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che ci dō che ci dō!
20th Mar 2009, 14:07
Hi everybody,

let's say one has to take off from a runway equipped with runway edge and center line lights and the reported RVRs are as follow:
A 150m, B 150m, C 50m
Somebody says it's possible to disregard point C provided I can demonstrate through performance calculation that in case of RTO the airplane can come to a complete stop well before the end of the runway (?!?)
As far as I know, according to appendix 1 to Eu-ops 1.430, when the RVR is below 200m ALL the RVR readings (A+B+C) must be available and above the applicable take off minima. Only exception for point A for which pilot assessment is allowed, therefore point C has to be taken always into account.

Is the above interpretation correct or do I miss anything?

spin_doctor
20th Mar 2009, 15:25
Take off ban

Take off not permitted unless:

TDZ RVR - Above minima
MID RVR - Above minima if reported
STOP RVR - ABove minima if reported and if specified in AOM

elpiloto
26th Mar 2009, 21:50
Somebody says it's possible to disregard point C provided I can demonstrate through performance calculation that in case of RTO the airplane can come to a complete stop well before the end of the runway (?!?)

Yep. If the ASDR is short enough that you'll stop before entering the last segment of the runway, then the last RVR can be disregarded as it's not relevant.

I think the key is in the wording... "The required RVR value must be achieved for all of the relevant RVR reporting points with the exception given in Note 3 above" - Appendix 1 to EU-OPS 1.430 (Note 3 being the bit about pilot assessment at the start of the runway)

FE Hoppy
27th Mar 2009, 00:04
(4) Exceptions to paragraph (a)(3)(i):
(i) subject to the approval of the Authority, and provided the requirements in paragraphs (A) to (E) have been
satisfied, an operator may reduce the take-off 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.
(ii) Subject to the approval of the Authority, an operator of an aeroplane using an approved lateral guidance
system for take-off may reduce the take-off minima to an RVR less than 125 m (Category A, B and C aeroplanes)
or 150 m (Category D aeroplanes) but not lower than 75 m provided runway protection and facilities
equivalent to Category III landing operations are available

it's note 4 in the table and Item E as stated above. If your ASDR is less than 2/3 of the runway then the 3rd reporting point is not relevant to your take off.

PGA
27th Mar 2009, 10:03
You have to have a 90M visual segment from the FD if the RVR is reported as 125M.

The note about replacing the RVR with pilot assessment is only applicable when the RVR is above 150M me thinks.

Henry VIII
27th Mar 2009, 12:15
The note about replacing the RVR with pilot assessment is only applicable when the RVR is above 150M me thinks.That's correct.
elpiloto and FA Hoppy as well.

spin_doctor
28th Mar 2009, 11:11
Quote:

Yep. If the ASDR is short enough that you'll stop before entering the last segment of the runway, then the last RVR can be disregarded as it's not relevant.

I think the key is in the wording... "The required RVR value must be achieved for all of the relevant RVR reporting points with the exception given in Note 3 above"

Relevant meaning:

TDZ
MID where reported
STOP where specified in AOM

I've never yet sat and calculated my ASDR in order to determine whether I'll be airborne before the last third of the runway....

FE Hoppy
28th Mar 2009, 21:29
Tables published in the E170-190 AOM make it very easy.

Henry VIII
29th Mar 2009, 02:15
I've never yet sat and calculated my ASDRSo, doctor, till now you never knew if you remain within the runway in case or RTO ? :eek:

spin_doctor
30th Mar 2009, 11:50
Henry VIII

I think it's pretty clear from my post that I was refering to the practice of calculating the exact point of rotation in order to work out whether or not you need the STOP RVR. I don't, because you don't need to.

Do I calculate the performance prior to take off to determine the relevant speeds/flex thrust settings, well obviously, duh!

Checkboard
30th Mar 2009, 13:40
spin doctor - it's not about continuing the take-off, it's about being able to see the runway if you are stopping. No requirement to calculate the rotation point.

Henry VIII
30th Mar 2009, 18:34
Checkboard already replyed for me.
Nothing to add.

spin_doctor
30th Mar 2009, 21:02
OK, lets see if I understand this right:

The take off ban requires that only TDZ RVR is above minima, but obviously this only applies if you know you are going to get airborne. If you are planning an RTO then you need STOP RVR above limits too.

Is that what you're saying?

elpiloto
31st Mar 2009, 00:06
It's not a question of whether you'll be airborne by the last third of the runway. If you're airborne, you won't need to see anything!

The question is, if you had an RTO just before V1 could you see enough to stop within the first 2/3 of the runway? If yes, then you can disregard the last RVR value as it's not relevant to your takeoff. It won't matter if you can't see two feet in front of you for the last third of the runway as you'll have stopped by then anyway.

For that matter, I suppose you could disregard the middle RVR value as well if your ASDR was somehow shorter than 1/3 of the runway length?

spin_doctor
31st Mar 2009, 14:50
Sorry guys, I just don't agree.

Our manuals clearly state I can take off in LVP's as long as the TDZ RVR is above limits. We need the MID RVR above limits too, but ONLY IF IT IS BEING REPORTED, otherwise its not a requirement. The STOP RVR is not a requirement on any take off, ever, unless it is SPECIFICALLY STATED in the AOM.

Since the Captains assessment of the RVR can be used at the TDZ end, I can, in fact, take off in LVP's with NO RVR's being given whatsoever.

You can interpret the rules all you like, it's there in black and white in my manuals. That's all we need.

Henry VIII
31st Mar 2009, 16:13
You can interpret the rules all you like, it's there in black and white in my manualsWe are not interpreting rules, they are clever enough.

Manuals are usually produced accordingly to the rules, interpreting any possible nuance of the greys areas to obtain some operational advantages.
Consider that what your manuals state could be not only on the edge of the rules, but beyond.

spin_doctor
31st Mar 2009, 20:26
Well, since all UK airlines' operating procedures are approved by the CAA, they must have missed this bit. Shame they don't have your experience and knowledge.

Think I'll stick with it though, but good luck calculating the ASDR next time it's foggy.

oligoe
1st Apr 2009, 20:17
I fully agree with PGA, the fact RVR can be replaced by pilot assessment has nothing to do with the "90m visual segment from the cockpit". But the pilot can assess the RVR himself and has to make sure it is above his requirement (125m or whatever...).

About the stop end RVR, you wouldn't always calculate your ASDA in relation to the stop end RVR, but if you take off with a light turboprop on a 4km runway i don't think it's relevant

Henry VIII
2nd Apr 2009, 10:37
Of course this is a different matter related to this thread, anyway the relations btw companies and CAA to obtain manuals approval are limited to the following 2 steps :
1- Submit manuals draft.
2- After a certain period of time consider the manuals approved according to the rule of silence.
Deeply investigations only in case of brand new company ops, such as etops or whatever.
Experience and knowledge are not required to know that.

Back on topic, be sure I perform my ASDR calculation all the time I go on to TO. Foggy or SKC.if you take off with a light turboprop on a 4km runway i don't think it's relevant For this reason, according to Jaa, stop end RVR is not required ;)