Hello all.

I’ve 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 ‘RVR value representative of initial part of take off run can be replaced by pilot assessment’. 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

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.

My interpretation is the 90 meters is an aircraft design issue, and with correct seat position you can see at least 90 meters

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.

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?

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

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.

ItYou don’t 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....

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).

I agree, there’s 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?

Yes I’m in EASA land ( well until 29th Mar but that’s a different topic).

Ive heard of the situation of cat3b let’s say AMS 18R you could use 1 RVR on 27 as it’s same Aerodrome.

Thanks I think I now understand the 90m segment.

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

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?

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.

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 that’s been turned to marmalade here.

Thanks flight detent. I found the document getting to grips with LVO. It’s a shame it’s not more updated like the cold weather one. It’s 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