POINT "B" RVR if "A" is missing

[LEM]

I remember from a previous company that we are legally allowed to use point "B" RVR for landing if "A" is missing (it must be at least equal to what would have to be A), but now I can't fing the written source.

Can anyone confirm this?

[towser]

Company i work for , if the touchdown RVR is not available then you may substitute it with the midpoint. In other words what you are saying!

[Miserlou]

I've never seen any regs permitting the absense of touchdown zone RVR. Our SOP says we must have required RVR at all relevant points. Touchdown zone is ALWAYS a relevant point but mid-point maybe reduced and stop-end disregarded.
Thus, for a long runway, touchdown shall have the required RVR and, as the speed will be much reduced by the midpoint, this RVR may be reduced and the stop-end disregarded because it is in excess of the required runway length.

What airport were you thinking about LEM and what company?

[dartagnan]

mid point can be reduced but:

rvr mid point can not be less than half A point (for taxi)

[Clandestino]

we are legally allowed to use point "B" RVR for landing if "A" is missing

Where I fly point A is everything. Point B may be half of whatīs availlable on A. C (and eventually D like in MUC) may be inop. From my short experience of LVOs, sometimes RVRs are bound to fluctuate wildly and independently, from point to point. So while it may be legal in some areas, wise it is not.

[tired]

My (JAA) Ops Manual allows touchdown zone RVR to be replaced by midpoint RVR if touchdown is not available. Midpoint RVR is not required, except in the US.

[None]

The FAA (USA) says...

While CAT I ILS operations permit substitution of
midfield RVR for TDZ RVR (when TDZ RVR is not available),
CAT II ILS operations do not permit any
substitutions for TDZ RVR. The touchdown zone
RVR system is required and must be used. Touchdown
zone RVR is controlling for all CAT II ILS operations.
This link will allow you to read it for yourself
http://www.faa.gov/library/manuals/a...%20CH%2005.pdf

[LEM]

My (JAA) Ops Manual allows touchdown zone RVR to be replaced by midpoint RVR if touchdown is not available. Midpoint RVR is not required, except in the US.

Ok, for the first sentence, that seems to be confirmend.
Regarding the second part, let's say poit B is not necessary if not available.
If reported, it MUST be above minima (125mt jar).

[tired]

"If reported, it MUST be above minima (125mt jar"

Not quite - if reported it must be >150m unless the TDZ minima are <150, in which case midpoint must be >TDZ minima

As always, this is a company-specific Ops Manual, it may well differ between companies.

[Clandestino]

Hey, I can do ILS approach with no reported RVR at all!

But then Itīll be CAT I strictly with reported vis at least 800m.

So are we talking here about CAT II/III or CAT I?

[Engineer]

LEM
It is stated in

Section 2 of JAR OPS 1 Subpart E. AMC OPS 1.430(b)(4) Effect on Landing Minima of temporaily failed or downgraded Ground Equipment Table 1A

Unfortunately if you visit the JAA website and look at JAR OPS-1 the only part that is accessible is Section 1. To view Section 2 which deals with Acceptable means of compliance(AMC) and Interpretative and Explanatory Material(IEM) you will have to buy the JAR OPS book

[TopBunk]

I think it is important to point out that there are different rules in different countries also.

JAR-Ops requirements differ from USA differ from Canada, for example.

The rules can vary markedly as to what RVR's are required / controlling / advisory in different conditions and what subsitutions are allowed.

It is a complex subject for which one of out skippers has produced a quick reference guide for on the day use. I don't have copyright or I would have posted it.

[Engineer]

With reference to FARs then the same criteria applies:

For Category III landing minimums below RVR600 (175 meters) using fail-operational rollout control systems, the Touchdown Zone, Mid, and Rollout RVR reporting systems are normally required and are controlling for all operations. If one of these RVR reporting systems is temporarily inoperative, these operations may be initiated and continue using the two remaining RVR reporting systems. Both RVR reports are controlling.

This can be found in the FAA Advisory Circular AD120-28D Appendix 7. (Unlike JAA you can view this one for free ) Canada will have a similiar quote and it should be found in one of the ICAO Annexes (6 could be a good starting point)
No matter if you are American or European the bottom line is when it comes to safety there cannot be that much difference in operating procedures
In my opinion it is not that complicated it just takes up a lot of reading time

[FlapsOne]

JAR OPS AMC has the answer.

If the TD RVR is unavailable the MID RVR may be used to substitute but must meet the TD requirements. The TD RVR is always controlling.

As to what RVRs are acceptable under JAR OPS - welcome to the confusion of JAR!

In essence from the JAR OPS table (but with some variation avail!)

Cat 1 550m/
Cat 2 300m/125m/75m
Cat3a 200m/125m/75m
Cat 3b 75m/75m/75m

Mid RVR may be reduced to 75m with serviceable rollout guidance
Mid and Stop end only if reported and relevant (=<60 kts in that sector)

That's how I read it - as I say there are slight variations for other conditions but those are the minima.

JAR-OPS 1.405

(f) The touch-down zone RVR is always
controlling. If reported and relevant, the mid point
and stop end RVR are also controlling. The
minimum RVR value for the mid-point is 125 m or
the RVR required for the touch-down zone if less,
and 75 m for the stop-end. For aeroplanes equipped
with a roll-out guidance or control system, the
minimum RVR value for the mid-point is 75 m.