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Transitioning To Visual Before MDA

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Transitioning To Visual Before MDA

Old 13th Sep 2010, 22:40
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Transitioning To Visual Before MDA

At JFK there is a VOR DME 22L Instrument Approach. It is often assigned for noise abatement even when it's CAVU. The final approach course is offset 9 degrees from the runway. "Technically" (which is why I'm asking), when are you allowed to "break off the approach" and line yourself up with the runway?

Much thanks,
Mike
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Old 14th Sep 2010, 00:21
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Inside the Final Approach Fix and the runway in sight.
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Old 14th Sep 2010, 01:39
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Inside the Final Approach Fix and the runway in sight.
Agreed.
A similar VOR approach is at LCE, with high terrain, south.
Caution advised, in this case.
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Old 14th Sep 2010, 10:04
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Inside the Final Approach Fix and the runway in sight.
Could you refer to any official docuement where this can be found?
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Old 14th Sep 2010, 10:22
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This sounds interesting. Any chance of having the approach plate posted here?

Here's a link to it:

http://freepdfhosting.com/5e455245ac.pdf

(from 169's link in the email)

Last edited by Capn Bloggs; 14th Sep 2010 at 13:28. Reason: link to plate added
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Old 14th Sep 2010, 12:33
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Why visual with the runway is not enough?

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Old 14th Sep 2010, 12:45
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Some capt. I fly with, actually insist that on an offset non-precison you should fly to the MAPt and thereafter position yourself on the runway track. In my opinion this increases the risk in having an unstable approach, but sometimes the offset is on purpose to avoid an obstacle on the extended centerline... (eg. VOR RWY 07 at EBCI is 10 degr. offset because of a church in the runway axis, not depicted on the chart however)

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Old 14th Sep 2010, 13:15
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Some capt. I fly with, actually insist that on an offset non-precison you should fly to the MAPt and thereafter position yourself on the runway track. In my opinion this increases the risk in having an unstable approach, but sometimes the offset is on purpose to avoid an obstacle on the extended centerline...
Actually, the offset (resulting from the offset location of the VOR or NDB - not on the CL) is to ensure that the approach track passes through the centreline at some point, at or near the MDA so you only need to do one slight turn to get lined up. Otherwise you would be left, at the MDA, with a double turn to get lined up. It's the nature of the beast that you may not be "lined up" with the runway by 500ft AAL during these types of approaches. Your stabilised Approach criteria should take this into account.

AS to when, in the JFK case, you could turn right to pick up the CL if visual, I'd say, why bother? Just fly the approach as published, and when getting close to the CL ie approaching the MDA, turn left the 9 and land.
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Old 14th Sep 2010, 13:32
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Thanks for the replies, everyone. A few more items:

1. Of course there are many offset approaches. I just used the one at JFK because I've flown it; and the question of "when to break it off" has actually come up.

2. Can anyone cite the reference for the answer "...Past the Final Approach Fix and runway in sight." It sounds reasonable.

3. An answer I've heard elsewhere is "...Arriving at Traffic Pattern Altitude." This would be at about 1500' agl for a jet.

4. I'm fairly certain at JFK the approach is for noise and not obstacles.

5. I know it's "only" a 9 degree offset, but especially with any crosswind, lining up with the runway at only a few hundred feet agl is quite challenging--and in VMC--unnecessary. Hence, I was hoping for an "official" answer letting us line up sooner.

Thanks again,
Mike
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Old 14th Sep 2010, 14:12
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an other view

Jeppesen view is better!

Shooting the VOR at JFK 7 dme, visual with the runway and supposedly clear for the visual approach ... you have the aircraft. What will you do?

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Old 14th Sep 2010, 16:50
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Cool

I'd Make It Simple And intercept the CL after the FAF And proceed visually and enjoy the manual flying :-)
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Old 14th Sep 2010, 17:53
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keep it simple.....

if u feel like shooting a full instrument approach, by all mean go all the way down to MDA, or VDP, thereafter align yourself with the rwy extended ctrline and continue to land... and if u see the rwy from 10 miles away and decided to discontinue the instrument approach for a visual approach, then tell the tower u are visual, and u can line yourself up with the extended ctrline even before u reach MDA or VDP...
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Old 14th Sep 2010, 23:26
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offset non-precison you should fly to the MAPt and thereafter position yourself on the runway track
I've come across this thinking before - I would have thought you fly to the MAPt because you are NOT going to land, because the visual references for landing have not been established.

Those references should be laid down in the AIP or JAR-OPS or whatever reference is used - it may not be necessary to actually see the runway, but at least some portion of the approach lighting should be available. The visibility minima should take this into account...

In this particular case, there is a minimum distance at which the final approach track can cross the extended centreline for the procedure to be considered 'straight-in' - ICAO PANS OPS is 1400m, TERPS used to be about 3000ft (900m), but may have changed. This is to allow for the final (visual) manouevre onto the runway. The offset is also limited to 30deg for Cat A/B and 15deg for Cat C/D.
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Old 15th Sep 2010, 00:38
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It's fairly simple: if you are designing an instrument approach, then you assume that the pilot cannot see (sometimes you have to state the obvious!) so all of the tracking criteria are based on the reliability and accuracy of the tracking aid the pilot will be using, and the buffers are applied to that.

If you are visual - then you can see obstacles in your path, and the only criteria is to avoid obstacles by 500' unless you are landing - which (as you are conducting a visual approach) you are.

So - once visual (I mean REALLY visual, and able to remain visual to the runway, able to VISUALLY see obstacles such a church spires and the like) then you fly visually. Break off tracking using the aids, and fly your VISUAL approach. (i.e. look out of the bloody window!)

Most major airports have a formal requirement written somewhere (usually in the noise abatement pages) requiring visual approaches to be not below the glide path of the ILS - usually 3.

Obvious to an old pilot, perhaps not so to the Children of the Magenta Path ...
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Old 15th Sep 2010, 01:26
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2. Can anyone cite the reference for the answer "...Past the Final Approach Fix and runway in sight." It sounds reasonable.
AIM Sec 4.5 alludes to it in several ways, but makes no absolute, direct statement. An instrument approach, by definition, is designed to get you into a position to land, at which you take over visually (Cat II/III excepted). I limit it to "Past the Final Approach Fix" because you are not generally looking for the runway until after the FAF, and ATC normally expects you to adhere to the procedure through the FAF.
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Old 15th Sep 2010, 10:17
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As you have been cleared to carry out a instrument approach procedure you must fly that, unless you negotiate something different with ATC. The concept of an instrument approach is to put you in a position whereby you can land visually. Unless this is a Cat3B No DH approach, you must at some point gain visual references in order to land. If you understand this logic is follows fairly simply that you must fly to the FAF, then when once visual you may adjust your flight path to conduct your visual landing.
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Old 15th Sep 2010, 13:29
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Well, whether right or wrong, here is the answer we got from a controller in the JFK tower:

"From an ATC perspective, we anticipate
the crews exiting the offset final whenever they determine they have visual
and need to line up. There is a variation between crews, and we have no
issue with that. I have even briefed the local communities regarding noise
issues that flight crews have the discretion to deviate."

More comments are certainly welcome and appreciated, but I thought his answer would be of interest.

Thanks everyone,
Mike
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Old 15th Sep 2010, 15:26
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76mike:
More comments are certainly welcome and appreciated, but I thought his answer would be of interest.
Note that your JFK ATC source was very careful in his wording; i.e., "From an ATC perspective..."

In other words from a traffic separation and close-in sequencing standpoint ATC has no issue with an aircraft departing the electronic guidance to line up with the runway at whatever point the pilot chooses. But, ATC has no authority to modify or amend a U.S. IAP issued under FAR Part 97, and your source obviously knows that.

From an IAP procedural standpoint, when to depart the electronic guidance on an offset, but straight-in IAP has always been vague. If the weather is good and ATC clears the pilot for a visual then the IAP is superceded. But, if the weather is good (more than reported 3 miles at the airport and clear of clouds, with runway in sight) then at what point can the pilot elect to depart the electronic guidance? The answer is: there is no regulatory or policy guidance on this at all.

But, what if the pilot is clear of the clouds and sees the runway but the airport weather report is less than 3 miles? That makes the JFK surface airspace IFR, so in that case the pilot cannot make any election to deviate from the IAP. But, obviously he does have to line up with the runway in sufficient time to make the line up safe. If the airport is IFR then that line up should not be done any sooner than deemed necessary by the pilot. That's my opinion based on having worked with this stuff for a very long time.

If you had a fed on the jump seat and the airport is officially IFR he could be quite critical about someone leaving the electronic guidance a "long way" out.

Clear as mud, right?

Last edited by aterpster; 15th Sep 2010 at 19:28. Reason: correct grammar
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Old 15th Sep 2010, 19:32
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If YOU can see the runway, then you may continue visually; it doesn't matter what the "official" visibility is reported as.... just as if you were on an ILS approach and once inside the marker the RVR is suddenly reported as being below minimums, then you may continue the approach and land if you can see the threshold at D/H.
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Old 15th Sep 2010, 20:58
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I'm sorry; I should have been more clear: I was asking when to leave the offset when it's "clear and a million" --not when there's ANY low ceiling or vis.

I also found out, the offset was designed for airspace reasons, not obstacles nor noise abatement.

And, yes, the opinion of the tower controller is "just" an opinion, albeit an important one, but not a regulatory statement.

It seems after all our posts, the answer is still in the "grey" area...


thanks,
Mike
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