Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

Low Visibility Ops in US

Tech Log The very best in practical technical discussion on the web

Low Visibility Ops in US

Old 28th Mar 2017, 11:57
  #1 (permalink)  
Thread Starter
 
Join Date: Apr 2009
Location: Canada
Posts: 606
Likes: 0
Received 0 Likes on 0 Posts
Low Visibility Ops in US

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.
Airmann is offline  
Old 28th Mar 2017, 15:03
  #2 (permalink)  
 
Join Date: Apr 2012
Location: In Space
Posts: 683
Likes: 0
Received 0 Likes on 0 Posts
If the airport is below MVFR/VFR and in IFR conditions you can assume its in LVPS's.
B737900er is offline  
Old 28th Mar 2017, 18:11
  #3 (permalink)  
 
Join Date: Jun 2013
Location: Or-E-Gun, USA
Posts: 326
Likes: 0
Received 0 Likes on 0 Posts
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.
No Fly Zone is offline  
Old 29th Mar 2017, 11:28
  #4 (permalink)  
 
Join Date: Dec 1999
Location: LHR/EGLL
Age: 45
Posts: 4,392
Likes: 0
Received 0 Likes on 0 Posts
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.
Gonzo is offline  
Old 29th Mar 2017, 14:01
  #5 (permalink)  
 
Join Date: Oct 2003
Location: If this is Tuesday, it must be?
Posts: 651
Likes: 0
Received 0 Likes on 0 Posts
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.
BizJetJock is offline  
Old 29th Mar 2017, 15:24
  #6 (permalink)  
 
Join Date: Jun 2001
Location: Wherever someone will pay me to do fun stuff
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
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!
LookingForAJob is offline  
Old 29th Mar 2017, 15:47
  #7 (permalink)  
 
Join Date: Oct 2015
Location: 43N
Posts: 264
Likes: 0
Received 0 Likes on 0 Posts
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.
CaptainMongo is offline  
Old 29th Mar 2017, 19:29
  #8 (permalink)  
Thread Starter
 
Join Date: Apr 2009
Location: Canada
Posts: 606
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by BizJetJock
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.

Originally Posted by LookingForAJob
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 is offline  
Old 29th Mar 2017, 20:24
  #9 (permalink)  
Thread Starter
 
Join Date: Apr 2009
Location: Canada
Posts: 606
Likes: 0
Received 0 Likes on 0 Posts
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/...er/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/O...VO%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
Airmann is offline  
Old 29th Mar 2017, 20:29
  #10 (permalink)  
 
Join Date: Sep 2014
Location: Canada
Posts: 1,257
Likes: 0
Received 0 Likes on 0 Posts
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.
peekay4 is offline  
Old 29th Mar 2017, 20:33
  #11 (permalink)  
Thread Starter
 
Join Date: Apr 2009
Location: Canada
Posts: 606
Likes: 0
Received 0 Likes on 0 Posts
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?

Last edited by Airmann; 29th Mar 2017 at 20:49.
Airmann is offline  
Old 29th Mar 2017, 21:14
  #12 (permalink)  
 
Join Date: Sep 2014
Location: Canada
Posts: 1,257
Likes: 0
Received 0 Likes on 0 Posts
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.
peekay4 is offline  
Old 29th Mar 2017, 23:11
  #13 (permalink)  
 
Join Date: Jun 2014
Location: Village of Santo Poco
Posts: 869
Likes: 0
Received 0 Likes on 0 Posts
Just an FYI, in just over 10 years with 3 airlines, I had whip out a Smigs chart exactly once.
Amadis of Gaul is offline  
Old 12th Feb 2018, 15:06
  #14 (permalink)  
 
Join Date: Sep 2009
Location: Europe
Age: 60
Posts: 9
Likes: 0
Received 0 Likes on 0 Posts
Still no ohne with a good Answer? At lebst YouTube US should be able, to explain this.
knarfo is offline  
Old 12th Feb 2018, 19:49
  #15 (permalink)  
 
Join Date: Sep 2003
Location: away from home
Posts: 889
Received 0 Likes on 0 Posts
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.
oceancrosser is online now  
Old 13th Feb 2018, 19:03
  #16 (permalink)  
 
Join Date: Apr 2008
Location: nowhere
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Airmann
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?
JammedStab is offline  
Old 13th Feb 2018, 20:40
  #17 (permalink)  
 
Join Date: Dec 2003
Location: Tring, UK
Posts: 1,832
Received 2 Likes on 2 Posts
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.
FullWings is offline  
Old 14th Feb 2018, 01:12
  #18 (permalink)  
 
Join Date: Nov 2008
Location: Melbourne, Australia
Age: 68
Posts: 365
Received 7 Likes on 1 Post
Every time that I've done a Cat II/III approach at LAX, everyone else seems to have diverted.
mrdeux is offline  
Old 28th Oct 2022, 16:53
  #19 (permalink)  
 
Join Date: Apr 2004
Location: Kappis
Posts: 66
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Airmann
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?
WhiteKnight is offline  
Old 29th Oct 2022, 01:56
  #20 (permalink)  
 
Join Date: Mar 2006
Location: USA
Posts: 2,511
Likes: 0
Received 0 Likes on 0 Posts
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.
Check Airman is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.