"LVPs in force"

[Tandemrotor]

Anybody help me with this relatively simple question.

In low visibility (eg: RVR 75-150m) is there a portion of JAROPS (or any other document) dealing specifically with whether a captain's assessment of visibilty, made from the flight deck prior to departure, can override the promulgated RVR for the touchdown zone?

A quote, and the reference would be really helpful, thanks.

[Brian81]

Hi TandemMotor.

With ref LVP's (in the UK).

Check out MATS (part 1) Section 7, Chapter 1, Paragraph 3.1 (phew...)

That gives brief details, (and Im quite new to this game, so my apologies if Im incorrect).

As I understand it, the broadcast made from the tower or on the atis contains the figures that ATC would quote each time it is required, (eg - pre take off roll, approach, landing etc)... However, if a pilot observes the situation to be WORSE than what is being broadcast the official RVR quote will be FOLLOWED with "Unofficial observation from a departing A/C at time (xx) was RVR x,y,z."

As I understand, we're not allowed to just change the broadcast, but we are allowed to add the "unofficial observation" thing to it.

Hope this helps.

Bri. :ok:

[brimstone]

Tandemrotor - I'm not a pilot so this reply comes with a health warning.

Appendix 1 to JAR-OPS 1.430 Aerodrome Operating Minima contains a note in the "RVR/Visibility for take-off" tables that says;

The reported RVR/Visibility value representative of the initial part of the take-off run can be replaced by pilot assessment.

This is a long and complex subject so you must read all of it.

[Captain Airclues]

Tandemrotor

My interpretation of APP1 to JAR-OPS 1.430 (h)(l) as mentioned by brimstone has always been that the reported TDZ RVR must be above minima unless the pilot assesses it to be lower in which case he cannot depart. However if the TDZ RVR isn't available then he can replace it with his own assessment. Some people interpret the rule as meaning that the pilot can go if he assesses the RVR to be above limits. However I would hope that he had a good lawyer if things went wrong
I don't have the relevant manual with me so can't be sure who is correct, but in pracical terms I would not want to take-off if I couldn't see the minimum number of required lights.

Airclues

[brimstone]

Captain - yes but the next bit "Note 4" which deals with the facility of having multiple RVR information says:

The required RVR values must be achieved for all the relevant RVR reporting points with the exception given in Note 3 above.

My understanding of that statement is that the RVR value for the initial part of the take-off run ie the Touchdown RVR does not need to be achieved but may be replaced by pilot assessment.

I repeat I am not a pilot and fortunately do not have to make such judgements.

[Tandemrotor]

brimstone et al

I am very grateful for your help. This is exactly the point that I want to clarify. I have worked for two seperate (though related) airlines with differing views.

One agreeing with Captain Airclues, one agreeing with brimstone.

Any further thoughts would be very much appreciated.

Thanks again.

[Captain Airclues]

brimstone

I think that you are probably correct. However, if I were to have an incident while taking off when the reported RVR is below minima then I would start being very very nice to Flying Lawyer. Hence my own personal view on the matter.

Tandemrotor

Have just dug out my old copy of BA FCOs (yes, I know that I should have handed them in!). FCO 725 states that take-off is not permitted if either the RVR as assessed by the captain or the reported TDZ RVR is below minima. However it later states that pilot assessment always overides the reported RVR. That last statement tends to support brimstones view. However, the first statement particularly the word 'either' tends to support my view. I think that even Flying Lawyer might have a problem with this one.

Airclues

[lucky luke]

We had this in ATPL theory course. Reported RVR values are valid, but the pilot can make his own assesment of the visibility and then make a go/no-go decision based on his own judgement.

[Tandemrotor]

Captain Airclues

Thanks. FCO725 has not changed, and is obviously quite categorical. However the same information transposed to a related operator's manual has a subtly different hue.

Which is why I would like to trace the source document.

Lucky Luke

Can you remember any supporting reference from your ATPL theory?

Thanks again guys.

[Right Way Up]

The difference comes down to your takeoff minima. Above 150m touchdown RVR maybe be overriden by pilot assessment. However for those cleared to takeoff below 150m RVR, the RVR must be satisfied by RVRs above minima for all zones, AND be confirmed by pilot assessment.

[Tandemrotor]

Right Way Up

and where is this written?

[Right Way Up]

The first reference for takeoff above 150m RVR is in JAR 1.430 Table 1 note iii)
"The reported RVR/Visibility value
representative of the initial part of the
take-off run can be replaced by pilot
assessment."

The reference regarding takeoffs below 150m is in JAR 1.430

"(4) Exceptions to sub-paragraph (a)(3)(i)
above:
(i) Subject to the approval of the
Authority, and provided the requirements in
paragraphs (A) to (E) below have been
satisfied, an operator may reduce the takeoff
minima to 125 m RVR (Category A, B
and C aeroplanes) or 150 m RVR (Category
D aeroplanes) when:
(A) Low Visibility Procedures
are in force;
(B) High intensity runway
centreline lights spaced 15 m or less
and high intensity edge lights spaced
60 m or less are in operation;
(C) Flight crew members
have satisfactorily completed training
in a [Flight] Simulator [ ];
**(D) A 90 m visual segment is
available from the cockpit at the start
of the take-off run; and
(E) The required RVR value
has been achieved for all of the
relevant RVR reporting points." **

Reference
http://www.jaa.nl/section1/jars/443844.pdf

[Tandemrotor]

Right Way Up

Thanks very much. You certainly seem to know the subject.

One final question, could you explain to me in words of one syllable what exactly is meant by the phrase;

"A 90m visual segment"

Or is there an actual definition written down?

Once again very many thanks.

[DFC]

There are a number of issues here.

A "Low visibility take-off" is a take-off on a runway where the RVR is les than 400m

So when the RVR is at least 150m but less than 400m, LVPs must be in force (there are certain rules for non-CAT 3 airfields).

In this case, the reported RVR/VIS of the initial part of the take-off run can be replaced by pilot assessment. Thus if the reported RVRs are 100m/150m/150m and required RVR is 150m then provided the pilot when lined up can see the required 150m, the requirements have been met.

The midpoint and stop-end RVRs can not be replaced by pilot assessment because if you could see that far from the threshold then LVPs would not be in force!

---

Subject to approval from the authority the minimum RVR can be reduced to 125m for CAT A,B and C.

In this case the requirements were as described by Right Way Up.

The required RVR value must be achieved for all the relevant RVR reporting points ( no substitution allowed); and

A 90m visual segment must be available from the cockpit at the start of the take-off run - This means that with RVRs of 125/125/125, when lined up the pilot must be able to see at least 6 runway centerline lights (15m spacing) before commencing take-off.

I believe that the idea is to prevent take-off where for example the fog is thicker on parts of the runway than at the RVR sensors or to allow for the fact that the B747 pilot may be up in the very low cloud while the citation pilot is below and can see further.

I remember Gatwick's RVRs sensors being very close to the ground and reporting very low RVRs when the fog only reached half way up the aircraft legs!!

Regards,

DFC

[Max Angle]

I remember Gatwick's RVRs sensors being very close to the ground and reporting very low RVRs when the fog only reached half way up the aircraft legs!! The other side of the coin is that airfields that have very tall control towers often have to go into LVPs because ATC are in the clouds whilst everyone at ground level can see quite clearly. Seen it happen at AMS a few times, perhaps time to draw a halt to the "mines taller than yours" competition that seems to be going on at the moment before they build the new one at LHR.

[swish266]

My company's AWOPS reads:
"The required RVR must be achieved for all of the relevant RVR reporting points. However the reported RVR of the initial part of the take-off run can be replaced by pilot assesment."
We are "JAR-compliant". Min for t/o is 150/150/150.

Ready

I don't know what type r u flyin, but it might have to do something wit d "fail-operational" and "fail-passive" conditions of an AFDS.

[GK430]

IRVR's will be a matter of record.

How will what you determine from the cockpit become a matter of record?

[DFC]

The visibility from the cockpit can be recorded;

1. On the Operational flight plan;

2. On the CVR; and

3. Via the R/T to the tower.

I would always use 3 because, it is a doubble edged sword - We are telling the tower that the actual conditions are different from the reported RVR and this could be because they are better or they are worse, and in the case of the 90m visual segment - if only just get it or fail to get it when the reported RVR is 125m, the following landing aircraft and departing aircraft might welcome this information. (R/T tapes are stored for 30 days along with strips).

Anyway provided that the procedure is complied with, how would the CAA prove that the visial segment did not exist?

There is an approach ban procedure - Is there a take-off ban?

Regards,

DFC