Who Needs Holds?
Sure, you're supposed to know how to do them, but have you ever noticed how ATC hardly ever uses the dumb things? Here's the real story about holding, and its cousin flow control.
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.
"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.
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."
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.
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!"