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LVO and 90m visual from cockpit A320 question.

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LVO and 90m visual from cockpit A320 question.

Old 28th Nov 2018, 20:11
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LVO and 90m visual from cockpit A320 question.

Hello all.

Iíve heard differing answers to these so wondering if I can get any clarity here.

In in the sim and performing LVTO with HIRL and 15m centreline light spacing minima RVR125m. On take-off rvr given by atc is 1st segment not working then 125/125 for mid and stop end. Our manual says ĎRVR value representative of initial part of take off run can be replaced by pilot assessmentí. How many centre line lights do I need to see in from of me? Is it 6 lights ( I.e 90m visual segment from cockpit which my aircraft complied to) or 8.3 lights to give me the 125m?

Lastly before approach ban point you are doing a Cat 3a approach with minima 200/125/75. Then twr give you TDZ RVR is NA/125/75. For cat 3a you need 2 RVR readings avail. Is it legal to complete the approach? The mid and stop are reported and controlling and at or above minima. Or do I need the TDZ RVR minima for the mid i.e NA/200/75.

Also what is meant by controlling RVR?

Thanks,

Mooneyboy

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Old 28th Nov 2018, 20:51
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1 - As far as I am aware, you can’t do a take off at 125m without the RVR working, so the lowest vis is 150m for take off, therefore you need to see 10 lights at 15m spacing.

2 - one RVR can be missing, therefore you can make the approach, if you can see what you need to see, land, if you can’t see what you need to,go around.
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Old 28th Nov 2018, 23:22
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My interpretation is the 90 meters is an aircraft design issue, and with correct seat position you can see at least 90 meters
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Old 29th Nov 2018, 08:09
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One one hand CATII/III requires a RVR of not less than 300/200 m on the first segment of the runway.
On the other, on runways equipped with two or more RVR assessment units, one may be inoperative.
Tricky one, but since the table with inoperative equipment does not specify which RVR may be inoperative, you can do the approach as I see it.

For take off you can replace the RVR for the initial part of the take off run with pilot assessment.
I see that as 6 lights = 90 meters and off you go. This is simulator stuff.
If you happen to do this in real life and somebody ask you how many lights you saw? Say 10. Impossible to check.
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Old 29th Nov 2018, 09:01
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You need 200 tdz, 75,75?
if tdz is inop I would think mid could substitute but would need to be at least 200 rvr at least before the approach ban/ FAF
(at least my guess?)
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Old 29th Nov 2018, 13:44
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Originally Posted by casablanca View Post
You need 200 tdz, 75,75?
if tdz is inop I would think mid could substitute but would need to be at least 200 rvr at least before the approach ban/ FAF
(at least my guess?)
Yes, or if we are in simulator thinking mode, what if the runway is 3600 m long and you use max manual braking and stop on the first third of the runway?
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Old 29th Nov 2018, 16:00
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Hi and thanks for the replies.

Lets say your in A320 avg pax/payload 2hr flt on 2000m RWY ( you need all 3 segments).

The example I gave was approach minima without Rollout but as correctly pointed out with rollout a cat3a minima is 200/75/75. It seems to be the consensus that the mid point RVR minima has to equal the TDZ RVR so you would need at least NA/200/75 and not NA/125/75 to make an approach ( no rollout) from above approach ban?

How does the 90m visual segment relate to RVR. Is it basically saying that if you can see 90m in front then this would equate to 125m RVR?

Thanks

Mooneyboy
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Old 29th Nov 2018, 16:21
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The visual segment requirements of 90m has nothing to do with replacing the RVR for the initial part of the take off run and everything to do with being able to takeoff with an RVR of 125m. i.e. IF you have LVPs in force, you are suitably trained, the runway is certified for takeoffs at 125m (15m HIRCL 60m HIREL and multiple RVR information-must be working for all relevant sections of the runway) AND 90m visual segment is available from the cockpit at the start of the take-off run, then you can go.

The ability to replace the initial RVR is for cases where the RVR is reported to be below whatever the limit is for your takeoff, whether it’s 500m for a runway with no lights or 125m. In those cases you can line up and make an assessment. It could be that you can see, for instance, an intersection down the runway that is more than 500m away in the 1st case, or it could be that you count 8 lights if need 125m.
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Old 29th Nov 2018, 16:34
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It
Originally Posted by Mooneyboy View Post
Hi and thanks for the replies.

Lets say your in A320 avg pax/payload 2hr flt on 2000m RWY ( you need all 3 segments).

The example I gave was approach minima without Rollout but as correctly pointed out with rollout a cat3a minima is 200/75/75. It seems to be the consensus that the mid point RVR minima has to equal the TDZ RVR so you would need at least NA/200/75 and not NA/125/75 to make an approach ( no rollout) from above approach ban?

How does the 90m visual segment relate to RVR. Is it basically saying that if you can see 90m in front then this would equate to 125m RVR?

Thanks

Mooneyboy
You donít replace the TD with midpoint anymore if the TD RVR is missing (in EASA land anyway). You used to do that but it was removed years ago. For CAT3B (no DH) you just one reading on the aerodrome, it could be on another runway a mile away....
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Old 29th Nov 2018, 16:45
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EGPFlyer,

with regards to the loss of an RVR reading, for CAT 2 and CAT 3A Ops EASA just says that if the runway has 2 or more assessment units then 1 can be INOP. So by that the TD RVR could be INOP, honestly can’t find a reference to whether the midpoint can/can’t be used instead (as long as it’s above the original TD minimum RVR).

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Old 29th Nov 2018, 16:51
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Originally Posted by Dct_Mopas View Post
EGPFlyer,

with regards to the loss of an RVR reading, for CAT 2 and CAT 3A Ops EASA just says that if the runway has 2 or more assessment units then 1 can be INOP. So by that the TD RVR could be INOP, honestly canít find a reference to whether the midpoint can/canít be used instead (as long as itís above the original TD minimum RVR).

I agree, thereís nothing in the EASA regs that say what to do with your remaining RVR value. Dare I say that common sense might come into play?
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Old 29th Nov 2018, 16:54
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Ay-up, common sense and EASA in the same sentence!?

You’re quite right though, just asking in case I’ve missed another angle to this scenario. EASA Ops says 1 can be INOP, and a the same time TD RVR is always controlling. However, it can’t be controlling if INOP (common sense again).
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Old 29th Nov 2018, 17:26
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Yes Iím in EASA land ( well until 29th Mar but thatís a different topic).

Ive heard of the situation of cat3b letís say AMS 18R you could use 1 RVR on 27 as itís same Aerodrome.

Thanks I think I now understand the 90m segment.

My ops manual says ĎThe touchdown RVR is always controlling for all instrument approachesí. However and this maybe the change that came in a couple years ago it then says ĎIf reported and relevant, the mid point and and stop end are also controllingí.

Does this imply if the TDZ rvr is not working then the mid point is now relevant and controlling? So if not using rollout you would need the 125m mid point as this is now controlling. Is this the right logic?
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Old 29th Nov 2018, 18:09
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Its relevant if you are planning to use it. You may only need 2000m of a 3000m runway. A suitable selection of autobrake might resolve a below limit stop-end rvr.
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Old 29th Nov 2018, 21:04
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Unhappy

I fail to see the funny side of the jokes here. Good riddance, google Getting to Grips with LVO you lot. It is written for pilots, should be easier to comprehend than the regulations thatís been turned to marmalade here.
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Old 30th Nov 2018, 05:59
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Originally Posted by FlightDetent View Post
I fail to see the funny side of the jokes here. Good riddance, google Getting to Grips with LVO you lot. It is written for pilots, should be easier to comprehend than the regulations thatís been turned to marmalade here.

How does a document, written in 2001, referring to JAA regulations help with EASA LVO regs?

Itís a great document, however it is out of date so caution is needed.
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Old 30th Nov 2018, 14:16
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It helps once you read it. It has all the information needed for the scope of this thread.

Except for a re-definition of the approach-ban point, nothing has changed with regards to LVP.

@Mooneyboy: The 90 m visual segment is not something you should assess by yourself for take-off. It is a design geometry issue, to be sorted out during your LVTO approval with local CAA.

Last edited by FlightDetent; 30th Nov 2018 at 20:29.
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Old 30th Nov 2018, 15:14
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Originally Posted by CAT.OP.MPA.305 Commencement and continuation of approach

(f) The touchdown zone RVR shall always be controlling. If reported and relevant, the midpoint and stopend RVR shall also be controlling. The minimum RVR value for the midpoint shall be 125 m or the RVR required for the touchdown zone if less, and 75 m for the stopend. For aircraft equipped with a rollout guidance or control system, the minimum RVR value for the midpoint shall be 75 m.
Originally Posted by GM1 CAT.OP.MPA.305(f) Commencement and continuation of approach - EXPLANATION OF THE TERM ‘RELEVANT

‘Relevant’ in this context means that part of the runway used during the high-speed phase of the landing down to a speed of approximately 60 kt.
Originally Posted by AMC1 SPA.LVO.100 Low visibility operations LVTO OPERATIONS – AEROPLANES

For a low visibility take-off (LVTO) with an aeroplane the following provisions should apply:
(a) for an LVTO with a runway visual range (RVR) below 400 m the criteria specified in Table 1.A;
(b) for an LVTO with an RVR below 150 m but not less than 125 m:
  • (1) high intensity runway centre line lights spaced 15 m or less apart and high intensity edge lights spaced 60 m or less apart that are in operation;
  • (2) a 90 m visual segment that is available from the flight crew compartment at the start of the take-off run; and
  • (3) the required RVR value is achieved for all of the relevant RVR reporting points;
Note well:
- the provision to "replace" the foremost RVR readout only exists as a note to table 1A, which does not come in play for LVTO 149-125 m. The idea it might apply to landing is grave lunacy.
- the requirement of 90 m visual segment stands for LVTO 149-125 m, where substitution of the measured RVR value is not allowed.
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Old 30th Nov 2018, 19:53
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Thanks flight detent. I found the document getting to grips with LVO. Itís a shame itís not more updated like the cold weather one. Itís a good document to have. Especially like the diagram explaining the 90m segment. As you say most major difference to now is the approach ban point.

Thanks for the info.

Mooneyboy
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Old 30th Nov 2018, 20:21
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Pleasure, be assured my aggravation was not pointed at you. When I read the Co. manual for the first time, I couldn't make any sense of it. Reviewing it after an explanation was somewhat more successful.

The first part's RVR may only be replaced by an assessment for LVTO 400-150 m. The 90 m segment is a required characteristic for 150-125 m, and no replacing or substitution is allowed. Such has been the case for long decades, irrespective of the fact that many very large airlines have been teaching their pilots the nonsense of counting lights for ages.
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