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New EASA LVO RVRs

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New EASA LVO RVRs

Old 2nd Feb 2024, 03:22
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New EASA LVO RVRs

So the new Fail Operational/Passive concept doesn't seem that different to the old CAT 3B/A. The Minimums for fail passive are now 175m vs the old 200m. But there doesn't seem to be any indication of the various RVR requirements for the 3 runway segments, the new table is not like the old one.

There is mass confusion in my airline regarding this as the new table only mentions one RVR, which we all agree is required for the touchdown RVR, but what about the mid point and stop end?

We now have three opinions going around my airline regarding the midpoint and stop end RVRs:
1) still the same as before (i.e. 125 or 75 with auto roll out)
2) doesn't matter anymore (is never relevant)
3) must be the same as touch down RVR

Can anyone point to a document that has an answer? I tend to favor number 1, but that's only based on what I consider logical.
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Old 2nd Feb 2024, 03:59
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You may have a look at this thread:

Controlling RVR
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Old 2nd Feb 2024, 05:59
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I am a EASA TRI/TRE. You are correct, option 1 applies. For a CAT 3 with DH 50-99 ft it is 175/125/75.

Unfortunately I lack official EASA documentation, but our OM-A is crystal clear on this.

Rgds,
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Old 2nd Feb 2024, 07:22
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Originally Posted by poldek77
You may have a look at this thread:

Controlling RVR
So according to the references provided in this thread only the touch down zone is controlling, the rest is advisory. So it's left to the Crew to decide.

So given that I have never trained or had experience taxiing in less that 75m visibility, I would never accept less than that for purposes of taxiing. Secondly, since I have never controlled an aircraft (either in the sim or in real life) during a manual roll out (or during a take off) with less than 125m vis I wouldn't accept less than that if I didn't have auto rollout. So I would just revert to the old concept by decision of my own margins.

It still leaves doubts in mind as it leaves one in the position where something can be legal, but doubtful as regards safety. Namely, a situation where the touch down zone RVR is ok but the mid point is below 125 in cases of a manual roll out or less than 75, leaving one wondering whether taxiing would be safe.

What's the lowest visibility in which the pilots on this forum have taxied? What was the aircraft and how comfortable did you feel?
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Old 2nd Feb 2024, 07:40
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As far as I can find, EASA says:

(a) The controlling RVR should be the touchdown RVR.(b) If the touchdown RVR is not reported, then the midpoint RVR should be the controlling RVR.(c) If neither the touchdown RVR nor the midpoint RVR is reported, then NCO.OP.210(a) is notapplicable.

And

Where additional RVR information is provided (e.g. midpoint and stop end), this is advisory;
such information may be useful to the pilot in order to determine whether there will be
sufficient visual reference to control the aircraft during roll-out and taxi.

And

However, for aircraft manually controlled during ‘roll-out’ EASA recommends the following RVRfor the MID and/or END:
<A table with rvrs depending on available lights>

​​​​
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Old 2nd Feb 2024, 14:46
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EASA documentation and guidelines here:

easa.europa.eu/community/topics/all-weather-operations-0

PDFs at the bottom of the page.

3.6.3 CAT III
The new AMC2 SPA.LVO.100(b) ‘CAT III operations’ transposes the requirements for CAT III operations from the
existing AMC5 SPA.LVO.100. The equipment requirements and operating procedures have been moved to
SPA.LVO.105 and the aerodrome requirements to SPA.LVO.110.
The subdivisions of category III have been removed. The lowest DH values to be used for particular aircraft
installations will be described in the AFM. The reference to the type of roll-out systems used is included to allow
the determination of the appropriate RVR value based on the pilot’s need to be able to control the roll-out (the
certification requirements are described in CS-AWO). GM2 SPA.LVO.100(b) offers additional information about
which systems are required for certain DHs.
The lowest RVR for a DH between 50 and 100 ft (previously CAT IIIA) will be 175 m (previously 200 m) to be
aligned with the new ICAO standard for CAT IIIA. The provision for an RVR of 150 m for aircraft certificated as
‘super fail-passive’ is removed. 175 m will now be required for DHs down to 50 ft. It is understood that this
provision was applicable to a single aircraft type that is no longer in production.
As the equipment of super fail-passive has been demonstrated as suitable for use down to 150 m, operators
with such aircraft could consider applying for an AltMoC.
The minimum RVR for DH below 50 is 125 m in the current rules, based on a fail-passive roll-out system; this has
been retained but based on input from an aircraft manufacturer, a provision has been inserted to allow a
minimum RVR of 75 m where this has been demonstrated during the equipment certification process.
The new ICAO (Annex 6) definition: Category III (Cat III): a decision height lower than 30 m (100 ft) or no decision
height and an RVR less than 300 m or no RVR limitation; AWO Manual will talk about fail-passive and fail-
operational CAT III and the associated values similar to the European rules.
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Old 2nd Feb 2024, 21:26
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I am intrigued, increasingly concerned, as to why many views across Pprune start from a legal position.
Flying is about safety, thus the primary position is to consider if the proposed action is safe, then compare with the requirements.
In the very rare event the choice of violating the rules, then the safety view is a basis for legal defence, if there is an unwanted outcome.
Safety first - providing we understand what safety means.
A worthy debate, but elsewhere.


Airman, "It still leaves doubts in mind as it leaves one in the position where something can be legal, but doubtful as regards safety. Namely, a situation where the touch down zone RVR is ok but the mid point is below 125 in cases of a manual roll out or less than 75, leaving one wondering whether taxiing would be safe". A good point

From research and experience in the late 70s, the variation of RVR in stable, thick fog (Cat III) was rarely less than one measurable division i.e. 175 and 75 very unlikely. [n.b. in transition fogs, forming, and particularly dispersing conditions, > 250 m, Cat II, the range of reported values can be large and change quickly. ]

Re taxiing; 50 m (now 75) was taken as a limiting factor for fire rescue services.
Experimrnts showed that day taxing in 60 m was feasible with green centreline lights, but at night 150 m reported was increasingly difficult. The point being that these values of RVR cannot be equated: in the above examples the met vis 'what it is really like' was very low and sufficiently low to shut down road transport; taxi, bus, fire rescue, refuelling, etc.

Question; does the basis of EASA Cat III fail-passive still allow manual landing after system failure below DH ?

My experience has been with the certification of the first 'super fail-passive' Cat III operation (50ft DH - AVRO RJ), which depended on extended proof of concept, technical evaluation - flight and technical simulation, and human factors of cockpit view and height above the runway.
Assuming that recent advances in technology would reduce the frequency of system failure, changing flight deck view and height (the human aspects) to include larger aircraft might not reduce the overall risk.
But then, certification risk assessment is a black art, i.e. because something is less likely to happen - failure below DH, then the human issues should not be used to offset the overall risk (discuss the different viewponts with Boeing, FAA, (737), and EASA; the concerns about experience, training, #4, might indicate that EASA's judgement is ill founded).

A previously judged very low risk, but now in a very safe industry, still deserves thought; at least to provide some clarity of what was considered and the basis of the certification judgement.

The majority of operational situations have some component of risk, the uncertainty, and not having experience and confidence.

Based on the initial operations with the AVRO RJ, some landings violated the rules - land after failure below DH in restricted RVR. From the investigations these incidents identified a minor hardware fault - AP disconnect button set too high, thus 'white knuckling' pilots were more likely to inadvertently disengage the AP, and that their judgement to land was not a safety issue - 'it was obviously safe to land'.
Some of the previous research did indicate that humans may more capable than imagined by certification and testing, but not always; we do not know how this relates to the situations which pilots misinterpret
Safety, risk, is the amount of uncertainty to be managed.

Ask the question, but don't loose any sleep over the probability.

Last edited by safetypee; 3rd Feb 2024 at 06:41. Reason: Format
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Old 3rd Feb 2024, 01:44
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Originally Posted by safetypee
I am intrigued, increasingly concerned, as to why many views across Pprune start from a legal position.
Flying is about safety, thus the primary position is to consider if the proposed action is safe, then compare with the requirements.
In the very rare event the choice of violating the rules, then the safety view is a basis for legal defence, if there is an unwanted outcome.
Safety first - providing we understand what safety means.
A worthy debate, but elsewhere.
The reason for the legal first approach is due to the modern trend in the highly competitive environment of aviation of dispatchers and managers putting new regulations, schedulating practices, flight planning strategies etc. forward that would make any pilot sqeemish and then telling them 'but it's legal'. Pilots who speak up tend to be frowned upon as being undesirable, leading to cultures where we are second guessing ourselves and our innate instincts. The days of the commander being the final say in overall safety is being quietly usureped in favour of the bean counters and other so called experts.

As an example one of the major global airplane manufacturers just recently killed 300+ people in their drive for profits all while declaring their planes perfectly safe.

But yes, you're you're, we do what's safe and shouldn't worry about the consequences, it's our sworn 'and legal' duty.
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Old 3rd Feb 2024, 07:35
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Originally Posted by safetypee
Airman, "It still leaves doubts in mind as it leaves one in the position where something can be legal, but doubtful as regards safety. Namely, a situation where the touch down zone RVR is ok but the mid point is below 125 in cases of a manual roll out or less than 75, leaving one wondering whether taxiing would be safe". A good point

From research and experience in the late 70s, the variation of RVR in stable, thick fog (Cat III) was rarely less than one measurable division i.e. 175 and 75 very unlikely. [n.b. in transition fogs, forming, and particularly dispersing conditions, > 250 m, Cat II, the range of reported values can be large and change quickly. ]
It is a good point, however, there are two sides to the story here.

The approach itself is executed by an automated system that doesn't need external visibility. For all that matters, it can handle the approach in 0/0/0 conditions (with rollout guidance). The "non-normal" is a failure case of either the guidance system on the ground, or the system on the aircraft, where the pilot is to interrupt the approach and "get-out". The visibility requirement is there because of the human factor, who needs to provide some kind of confirmation. The 75m requirement to me has always been one of "the section of the runway where - at the expected speed - should be able to stop manually and evacuate safely".

The taxi "RVR" is a different ballgame. The decision making process is different, as nothing stops you from stopping, setting the parking brake, and requesting guidance when the provided guidance is not sufficient to you. We are talking visibility here, not RVR. Because yes, as you mentioned, ground traffic has limitations as well. I recall a landing down to the minimums with a dense bank of fog over the apron. It requires you to stop, request assistance and even request if the guy on the ground in his car needs you to put on the lights so he can see you and not drive into your engine or gear... and the safety report will be your a answer to management and authorities, which in turn might change things around the airport. But the main ”get-out" here for you as a PIC is to stop and set the parking brake. Even on the runway if you feel you need to.

Last edited by BraceBrace; 4th Feb 2024 at 07:00.
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Old 20th Feb 2024, 06:24
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Originally Posted by the_stranger

However, for aircraft manually controlled during ‘roll-out’ EASA recommends the following RVRfor the MID and/or END:
<A table with rvrs depending on available lights>

​​​​
After further clarification this seems to be the correct answer. Unfortunately the table you reference was not inserted into the post. But here it is



Im assuming, and correct me if I'm wrong, the simplest way to find out the runway equipment is to look at the Jeppesen 10-9A chart for the lowest available RVR for low vis take off minimum, which will correspond to the RVRs in the table.

On a separate note, can we assume that auto rollout is authorized on a CAT2 or CAT3 fail passive only equipped runway? Or does the runway need to be CAT 3 fail operational to use auto rollout? Or is this aircraft dependant?
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