Today, Air Traffic Controllers use what they call ‘flow control‘ in an attempt to prevent in-flight holding patterns. That means that when a holding pattern becomes necessary it is due to an unexpected event — therefore, the pilot will get very little time to think.
STOPPING DELAYS… BY STOPPING TRAFFIC?
Controllers try to prevent delays in the air by stopping an IFR departure on the ground prior to takeoff. This is why, sometimes, you are told to ‘hold for release‘ even when the weather at the departure airport is no problem. Once in the air, any anticipated delays are already taken care of — but occasionally there will be an unanticipated delay which will cause the pilot to waste time (and fuel) by flying a holding pattern. An airplane ahead of me on an instrument approach blew a tire upon touchdown — this was an unanticipated delay that put me into a holding pattern for several minutes. Airplanes cannot waste time by hovering in one spot, so instead we fly a racetrack pattern in the sky. But this racetrack must be flown at a particular location. The good news is that these delays are rare. The bad news is that, because they are rare, we seldom practice them and it is easy to forget how to do it.
Note: The IFR recent experience rules now require that pilots practice holding patterns at least every six months in order to maintain IFR currency.
WHAT DID THEY SAY?
Because a holding pattern can be necessary due to an unanticipated delay, there may be little or no time between receiving hold instructions and actually having to enter the hold. The controller will be under stress to stick you somewhere out of the way so that they can get back to solving the real problem elsewhere on their radar screen. The instructions, therefore, will come from the controller with a sense of urgency — which means they will come out fast. It pays to understand the lingo and order of a hold clearance.
HOW IT WORKS:
The hold clearance comes out in code, but it always comes out in the same order each time. ‘N4601Romeo, Hold West of the Shelbyville VOR, on the 270 degree radial, Left Hand Turns, EFC at 55, time now 40, over‘ Lets break down that hold clearance and decode it.
- ‘Hold West of the Shelbyville VOR‘
Whenever the controller uses a general direction by its name: Southwest, East, Northwest, South, etc., they are talking about the general direction of the outbound leg. Every holding pattern is shaped so that the pilot will fly straight and level to a ‘fix’ and then, after crossing the fix, they start a turn. A ‘fix‘ can be any location that can be identified by using radio navigation: passing a VOR or NDB, a DME position along a radial, the intersection of two radials, etc. The turn can either be right or left depending on the instructions. The outbound leg is the leg flown away from the fix on the ‘back stretch‘ of the racetrack.
- ‘on the 270 radial‘
The 270 radial is used in this example as the holding line and will also be the inbound leg of the holding pattern. Once in this holding pattern, the pilot would fly straight and level inbound to the VOR on the 270 radial — which would make their inbound heading approximately 090 degrees. Once over the station, the pilot would make a 180-degree turn to the outbound direction. That outbound direction in this example will be in the general direction of West. (I say ‘general direction’ instead of exactly 270 to allow for wind correction angles.)
- ‘Left Hand Turns‘
Standard Traffic Patterns are made to the left — this makes it easier for the pilot, who normally sits on the left, to see the runway. But, Standard Holding Patterns are to the right. Often a controller will issue the holding instructions and never mention anything about the turn direction. When that happens, it was omitted on purpose. If the controller makes no mention of the hold’s turn direction — then you assume it will be a standard right hand pattern. If the turns are to be made to the left, the controller must say ‘left hand turns‘ as in this example.
The diagram illustrates the holding pattern to be flown from these instructions, but this is just one example. How many holding patterns do you think are possible at a normal VOR station? There are 720 possibilities –you could hold on each one of the 360 radials using right hand turns and again on each radial using left hand turns a total of 720 different holding patterns. You can’t memorize them all, so you must be able to interpret the hold instruction individually.
- ‘EFC at 55, time now 40.’ This means that you have a clearance to hold until 55 minutes past the hour. EFC means you should ‘Expect Further Clearance‘ at that time. To make sure that your watch matches the controllers watch they say ‘time now 40‘ as a suggestion that you synchronize your watch with theirs. The EFC is your insurance policy against two-way radio communication failure.Important: What if you had no EFC, but entered into a holding pattern in the clouds anyway. If your comm radio failed what would you do? You can’t hold forever, eventually you would run out of fuel. But you can’t just leave the holding pattern anytime you want, because you could be flying into the very congestion problem that caused your hold in the first place. Without an EFC you would be stuck, so the thing to remember is that you should never accept a hold clearance without an EFC. If you must hold past the EFC time — get another one from ATC if one is not offered.
BOTTOM LINE: We all hope we never have to hold, but if we do we must insure that we hold at the proper location, making proper turns, and with an insurance policy against communications radio failure. It’s never a bad time to brush up.