RVR requirements

[longobard]

JAR OPS are rather unclear on this matter.

It says that RVR min values for mid and stop end point are 125m (75m with roll out guidance) and 75m respectively. If not relevant can mid and stop and values be disregarded even if lower than the above values ?

thanx!

[A Very Civil Pilot]

I think it's to do with LDA. If you have a long runway, you'll have most of the landing over in the 1st 1/3. On a short one, you'll still be going reasonably fast in the 2nd 1/3, so the 125 m will be limiting (and so on to the last 1/3)

[baby hormones]

Hi,

The term relevant is usually type specific and can be found in the a/c Part B.
Relevant= The runway used before the aircraft is below 60 knots.
Further the company SOP is as follows:
Runway length:

3000m and above= Only take touchdown zone as limiting
3000m-1500m= Touchdown and mid-point
1500m and less= Obviously you take all three.
Like I said this can be type/ company specific though.

Hope this helps

baby.

[Pilot Pete]

Relevant is as pointed out (during the 'high speed' portion of the landing roll (regarded as above 60kts)). Best thing to do is look at how long your landing roll will be (from your performance charts) and then you can work out if you are going to be in the 'mid' or 'stop' end portion for the runway you intend to land on. If you will be then they are controlling, just as the T/D zone is.

On the 737 we check the autobrake stopping distance for the configuration and decide on a setting suitable for the conditions. Many factors can come into it, but for instance if the stop end was out of limits (if it were controlling), then we may be able to up the autobrake setting to pull up quicker and hence not enter the stop end and thus be able to disregard the stop end RVR and therefore be able to make a landing on said runway!

Hope this helps.

PP