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Paul Berge |
This article originally appeared in IFR MAGAZINE and is reprinted here by permission of Belvoir Publications.
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Remember when you were studying for your instrument written and
you came to the chapter on holding? Remember how your brain went
numb and you had flashbacks to high-school algebra class? I realize
there are a few people who actually understood algebra (not me)
and those same individuals probably understand how to enter a
holding pattern while calculating their weight and balance and
fuel remaining.
Luckily, as a controller, I'm never taxed to that extent. To the
average Midwestern radar controller, the holding pattern is about
as relevant as the light gun in the control tower. Not every controller
can tell you with certainty what an alternately flashing red and
green signal means. That's why every light gun has a sticker on
the back with all the signals decoded. In short, light guns, like
holding patterns, belong in the Smithsonian:
"Yes, son, that's a holding pattern. We used those when there
was too much traffic on the NDB approach."
"Gee, Mom...what's an NDB?"
The Old Days
Or maybe I should rephrase that to ask: "What's a hold?"
The fact of the matter is, holds don't top the list of clever
ways to cope when there's just too much traffic. Instead of figuring
out an EFC time that the pilot won't believe anyway, when radar
is in use, it's just a lot easier to slap on speed restrictions
and issue a few wide vectors. Pretty soon, everything smooths
out and settles back down to routine chaos.
As you can probably surmise, it wasn't always that way. In the
old days, when pilots smoked cigars and controllers wore white
shirts with skinny ties, holds were a standard way of doing business.
Since radar didn't exist, issuing vectors to airplanes you couldn't
see wasn't considered too sporting. All controllers could do was
rely on a pilot's position reports and park him in a hold if he
got too close to other airplanes.
Back then, when controllers were first hired, they were sent to
the FAA Academy in Oklahoma City. After the usual haircuts and
immunizations, we were placed in a tiny classroom for many weeks
working simulated nonradar traffic. Each student would sit before
a board with lots of tiny flight progress strips representing
aircraft with notations on route and altitude. The ATC instructor
would "start the clock" and airplanes would check on
frequency. The roles of the pilots were played by North Korean
POWs masquerading as fellow student controllers.
Using the strips, the student would form a mental image of where
the traffic was. For me, it was always a rather muddy image. As
more and more simulated pilots checked on frequency, aircraft
would come into conflict-meaning they would hit. To avoid conflict,
the student controller could whip a hold on a pilot, stopping
one aircraft's progress along an airway until the conflicting
aircraft had crossed safely, then the holding aircraft would be
cleared on course. This is basic non-radar ATC.
It ain't easy. We hated it.
What's even tougher is having an instructor sitting behind you
evaluating your non-radar control technique, or lack thereof.
As traffic complexity increased and controller perspiration responded
exponentially, more and more aircraft would come into conflict.
Eventually, the simulated skies would be loaded with simulated
aircraft simulating midair collisions. That's when the instructor
would throw down his clipboard and shout, "STOP THE CLOCK!"
With a flick of a switch on the timer, all the traffic would freeze
and the instructor could point out the conflicts and offer the
trainee a resolution, such as finding alternate employment. The
point is, when air traffic becomes too congested, it has to be
stopped. In the real world, we can't stop the clock, so we have
to stop the traffic.
That's easy when they're on the ground. If the radar room finds
itself buried in traffic, a controller can hit the panic button
and tell the tower to stop departures. But if a radar controller
is inundated with arrivals and the localizer loads up, the preferred
response is to just vector everyone around a little bit until
the spacing sorts itself out.
Speed reductions can smooth out an arrival operation, too. Slow
everybody to 170 knots and you suddenly have a manageable group,
except for the Cherokee who couldn't do 170 knots pointed straight
down with the wings folded. (I don't recommend that, by the way.)
Believe it or not, holding really is a last resort, which is why
you don't do it very often.
Huh, No Radar?
Quite a few ATC facilities
still work traffic non-radar. If you're flying to one of those
destinations and you need to shoot an approach-even a visual-and
there's anyone else ahead of you, you can expect holding. If lots
of airplanes are inbound, a stack of airplanes is built over the
same fix.
Once the first aircraft lands or cancels IFR, the next in the
stack is cleared for the approach. If the stack on final gets
too crowded, then aircraft are held at outlying fixes and moved
up as the final-approach holding pattern clears.
Building a stack is easy. The first aircraft in line is cleared
for the approach, then the second is held 1000 feet above the
first, then the third aircraft is held 1000 feet above the second
and so on. This continues until approach runs out of airspace
or the pilots can't breathe. At Des Moines, we can only stack
to 10,000 feet without invading Center airspace. As an aircraft
vacates an altitude, the whole stack is lowered a notch and the
latest arrival is tossed on top.
But what happens if you're arriving in your past-TBO Cessna 172
with your 250-pound mother-in-law and the stack tops out at 10,000
feet? Are you expected to climb up and hold? Sometimes you are,
but, as PIC, you can always decline that. It's not unusual, in
non-radar, to ask a pilot to climb 1000 feet for a hold or some
other form of separation. Vertical separation is the easiest and,
when I work, the safest form of separation.
Custom Patterns
When the Cessna arrives and can't climb-maybe there's ice above-
then the controller will park it at an alternate fix. Each approach
facility has a rather crude non-radar map of the airspace. Holding
patterns are depicted by large ovals surrounding various fixes-VORs,
intersections, whatever. These holding patterns are not necessarily
depicted on pilot charts and are drawn according to TERPs rules
which say how much airspace is needed. The protected airspace
for a holding pattern increases with altitude, aircraft speed
and distance from the navaid. Two holding patterns that are charted
to be separated at 5000 feet might overlap at 14,000, so only
one can be used at a time at the higher altitude.
The maps are usually hand drawn using stencils for the various
holding patterns. The only problem is when the non-radar procedures
are actually used, controllers have no idea what the pilot is
doing in that holding pattern or even if the pilot has remained
inside the protected airspace.
It's a system built on trust and a big sky. In a non-radar hold,
the only "snitch" is the guy in the holding pattern
next to you who's getting tired of watching you overshooting the
fix.
In non-radar operations with more than a one-in-one-out operation,
the controller can resort to a really ancient procedure: timed
approaches. When one aircraft reports FAF inbound, the next aircraft
in the pattern can be cleared for the approach with a restriction
to cross the FAF at or after a specified time. Tightly run timed
approaches can move a lot of airplanes if everyone hits the slot.
The AIM (section 5-49) describes all of this, but don't worry
too much if you've never heard of it. Your chances of encountering
a timed approach are maybe a little less than hitting the Play
20 lottery.
If you're planning to operate in airspace controlled by a real
nonradar approach control, then be ready to deliver when a controller
issues you a hold. Non-radar approach controls sometimes work
with smaller chunks of airspace than a radar facility might have.
As a result, holding patterns are crammed in as close as possible.
Staying inside your protected airspace is crucial.
Controllers are required to issue holding instructions at least
5 minutes prior to the aircraft entering the hold. This gives
the pilot a chance to reread the AIM chapter on holding and get
the plane slowed to proper holding speed. Holding airspace is
protected around the fix based on the aircraft overshooting the
fix upon entry. Enter too fast and you might slop into someone
else's protected airspace.
One of the surest ways to avoid a hold is to never get there.
If ATC says, "Mooney One Two Three, cleared to the Ralph
VOR; hold south on the 180-degree radial; expect further clearance
at 1545; time now; 1530," then you may wish to reduce speed
and eat up the delay en route rather than make circles. Of course,
if ATC says, " . . .expect further clearance at. . . "
then asks if you have a calendar handy, you may be in for a delay
in the hold.
Technically, you are expected to begin speed reductions (if necessary)
3 minutes prior to entering the hold . If you opt for the speed
reduction prior to that to avoid the hold, you should inform ATC.
Probably they won't care. A Cessna at 80 knots isn't much different
than one at 110 knots. The main reason ATC needs to know who wants
to slow down to avoid a hold is so they can identify the weak
sticks in the flow and make certain they're last when things open
up.
"Hey, Eudrice, watch this Cessna! He doesn't know how to
hold!"
Okay, so except for non-radar, you don't encounter holds very
much and even when you do, the controller may issue holding instructions
even though he or she knows you'll probably never enter the assigned
hold. Air traffic control involves a lot of rigid rules and looking
ahead to see where everyone will be in a few minutes.
If two aircraft are inbound for the same airport, then, obviously,
someone's first and someone else follows. In the radar environment,
a single minor heading change can establish the sequence.
When traffic volume increases, a combination of headings and speed
control establishes the order of events. When two aircraft must
shoot a non-radar approach, but the first aircraft will probably
cancel IFR before the second one arrives, and the controller can't
100 percent guarantee that, then the second aircraft is issued
holding instructions, or "cleared short" of the destination.
If I'm working two aircraft in that situation, I'll clear the
first one for the approach and inform the pilot that someone's
waiting for him/her to cancel IFR. This is called "pimping"
(see Pilot/Controller Glossary) and is used mostly at satellite
airports without control towers to encourage a pilot to cancel
before actually landing. Of course, as PIC, if you're feeling
you don't want another aircraft right behind you as you circle
to land, then you have every right to hold off on your cancellation.
In this case, the second aircraft in line is issued holding instructions,
but the controller expects the first aircraft to be down before
the subsequent aircraft has to enter the hold The holding takes
place only on paper and is called a "paper stop."
Real Holds
When radar facilities do issue honest-to-goodness holds, it's
usually because of weather, and often the hold comes at the pilot's
request. Part 121 and 135 operators have varying op specs, but
all share one requirement: The airport has to be reporting the
minimum visibility required for the approach before they can accept
an approach clearance.
In really low weather, RVR rises and falls almost by the minute,
and if the field reports below minimums before the aircraft passes
the FAF, the crew will often request a hold until the RVR comes
up. Often, we can spend a morning chasing the RVR up and down,
switching from one runway to the other in hopes of getting a better
combination of RVR reports and wind conditions. Despite everyone's
efforts, no one lands and, soon, the diehards in the hold are
figuring their fuel and continually asking ATC if the RVR has
improved.
Of course, as a Part 91 driver, you can ignore that requirement
and cruise right past that commuter doing spins over the marker
at 5000 feet. (You still need landing minimums, however.) You,
the PIC, make the decision whether to shoot the approach when
the visibility deteriorates. A controller may have no idea what
your requirements are or whether you're operating under Part 91,121
or 135. If I inform you that runway 31R RVR is 800 feet and you
say you want the approach, I'm going to clear you for it and tower
will clear you to land. It's your call and the fact that three
airliners are in the hold awaiting another 400 feet of RVR has
no bearing on it.
Special Programs
Not all holding operations are because ATC has too many airplanes
or because the weather stinks. Special operations, such as the
arrival of presidential aircraft, can throw everyone else into
holding. Expect further clearance times are based on which political
party is onboard Air Force One. Republicans time their arrivals
and departures to the exact second, so we can issue EFCs with
some accuracy. A recent unnamed Democratic president, however,
can't seem to keep to a schedule, so EFCs tend to be vague. I
miss the Reagan years. When Nancy said A1 was departing at 1755Z,
well, it departed.
When we actually do issue holds under radar control, we get to
watch the pilots fumble through the entries. Entering a holding
pattern without looking like you're trying to copy a Sean Tucker
aerobatic maneuver takes a little skill. But not much. What may
begin as a teardrop entry can degenerate into an endless clover
leaf that sorta, kinda goes around the holding fix.
When in doubt, some pilots panic and just dive on the fix the
best way they can in hopes of becoming reoriented. We call this
the "tethered or bungee hold." Any attempt at timing
either inbound or outbound legs becomes sheer fantasy. The tethered
pilot just wanders around the fix trying to hold altitude and
hoping ATC comes up with a clearance out of the hold.
Many pilots labor under the misconception that controllers know
all about hold entries and that they'll spank you on the frequency
if you fly a parallel when you should have done a teardrop. Take
it from me: nobody cares. As long you're flying vague ovals somewhere
near the assigned fix and you stay out of everyone's way, life
goes on.
Twists and Turns
When holding in a radar environment, the controller is not required
to apply merging-target procedures to turbojets at any altitude
or recips above 10,000 feet (see ATC 7110.65, 5-8). This means
you may see the same MD-80 belly passing over you again and again
with no traffic call, while holding at Denver. If you don't like
your holding pattern you can ask for variations. If you want longer
legs or alternating left and right turns, you can request it.
You can even request a block altitude in the hold if there are
some clouds around you that might be fun to chop up while you're
waiting. There's no regulation that says holding can't be interesting.
Speaking of interesting, find a copy of Ralph Nader's latest diatribe
against living without a safety helmet. The book is entitled Collision
Course (Tab Books.) I suppose all of us owe our very existence
to Ralph, and although his book is well written, (despite every
sentence sounding like an air-raid warning), those who actually
use the system might occasionally wince. Ralph, of course, is
convinced the sky is falling.
Ralph devotes a few pages to the lost art of holding and seems
to mourn the declining use of the procedure. "First and foremost
among these (lost ATC skills) is the art of holding airplanes...."
Ralph probably misses steam locomotives, button hooks and leisure
suits. He goes on to quote an unnamed ATC source: "Unfortunately,
holding is fast becoming a lost art, except in the Eastern part
of the United States."
Well, a tip of the headset goes out to all you folks holding over
New Jersey. But out here above the prairie, we've set that lost
art out back of the barn with the old steam combine. Sure, we
could fire either one up should the need arise (spit), but I reckon
we can muddle along by keeping holding-pattern use to a minimum.
And if any of you Easterners would like to check up on us, then
just stop by the DSM tower, and we'll brush the checkers off the
radar scope and show you we can still issue a holding clearance.
It's easy. We just holler, "STOP THE CLOCK!"
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