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Sidestep Approach Minimums

Old 03-12-2010, 05:38 PM
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Originally Posted by USMCFLYR View Post

The EEftPP reference book uses AIM 5-4-18 and states:


3. Landing minimums to the adjacent runway will be based on nonprecision criteria and ...

Using the above reference (AIM), it seems to say that if the runways are within 1,200 fet of each other then you can shoot the NP approach using the NP mins for the one you are shooting, then plan to side-step and do so ASAP. I assume this means then that you could shoot this approach and plan to side-step without actual side-step minimums.
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It is true that the minimums for a Side-Step Maneuver are based on non-precision criteria, but it does not say they are the same non-precision minumums as used for the straight-in approach. Surely you've seen approaches that have multiple non-precision minimums based on lighting, Approach category, Navaid capability, and even altimeter settings. They are all computed using non-precision criteria, but that doesn't make them the same, nor does it make them interchangeable.


Originally Posted by USMCFLYR View Post

The EEftPP reference book uses AIM 5-4-18 and states:


1. ATC may authorize a nonprecision approach procedure which serves either one of the parallel runways that are separated by ,1200 feet or less ...

Also assuming that you would have to have separate side-step mins if the runways are further than said 1,200 feet apart and may be the case in the examples posted above (I didn't look).

The paragraph you quoted contradicts that. In the most current version of the Aeronautical Information Manual (I had to check, and found the one on my hard drive to be out of date. The most current is dated Feb 11, 2010 -- practically brand new!) the paragraph you cited is titled "Side-Step Maneuver." It's actually 5-4-19, and it's the same paragraph Rustee and I cited. If the runways are more than 1,200 feet apart, there can be no side-step maneuver. There can be a circling maneuver that looks very much like a side-step maneuver, but it's not a side-step maneuver. The existence or absence of side-step minimums is not the determining factor if the runways do not meet the criteria for a side-step maneuver.






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Old 03-12-2010, 06:04 PM
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I mentioned AIM 5-4-20.d. before, now I'll revisit it.
d. Side-Step Maneuver Minimums. Landing
minimums for a side-step maneuver to the adjacent
runway will normally be higher than the minimums
to the primary runway.
Why would the Side-Step Maneuver Minimums "normally be higher than the minimums to the primary runway"? Look at how the minimums are derived.



5-4-20. is titled Approach and Landing Minimums, and it discusses a. Landing Minimums, b. Obstacle Clearance, and more. Under the second sub-paragraph, we get a glimpse into why the minimums might be higher:
b. Obstacle Clearance. Final approach obstacle
clearance is provided from the start of the final
segment to the runway or missed approach point,
whichever occurs last. Side-step obstacle protection
is provided by increasing the width of the final
approach obstacle clearance area.
The non-precision minimums for the straight-in approach do not take into account obstacles that may affect the adjacent runway. Circling minimums for the approach would account for those obstacles, and side-step minimums would account for them, but straight-in non-precision minimums would not account for them.






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Old 03-12-2010, 06:15 PM
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This has been an educational discussion. I think I got it now...

Parallel runways 1200' apart or less = side-step minimums
Parallel runways 1201' apart or more = circling minimums

For all practical purposes, side-stepping to a parallel runway is a side-step maneveur... in terms of how you control the airplane and the path you fly. But technically speaking, if the distance between the parallel runways is an inch above 1200, it is now a circling maneuver, subject to non-precision criteria and MDA (ie circling minimums).

Straight-In minimums don't apply.

Last edited by AKASHA; 03-12-2010 at 06:44 PM.
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Old 03-12-2010, 06:30 PM
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Originally Posted by TonyC View Post
5-4-20. is titled Approach and Landing Minimums, and it discusses a. Landing Minimums, b. Obstacle Clearance, and more. Under the second sub-paragraph, we get a glimpse into why the minimums might be higher:
b. Obstacle Clearance. Final approach obstacle
clearance is provided from the start of the final
segment to the runway or missed approach point,
whichever occurs last. Side-step obstacle protection
is provided by increasing the width of the final
approach obstacle clearance area.
The non-precision minimums for the straight-in approach do not take into account obstacles that may affect the adjacent runway. Circling minimums for the approach would account for those obstacles, and side-step minimums would account for them, but straight-in non-precision minimums would not account for them.
.
This describes how side-step minimums are derived, but not the requirement for side-step minimums to be published. I can see the argument for both cases. You could say that if it's not published, it's not authorized. On the other hand, AIM 5-4-19 seems to imply (as USMCFLYR quoted) that such minimums are not required for ATC to authorize the maneuver. If that is the case, then you would use straight-in nonprecision minimums for the side-step, which AIM 5-4-19 does clearly state.
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Old 03-12-2010, 06:34 PM
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Excerpt from:
Effective Date February 11, 2010
Subject: Air Traffic Control
Chapter 4. IFR


Section 8. Approach Clearance Procedures



4-8-7. SIDE-STEP MANEUVER


TERMINAL

Side‐step Maneuver. When authorized by an instru-
ment approach procedure, you may clear an aircraft
for an approach to one runway and inform the aircraft
that landing will be made on a parallel runway.

EXAMPLE-
“Cleared I-L-S Runway seven left approach. Side‐step to
runway seven right.”

NOTE

Side‐step maneuvers require higher weather minima/
MDA. These higher minima/MDA are published on the
instrument approach charts.

REFERENCE-
FAAO JO 7110.65, Para 3-3-2, Closed/Unsafe Runway Information.
P/CG Term- Side-step Maneuver.






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Old 03-12-2010, 06:37 PM
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Originally Posted by Rustee View Post
If that is the case, then you would use straight-in nonprecision minimums for the side-step, which AIM 5-4-19 does clearly state.
FALSE. Even you admit it is not stated.
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Old 03-12-2010, 06:43 PM
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Originally Posted by Rustee View Post

On the other hand, AIM 5-4-19 seems to imply (as USMCFLYR quoted) that such minimums are not required for ATC to authorize the maneuver.

I disagree with the inferences you're making that side-step minimums are not required, but I understand how you're getting there.



Originally Posted by Rustee View Post

If that is the case, then you would use straight-in nonprecision minimums for the side-step, which AIM 5-4-19 does clearly state.

I suggest you read 5-4-19.3. again. You will not find the word "straight-in" in that paragraph.


The minimums for the side-step maneuver and the minimums for the straight-in are derived using the same procedures, but they are not the same. The former includes obstacle clearance for both runways. The latter does not.


[EDIT: Oops. Looks like I'm typing over AKASHA. <insert smiley here> ]






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Old 03-12-2010, 06:46 PM
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Originally Posted by AKASHA View Post

This has been an educational discussion. I think I got it now...

Parallel runways 1200' apart or less = side-step minimums
Parallel runways 1201' apart or more = circling minimums

For all practical purposes, side-stepping to a parallel runway is a side-step maneveur... in terms of how you control the airplane and the path you fly. But technically speaking, if the distance between the parallel runways is an inch above 1200, it is now a circling maneuver, subject to non-precision criteria and MDA (ie circling minimums).

Straight-In minimums don't apply.

That's the way I see it.






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Old 03-12-2010, 07:01 PM
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Here's another interesting case study.If you look at that approach, you'll see minimums for the straight-in ILS (S-ILS), the straight-in Localizer (S-LOC), and for circling. What you won't see on that approach plate are minimums for a Side-Step to Runway 7R.

Being unfamiliar with the airfield, we might assume that Runways 7L and 7R are more than 1,200 feet apart, and therefore not eligible for this cool Side-Step maneuver. And, we'd be wrong. How do we know we're wrong? Well, it's because there ARE Side-Step minimums for the Ted Stevens Anchorage Intl (ANC) ILS or LOC/DME RWY 7R. The SIDESTEP RWY 7L minimums are higher than the straight-in Localizer minimums, but lower than the circling minimums.

Based on the information available on those approach plates, then, I would deduce that it is permissible to fly the ILS RWY 07R Side-Step 07L, but it is not permissable to fly the ILS RWY 07L Side-Step 07R.






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Old 03-12-2010, 07:03 PM
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Originally Posted by TonyC
I disagree with the inferences you're making that side-step minimums are not required, but I understand how you're getting there.
I believe there is a strong inference there, if you read how it is worded.

b. Aircraft that will execute a side‐step maneuver will be cleared for a specified approach procedure and landing on the adjacent parallel runway. Example, “cleared ILS runway 7 left approach, side‐step to runway 7 right.” Pilots are expected to commence the side‐step maneuver as soon as possible after the runway or runway environment is in sight. Compliance with minimum altitudes associated with stepdown fixes is expected even after the side-step maneuver is initiated.

If you have runway environment in sight, you are permitted to descend from the MDA for landing (assuming the requirements of FAR 91.175 are all met). What this implies is that you are flying straight-in for runway 7 left and only side-step to runway 7 right after you have runway environment in sight, at which point you are now responsible for obstruction avoidance as you leave lateral limits for the straight-in to runway 7 left. If this is true, then wouldn't that imply that (if no side-step minimums are published) you would be using the straight-in nonprecision minimums?
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