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-   -   LIDO cat3 minima (https://www.pprune.org/tech-log/664108-lido-cat3-minima.html)

the_stranger 8th February 2025 07:27

LIDO cat3 minima
 
Soon I will be flying on an aircraft which has cat3 capabilities, fail operational. As this company is using lido manuals/charts I am "pre studying", but don't have the possibility yet to ask questions. And the lido legend isn't the most readable thing I've ever seen... If the aircraft is fully functional, we are trained appropriately, not additions to minima, etc, what would be the cat3 minima for this approach? https://cimg7.ibsrv.net/gimg/pprune....e674b12c86.png
My thoughts are either, even though we can do a no DH - 75m approach, according the lido legends, the mentioned 50-200r are the lowest minima for this approach, so my minima too. Or are these the minima we must observe if, for some reason (tech?), we can't do a DH<50ft-75r (fail operational) approach? So if fail operational we can do no DH-75, otherwise 50-200. But what's the "company" line? According lido, company regs and minima must be observed. Are they only valid when those are somehow higher than the (in this case) 50-200r?

ploughman67 8th February 2025 07:58

In the Cat 3 DME column it refers you to Company specific minima. Look in the airfield’s General>CCI 01 tab and you’ll find specific minima for each type your company operates.

STBYRUD 8th February 2025 08:15

The point is that when it comes to LVO its all about what your company has been approved for, you won't find the values written in the LIDO Legend, but instead in your company documentation (and the certificates by the relevant aviation authority).

the_stranger 8th February 2025 08:25

Well, aa the company is allowed to do no DH, in this case I'd say I can fly that in this approach. But what does the 50-200r mean than? Why is it mentioned in the minima box?


wiggy 8th February 2025 08:32

the_stranger


Originally Posted by the_stranger (Post 11824165)
If the aircraft is fully functional, we are trained appropriately, not additions to minima, etc, what would be the cat3 minima for this approach?

Agree with previous:

The cat3 minima will be whatever the company has decided, and will be on the “company” page for that approach.

Problem you have with your pre-studying is it sounds as if you don’t yet have access to that bit of the documentation, it should all become a bit more clear when you do.


sonicbum 8th February 2025 09:58


Originally Posted by the_stranger (Post 11824165)
Soon I will be flying on an aircraft which has cat3 capabilities, fail operational. As this company is using lido manuals/charts I am "pre studying", but don't have the possibility yet to ask questions. And the lido legend isn't the most readable thing I've ever seen... If the aircraft is fully functional, we are trained appropriately, not additions to minima, etc, what would be the cat3 minima for this approach? https://cimg7.ibsrv.net/gimg/pprune....e674b12c86.png
My thoughts are either, even though we can do a no DH - 75m approach, according the lido legends, the mentioned 50-200r are the lowest minima for this approach, so my minima too. Or are these the minima we must observe if, for some reason (tech?), we can't do a DH<50ft-75r (fail operational) approach? So if fail operational we can do no DH-75, otherwise 50-200. But what's the "company" line? According lido, company regs and minima must be observed. Are they only valid when those are somehow higher than the (in this case) 50-200r?

As others have already pointed out, when dealing with LVPs it is pretty much all Operator specific. Your main reference on what you can or cannot do is your Operator's OM-A section 8.4, in addition to other publications you might have such as low vis manuals etc..

ploughman67 8th February 2025 10:11


Originally Posted by the_stranger (Post 11824190)
Well, aa the company is allowed to do no DH, in this case I'd say I can fly that in this approach. But what does the 50-200r mean than? Why is it mentioned in the minima box?

If you have access to LIDO>Documents>General>1.8.3.4.6.1.3. Minima Boxes you’ll find an explanation: Basically first figure MDH/DH, second visibility.

What does your CCI 01 page say for the runway as that is your absolute minima for that particular runway.

the_stranger 8th February 2025 10:18


Originally Posted by ploughman67 (Post 11824262)
If you have access to LIDO>Documents>General>1.8.3.4.6.1.3. Minima Boxes you’ll find an explanation: Basically first figure MDH/DH, second visibility.

What does your CCI 01 page say for the runway as that is your absolute minima for that particular runway.

I do have that reference, but what does it tell me?

Apparently, the MDH isn't valid, as we can we do a no DH approach. So why is it mentioned?
Is it when I am downgraded to fail.passive and have to increase my DH to 50, than the mentioned value (50-200r) becomes valid?

deltahotel 8th February 2025 10:19

.....Yes

Max Angle 8th February 2025 12:15


Apparently, the MDH isn't valid, as we can we do a no DH approach. So why is it mentioned?
You can't do a NO DH approach, the figures on the top line are the lowest state or system installation minima.

Company specific authorisation is required from the state authority governing the airport to fly a CAT3 approach and those approved figures will be published on the CCI page which is company specific.

They may be higher than the minima on the top line of box but they won't, or shouldn't be, lower.

For instance the LIDO chart for Warsaw 33 shows 0-175R in the minima box so in theory the airport will allow a NO DH approach at not less that 175m but our company CCI page shows 200m and 50ft (CAT3A) so that is what we are authorised to fly and we can't go lower than that. T

The figures may have come from the authority or perhaps the company have decided that they don't want operate lower at that airport but whatever the reason those figures are the minimum you can operate to.

the_stranger 8th February 2025 12:43


Originally Posted by Max Angle (Post 11824347)
You can't do a NO DH approach, the figures on the top line are the lowest state or system installation minima.

Company specific authorisation is required from the state authority governing the airport to fly a CAT3 approach and those approved figures will be published on the CCI page which is company specific.

They may be higher than the minima on the top line of box but they won't, or shouldn't be, lower.

For instance the LIDO chart for Warsaw 33 shows 0-175R in the minima box so in theory the airport will allow a NO DH approach at not less that 175m but our company CCI page shows 200m and 50ft (CAT3A) so that is what we are authorised to fly and we can't go lower than that. T

The figures may have come from the authority or perhaps the company have decided that they don't want operate lower at that airport but whatever the reason those figures are the minimum you can operate to.

So if I fly to the mentioned airport with a fail operational aircraft, with which we can and are allowed to do a no DH-75m approach on other airports, for this approach I still have to use 50-200r as my minima, correct?
And if we become fail.passive (in that case, we normally have minima of 50-175), we still have the same minima (50-200r) at this specific approach?

Max Angle 8th February 2025 13:35

It really isn't that hard, you are over thinking it, forget the minima page on the plate, for CAT3 operations you fly to whatever your company specific CCI page says.

Fail operational (CAT3 DUAL in Airbus speak) and fail passive (CAT3 SINGLE or CAT2) aren't associated with any specific minima, they are the operational landing capability based on the technical state of the aircraft.

If you have CAT3 DUAL on the FMA you can operate down to whatever CAT3B minima are included on the CCI page, if you have CAT3 SINGLE you can only go down to CAT3A minima and if CAT2 down to the CAT2 minima on the approach plate.

BUT be aware that some failures that downgrade landing capability are not sensed by the aircraft (Windshield heat, standby horizon etc.) so with a failure you must check the required equipment table to check you still have the required landing capability.

FlightDetent 8th February 2025 13:36

1 Attachment(s)

Originally Posted by wiggy (Post 11824197)
Agree with previous:

The cat3 minima will be whatever the company has decided and will be on the “company” page for that approach.

Cannot agree, sorry. The posts above suggest a certain way the whole CIII/II _may_ be handled by the airline, but not necessarily. I was once the person responsible for getting NAA approval for LIDO charts in a certain country, as we were the first AOC holder to bring them in. The job included creating the training course for minima interpretation and getting that approved. I hope you like my CCI design, which we needed for a certain binder - approved to be developed in-house by the kind LSY people.

You may not need a company page at all. Our case was easy: We operated C3-operational under EASA to the NoDH-75 standard.

So we asked LIDO to print the minima boxes in all our manuals to EASA specs, which we had in our OM-A, and that was it. (you can even ask Jeppesen to do this for you; it is so pricey nobody does). The AOM where lower, applicable for our 737-4/500 and A321 for France were kept in OM-B / Type Operating Limitations - near where the demonstrated cross-wind was converted to company hard limits.

I understand why some airlines or NAAs might want to have those in OM-C but let's not confuse the OP by saying that as a given.



FlightDetent 8th February 2025 13:43

To OP: what you are seeing is MOST LIKELY just LIDO showing you the lowest minima authorized for the approach (is that Belgium?). If your company minima is less, you need to observe the more conservative value you already suggested.

If it is still a thing, be careful for France, where NoDH-75 was not authorized thus 0-75 was printed meaning "must have a DH". For our 321 the AFM would require C3-OP + DH to be around 21'.

the_stranger 8th February 2025 14:16

I'm still utterly confused.

I asked and this company does not know CCI pages. It does have company minima, which states, fail operational you can do from NO DH tot 99 feet, with a minimum rvr of 75 (dh<50) and 175 (50<dh<99).

​​​​​​This particular approach is the 08r at LROP and the only thing I want to know, if I do fly there with my shiny Airbus, what minima do I put in the box?
And what visibility do I need to continue the approach/use for planning?


I'm both reading our company limits (So no DH and 75m as well as the mentioned limits 50-200.)

Max Angle 8th February 2025 14:55


if I do fly there with my shiny Airbus, what minima do I put in the box?
Whatever the company tells you to, you won't get it from LIDO unless the company has used the CCI page (Company and Crew Information) or had them printed on the main plate which it seems they haven't.

Perhaps it would be more useful to ask your employer, they must an approval so the figures will be somewhere.

Who is the operator? If the figures aren't available for a particular runway they may not have approval to operate CAT3 on to it so I would be cautious.




the_stranger 8th February 2025 15:26


Originally Posted by Max Angle (Post 11824422)
Whatever the company tells you to, you won't get it from LIDO unless the company has used the CCI page (Company and Crew Information) or had them printed on the main plate which it seems they haven't.

Perhaps it would be more useful to ask your employer, they must an approval so the figures will be somewhere.

Who is the operator? If the figures aren't available for a particular runway they may not have approval to operate CAT3 on to it so I would be cautious.

Thanks all for trying to explain it, it might help me get closer to understanding.
Of course I will ask later, but really would like to get to grips with it, if possible.
So assuming there indeed are CCI pages, can they show values below what is mentioned on the minima box. So below 50-200r in this case?

If not, question answered I guess. I use the ones in the CCI.

If they can show lower values and I if do use those lower values, what does the minima box tell me then? Assume the CCI shows 20-75r, what do I do with the mentioned 75-200r?

Reading the lido legends, it seems to come down to this part:
https://cimg7.ibsrv.net/gimg/pprune....a655598dfe.jpg
Which seems to suggest that for this specific LROP approach, there is no cat 3-75R published, there is only a cat 3-175r available, which is also slightly raised to 200r.
So even in my fail-operational Airbus I still need to use at least the minima (50-200r) shown in the box as there is no "better" (cat3-75r), unless the company limits (either in CCI or else) are even higher.

(I'm not naming the airline yet, as I'm slightly paranoid about giving too much personal info away, but it's a western Europe legacy.)

sonicbum 8th February 2025 19:09


Originally Posted by the_stranger (Post 11824436)
Thanks all for trying to explain it, it might help me get closer to understanding.
Of course I will ask later, but really would like to get to grips with it, if possible.
So assuming there indeed are CCI pages, can they show values below what is mentioned on the minima box. So below 50-200r in this case?

If not, question answered I guess. I use the ones in the CCI.

If they can show lower values and I if do use those lower values, what does the minima box tell me then? Assume the CCI shows 20-75r, what do I do with the mentioned 75-200r?

Reading the lido legends, it seems to come down to this part:
https://cimg7.ibsrv.net/gimg/pprune....a655598dfe.jpg
Which seems to suggest that for this specific LROP approach, there is no cat 3-75R published, there is only a cat 3-175r available, which is also slightly raised to 200r.
So even in my fail-operational Airbus I still need to use at least the minima (50-200r) shown in the box as there is no "better" (cat3-75r), unless the company limits (either in CCI or else) are even higher.

(I'm not naming the airline yet, as I'm slightly paranoid about giving too much personal info away, but it's a western Europe legacy.)

You will find your answers mainly in:

OM-A 8.4
OM-C Airfield briefings or other LVO related chapters
LVO Manual (if it’s a legacy there will be something like this)


swh 9th February 2025 08:56


Originally Posted by the_stranger (Post 11824165)
My thoughts are either, even though we can do a no DH - 75m approach, according the lido legends, the mentioned 50-200r are the lowest minima for this approach, so my minima too. Or are these the minima we must observe if, for some reason (tech?), we can't do a DH<50ft-75r (fail operational) approach? So if fail operational we can do no DH-75, otherwise 50-200. But what's the "company" line? According lido, company regs and minima must be observed. Are they only valid when those are somehow higher than the (in this case) 50-200r?

Paris used to have a DH on Cat 3B, not every airport is NO DH. To qualify for Cat 3B, the DH needs to be less than 50 ft. Only Cat 3C requires zero DH.

Just because the aircraft is NO DH capable still need
- Airport qualified
- Airline approval
- Crew qualified

the_stranger 9th February 2025 09:48


Originally Posted by swh (Post 11824804)
Paris used to have a DH on Cat 3B, not every airport is NO DH. To qualify for Cat 3B, the DH needs to be less than 50 ft. Only Cat 3C requires zero DH.

Just because the aircraft is NO DH capable still need
- Airport qualified
- Airline approval
- Crew qualified

As far as I know, in the EASA all weather ops, the cat3 A/B/C distinction has been discontinued, correct? Replaced by cat3-75 and cat3-175.
​​​
But apart from that, it still doesn't answer the question. What does the weather line(lido term, in this case 50-200r) tell me, what do i use it for and what is the link with the second line (company)?

If I am fully trained for no DH approaches and the aircraft is fail-oper., the one thing left is the airport. Does the 50-200r tell me that runway is designed as such that the lowest minima for that runway/approach is 50-200r? And therefore also my minima (assuming there is no airline higher limit)?
If not, what does it tell me?

(The company has no CCI pages, only company minima which go as low as no-dh/75m).


FlightDetent 10th February 2025 08:08

You are not fully trained. Otherwise you would not be asking these questions.

oceancrosser 10th February 2025 10:06

My company hs CCI pages, but the minimas are only on the approach plates.

the_stranger 10th February 2025 11:36


Originally Posted by FlightDetent (Post 11825339)
You are not fully trained. Otherwise you would not be asking these questions.

Like I stated, that's true, as I am about to start. That is not very relevant for my question, for which there still isn't an answer. I believe the question is quite straight forward, you fly/divert to this airport, you can fly a cat 3, what would be your minimum rvr (and what dh would you enter into the fms (if that's what your fms needs)?


Originally Posted by oceancrosser (Post 11825428)
My company hs CCI pages, but the minimas are only on the approach plates.

If I may ask, in this specific case, what would be the minima you would use?
You divert to this airport, you fly a cat 3 on this runway (assuming you are allowed), what would you take as your minimum rvr required and what DH?

Jwscud 10th February 2025 12:25

This is more properly a question for your company training and technical department. Nobody on the internet without knowledge of your company OM A can offer any advice I’m afraid.

FlightDetent 17th February 2025 13:16

I am willing to talk you through it. We've done the same as oceancrosser, without CCIs. No sweat.

After explaining to pilots and making them understand how to determine the minima of the day, where to find the numbers in the books and how to apply them to what's printed in LIDO. So I insist you not being trained in the "where do I find the minima" expertise is relevant a.t.m.

Happy to answer the question from #23 (which is straightforward as much as the answer is useless to you):
- in 2009 I would take RVR 200 + RA 50'
- in 2014 I would take RVR 200 + RA 50' (different reason, kind of)
- in 2019 I would take RVR 300 + RA 100'
- in 2024 I would take RVR 550 + DH 200' above TDZE

All the same airplane, well AFM. My initial LVP qualification was directly from Airbus to C3-operational standard + no DH, pre-dating the examples above.

There's nothing wrong with your thinking in the first post, moreover your own #17 pretty much has all the answers. Please ask....



Noknoipobin 20th February 2025 09:54

For cat3 minima on Lido ILS approach chart “ 50-200r/company”.The 50-200r is state minima ,the lowest permissible landing minimum for this ILS approach. Even your company reg is down to 0-75r, your approach minima is just 50-200r. That means you have to compare between state minima and company minima.The higher one is the minima for you.


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