200ft. included?

What happens if the RVR is between 1200-1800ft (both excluded). That's lower than Cat 1 but as per what has been stated LVO would not be in force? Can you go down to CAT 2 minima in the US without LVO being in force?

This is the key question. Using LAX as an example.....The Jepp charts show 1800 RVR on the most frequently used runways for landing. What if it is less than 1800 but not below 1200 RVR?

FullWings
13th Feb 2018, 21:40
I hear ya, 32 yrs of flying to the US and I have never done a Cat. II/III there. EUR is a very different story.
Similar but I have done a couple, one at JFK where we scratched our heads, set up for an autoland then followed everyone else in. At the time, wasnít completely sure as to whether Iíd followed our SOPs so didnít ask for clarification...

LVPs in the EU, as you say, seem much more formalised but the real-world results donít appear to differ. :confused:

mrdeux
14th Feb 2018, 02:12
Every time that I've done a Cat II/III approach at LAX, everyone else seems to have diverted.

WhiteKnight
28th Oct 2022, 17:53
Is 1200ft. included?

What happens if the RVR is between 1200-1800ft (both excluded). That's lower than Cat 1 but as per what has been stated LVO would not be in force? Can you go down to CAT 2 minima in the US without LVO being in force?


Does someone has an answer to that question?. I just recently overflown JFK and the visibility was around 1500RVR. On the ATIS it didnít mention low vis ops in use. Cat 1 minima is 1800RVR. My company procedure wants me to have low visibility operation in force for a CAT 2/3 approach. How does it work in the US?

Check Airman
29th Oct 2022, 02:56
How does it work in terms of what? Letís say itís 1500RVR, ATC would normally be protecting the ILS critical area, and youíll be cleared for the ILS as usual. When you leave the runway, if thereís an applicable SMGCS chart, you use it.

WhiteKnight
29th Oct 2022, 08:28
Maybe I am just pedantic. According my company procedure I cannot fly a CAT 2/3 approach, unless low visibility procedures are in force. ( I assume it’s not only signal protection but also other precaution measures)
As far as I understand in JFK they only put them in force below RVR 1200. Above 1200 RVR they somehow protect the signal. But what’s the difference? Why don’t they apply low visibility procedures as soon as the weather gets below CAT 1 minima?

hans brinker
29th Oct 2022, 19:00
Maybe I am just pedantic. According my company procedure I cannot fly a CAT 2/3 approach, unless low visibility procedures are in force. ( I assume it’s not only signal protection but also other precaution measures)
As far as I understand in JFK they only put them in force below RVR 1200. Above 1200 RVR they somehow protect the signal. But what’s the difference? Why don’t they apply low visibility procedures as soon as the weather gets below CAT 1 minima?

To the best of my knowledge as a line Pilot:
Any time ceiling and visibility are below 800' or 2 miles, ATC has procedures to protect the signal accuracy of the ILS. Those include holding short further away from the RWY for departing/taxiing aircraft, vehicle traffic in the antenna area, and so on. So any time you have to do an ILS approach because weather doesn't allow for a visual, you know the signal is protected, at least at a towered airport.
The FAA has decided that for ground movement RVR of 1200 and above does not require LVP, as, in their opinion, there is no problem maneuvering around the airport at low speed in those conditions. For operations below RVR 1200, there will be different taxi diagrams, and for operations below RVR 600 there would be another set of diagrams, but not all airports will have those.
If you work for a US company your OpSpecs will authorize and explain how to comply with these rules.
If you work for a foreign company, and fly into the US, you should have a chapter somewhere in your manual explaining the difference between your local rules and the US, and how to handle this situation.
If there is nothing in your manual, it sounds like you would be unable to accept an approach into JFK with a visibility between RVR 1200 and RVR 1800, and that doesn't really make sense.

https://www.faa.gov/documentLibrary/media/Order/Order_800094A.pdf
ORDER 8000.94A
4. Scope. This order establishes an FAA inter-service agreement that provides for consistent low-visibility (less than RVR 1200) airport operations; establishes requirements for uniform lowvisibility airport equipment and enhancements; and implements uniform air traffic control (ATC) and airport operator practices and expectations. Note: For the purposes of this order, LVO means those airport operations conducted at visibilities of less than RVR 1200.

https://www.faa.gov/documentLibrary/media/Order/7110.65Z_Bsc_w_Chg_1_and_2_dtd_5-19-22_FINAL.pdf
FAA Order JO 7110.65, Air Traffic Control
3−7−5. PRECISION APPROACH CRITICAL AREA a. ILS critical area dimensions are described in FAA Order 6750.16, Siting Criteria for Instrument Landing Systems. Aircraft and vehicle access to the ILS critical area must be controlled to ensure the integrity of ILS course signals whenever conditions are less than reported ceiling 800 feet or visibility less than 2 miles. Do not authorize vehicles/aircraft to operate in or over the critical area, except as specified in subparagraph a1, whenever an arriving aircraft is inside the ILS outer marker (OM) or the fix used in lieu of the OM unless the arriving aircraft has reported the runway in sight or is circling to land on another runway.

WhiteKnight
29th Oct 2022, 21:12
Thank you very much for your detailed explanation.

hans brinker
30th Oct 2022, 15:30
I hear ya, 32 yrs of flying to the US and I have never done a Cat. II/III there. EUR is a very different story.

6 years in the EU, did 1 into Zurich. 10 years CAT2/3 qualified in the US, I've done 4, 2 of which in to LAX 25L. And during the last one into LAX they were doing visuals to 24R!

hans brinker
30th Oct 2022, 15:34
Thank you very much for your detailed explanation.

You're welcome!

Amadis of Gaul
11th Nov 2022, 14:29
6 years in the EU, did 1 into Zurich. 10 years CAT2/3 qualified in the US, I've done 4, 2 of which in to LAX 25L. And during the last one into LAX they were doing visuals to 24R!
Happens also at DTW. 3R will be Cat II, 4L will be VMC.