Do the side-step: you can land from an approach in one of three different ways. Straight in is common and circling is much discussed, but did you know you can be cleared to side-step?
Uh, What's That?
You've been out playing on a nice day and it's time to head back home. Your airport has parallel runways. The left, shorter runway is primarily used by piston GA and the longer right one is frequented by the kerosene burners.
But it's such a nice day that you're not the only one out having fun, and your left runway pattern is full. From your direction, it's just as easy for the controller to feed you to the longer right runway. But, by a couple miles out, he's opened a hole for you on the left and offers it to you. You accept and sidle over and land on your preferred runway.
Often erroneously called a side-step, that's just a VFR maneuver to land. Also, if you use an instrument approach to get through a layer, but the airport is officially VMC, you may request or be offered a parallel runway once you're below the layer. We're going to look at a similar maneuver that's at the end of an instrument approach, usually in less than VMC.
In this context, a side-step is a maneuver conducted between two runways at the conclusion of an instrument approach. Although that sounds like a circling approach, the side-step is its own maneuver with its own minimums.
The Pilot/Controller Glossary defines it: A visual maneuver accomplished by a pilot at the completion of an instrument approach to permit a straight-in landing on a parallel runway not more than 1,200 feet to either side of the runway to which the instrument approach was conducted.
Now we have some criteria. It's a visual maneuver, much like a circle-to-land, but this maneuver can only be conducted between runways that are parallel to each other within 1,200 feet.
Part of Your Clearance
The AIM says: 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.
Side-step maneuvers should be included in our clearance for the approach we are executing, and not as an "Oh, by the way" add-on as you pop out of the clouds. This is supported by "Order JO 7110.65S, Air Traffic Control" (the ATC Handbook), but we'll get to that in a moment. The AIM goes on to advise us to commence the side-step maneuver, which we have been expecting since our approach clearance, as soon as possible as the runway, or runway environment is in sight. We all know what a runway is, but what is "the runway environment"?
Curiously absent from the pilot/controller glossary, this term is best defined by 14 CFR 91.175 (c)(3), which summarizes the things we need to see in order to descend below DA or MDA for the purposes of landing from an instrument approach. This is exactly what we're planning with the side-step maneuver.
OK, so we don't have to wait to get down to MDA before we conduct the maneuver. We can slide over to final for the parallel as soon as we can do so visually; however, we can only descend towards the parallel provided there are no step-downs to comply with.
Let's look at the Ted Stevens International Airport in Anchorage, Alaska. The ILS or LOC/DME RWY 7R has side-step minimums for landing on Runway 7L. The reverse is not true, as Runway 7L is offset 4,500' to the east and might make for some interesting gyrations for a left-to-right side-step.
Notice that the LOC 7R, on which the side-step is based, has a stepdown fix (WIVDA) at 4.8 NM out on the localizer, likely due to Fire Island sitting conveniently under the final from about 5-8 DME. Should you be cleared for the sidestep maneuver, and pick up the runway or runway environment at 1,200' feet, you would be expected to stay at or above 1,000 MSL until passing 4.8 DME from 1-ANC.
What obstacle clearance can we expect? AIM 5-4-20 has a couple of hints: Side--step obstacle protection is provided by increasing the width of the final approach obstacle clearance area. Knowing that TERPS criteria gives us a minimum of 250 feet of required obstacle clearance between the FAF and the MAP on a localizer approach, you can expect side-step minimums to be higher than straight-in. AIM 5-4-19 confirms it: Landing minimums for a side--step maneuver to the adjacent runway will normally be higher than the minimums to the primary runway.
Speaking of minimums, when cleared for a side-step maneuver as part of our approach, we need to pay attention to the approach minimums--particularly visibility--for the side-step maneuver. Although, Part 91 doesn't require minimum visibility to commence the approach as is required by 121 and 135 regulations, it's still a good guideline and we should have clear expectations if we do begin the approach with less than the required visibility.
Can You Do It?
Notice the LOC 8L approach into Atlanta. In order for a certificated operator to even begin this approach or for anyone to descend below the MDA, the straight-in visibility requirement is only 2400 RVR, half a mile. However, if you are cleared for the LOC 8L side-step to 8R, the required visibility increases to 5000 RVR, a mile. We'd be wise to brief the MDA and visibility minimums for the side-step when conducting an approach with a parallel runway less than 1200 feet away.
Another question that surfaces is "Can I conduct a side-step maneuver to a parallel runway when no side-step minimums are published?" For instance, last time you flew to San Francisco, you were cleared for an ILS 28R, side-step to 28L, for which an MDA and minimums of 480 MSL and 5000 RVR are published. But today you're expecting the other runway, an ILS 28L and you're wondering if you can expect to be asked to jog to the right, even though there are no side-step minimums on the approach chart.
The answer is no, and for backup we refer to the ATC Handbook. Section 4-8-7 states: When authorized by an instrument 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. If a transition to another runway is desired, a circle-to-land maneuver becomes the only option in the absence of published side-step minimums.
What if you don't want to side-step? Whatever your reasons, follow the standard maxim of not accepting a clearance with which you can't or don't want to comply. Much like a land and hold short clearance, only accept it if you are comfortable and prepared. This fact should be communicated to ATC as soon as possible, so they can make necessary accommodations, which may involve some delays.
Another thing you should be prepared for, especially when you're the first arrival in some time or the weather is changing rapidly, is that when you get to side-step minimums you might only have the familiar view of the inside of the milk carton--still IMC.
This has happened to me on several occasions when I was cleared for a circle-to-land approach, or told to expect a visual transition to a different runway. In these cases, it's best to mentally reset and miss to come around for another try at the approach after briefing yourself on the straight-in criteria. Of course, if you have the time and room to let ATC know that you're still IMC, you could continue down to the straight-in MDA. But it's generally risky to make last second changes like that unless you're fully briefed and prepared.
You may never get the opportunity to conduct a side-step maneuver, but if you ever notice that your destination airport has closely space parallel runways, check the minimums section for "side-step" numbers--you may soon be hearing that phrase from ATC.
Evan Cushing is a safety manager at a regional airline. In 15 years there, he's served as pilot, check airman, instructor and fleet manager.
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|Title Annotation:||SYSTEM NOTES|
|Date:||Oct 1, 2013|
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