approach ban question(s)

[The People's Pilot]

i know this has been hit on the head a lot recently but i had a couple of specific examples that i wanted to clarify:

- assume 704 without ops spec.
- rwy cap advisory vis: 1 RVR 50
- therefore vis report = 3/4 RVR 40 (75% of CAP)
- assume u have not passed faf inbound
- airport is south of 60N latitude


WOULD APPROACH BE AUTHORIZED under these scenarios? (if so, why?)...

scenario#1

- reported RVR 3000
- grd vis fluctuating 1/2sm - 1sm

scenario#2

- reported RVR 4000
- grd vis 1/4sm

thanks for your help.

[Aeros]

i know this has been hit on the head a lot recently but i had a couple of specific examples that i wanted to clarify:

- assume 704 without ops spec.
- rwy cap advisory vis: 1 RVR 50
- therefore vis report = 3/4 RVR 40 (75% of CAP)
- assume u have not passed faf inbound
- airport is south of 60N latitude


WOULD APPROACH BE AUTHORIZED under these scenarios? (if so, why?)...

scenario#1

- reported RVR 3000
- grd vis fluctuating 1/2sm - 1sm

NO -- "An RVR report will take precedence over a runway visibility report of a ground visibility report." In this case the RVR is less than that required for the approach. The RVR will trump the ground visibility report. If there had not been an RVR report then you would have been OK.

scenario#2

- reported RVR 4000
- grd vis 1/4sm

YES -- As above, the RVR report will take precedence. Since the RVR is greater than you require you are OK to fly the approach.

That's my take on the rules.

[tired of the ground]

In case 1 the only caveat would be local phenomena. If there was something that would make the RVR inaccurate you could continue the approach with the reported VIS fluctuating like that.

[TopperHarley]

In case 1 the only caveat would be local phenomena. If there was something that would make the RVR inaccurate you could continue the approach with the reported VIS fluctuating like that.

I would disagree. CAR 704.37.2(d) states that the viz has to be equal to or greater than the viz in the CAP (not the 75% value, but the CAP advisory value). So the viz would have to be steady or greater than 1sm for you to be able to continue the approach in scenario 1.

The RVR however can be fluctuating above and below the specified value, according to 704.37.2(d)(ii).

http://www.tc.gc.ca/CivilAviation/Regse ... m#704_37_1

[YWGVOR]

1) NO 1 RVR 50 needs greater than 3/4SM or RVR or Rwy Vis 4000
RVR wins the battle

2) YES RVR wins the battle

[full_throttle]

difficult to understand that car, where does the 75% come from?

[Benwa]

Here's what I understand

704.37 (1) For the purposes of subsections (2) to (4), the visibility with respect to an aeroplane is less than the minimum visibility required for a non‑precision approach, an APV or a CAT I precision approach if, in respect of the advisory visibility specified in the Canada Air Pilot and set out in column I of an item in the table to this section,

Okay, from the looks of it, we need to refer to a table.

TABLE
APPROACH BANS‑VISIBILITY

Column I.......................................Column II
Canada Air Pilot Advisory Visibility....Visibility Report
SM - RVR (feet)...............................SM - feet
1/2 - 2600.......................................1/4 - 1200
3/4 - 4000.......................................3/8 - 2000
1 - 5000..........................................1/2 - 2600
1 1/4...............................................5/8 - 3400
1 1/2...............................................3/4 - 4000
1 3/4................................................1 - 5000
2......................................................1 - 5000
2 1/4................................................1 1/4 - 6000
2 1/2................................................1 1/4 - Greater than 6000 don't ask why the difference with above ???
2 3/4................................................1 1/2 - Greater than 6000
3......................................................1 1/2 - Greater than 6000

a bit more CARs

(2) No person shall continue a non‑precision approach or an APV unless
...
(c) the instrument approach procedure is conducted to straight‑in minima; and

(d) a visibility report indicates that //looks like column 2 to me

(i) the visibility is equal to or greater than that set out in subsection (1),

(ii) the RVR is varying between distances less than and greater than the minimum RVR set out in subsection (1), or

(iii) the visibility is less than the minimum visibility set out in subsection (1) and, at the time the visibility report is received, the aeroplane has passed the FAF inbound or, where there is no FAF, the point where the final approach course is intercepted.

See in the next quote, they mention column II. So it's pretty much 50% CAP Vis.

subsection (1)
(a) where the RVR is measured by RVR “A” and RVR “B”, the RVR measured by RVR “A” for the runway of intended approach is less than the visibility set out in column II of the item for the approach conducted;

(b) where the RVR is measured by only one of RVR “A” and RVR “B”, the RVR for the runway of intended approach is less than the visibility set out in column II of the item for the approach conducted;

(c) where no RVR for the runway of intended approach is available, the runway visibility is less than the visibility set out in column II of the item for the approach conducted; or

(d) where the aerodrome is located south of the 60th parallel of north latitude and no RVR or runway visibility for the runway of intended approach is available, the ground visibility at the aerodrome where the runway is located is less than the visibility set out in column II of the item for the approach conducted.

Now with our given example...

- assume 704 without ops spec.
- rwy cap advisory vis: 1 RVR 50
- therefore vis report = 3/4 RVR 40 (75% of CAP)
- assume u have not passed faf inbound
- airport is south of 60N latitude

scenario#1

- reported RVR 3000
- grd vis fluctuating 1/2sm - 1sm

scenario#2

- reported RVR 4000
- grd vis 1/4sm

CAP Advisory Vis is 1 RVR 50, a quick look at the table....

And voilà ! 1/2 - 2600.

Scenario 1 : GO !
Scenario 2: GO !

[bcflyer]

I believe you have the wrong table. The table you provided can only be used if you have either an HGS or are doing an SCDA or APV type of approach. The correct table indicates a min of 3/4 mile or RVR 4000 as was stated in the first post.

[full_throttle]

well the table he has shown is the one i saw in the car we're talking about

[bcflyer]

The table shown is only good if you have the ops spec to use it. The general approach ban is 75% of the CAP requirement. There is a bit more to it, but basically if you don't have A) an HGS or B) are doing a SCDA, RNAV or LPV approach, your approach ban is 75%. I've posted the two charts below. (didn't post the whole thing since its really long!!! )

Transport Canada > Civil Aviation > Commercial & Business Aviation > Advisory Circulars


Annex A
Table 1. Approach Ban - General (Subparts 700/720 of the CARs)

CAP Advisory Visibility
[sm RVR x100 ft]
Visibility Report
[sm RVR x100 ft]
1/2 RVR 26 3/8 RVR 16
3/4 RVR 40 5/8 RVR 30
1 RVR 50 3/4 RVR 40
1-1/4 1 RVR 50
1-1/2 1-1/4 RVR 60
1-3/4 1-1/2 RVR >60
2 1-1/2 RVR >60
2-1/4 1-3/4 RVR >60
2-1/2 2 RVR >60
2-3/4 2-1/4 RVR >60
3 2-1/4 RVR >60

Table 2. Approach Ban – Ops Spec (Subparts 703/723, 704/724 or 705/725 of the CARs)

CAP Advisory Visibility
[sm RVR x100 ft] Visibility Report
[sm RVR x100 ft]
1/2 RVR 26 1/4 RVR 12
3/4 RVR 40 3/8 RVR 20
1 RVR 50 1/2 RVR 26
1-1/4 5/8 RVR 34
1-1/2 3/4 RVR 40
1-3/4 1 RVR 50
2 1 RVR 50
2-1/4 1-1/4 RVR 60
2-1/2 1-1/4 RVR >60
2-3/4 1-1/2 RVR >60
3

[Benwa]

BCFlyer, you're right. I only read the 703 and 704 CARs minimums. There is a general CARs 700 approach ban table.

http://www.tc.gc.ca/CivilAviation/Regse ... m#700_10_4

[bcflyer]

No worries. The only reason I knew about it was the company put together a nice little memo for us with both tables and an explanation as to when to use which table.

[2milefinal]

The scenario

No Ops Spec.
Non precision approach and no FAF
The weather at the airport (with a FSS) you are landing at reports the vis at 1mile, the CAP advisory vis is 1.5 miles which means you need 1.25 miles for the approach, you turn final and you can see 2+ miles (with ground visible) do you report the vis to the FSS, and land or do you do the miss?

[TopperHarley]

The scenario

No Ops Spec.
Non precision approach and no FAF
The weather at the airport (with a FSS) you are landing at reports the vis at 1mile, the CAP advisory vis is 1.5 miles which means you need 1.25 miles for the approach, you turn final and you can see 2+ miles (with ground visible) do you report the vis to the FSS, and land or do you do the miss?

Report the viz right away and continue the approach. That's assuming you do in fact have the 2 miles viz.

[2milefinal]

That's assuming you do in fact have the 2 miles viz

of--course