Ques regarding minimums (RVR, VIS, etc)

[meatlover]

Hey guys. Please try to keep this simple for a fairly new guy.

Basically if I'm looking to shoot an ILS approach cat 1, RVR on my jeppeson plate says 550 and DA is 405.
If I have that RVR and that ceiling, I can shoot the approach, simple as that.
If not, I can try to shoot it till approach ban/outer marker or 1000 feet, correct?
What if the weather given to me is VIS and not RVR?

Also, I see a conversion table, I had to crop the top out I'm sorry but it basically says it explains when conversion of Reported Visibility to Equivalent RVR is allowed:
http://i.imgur.com/HjBGm.png

So when you have an RVR, you're allowed to convert.
I don't quiet understand this, it's very confusing to me.
Can someone please simply explain this to me.

Very much appreciated.

[Just want to fly]

You may commence an instrument approach regardless of the reported RVR/Visibility but the approach shall not be continued beyond the outer marker, or equivalent position, if the reported RVR/Visibility is less than the applicable minima. You don not need to take the cloud base into account.

Where RVR is not available, the pilot-in-command may derive an RVR value by converting the reported visibility for non-precision and Category I approaches only. Use your table for this e.g reported visibility of 300m will give a converted RVR value of 600m IF the airport has high intensity approach lights AND it is night. The reason being that the lights will shine through the cloud better in the dark.:ok: Although most airports with HIAL's will most likely have transmissometers as well.:ugh:

If, after passing the outer marker or equivalent position in accordance with the above, the reported RVR/Visibility falls below the applicable minimum, the pilot-in-command may continue the approach to DA/H or MDA/H.

Where no outer marker or equivalent position exists, the pilot-in- command shall make the decision to continue or abandon the approach before descending below 1000 ft above the aerodrome on the final approach segment.

The basics are outlined above but beware of the 'applicable' minima discussed. You may have higher regulatory or company imposed limits that are higher than the Jep minima. If you are single pilot for example you will be restricted to 800m RVR.

[EGPFlyer]

If your flying to new eu ops standard then the minimum RVR you can convert to is 800m therefore in the example given above with a 300m visibility, no conversion is allowed.

The difference between vis and RVR comes down to the fact that the runway lighting is taken into account. Essentially vis is what you would see without the bright runway lights. Hence with daylight and no lights, reported met vis = RVR. With HIALS and at night when your staring down the runway the distance that you will actually see is approximately twice that of someone looking down an unlit runway.

Ceiling is only a factor at the planning stage when you are looking at the requirements for your destination and alternates, and then, only if the available approaches are non precision or circling. Once your airborne only the RVR is limiting.

[SpanWise]

Ceiling is only a factor at the planning stage when you are looking at the requirements for your destination and alternates, and then, only if the available approaches are non precision or circling. Once your airborne only the RVR is limiting. Once airborne both Vis/RVR and ceiling are limiting. After take-off, the 'operating minima' is applicable which includes all the limits of the intended approach.

[FlyingStone]

Once airborne both Vis/RVR and ceiling are limiting.

Unless chart specifically states "Ceiling required" (Jeppesen), there is no need to have the required ceiling when starting approach or pasing OM (or equivalent point) - you do need required RVR/visibility to continue approach though - see EU OPS Appendix 1 to OPS 1.430 (new).

OPS 1.405
Commencement and continuation of approach
(a) The commander or the pilot to whom conduct of the flight has been delegated may commence an instrument approach
regardless of the reported RVR/Visibility but the approach shall not be continued beyond the outer marker, or equivalent
position, if the reported RVR/visibility is less than the applicable minima (see OPS 1.192).
....
(c) If, after passing the outer marker or equivalent position in accordance with (a) above, the reported RVR/visibility falls
below the applicable minimum, the approach may be continued to DA/H or MDA/H.

To keep it simple: one can make an NDB approach to MDH/MAPt with 9999 OVC001, but one can't shoot an ILS Cat I with 0200 SKC.

[meatlover]

Hey guys. Thanks a lot for the responses, makes things clearer.
Got another ques.

"Visual Reference

No pilot may continue a precision approach CAT 1 below the DH unless the reported visibility is equal or greater than 800m; or a RVR is given and at least one of the following visual references for the intended runway is distinctly visible to, and identifiable by the pilot:

– elements of the approach lighting system;
– the threshold, or its markings, lights or identification lights;
– the visual glide slope indicator(s);
– the touchdown zone or zone markings or zone lights;
– the runway edge lights."

Ques I have is that if I have an RVR given, I match that to what I have on my jeppeson plate, and if I have what I require, I should be okay.
Now usually on the ATIS I hear visibility, if they've said I have 800M, according to the above, I should be okay. Now if I have 700 m, can I convert to RVR?

Also. What happens when my RVR is okay, but ceiling is not?



Sorry but this is all new and confusing to me :ugh:

[Just want to fly]

If your flying to new eu ops standard then the minimum RVR you can convert to is 800m therefore in the example given above with a 300m visibility, no conversion is allowed.

EGPFlyer you are absolutely correct. That was probably not the best example on my behalf. I should also add:

Converted met vis must not also be used for take-off.

Converted met vis must only be used when no RVR is available.

[EGPFlyer]

Ceiling is irrelevant to flying the approach. You might not see anything at DA if the cloud is low but nothing precludes you from continuing to DA and having a look.

Where's your quote from? It doesn't really make sense to me as I only have experience of EU-ops. First of all, for cat I you will have a Decision altitude, not a Decision Height. Secondly, your quote says you can continue below this 'DH' if the visibility is greater than 800m regardless of visual reference. That seems a bit silly.

If you have a vis of 700m you can convert it to RVR only if the resulting RVR after the conversion is at least 800m. This would only be the case if you had HI approach and runway lights, day or night, or any other lighting and it was night only.

[Citation2]

Meatlover, converting Vis, does not depend on the reported vis but on the Required RVR . The required RVR of the approach plate ( in your jeppesen) must not be lower than 800m.
If your approch plate requires an RVR of 700 m, you cannot convert anything. If the tower gives you a vis of 1000m you cannot shoot the approach. Because you need an RVR and you are only allowed to convert when the REQUIRED is not below 800 . So in my exemple any reported vis is useless from a legal point of view, whether the vis is higher or lower .

2nd exemple: if your approach plate shows an RVR of 900 m you can convert the reported vis by tower. If they give you 450 m , you might be fine by night in HIALS and runway lights equipped airport.

Eu ops reference: "An operator must ensure that a meteorological visibility to RVR/CMV conversion is not used for takeoff, for cal-culating any other required RVR minimum less than 800 m, or when reported RVR is available"

[747dieseldude]

Trying to make it simple:

Planning:
Ceiling is required.
Vis/RVR is required. In most cases you only have forecast vis. unless dispatching for a short sector based on METAR which include RVR. METARs are valid for 2 hours, provided there's a NOSIG at the end.

In flight, in order to continue past the OM or 1000ft if no OM:
Only Vis/RVR is required.
Ceiling is not a factor unless "Ceiling required" is indicated on the chart.

If RVR is reported, it must be used. Controlling is TDZ RVR, unless it is u/s, in which case it may be substituted by MID RVR.

If RVR is not available, you can use the convert the Vis to RVR, but only if the reported visibility is 800m or more.
If reported visibility is less than 800m, you must have RVR reported.

After passing the OM / 1000 ft, you can continue down to minimums, and if you see the required visual elements you can continue to land.

Examples:
1. Required RVR/CMV 550m:
RVR reported as 550/175/175 (TDZ/MID/ROL) or better, you can start the approach.

No RVR, vis below 800m: below minima, you cannot pass the OM.

Vis is 800m or more: you can start the approach.

2. Required RVR/CMV 1200 (lets say non precision approach).

RVR is 1200/175/175 or better, you can start the approach.

RVR not available, Vis is below 800m: cannot start the approach.

RVR not available vis is 800m, night, HIALS, then CMV=800 x 2 = 1600m: you can start the approach.

Hope that clears things up a bit.

[bookworm]

If reported visibility is less than 800m, you must have RVR reported.

Not so.

Appendix 1 (new) (l) (1) prohibits the use of an RVR/CMV conversion when the required RVR is less than 800 m.

[meatlover]

"All Pilots must ensure that a meterological visibility to RVR/CMV conversion is not used for:

• Takeoff
• For calculating any other required RVR minimum less than 800m,
• Or when reported RVR is available"


So basically I can always convert my VIS if it will give me an RVR of at least 800m.
So at night, with high app lights, and a VIS of 400 m, gives me an RVR of 800m.
Good to go?

These are all obviously cat 1 approaches.
Are cat 2/3 also complicated?
Haven't gotten there just yet:O

[time2leave]

Dont forget that as a single pilot you can fly to 550m, if using a coupled ILS down to a DH of not less than 1.25 times the minimum allowable height of the autopilot.

[meatlover]

Required RVR from chart is 550.
I don't have RVR reported, and VIS is 350.
I cannot convert in this case since the required RVR is less than 800.
This case I can only start the approach till the outer marker / equivalent point, and discontiue if not in sight?

Also, another one.
If the chart requires RVR and VIS, but I only have one of the two reported(RVR for example), and it is above what i require, then is it the same scenario as above(OM/equiv point)

[JeroenC]

If RVR is reported, it must be used. Controlling is TDZ RVR, unless it is u/s, in which case it may be substituted by MID RVR.

In our table (defective equipment) the quote above is only applicable to Cat2&3. Cat1 states "no effect".

Example 1: TDZ RVR u/s, cat1 installation, RVR required 550 m. RVR midpoint reported 600m.
Q: since the table doesnt explicitly allow midpoint RVR to be substituted for TDZ RVR, can I fly beyond OM?

Ex 2: TDZ RVR u/s, cat1 installation, now vis 600 given and RVR required 900 m, midpoint RVR 400, night, HIALS. Since midpoint IS given but TDZ not, can I convert, MUST I use midpoint for TDZ or???

[Stanley Eevil]

Required RVR from chart is 550.
I don't have RVR reported, and VIS is 350.
I cannot convert in this case since the required RVR is less than 800.
This case I can only start the approach till the outer marker / equivalent point, and discontiue if not in sight?

I believe you are correct. To obtain a legal met vis for the approach, with no RVR available, you would have to convert 800M since that is more limiting than the chart requirement of 550M.
So, minimum MET VIS to proceed beyond the approach ban point would be:
400M at NIGHT
550M by DAY
If you get the RW visually by the Approach Ban point you would NOT be legal unless you declare/ are cleared for a visual approach with a minmum visibility/RVR of 800m to allow for the shallow fog risk at the threshold.

[meatlover]

Thank you so much Stanley,

Just one last ques before I'm fully done with this topic.
If the chart requires an RVR AND VIS.
Surely if I have been given both values, and don't satisfy either, I cannot continue past the 1000 feet / outer marker unless visual.
But what if ATC only reports RVR, or only VIS, and i am above what I need in the chart, however I've not been given the other value..

Now?
Thanks again