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When VFR is IFR
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By Fletcher Anderson
When you first began training for a private pilot’s license, you did some flying under the hood. But all the while your instructor was drilling into you the notion that just because you were being trained to fly through a cloud didn’t mean you could now just go out and do it. Later, if you got an instrument rating, the instructor must have stressed more times than you can count that on any given flight you are either VFR or you are IFR. You can’t be both. The reason for this is understandable enough — while your IFR skills and equipment can keep you from running into stationary objects you can’t see, like the ground or a mountain, they cannot keep you from running into other planes. You avoid running into other planes because when you are in the clouds, everyone is flying assigned routes and altitudes and is talking to traffic control, who handle the traffic separation for you.
Regardless of the legalities and traffic, year after year the most common cause of accidents in small aircraft is accidental flight into IMC conditions. It really does not pay to try flying “almost IFR” or “almost VFR.”
If you fly a big plane, then at this point you are probably thinking, so what? Whether or not you can see, you are virtually always in the instrument traffic control system anyway. On the other hand, if you fly a small plane, you almost always prefer not to fly on instruments. The instrument workload is dramatically higher. The assigned routes are anything but direct, and the time lost is significant. Small planes carry ice poorly, so you hope to stay out of clouds entirely in the winter months. Enroute altitudes for instrument flight more often than not involve oxygen, and at least in the Mountain States, they can require altitudes your small plane can’t reach anyway. Finally, when flying VFR you are making your own decisions about terrain and weather rather than letting someone hundreds of miles away in a windowless room make those decisions for you.
For an awful lot of small plane pilots, instrument weather conditions means the same thing as postponing the trip. But there are circumstances when you can fly visually both legally and reasonably safely when the weather is below visual minimums. There can be times when you might decide these seemingly marginal operations might be safer than just flying on instruments. Let’s look at three examples:
IFR to VFR on Top
You can fly perfectly well in good visibility above a layer of clouds, provided you have a safe way to get up and far more importantly, a safe way to get back down.
Along the Pacific Coast, particularly in winter, there can be dense early morning fog with visibility less than half a mile on the runway, but the fog layer tops out in bright sun only a thousand feet higher. Even the low coastal hills are above it all in clear air, as are all the inland airports. Closer to home, most, if not all, airports located in the bottom of a valley can experience the same thing, particularly after a nighttime temperature inversion.
Don’t you wish you were flying? Sure it’s dark and gloomy on the ground, but it’s a beautiful day just a couple of hundred feet higher. Once above the clouds, wouldn’t you be happier to maneuver at will? What if the purpose of the flight is something like sightseeing or photos rather than point to point? Instead of flying the whole flight on an IFR flight plan along assigned routes, you can file a flight plan for IFR to VFR on top.
Here is how to do it: Instead of filing IFR, you file you file your flight plan IFR to VFR ON TOP. You still go through all the complete instrument procedures of getting a clearance before you take off, reading it back, flying an assigned route or assigned departure procedure, squawking an assigned code on your transponder, contacting a controller, and so forth. In short, you depart on an instrument flight just like any other instrument flight. The difference is that the instructions in your instrument clearance read something like “…departure frequency xxx.xx, climb as filed to VFR on top, if not VFR by xxxx feet, maintain xxxx feet and advise…” Once you break out on top of the clouds, you can cancel IFR and fly VFR.
A word here about procedures though: Remember again that IFR flight is an entirely controlled procedure, while VFR flight outside the boundaries of an airport is uncontrolled. The same controller who was just telling you what to do is now only advising you. You cannot casually lapse back and forth from one to the other. The controller is going to remind you of this after you cancel IFR by instructing you to “Maintain VFR.” In fact, while the Instrument portion of the flight is handled by an air route traffic control center (called XYZ Center on the radio), the visual portion of the flight plan is on file with a Flight Service Station located somewhere else on a different frequency, (called ABC Radio). In effect, you have two flight plans on file with two different groups of people, each of which needs to be activated and closed. The Instrument flight plan opens automatically when you are cleared for takeoff. It closes when you tell a controller “cancel IFR.” The visual portion of the flight plan does not then automatically activate. It activates when you call Flight Service and activate it, and closes when you call and close it. After you cancel IFR, you need to call a Flight Service radio — whose frequency is typically found on your sectional chart — and activate your VFR flight plan. Then you need to close it either by phone or radio when you land.
Why this second flight plan? Well, if for some reason you don’t break out of the clouds as expected, you need some sort of assigned routing to continue with. Also, if you don’t arrive at your destination, someone will come looking for you and they will know where to look.
Special VFR
Just what’s so special about Special VFR? It allows you to fly visually in what are technically instrument weather conditions. If this sounds too good to be true, then it probably is. If this sounds stupid and dangerous, it probably is as well. Why would you be tempted to try something stupid and dangerous? Let’s quickly review cloud clearance and visibility minimums.
In class C or D airspace you cannot fly unless you are 1000 feet above, 2000 feet to the side of, or 500 feet below clouds, and you need three miles visibility. Some of these airports will have their own published instrument departure minimums as well. The same cloud clearance and visibility requirement is true for class E airspace below 10,000 feet msl, which generally includes Victor airways and most of the airspace around non-towered airports that have instrument approaches. These requirements are not so much to keep you from hitting the ground as they are to keep you from colliding with instrument traffic coming through the clouds.
In class G airspace though, which includes most rural areas here in the Southwest, if you are within 1200 feet of the ground, you only need one mile visibility and clear of clouds. Special VFR allows you to fly using the more relaxed class G minimum visibility requirements in more restrictive airspace.
Now all of your friends are sincerely hoping that you are not planning to head out scud running close to the ground on a long cross country flight in that kind of marginal weather and visibility. How will you save yourself if things get just a little worse? But you can take advantage of these regulations to take off when you know better conditions are close at hand. You might want to climb above a very low broken cloud layer or fly out of the clouds nestled in a valley into conditions known to be better a couple of miles away.
To do this, you need a Special VFR clearance. Don’t expect to be given such a clearance at a very busy airport. In fact, most class B airports have “no special VFR” written right on the chart. The best advice is not to try this at night either, although it is legal for instrument rated pilots flying instrument capable aircraft.
While this is arguably not an IFR procedure, like an IFR procedure, it is a procedure requiring a clearance from an instrument controller, usually arranged through the airport’s tower. You need to be in contact with someone on the radio who can advise you about and keep you separated from the IFR traffic flying through the clouds you are maneuvering around.
Contact Approach
Finally, at the end of a flight you need to land. Normally this means either a visual approach, (which is still an IFR procedure if you are on an instrument flight until you either cancel IFR or report yourself on the ground); or a published instrument approach. There is also a seldom used third possibility. That is a contact approach.
The weather requirements for a contact approach are pretty much the same as for special VFR. You need to be clear of clouds and maintain at least one mile visibility. If those conditions can’t be met, don’t bother asking- you cannot be cleared for this kind of approach.
A contact approach is only possible at an airport with a published instrument approach procedure. Although flown visually, it is an instrument procedure and thus requires a clearance from an instrument traffic controller. Unlike all the other kinds of possible approaches, you only get a contact approach if you ask for one. The controller will never automatically assign it. Because this is an instrument procedure, both pilot and aircraft have to be IFR legal and capable… and rightly so. If visibility gets just a little worse or the clouds just a little too close together, then you have to be able to climb back up through them and execute the published missed approach procedure. If you can’t do that, you could suddenly find yourself blind and very, very close to the ground.
While the controllers will be providing separation from IFR and Special VFR traffic, they are not technically providing the traffic separation from normal VFR traffic that you are probably hoping for. That is not because they won’t advise you if they can, but rather because the normal VFR traffic is not under their control and not necessarily talking to them. Terrain and obstruction clearance are entirely your responsibility in part because the controllers cannot see it for you and you are likely below the published altitudes known to be obstruction free.
This sounds inherently just a little dangerous; no doubt because it is. When and why would you ask for a contact approach?
If conditions are not really all that bad, but there is a cloud layer to descend through, you might find it quicker to drop through a convenient hole in the clouds. Then fly straight in beneath the ceiling at lower than the published minimum instrument flight altitude. In so doing, you might feel safer because you can maintain ground reference all the way in.
At many mountain airports, because of the very high terrain nearby, it is not possible to get down very low on the instrument approach. At Telluride, while you can get within a mile from the end of the runway, you can only descend to 1800 feet above the airport on the localizer approach, and not even within 3000 feet of elevation above the runway on the VOR approach. At Aspen, you can only get down to 2200 feet above the runway. Same story at Eagle, CO. You can actually fly around near the airport VFR underneath the clouds while all the instrument traffic above you can’t get in. Using a contact approach, you could drop down under the ceiling if you find a convenient hole in the clouds some distance out from the runway and continue in under the clouds. Contact approaches are also useful if you find that you have descended down to a point where you have good ground reference and a mile visibility, but can’t see the end of the runway yet.
I will speculate that an instrument approach with a minimum descent altitude more than 3000 feet above the runway is not really intended to help you fly in at minimums and then land. Really, it is a procedure to get you below a high cloud layer and let you find ground reference somewhere in the neighborhood so that you can then make either a visual or a contact approach.
Most recently, I used a contact approach because the aircraft I was flying had an inoperative glide slope indicator. The ILS approach would only get me down to 200 feet above the end of that particular runway. Without a glide slope indicator, the next best alternate approach was a VOR or GPS approach that would only get you down to 1000 feet above the ground. On that day, you would still be in the clouds above the reported 900 foot ceiling- not good enough to see the ground yet. But the cloud cover only extended about seven miles from the airport. Dropping down under the clouds that far out, I could fly in with four miles visibility about 600 feet above the relatively flat terrain to land.
Could the same thing legally be done VFR? At some airports, yes. If the floor of class E airspace is 1200 feet above the ground (blue shading on the chart) or 700 feet above the ground (magenta shading on the chart), then perhaps it can. At other airports, no. If E airspace goes to the ground (magenta dotted line around the airport) then you need a clearance. If the airport has a tower (blue colored airport on the chart) then you need a clearance.
Is this a good idea? Is it very safe? Certainly it is far less safe than flying the same procedure with no clouds and perfect visibility, but we don’t always have perfect days. Because of the flat terrain, the much better than required minimum visibility under the overcast, and, above all, because I was very familiar with the area from many flights there in better conditions, I was comfortable with the procedure. If all those conditions could not be met, I would have decided to land elsewhere.
Summarizing
IFR to VFR on top, Special VFR, and Contact Approaches can be useful tools that allow you to do something visually that would otherwise have to be done in the clouds, if it could be done at all. Properly used, they can increase your safety. At the same time, these are procedures used in visually marginal conditions. That in itself is inherently dangerous. These are by no means absolutely safe procedures, but then nothing is completely without risk.
It is obviously safer to consider these options when visibility and cloud clearance is well above the absolute legal minimums. They are safer when flown at airports with few nearby obstructions, but probably unacceptably dangerous near rugged high terrain. They fall into that broad category of things you would be comfortable with at your home airport, where you could instantly identify all the landmarks you were flying over, but uncomfortable with at an unfamiliar airport. Sound, cautious judgment will often tell you not to try any of these ideas even when they are technically still legal.
They are unconventional, but perfectly legal tools which can be very useful to you in the right, but admittedly limited circumstances.
Fletcher Anderson is a flight instructor and charter operator based in Telluride, CO. His textbook “Flying the Mountains” is in bookstores now. |
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