Techniques for Handling Instrument Approaches

By Mike Roda, ZDC ARTCC

The purpose of this article is to cover some of the techniques that can be used for providing approach control services to aircraft on instrument approaches. While it's impossible to cover all types of instrument approaches you may encounter, this article will present three main techniques that will handle most situations. All of the examples in this article will use approaches into airports within the ZDC ARTCC.

1. Vectoring onto the final approach course

By far the most commonly used technique for getting aircraft established on an instrument approach, especially on VATSIM, is to vector aircraft to the final approach course. Many times it is just more efficient to vector aircraft to the final approach course because the IAF is too far out of the way, or you are having to deal with a lot of traffic, particularly when such traffic is arriving from different directions. Sometimes there isn't an IAF published on the instrument approach plate even!

Yet another reason is that many VATSIM pilots are unable or just plain don't know how to fly the full approach from an IAF. For this first example, an aircraft is arriving on the COATT4 STAR into IAD:

United 24, depart BARIN heading 340, expect the ILS runway 1R approach

This should keep him clear of the restricted airspace (R6608) and suffice for intercepting the localizer. Then all that's left is the PAC:

United 24, 6 miles from MOSBY, maintain 3000 until established on the localizer, cleared ILS runway 1R approach

Remember, when using radar vectors, we are subject FAA 9110.65 section 5-9-4 (Radar Arrivals) and must give him all four pieces of information - position, turn, altitude, and clearance.

Once the pilot has been told what approach to expect, he should have the plate up. Often the STAR is designed to take the pilot at an almost straight in direction to the final approach course, and all that is needed is to give the pilot direct to the first fix on the approach. Take the BUZZY6 into RDU. After BUZZY, the pilot should be flying direct to RDU. This takes the pilot very close to the final approach course for both the 5L and 5R ILS. Washington Center will hand the pilot off to RDU_APP just before BUZZY and approach will make initial contact:

Southwest 824, Raleigh Approach, good evening, expect the ILS runway 5R approach, Raleigh altimeter 29.95.

At this point the pilot should get the approach plate up for the ILS 5R. We see the first fix on the approach is PECIT and has an intercept altitude of 4,000:

After BUZZY, we can simply give him direct PECIT and clear him for the approach since the angle of intercept will be less than 30 degrees:

Southwest 824, proceed direct PECIT, cross PECIT at or above 4000, cleared ILS runway 5R approach.

Note that by giving direct to a fix, we have essentially given him a radar vector and are bound by the MVAs in the area, which are 3,300. Since the ILS 5L has aircraft intercepting SCHOO at 3000, we could not simply give the pilot direct SCHOO and instead would have to vector the pilot to intercept outside of SCHOO at 3,300 or above.

While the Raleigh TRACON has lots of room to work with, it gets a lot more complicated when working an approach sector with very tight airspace boundaries, such as those DCA_APP has to contend with in the northwest quadrant for aircraft arriving on the IRONS4 and the field running south ops. High terrain - and the MVAs that go along with it - also poses complications. Combine tight approach sectors with high terrain, as you have around southern California, and you really have to plan ahead.

N421MR is a type King Air and is headed from Greenbrier Valley (KLWB) to Hot Springs (KHSP) at an altitude of 7,000 feet. His cleared route is LWB V290 MOL and he's looking for the ILS approach to runway 25 from there:

Note that MOL is a feeder fix for IAF IFAVU so we could let him go all the way there and use that to get to the IAF, but that would take him way out of his way. What we really want to do is vector him on a base leg to intercept inside of AHLER.

King Air 1MR, turn left heading 340, vector ILS runway 25 approach

There's just one problem: the final approach fix is the DURAN OM with an intercept altitude of 5,000, but the MVAs in the area are 6,000. So how can we make this work without sending him farther to the east outside of AHLER?

The trick is to get him established on the final approach course, which is a published route with MEA of 5,000 betweeen AHLER and DURAN, before giving the approach clearance. Of course we will have to keep 1MR at 6,000 until he's established on the localizer.

We will need to break the traditional PTAC into two parts - a technique called T/PAC. First the turn - we vector him to intercept the localizer but we won't give him a descent yet, and we will withhold the approach clearance:

King Air 1 MR, turn left heading 270, intercept the localizer, track it inbound, report established

He should pick up the localizer and report established when he's about 3 miles east of the outer marker. At this point, the 6,000 MVA no longer applies, and the MEA takes over which is 5,000. Now comes the PAC:

King Air 1MR, 3 miles from DURAN, cross DURAN at or above 5,000, cleared ILS runway 25 approach

Important: You want to make sure he's got enough room to get down to the intercept altitude before reaching the next fix. Nothing makes a pilot mad like being brought in too high for an instrument approach. But in this case, 3 miles should be more than enough distance to lose 1,000 feet.

2. Clearance from an Initial Approach Fix (IAF)

We don't have too many of them at ZDC, but there are some STARs that terminate or go through the IAF of an instrument approach at the airport, and this makes our job very easy. Let's take a look at a couple of specific examples. Although it must be assigned by ATC and therefore seldom used, the CASANOVA2 is a good example of a STAR that ends on the IAF of an instrument approach. In contrast to the more common JASEN4, for an aircraft on the CASANOVA2, you can give the approach clearance simply as:

Jet Blue 56, cross Casanova at 5000, cleared ILS runway 1L approach

Why doesn't approach have to give the full PTAC (position, turn, altitude, clearance) sequence here? Take a look at the approach plate:

As you can see, the CASANOVA2 tells the pilot to expect clearance to cross CSN at 5,000 so that is what we gave. And we see that CSN is an Initial Approach Fix (IAF) for both the ILS 1L and 1R approaches. Once the pilot has been cleared to the specific approach, the pilot has all the routing information he needs to join the approach. It is unnecessary to report position since you haven't vectored him off his route; in other words you are not using radar and therefore not subject to FAA 9110.65 section 5-9-4.

The same technique can be applied for aircraft on the COATT4, since it takes the pilot over BRV, which is the IAF for the ILS runway 1R approach. This is somewhat less ideal than the CSN2 however, since the COATT4 plate doesn't end at BRV. It tells the pilot to expect radar vectors after BARIN, not an approach clearance at BRV. Nevertheless, it's still legal and if you have a savvy pilot, he should be able to fly it.

Whenever the pilot's route takes him to an IAF on an instrument approach, you can use this method to clear him for the approach without radar vectors.

By the way, if he reports the field in sight before you terminate radar service, you might as well ask him if he wants to cancel IFR; there's nothing more he needs you for and no reason to wait until he's on the ground.

In the next example, King air 1MR is flying from Chicago O'Hare (ORD) to Manassas Regional (KHEF), using the route: ORD1 ELX CRL DJB J34 AIR J162 MGW JASEN4, altitude 11,000 feet. This time he's requesting the GPS approach to runway 34R at Manassas. The approach plate shows the IAF is BRV:

The problem here is that his routing doesn't take him to BRV, in fact no where near BRV. He will enter IAD_APP airspace at DRUZZ and stay on the JASEN4 to GILBY, about 30 miles northwest of BRV, as he's establishing on the AML R-300 inbound. Another complication is the restricted airspace (R6608) between his route and the IAF at BRV. Because of this, we can't just vector him directly to BRV. We're going to need to do this in two steps, vectoring him first south and west of R6608:

King Air 1MR, Potomac Approach, good evening, Manassas reporting winds calm, visibility 3 miles, scattered clouds 1,000, altimeter 30.01, depart GILBY heading 190, expect GPS runway 34R approach

Once he's clear of the restricted airspace and over the 2000 MVA area we'll send him to BRV and give a descent:

King Air 1MR, turn left heading 130 direct BRV when able, descend and maintain 3,000

Although BRV isn't listed on the vertical profile at bottom right, the chart states that the MEA (Minimum Enroute Altitude) between BRV and HANOK is 3,000 and it is 14.4 miles. 14.4 miles is more than enough distance for him to lose some altitude, but we might as well get him down to 3,000 prior to BRV since the MVAs in the area allow it and that way we can bring any IAD arrivals going to 1L/1R overhead without a problem.

Note in this specific example, the IAF was a VOR, it could just as well been an intersection. Before you instruct an aircraft to fly direct to an intersection, make sure the aircraft is capable of doing so. The equipment suffix on the flightplan should tell you - keep a table handy for reference. A lot of general aviation planes are /A meaning they can go direct to a VOR but not necessarily an intersection. Most GA pilots are aware of equipment codes but if the pilot didn't file one, don't be afraid to ask him what it is and amend his flightplan.

Back to our example, 1MR is heading direct BRV and descending to 3,000. Since we gave him a radar vector, we are now subject to FAA 9110.65 section 5-9-4 (Radar Arrivals) and must give him position. As always, we will remind him of crossing altitude as well. But there is no turn since he's already direct to the IAF. Therefore you can issue a PAC:

King Air 1MR, 8 miles from BRV, cross BRV at or above 3000, cleared GPS runway 34R approach

Remember that on VATSIM, unless a tower is online, we usually simulate class D towers as uncontrolled fields. You cannot release an IFR departure out of Manassas or clear another aircraft for the approach until 1MR has landed and cancelled IFR:

King Air 1MR, radar services terminated, change to advisory frequency approved, report IFR cancellation or missed approach this frequency

A lot of airports have a common IAF, such as a VOR or an intersection on an airway, so a carefully planned route doesn't need any vectoring. If things are slow and you have time, feel free to amend a pilots routing well ahead of time to set things up easier for yourself later!

3. Clearance from an Initial Approach Fix with procedure turn or hold

This last section deals with instrument approaches with a procedure turn or hold. As with the last section, we will get the pilot to the IAF but this time we can use a procedure turn or hold for descent.

King Air 1MR is flying from Shenandoah Valley Regional (KSHD) to Greenbrier Valley (KLWB), having been cleared along a route on MOL V290 NATTS LWB. You check this flight plan and see in his remarks that he's requesting the VOR RWY 4 approach into Greenbrier. You pull up the chart and here's what you see:

The intercept altitude for LEFAP is 4,200, but the MVA extending a few miles on either side of the approach course is 4,900, and beyond that is 6,000. It would be possible to vector him onto the approach course but you would have to vector him pretty far out.

LEFAP is both the initial and final approach fix, how can this be? On the vertical profile, notice the arrow moving downward from LEFAP with the 228 heading. This approach allows a procedure turn to be flown - it has both an outbound and inbound leg, both flown from the same VOR radial. On the outbound leg, the pilot would fly the reciprocal heading of 228 instead of 048. The outbound leg is used to two purposes: to lose altitude and get established cleanly on the inbound approach course when the pilot has entered the approach from any direction.

This is called a procedure turn and indicates that there is a safe area within a defined radius around some fix for the pilot to make this turn. In this case it is 10 nautical miles around LEFAP which you can see from the chart. To fly this approach, a pilot will cross LWB, intercept R-228 outbound, check his DME readings to see when he passes LEFAP (the IAF, which is 6.1 DME from LWB), then make a 45-degree right turn to heading 273, and begin a descent to 4,200. He'll go for awhile (making sure to stay within 10 NM of LEFAP) and then make a 180-degree left turn to heading 093. From here he can re-intercept the LWB R-228 inbound and descend to cross LEFAP at 4,200.

The MEA from NATTS to LWB is 5,500 so he'll have to cross LWB at that altitude. He'll know he has to fly the full approach when we tell him to join the approach like so:

King Air 1MR, join the LWB R-228 outbound

Once he's tracking the radial, you issue the approach clearance as follows:

King Air 1MR, 4 miles from LEFAP, cross LEFAP at or above 5,000, make procedure turn within 16 DME, do not descend below 5,000 until inbound on the approach, cleared VOR/DME-B approach

The DME and altitude restrictions are not necessary since those restrictions are already published on the chart, but it is not a bad idea to include them in the clearance. The DME restriction let's the pilot know you want them to keep the turn tight and not run all over your airspace flying that full approach

The last type of approach we will cover is the holding pattern. This time King Air 1MR is flying from Grant County (W99) to Leesburg Executive (KJYO). The assigned route is ESL V4 AML, at an altitude of 7,000 feet. King Air 1MR is requesting the VOR-A approach into Leesburg. Note that instrument approaches can be to a specific runway, or they can bear the A/B/C/D suffix, indicating that the pilot is to fly the approach to the field, and circle to land on the desired runway.

Looking at the VOR-A approach plate, we can see why it bears the A suffix; the approach serves both runways:

The one and only IAF for this approach is AML, which just so happens to be the last fix on our pilot's flight plan. Looking at the vertical profile at bottom left, we see that the intercept altitude for AML is 2,000, but the MEA along V4 to AML is 5,000. The MVAs in the area area 3,500 and 2,500 so that is no help. Even if the MVA were 2,000 we couldn't give that to the pilot unless we vectored him off the airway. Why you ask? Because as long as he is on the airway he is on his own navigation and there is no guarantee he will still be able to receive the navaids below the published MEA on that route, due to obstructions like mountains, whatever.

Since this is not a pure vectored type approach, rest assured there is going to be some mechanism built into the approach plate to allow for the pilots descent. While this one doesn't allow a procedure turn, it does allow the aircraft to enter a holding pattern at AML in order to lose some altitude and get down to 2,000. We will instruct the pilot to cross AML at 5,000 and then the pilot will descend to 2,000 while in the hold. Once he has reached 2,000 he can begin inbound on the approach and descend to cross FUZZI at 1,500.

As always, we will give an altitude in the clearance but this time we don't need to include a DME restriction since the hold is at a specific fix and not within a general area like the procedure turn:

King Air 1MR, cross AML at or above 5,000, cleared VOR-A approach

Since the pilot is still on his published route, position and turn are both unnecessary; however, we do need to remind him of the crossing altitude for AML. He will fly the approach to the field and when he has the field in sight he will either enter a straight in final for runway 35 or enter a downwind for 17. For an uncontrolled field like Leesburg, or a class D field without a tower online (which is almost all of the time), once the pilot is established on the approach we'll terminate radar service and send him over to the advisory channel where he can talk to any other planes in the traffic pattern.

Acknowledgements: This article was inspired by another article "Everything You Ever Wanted to Know About Instrument Approaches" by Mark Sykes, former ATM of ZLA ARTCC. I learned tremendous amount from that original article and strongly desired to write a similar article but adapted for ZDC airspace. I also need to thank the countless instructors who have provided me approach training or answered questions, including Travis Faudree, Bob Henry, Dudley Whitney, Craig Merriman, and Aaron Flodin.