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A Controller's Guide to Instrument Approaches By Eric Stearns (ES)
| Procedures
and phraseology for instrument approach clearances can be confusing and
complex. In this article we'll try to create a basic framework for
dealing with any instrument approach. This article is aimed at
controllers, not pilots. While pilots may find this information useful,
pilot specific information is available at the
Vatsim Pilot Resource Center or ZLA's own
Pilot Certification Center. The article presumes an understanding of how to read an approach chart. If you need help
with that, there are several tutorials available. Ask a mentor or instructor for help in finding them. |
|
| Overview: |
The
first question to ask when dealing with an instrument approach is which
section(s) of the 7110.65 is applicable. All approach clearances must
comply with section 4-8. Aircraft vectored to the final approach course
must receive approach clearances that also comply with section 5-9.
We'll look at each of those sections separately. The main distinction
between these sections is that approach clearances issued using the
phraseology in 4-8 must have the aircraft routed over an initial
approach fix or feeder fix. If the aircraft will not overfly an initial
approach fix/feeder fix, its approach clearance must use the
phraseology prescribed by section 5-9.
This
article will cover the central points of interest.
There is a related article that covers advanced topics. All approach
controllers need to be familiar with the material in this article. As
you progress through your approach training, you will eventually want
to become familiar with the advanced topics article. |
|
| Definitions: |
| Rather than reproduce several definitions here, please refer to the
Pilot/Controller
Glossary
if you are not familiar with any of the following terms: approach gate,
feeder fix, final approach course, final approach fix, or initial
approach fix. |
|
| Section 4-8 (Approach will begin at an initial approach fix) |
If
a pilot will overfly an IAF or feeder fix on his route (in the case of
an RNAV approach, this same section can be used for aircraft routed
over an intermediate fix as well), the approach clearance can be issued
using this section. This section is very straight-forward, and there is
no difference between non-precision and precision approaches; all
approaches are handled in the same way. If the pilot is flying a
published route (airway, SID, or STAR) which includes minimum altitude
information all the way to the IAF or feeder fix, the pilot just needs
to be cleared for the approach. This can be done in a few different
ways:
- "Cleared
Approach" - This authorizes the pilot to fly any instrument approach
(note that a visual approach would require a separate clearance) at the
airport; obviously, it should only be used when the controller doesn't
care which instrument approach the pilot flies.
- "Cleared ILS Approach" - If there's only one ILS approach (or VOR/NDB/RNAV, etc) at the airport, then the runway
information is not required.
- "Cleared ILS runway Two Five Left approach" - If there's more than one type of an approach at an airport (like at
LAX, where there are eight ILS approaches), then the runway information must be included.
Depending on the type of approach and the direction from which the
pilot approaches, the pilot may or may not have to perform some type of
course reversal (procedure turn, holding pattern reversal, or
teardrop). We will cover some scenarios involving what to expect from
the pilot later in this article.
If the pilot is not flying a published route (i.e. the pilot is not
routed on an airway, SID, or STAR), then the pilot does not have
minimum altitude information like he would if he was flying a published
route. In that case he must be assigned an altitude restriction to keep
him safely above the terrain until he is established on a published
route, then cleared for the approach using the same phraseology as
above. This can be phrased a few different ways, but normally will be
something like, "cross XXX at or above 5000, cleared VOR approach."
Unlike vectored approach clearances, when issuing clearances under this section, distance from a fix is not
required in the approach clearance. |
|
| Section 5-9 (Approach does not begin at an initial approach fix) |
If
a pilot will not overfly an IAF or feeder fix on his route, then he
will be radar vectored to the final approach course. Even though he
might be navigating direct to a fix on final, his approach clearance is
still governed by this section. There are times when a controller may
not radar vector to final (discussed below); in those cases, the pilot
must be issued a clearance so that he will overfly an IAF and issued an
approach clearance using the phraseology above.
Requirements to Vector an aircraft to final:
Section 5-9 has a long list of rules to be used when vectoring to
final. We'll look at each paragraph and discuss its meaning below.
- Paragraph 5-9-1-a: "Vector arriving aircraft to intercept the final approach course...at
least 2 miles outside the approach gate"
This provision has been established to permit the pilot an opportunity to become oriented on
the approach. The approach gate is 1 mile from the final approach fix, so the vector to final must intercept
final at least 3 miles from the final approach fix. Note the emphasis
on the word "intercept." It's not that the pilot must be issued the
turn to final 3 miles from the FAF, but that the pilot must intercept 3
miles from the FAF. Obviously, the turn to final will need to be made
further out. There are two exceptions to this rule. One is for good
weather, the other is if the pilot requests to be turned on closer to
the FAF; see section 5-9 for more information.
- Paragraph 5-9-1-b: "For
a precision approach, at an altitude not above the glideslope/glidepath
or below the minimum glideslope intercept altitude specified on the
approach procedure chart"
This is fairly self explanatory, but one issue that comes up from
time-to-time is how to figure out what altitude is "not above the
glideslope." The easiest way to comply with this rule is to vector to
intercept at or below the altitude published for the next fix on the
approach. At some airports, the MVA will be higher than the minimum
altitude charted. In that case, you can use a little math to estimate
where the glideslope is. Most glideslopes have an angle of three
degrees. That works out to about 300' per mile. So if the aircraft will
intercept final on a 10 mile final, he should be no higher than 3000'
above the airport elevation. We'll see a few examples of applying this
rule later.
- Paragraph 5-9-1-c: "For a nonprecision approach, at an altitude which will allow
descent in accordance with the published procedure"
This rule is a little more vague. However, you can comply with it using
the same rules-of-thumb give above for precision approaches. Either
vector to final at the next charted minimum altitude on the procedure,
or use the 300' per mile rule. There's a longer discussion of this rule
in the "advanced topics" article and several
examples are provided later.
- Paragraph 5-9-2-a: "Assign headings that will permit final approach course interception
on a track that does not exceed [a 30 degree angle to the final approach course]"
This quote is paraphrased since the 7110.65 paragraph is slightly more
complex. But, in almost all cases, you must vector to the aircraft to
intercept final at no more than a 30 degree angle to final. The only
exception is for helicopters, which may be vectored to intercept at up
to a 45 degree angle. The 20 degree intercept described in this
paragraph doesn't apply to ZLA as long as you comply with item 1 in
this list.
- Paragraph 5-9-3: "Inform the aircraft whenever a vector will take it across the final
approach course and state the reason for such action"
This is self explanatory...the phraseology should be "N123SX, fly heading 180, vector across final for spacing."
As you can see there's a lot to think about when vectoring to final. It
can be especially challenging at certain airports which we'll discuss
later. |
Phraseology for vectored approach clearances:
|
The phraseology required for vectored approaches to final is a little more complex than for approaches from
an IAF. The basic phraseology uses the PTAC phraseology. In a standard case, the aircraft must be issued
its Position relative to a fix on the approach, a Turn to intercept the final approach course (generally must
be a 30 degree intercept angle or less as discussed above), an Altitude to maintain until established on the approach,
and finally issued the Clearance for the approach. For example:
"N123SX, Six miles from JETSA, turn right heading two two zero, maintain two thousand five hundred
until established on the localizer, cleared I-L-S runway two four right approach."
"N123SX, Five miles from BEVEY, turn left heading two four zero,
maintain three thousand until established on the final approach course,
cleared V-O-R Alpha approach."
In some cases, it isn't necessary to issue all elements of the "PTAC." All vectored
approach clearances must include at least the "P" and "C" of PTAC. If
the aircraft has already intercepted the final approach course, then a
turn is not needed (because the pilot is already tracking the approach
course) and an altitude isn't necessary (since this information is
published on the approach chart). The phraseology should be:
"N123SX, Eight miles from BUDDE, cleared I-L-S runway eight approach."
You might also clear an aircraft direct to a fix on the approach (if
this fix is not an IAF, then it's still considered a vector, so the
intercept angle must be no more than 30 degrees). If an aircraft has
been cleared direct to a fix on the approach, then the "T" of PTAC
isn't required:
"N123SX, Five miles from PETIS, cross PETIS at/or above four thousand two hundred, cleared I-L-S
runway two six left approach."
OR
"N123SX, Five miles from PETIS, maintain four thousand two hundred until established on the
localizer, cleared I-L-S runway two six left approach."
If the aircraft is already assigned a heading that will permit an
appropriate intercept angle, then the heading may be omitted:
"N123SX, Seven miles from KOAKS, maintain five thousand until established on the final approach
course, cleared Localizer D-M-E Backcourse Alpha approach."
|
|
| Circle to Land (.65 4-8-6 / Pilot Controller Glossary) and side-step (.65 4-8-7 / AIM 5-4-19 /
Pilot Controller Glossary) clearances: |
Sometimes a pilot will fly an approach to one runway and circle to land on another runway, or fly an approach
that does not have straight-in minimums published (like the VOR-A to SMO or VOR/DME-A to LAS). If there is an operating
control tower at the airport, then include circling instructions in the approach clearance. For example, if a pilot is
vectored to the VOR/DME-A at LAS and requesting to circle to runway 25L, the phraseology should be:
"N123SX, Five miles from NICZU, turn right heading three four zero, maintain five thousand four hundred until
established on the final approach course, cleared V-O-R D-M-E Alpha approach, circle to runway two five left."
At uncontrolled airports, controllers do not issue circling
instructions; however, it's important to note that at uncontrolled
airports the approach clearance always authorizes the pilot to execute
a circle-to-land maneuver. The pilot does not need a specific clearance
to circle, it's an unspoken part of every approach clearance to an
uncontrolled airport. This can cause separation issues at closely
spaced adjacent airports.
Another maneuver similar to a circle-to-land is a side-step. For some
airports with closely spaced parallel runways, "side-step" minimums are
established. For an example of this, see the LAX ILS 24R chart below
which has published side-step minimums to runway 24L. To clear an
aircraft for this type of approach, use standard phraseology under 4-8
or 5-9 and for the approach clearance it should be "cleared ILS runway
24R approach, side-step to runway 24L." The term "side-step" only
applies to this specific case where these minimums are published. An
aircraft on the ILS 24R could not be cleared to side-step to runway
25R, since no side-step minimums are published. If a pilot on the ILS
24R wanted to change to 25R, then the circle-to-land minimums apply and
the phraseology should be "change to runway 25R." Just like circling
clearances, side-step clearances are only issued to pilots landing at
controlled airports. |
|
| Visual Approaches (.65 7-4 / AIM 5-4-22 & 5-5-11): |
Visual
approaches are generally helpful for the controller. There aren't the
limits that exist for vectoring for an instrument approach. As its name
implies a visual approach requires visual conditions (if the
destination airport reports weather, the ceiling must be at least 1000'
and the visibility must be at least 3 miles), and that the pilot have
the airport or preceding aircraft in sight (more on this in the
"advanced topics" article). For the controller to initiate
vectors for a visual approach there must be even better weather
reported. Section 7-4-2 requires that the ceiling be at least 500'
above the MVA for the controller to initiate vectors for a visual
approach. In the case of LAS, the MVA over the airport is 3800' and the
airport elevation is roughly 2200'. This is a difference of 1600'; so a
ceiling of at least 2100' must be reported for the controller to
initiate vectors for a visual approach. Keep in mind that, as long as
the ceiling is 1000' or greater and the visibility 3 miles or more, the
pilot may be cleared for a visual approach. The "500' above the MVA
rule" only applies to a controller initiating a vector for a visual
approach (i.e. telling an aircraft to expect a visual approach). Once cleared for a visual approach, the pilot is responsible for his navigation to the airport and
avoiding obstacles and terrain.
The phraseology for a visual approach clearance is pretty simple. At
uncontrolled airports, the controller can't assign a runway, so it's
"cleared visual approach to Camarillo Airport." At an airport with a
tower, a runway should be assigned and the phraseology is "cleared
visual approach runway two four right." Restrictions may be added to
separate aircraft like, "turn final at or above 3000," "remain north of
the Santa Monica zero seven zero radial," "remain within five miles of
the airport," etc. Keep in mind that aircraft on a visual approach must
still be provided IFR separation from other IFR aircraft. In most cases
there is no difference in the required IFR separation on a visual
approach; however, there are a few differences in the separation
required for a visual approach and instrument approach. Most of those
differences are covered in the "Advanced Topics" article. |
|
Means of navigation on an approach
|
There are several ways a pilot can navigate on an approach. The possible means of navigation include localizers, VOR radials, TACAN
radials, NDB bearings, DME arcs, and area navigation (RNAV). For the most part, the means of navigation used by the pilot is transparent to a controller, but the
phraseology for each type of navigation aid varies. For much more detailed information on each type of navigation aid, see the Aeronautical Information Manual chapter
1.
Localizers are normally used with ILS approaches, and transmit a single course which is used to navigate to the runway with high precision (they also provide a
"backcourse" signal in the opposite direction). Localizers can also be used to identify intersections (for example, see TUSTI intersection, a fix on V64, which is
identified by the LDA 19R localizer at SNA) or for LDA approaches. The width of a standard ILS's localizer is calibrated to be 700 feet wide at the runway
threshold, so the width, in degrees,
of a localizer will vary based on the length of the runway. An ILS or LOC approach may be offset from the centerline of the
runway by up to three degrees and still be called an ILS or LOC approach. This offset is very rare and I don't believe any exist in ZLA; for an example, see the
BOS ILS 15R approach which is offset from the centerline by 1.6 degrees. If the localizer is offset from the centerline of the runway by more than three degrees,
it is called an LDA approach. For examples, see the LDA-C approach to VNY and the LDA 19R to SNA. The means of navigation is the same for the pilot as it would be for an ILS or LOC approach. If a
controller wants the pilot to intercept a localizer the phraseology should be "intercept the runway two five left localizer" or it could be just "join the
localizer" if there's only one for the airport or the pilot knows which approach to expect at the airport. An approach may also be defined using the "backcourse"
of the localizer. For examples of these, see the LOC/DME BC-A to SMX or the LOC/BC 1L to SNA. Another navigation aid very similar to a localizer is a SDF. ZLA doesn't have any SDF approaches, but
they are discussed in the AIM chapter 1 referenced above; for an example SDF approach see the SDF 23 approach to SCX.
There are many approaches based on VOR radials and TACAN radials. From a practical standpoint, a VOR or TACAN facility has 360 radials from it, each defined by the
magnetic bearing from the station (e.g. a radial aligned with magnetic north is called the 360 radial, one aligned with magnetic south is called the 180 radial).
From a controller's perspective, a VOR and TACAN are exactly the same. TACAN is not modeled in the default version of MSFS, but pilots may have made modifications
to MSFS so that TACAN navigation is available. The key thing to remember is that the radial from a VOR or TACAN is always expressed as the course from the station
even if the pilot will navigate toward it. To instruct a pilot to join the SMO VOR-A final approach course you would instruct him to "join the Santa Monica zero
three two radial" (.65 2-5-2-a) even though the inbound course is 212; it is also acceptable to just issue "join the VOR Alpha final approach course" in this
case.
An approach may also use an NDB bearing to define parts of the approach. An NDB also has 360 bearings to/from it, just like a VOR. NDB courses are assigned based
on the course to or the bearing from the station. For example, a pilot inbound from the east flying direct SB NDB for the SBD NDB 6 approach, would fly the 236 bearing from the NDB, make a procedure turn, then track inbound on the
056 course to the SB NDB and then fly the 056 bearing from the NDB to complete the approach. To instruct an aircraft to join one of these courses the phraseology
would be "intercept the two three six bearing from Petis radio beacon" or "join the zero five six course to Petis radio beacon" (.65 2-5-2-d). As with other
approaches, you could also assign, "join the NDB runway 6 final approach course."
An approach may also use a DME arc to define a portion of the approach. A DME arc is a curving path along a fixed distance from a navigation aid. The best example
in ZLA is the VOR/DME 34 approach to SGU. This uses DME arcs from the two IAFs and also to define a
portion of the missed approach. To instruct an aircraft to fly the 16 mile arc south of LOISS intersection on the VOR/DME 34 approach, the phraseology would be
"join the one six mile arc west of Saint George VOR" (.65 2-5-2-b). In most cases it will be obvious to the pilot which direction to fly the arc; when it is not
obvious append the direction of the arc to the end of the instruction using the phraseology "join the one six mile arc west of Saint George VOR, arc south." In the
case of the Saint George approach, you could just clear an aircraft for the approach using the phraseology in 4-8 as long as he's routed via one of the IAFs. For
example, an aircraft inbound on V8 from the NE will overfly LOISS intersection, so you can just issue "N123SX, cleared VOR/DME runway three four approach." No
additional information is needed about the arc in this approach clearance. If you are permitted to vector to the approach by 5-9, you can vector an aircraft to
intercept a published arc using the phraseology above. For example, you are permitted to vector to the ILS 1L approach to LAS. If the aircraft was routed via DICSA intersection, you could use the same phraseology used at SGU. But,
you could also vector to the 14 mile arc. In this case, the phraseology for the approach clearance could be "N123SX, 8 miles from HETAX, turn left heading 280,
maintain 6800 until established on the one four mile arc, cleared ILS runway one left approach." You could also vector directly to the localizer and bypass the arc
altogether. There are a few approaches that define the final approach course using DME arcs; none exist in ZLA, but see the VOR/DME 15 to MTN airport or the
VOR/DME 10 approach to WAL airport for examples.
The final form of navigation on an instrument approach is area navigation. This is normally thought of as GPS, but other systems can provide area navigation
capability. These are discussed at length in the AIM. Area navigation allows a pilot to navigate directly (or even via curved paths like a DME arc) between fixes.
The phraseology associated with RNAV is pretty simple; it normally just consists of clearing pilots direct to fixes. Generally, RNAV approaches are the same as any
other instrument approach. Use the phraseology in 4-8 for approaches that will begin at an IAF or IF; or you have the option of using the phraseology and
procedures specified in 5-9 if it is permissible to vector the aircraft to final. There are some subtle differences between RNAV approaches and conventional
approaches; these differences are discussed elsewhere in this article. |
|
| Example Approaches: |
To better illustrate the application of all these rules, we'll give some examples of approaches and methods
to deal with them. This still won't address every conceivable situation, but will address most common approaches.
|
| LAX ILS 24R: |
This
is one of the most common approaches flown in ZLA. For aircraft
arriving on the SADDE arrival from the N and W it will almost always be
a radar vectored approach. For aircraft arriving from the NE-SE on the
CIVET and SEAVU arrivals it will normally be an approach beginning from
the PALAC IAF. If the aircraft will overfly one of the four IAFs for
this approach, they may be cleared for an approach using the
phraseology in section 4-8. For example, if the pilot is routed via the
SADDE6 arrival, since the SADDE6 arrival provides minimum altitudes on
its published route and includes the SMO IAF, he may just be issued:
"N123SX, cleared I-L-S runway two four right approach."
This is very unrealistic and probably never done in the RW at LAX, but
it is legal. In that case, the pilot would be expected to depart SMO on
the 068 radial and could descend at his discretion to 5000'. As he
approached SAPPI, he would turn to intercept the SLI 330 radial and
could descend to 4000'. As he approached MERCE, he would turn to
intercept the localizer and could descend at his discretion to 2200',
and intercept the glideslope to complete the ILS approach.
If the aircraft was enroute from SAN and routed direct SLI, then the
phraseology in section 4-8 can be used (because SLI is an IAF).
However, the aircraft is not on a route that provides minimum altitude
information. So an altitude restriction must be included:
"N123SX, cross seal beach at or above 4000, cleared I-L-S runway two four right approach."
Note that the MVA south of SLI for this arrival is much lower than
4000, but the procedure specifies a minimum altitude of 4000 for the
approach after SLI. If you needed to for traffic, you could assign an
altitude higher than 4000, just not lower.
Aircraft inbound from the
CIVET/SEAVU arrivals will overfly an IAF, but we sometimes add "after
PALAC" to the beginning of the instruction to make the approach
clearance effective once the aircraft leaves LAX_FE_APP airspace. The
phraseology in that case is:
"N123SX, after PALAC, cleared I-L-S runway two four right approach."
Most commonly, aircraft will be radar vectored to this approach. As we
discussed there are several rules which need to be complied with in
order to vector to the final approach course. First, he must be
vectored at least three miles from the final approach fix (on a
precision approach, the final approach fix is depicted by the
"lightning bolt" symbol). So your vector must result in the pilot intercepting final at
least 3 miles outside JETSA on this approach. Second he must intercept
final at or below the glideslope and at or above the minimum charted
glideslope intercept altitude (which is 2200' for this approach,
depicted by the same "lightning bolt" symbol). Finally, the intercept
angle must be 30 degrees or less. Since the final approach course is
249, the heading to intercept should be in the range of 220-280.
Let's say we're vectoring this aircraft to final off the SADDE arrival.
The aircraft must intercept final at least 3 miles from JETSA, so we
probably should initiate the turn so he'll be at least 5 miles from
JETSA as he rolls out on his intercept heading. If he does intercept
final exactly three miles from JETSA, he'll be about 10 miles from the
runway and the glideslope at that point will be at roughly 3000' (using
the 300' per mile rule described near the beginning of this article).
So the assigned altitude should be no higher than 3000' (also the
aircraft's actual altitude should be no higher than 3000' when he
intercepts final). The minimum charted glideslope intercept altitude is
2200', so the assigned altitude should be no lower than 2200'. In this
case the MVA is no factor, since it is 1900' in this area. The
phraseology for the approach clearance should be:
"N123SX, 6 miles from JETSA, turn right heading two two zero, maintain two thousand two hundred
until established on the localizer, cleared I-L-S runway two four right approach."
The assigned heading could be anything from 220-240 to intercept final
and the assigned altitude could be anything between 2200' and 3000'.
The LAX approaches get more complex when running simultaneous ILS
approaches or simultaneous visual approaches. Those are covered in the
"Advanced Topics" article. |
|
| SMX ILS12 |
You won't see this approach as a controller until you work center, but
it clearly illustrates a point that comes up from time-to-time. The
area along the localizer course has a relatively high MVA of 3500'. We
have to vector 3 or more miles outside of the FAF, but also at or below
the glideslope. The glideslope crosses HILDY at roughly 2000' MSL. But
we have to vector onto final no lower than 3500' due to the MVA. So how
far from HILDY will the glideslope be 3500'? This is a great chance to
use our 300' per mile rule. 3500' MSL is 1500' above the glideslope
altitude of 2000' at HILDY. Using 300' per mile, we must vector to intercept at least 5 miles from HILDY. It would be
nice to give the pilot a couple of extra miles to get oriented in this
case, so I like to vector to intercept 7 or 8 miles from HILDY on this
approach, this part is not required, just a technique. The phraseology
here is the same:
"N123SX, one zero miles from HILDY, turn right heading 090, maintain 3500 until established on the
localizer, cleared I-L-S approach."
Once the pilot establishes himself on the published procedure, he may descend to 2000' at his discretion.
You could also clear an aircraft for the approach from any IAF using
the phraseology in section 4-8. This approach also uses what's known as
a "feeder fix." ORCUT is not labeled as an IAF, but provides a route to
GLJ VOR which is an IAF. If a pilot was routed over ORCUT intersection
via V27, he could be cleared for the approach using:
"N123SX, cleared I-L-S approach."
No altitude information is needed since he's on a published route with
a minimum altitude. If he was cleared direct ORCUT, you would have to
provide a minimum altitude to maintain until ORCUT:
"N123SX, cross ORCUT at or above three thousand five hundred, cleared I-L-S runway
one two approach."
In either case the pilot would fly inbound from ORCUT on the GLJ 116
radial, then outbound on the GLJ 320 radial until commencing the
teardrop turn to join the localizer. He has minimum altitudes published
throughout the approach, so he can descend at his discretion.
Also, note that the
phraseology for this approach clearance could be "cleared approach"
(although this would permit the pilot to fly any other instrument
approach at SMX also), "cleared I-L-S approach" (since there's only one
ILS at SMX), or "cleared I-L-S runway one two approach." Any of those
is equally correct. |
|
| CRQ ILS 24 |
Many approach students start out on SAN_APP which is a large approach
sector, but has some of the more challenging approaches to vector onto
in ZLA. If the aircraft will overfly an IAF or feeder fix, you can
issue an approach clearance using the phraseology of section 4-8.
That's pretty straight-forward; we'll look at vectoring to this
approach.
The final approach fix is just slightly outside DEASY (again, on an
ILS, the FAF is shown using the "lightning bolt" symbol...in this case
it's 2300' MSL on the glideslope. The glideslope crosses DEASY at 2106'
MSL, so DEASY and the FAF are not colocated). We must vector onto final
at least three miles from the FAF. The FAF is a little less than 1 mile
from DEASY, so we need to vector to intercept
final at least 4 miles from DEASY. Four miles from DEASY on the
localizer is well into the 3400' MVA area. Remember that we must also
vector onto the localizer at or below the glideslope. To estimate the
glideslope altitude at any point we may use the 300' per mile rule
previously discussed, or use charted crossing altitudes on the
procedure. ESCON has a minimum crossing altitude of 3500' depicted, so
if we vector to intercept at or outside of ESCON, an altitude of 3500'
or lower will be below the glideslope. The problem with vectoring
outside ESCON is that there's a 5400' MVA and a 4000' MVA both located
close to it. If you can vector precisely, you can get aircraft down to
3400', vector them to intercept outside of ESCON, and keep them clear
of the higher MVA areas. Then you can use phraseology like:
"N123SX, 2 miles from ESCON, turn right heading 220, maintain 3400 until established on the localizer,
cleared I-L-S approach."
This requires very precise vectoring and close attention, otherwise
you'll likely end up with an MVA bust. If you can't keep the aircraft
inside the 3400' MVA area, you'll (obviously) want to keep them at 5400
or 4000', as appropriate for the MVA. This is where the approach
becomes tricky. If you look at the chart, there's no published
procedure on the localizer course outside ESCON intersection (there is
on the JLI 258 radial, but not on the localizer course). If you use the
"maintain xxx until established..." phraseology, the pilot will have to
maintain that assigned altitude all the way until ESCON where the
published procedure begins. 4000' would be above the glideslope and
5400' would be way above the glideslope at ESCON. There are a number of
ways to deal with this, but you must make sure the pilot is given a
clearance which will get him below the glideslope. Here's one way to
deal with it, if the pilot will approach from the 4000' MVA area (pilot
responses are omitted for brevity):
"N123SX, turn left heading 270, intercept the localizer."
When outside the 4000' MVA area:
"N123SX, 3 miles from ESCON, maintain 3400 until established on the localizer, cleared I-L-S runway
two four approach."
I don't recommend vectoring to final from the 5400' MVA if it can be
avoided (like by vectoring across the localizer and having the downwind
leg on the south side). If you decide to do it, the aircraft will be at
or a little above the glideslope when it crosses into the 4000' MVA
area and will require a steeper descent than normal. Also, in this
case, you'll need to issue two step down clearances, one to 4000', then
one to 3400'.
|
|
| SBA VOR or GPS 25 |
For the most part, any approach procedure that is not titled "ILS" is
considered a non-precision approach. One of the main differences
between the two types of approaches is that a non-precision approach
isn't always aligned with the runway; this is the case with the VOR 25
approach to SBA. Other than that, from a controller's perspective,
there really aren't many differences between precision and
non-precision approaches. In fact, if the pilot begins the approach
from an IAF and you use the phraseology in section 4-8, precision and
non-precision approaches are exactly the same. If the pilot was routed
via V27 to GVO and planning the VOR 25 approach, you could just clear
him using "cleared approach" (keep in mind that this also authorizes
the pilot to fly the ILS 7 if he chose to), "cleared VOR approach,"
"cleared GPS approach," "cleared VOR runway two five approach," or
"cleared GPS runway two five approach." Just like with the ILS
approaches we've already looked at, if the pilot were cleared direct
GVO or any other IAF, you have to include an altitude restriction since
he wouldn't be on a published route. Note that a procedure with "or" in
the title means that you clear an aircraft for one approach or the
other; don't use "cleared VOR or GPS runway two five approach."
It's also important for the controller to understand what the pilot
will do once he begins the approach. For this procedure, if the pilot
begins at GVO, he'll depart GVO on the 099 radial and maintain 6000 (or
descend to 6000 at his discretion if at a higher altitude). After ZACKS
intersection (identified by either the GVO 20.7 DME, or the RZS R-145),
the pilot can descend at his discretion to 3000. He must complete a
course reversal on the south side of the GVO R-099 while remaining
within 10 miles of ZACKS intersection. Once he's established inbound
back toward ZACKS, he can descend at his discretion to 2100'. After
ZACKS, he can descend to 920' at his discretion. Once he sees the
runway, he can maneuver to line up with the runway and further descend
at his discretion. If the pilot doesn't see the runway by the missed
approach point (defined on the chart as GVO 14.7 DME), he will execute
a missed approach. As a controller you always need to know the missed
approach procedure, because an instrument approach clearance is also a
clearance to fly a missed approach.
Vectoring to final for a non-precision approach is very similar to an
ILS. The only difference is that, since there's no glideslope to vector
below as with an ILS, the .65 requires that you vector so that they
intercept "at an altitude which will allow descent in accordance with
the published procedure." As discussed previously, the 300' per mile
rule still works here for figuring out if that at an appropriate
altitude for the intercept.
Since this approach is mostly out over the Pacific Ocean, there are no
MVA concerns when vectoring to final (there is high terrain and high
MVAs in the area, just not near the final approach course). The MVA
south of the final approach course is 1900'. Since the charted final
approach fix altitude is 2100', we should vector to final no lower than
2100'. In this case, the phraseology would be:
"N123SX, 5 miles from ZACKS, turn left heading 300, maintain two thousand one hundred until established
on the final approach course, cleared V-O-R runway two five approach."
Because of the high terrain in the area, you might have an aircraft
still descending toward 2100 when you're turning him to intercept.
That's ok, just make sure that his actual altitude complies with the
300' per mile rule. So if he will intercept final 10 miles from ZACKS,
he can be as high as 5100' MSL (2100' FAF altitude plus 300' times 10
miles) at the point of intercept. |
|
| LAS VOR/DME-A |
This is an approach LAS_APP students will see regularly during their
training. Note that it doesn't have a runway in the title, just a "-A".
If no runway is specified it means one of two things; either the
approach is not aligned within 30 degrees of a runway at the airport,
or that the descent angle from the final approach fix to the runway is
too steep. In this case, the approach is reasonably well aligned with
runways 1L and R, but because the final approach course does not
intersect with the runways' extended centerlines, it can't have
straight-in minimums published. However, a pilot may still request to
fly the approach and land on 1L or R.
This is a more challenging approach to vector aircraft from the west
side of the final approach course. The terrain S of LAS rises fairly
rapidly and we still need to vector so that pilots intercept "at an altitude which will allow descent in accordance
with the published procedure."
It's common to vector aircraft for the approach off the CLARR2/KEPEC1
arrivals from the SW. They eventually approach through a 7700' MVA
area. If we tried to vector to intercept 3 miles from NICZU (just like
an ILS, we must vector to intercept at least 3 miles from the
final approach fix) from the west side of final, the aircraft will have
to be kept at 7700' until very close to intercepting final. The charted
minimum altitude at NICZU is 5400'...a 3 mile intercept would require
that aircraft be no higher than 6300'. The solution here is to vector
to a longer final. Note that the charted minimum altitude at KACCY is
7100'. If we vector so that the aircraft intercepts at least 2 miles
from KACCY (based on the 300' per mile rule), then we can keep them at
7700' and they'll be "at an altitude which will allow descent in
accordance with the published procedure."
The phraseology is the same as other approaches, but we'll include a circle-to-land instruction:
"N123SX, 4 miles from KACCY, turn left heading 020, maintain seven thousand seven hundred until established
on the final approach course, cleared V-O-R D-M-E Alpha approach, circle to runway two five left."
Also note that this approach has one IAF (KACCY) and two feeder routes
to the IAF (from BLD and LAS). If aircraft will overfly any of these
fixes, they may be cleared for the approach using the phraseology in
section 4-8. |
|
| SMX LOC/DME BC-A |
This is an example of an approach which has only circling minimums
published, but is perfectly aligned with runway 30. The reason for the
circling only minimums in this case is that the descent gradient is too
steep (if you are interested in numbers, this is defined as exceeding
400' per NM...this case works out to approximately 450'/NM) between the
final approach fix and the runway to allow for straight-in minimums.
The pilot may still choose to land straight-in on 30, but must comply
with the published circling minimums until he sees the airport. This
approach only has one IAF, which is RZS, and there are no feeder fixes.
If a pilot approaches from the SW-NE, you'll probably end up vectoring
him to final. There's nothing too complicated in this case though. The
MVA is 3500 in the area of KOAKS. The MVA does rise to 5000' pretty
quickly NE of the final approach course, but as long as the pilot
intercepts a couple of miles outside KOAKS, 5000' would be acceptable.
The usual rules apply, you must vector to intercept at an angle of no
more than 30 degrees, at an altitude that will allow the pilot to
descend in accordance with the published procedure (and, obviously,
at/above the MVA). The approach title can be a mouthful:
"N123SX, 8 miles from CAMCO, turn left heading 330, maintain 3500 until established on the final
approach course, cleared Localizer D-M-E Backcourse Alpha approach."
Remember that circling instructions are only issued if there's an
operating control tower and a circling maneuver will be performed. If the pilot flying this
approach
planned to land straight-in on 30, there'd be no circling maneuver and
we wouldn't issue circling instructions. |
|
| SMO VOR or GPS-A |
Santa Monica is probably the most complex class D airport in ZLA for a
radar controller. It sits just a few miles from LAX and its procedures
have the potential to conflict with LAX's procedures. Its only
approach, the VOR or GPS-A, is a somewhat complex procedure as well.
The terrain north of SMO and north through northeast of DARTS
intersection makes this a challenging approach for a controller. The
easy way out is to have an aircraft inbound from the east on V186.
ELMOO intersection (the only IAF) is on V186 and those aircraft can be
cleared for the approach by just stating "cleared approach." But what
about an aircraft routed via the FERN5 or KIMMO2 arrivals?
One of the requirements to vector to final is that aircraft must be
turned to intercept at least three miles from the FAF. BEVEY is the
FAF; if you measure 3 miles from BEVEY in ASRC or VRC, you'll see that there's a relatively small area to vector
aircraft to final before the terrain rises very rapidly to the northeast. These vectors also require a slow speed to ensure a
good turn rate; regardless of aircraft size, its airspeed will
determine its turn rate and radius at a particular bank angle (e.g. at
170 knots, a King Air and a 747 will have the same turn rate and radius
with a 25 degree bank angle). As long as the aircraft was in the 3000' MVA
area, the phraseology would be familiar:
"N123SX, five miles from BEVEY, turn right heading 180, maintain 3000 until established on the final
approach course, cleared V-O-R Alpha approach."
There is at least one alternative. You could vector the aircraft to the SE side of the
final approach course where the aircraft could have a longer final and still
be within the 3000' MVA area and
in good shape for the descent once established on the approach. Note
that a person working BUR_APP as a single sector would need to request
a pointout as the vector would enter LAX_APP's airspace.
Keep in mind that, unless the pilot will actually execute a circling maneuver,
circle-to-land instructions are not required. Note that if runway 3 is in use, the
pilot is required by the
procedure to make right traffic; even pilots who fly a tight traffic
pattern would likely conflict with LAX departures. When clearing an
aircraft for any circling approach, always make sure
you protect the airspace he'll need or issue the pilot restriction(s) to prevent a conflict
between aircraft at adjacent airports. |
|
| SAN LOC 27 |
This is probably the most common non-precision approach in ZLA. Because
of obstacles in the approach path, it doesn't meet the requirements for
an ILS approach. There is one IAF, so you could clear an aircraft
direct RYAHH, which is a fix on V66 but not included on any of the
STARs for the airport. Most of the time you will vector to final for
the approach.
This approach has some fairly complex MVA considerations. As with any
approach you must vector to intercept final at least three miles from
the FAF (REEBO in this case). REEBO has a published minimum altitude of
2000'. With very precise vectoring, it might be possible to vector an
aircraft to intercept final inside the 2100' MVA area exactly 3 miles
from REEBO. However, a little over 4 miles from REEBO, the MVA rises to
3800'. You will normally vector to this approach through this 3800' MVA
area. At 3800', the aircraft would be 1800' above the minimum altitude
at REEBO. Using our 300' per mile rule, this means that the aircraft
must intercept final at least 6 miles from REEBO if he's at 3800' (again, he must be at 3800', not
issued a descent clearance to 3800'). The phraseology would be familiar:
"N123SX, 8 miles from REEBO, turn right heading 250, maintain three thousand eight hundred until
established on the localizer, cleared Localizer runway two seven approach."
Further out on the localizer, the MVA rises to 5000'. Similar to the
ILS 24 at CRQ we previously discussed, there is no published procedure
on the localizer course east of VYDDA. If you vector to intercept
through the 5000' MVA area and use "maintain 5000 until established on
the localizer," the pilot will have to remain at 5000' until VYDDA
where the published approach begins. This will put him at an altitude
higher than the 300' per mile rule allows. If you vector through the
5000' MVA area, one solution is to delay issuing the approach clearance
until the aircraft enters the 3800' MVA area. Use phraseology like:
"N123SX, turn right heading 250, join the localizer"
Once he's clear of the 5000' MVA area:
"N123SX, 4 miles from VYDDA, maintain three thousand eight hundred until established on the
localizer, cleared Localizer approach."
There will be times where you will want to break the approach clearance
up into separate transmissions for other reason too. This might be
desirable because of pilot proficiency, frequency congestion, or due to
traffic. This is always permissible for any type of vectored approach
clearance, and here is a sample application of this procedure for this
approach:
"N123SX, turn right heading 250, intercept the localizer."
Once he reports established or is observed to be established on a published segment of the final approach course:
"N123SX, Over SWATT, cleared Localizer approach."
If the pilot is established on a published segment of the approach, no
altitude information is needed in the approach clearance. |
|
| L35 RNAV 26 (Big Bear City) |
At first glance, this approach looks relatively simple, and it is. It's
a good approach to illustrate one of the requirements for RNAV approach
clearances. In section 4-8, the .65 adds one additional requirement
that is unique to RNAV approaches. It's 4-8-1-b-3 which requires that
aircraft be "Established on a heading or course that will intercept the
initial segment at the initial approach fix...for a GPS or RNAV
instrument approach procedure at an angle not greater than 90 degrees.
Angles greater than 90 degrees may be used when a hold in lieu of
procedure turn pattern is depicted at the fix for the instrument
approach procedure." Since there's no hold depicted at OKACO that's
part of the approach procedure (the hold that is depicted is part of
the missed approach, not a hold in lieu of a procedure turn), the pilot
must approach OKACO on a course of 166 clockwise through 346. If an
aircraft were routed via V386 from PMD to OKACO, that would set the
pilot up for an intercept angle greater than 90 degrees. In that case,
even though the pilot will overfly an IAF, he'd have to be routed out
to the east somehow to set up an acceptable intercept angle. Once the
intercept angle was acceptable, the approach clearance phraseology is
the same as we're used to:
"N123SX, cross OKACO at or above one one thousand, cleared approach."
Remember that distance is not required in the approach clearance if the
approach will begin at an IAF. You could also radar vector to final for
this approach. The MVA along most of the approach course is 10,000. The
minimum altitude at HALVI is 9100'. Using our 300' per mile rule, we'd
need to intercept at least 3 miles from HALVI, which conveniently is
exactly how far we must always intercept final from a radar vector
anyway. So, the phraseology could be:
"N123SX, 7 miles from HALVI, turn right heading 230, maintain one zero thousand until established
on the final approach course, cleared R-NAV runway two six approach."
Just like the LOC 27 example above, you might want to break this approach clearance up into two parts:
"N123SX, turn right heading 230, intercept the final approach course."
Once he reports established or is observed to be established on a published segment of the final approach course:
"N123SX, 5 miles from HALVI, cleared R-NAV approach."
However, if the pilot intercepted final outside of OKACO, then he would
not be on a published segment of the approach and would need altitude
information in some form with his clearance; some possibilities are
(these transmissions all assume that the pilot has been issued the
first instruction above with a heading and instructions to intercept
final):
"N123SX, 3 miles from OKACO, cross OKACO at or above one zero thousand, cleared R-NAV runway two six
approach."
or
"N123SX, 4 miles from OKACO, maintain one zero thousand until established on a published segment
of the approach, cleared approach."
or
"N123SX, 2 miles from OKACO, maintain one zero thousand until established on the final approach
course, cleared approach." ****
**** Note that this phraseology should only be used if the pilot is not
already established on the final approach course. For this approach, if
the pilot is established already inside OKACO, the altitude information
may be omitted; if he's established outside OKACO, then use either of
the two previous phraseologies. |
|
| PSP RNAV Y 13R |
At first glance this approach looks pretty complex; and it is...for the
pilot. The .65 doesn't address these new procedures (yet); but from a
controller's standpoint, we can't vector to final because the MVAs are
too high along much of the approach course, and it would be difficult
to establish a 30 degree intercept angle with a curving approach path.
If we can't vector to final, we're left with section 4-8, which means
the pilot must begin from an IAF. A pilot inbound on the SBONO1 arrival
(which ends at SBONO intersection...one of the IAFs) could just be
issued:
"N123SX, cleared R-NAV Yankee runway one three right approach."
Note if something's enclosed in parentheses in the approach title, it's
not spoken. In this case, the "(RNP)" is not spoken; the same is true
with the more common "RNAV (GPS)" approaches, the "(GPS)" part is not
spoken. |
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