Boxed in by Weather

There are a whole sleeveful of tricks VFR pilots can use to keep themselves out of the soup


The accident involving JFK Jr. has focused a lot of attention on the plight of VFR pilots flying in marginal visibility and at night because it is a common cause of fatal accidents.

Getting boxed in by weather is easy to do, but preventing it is almost as easy. Dealing with it, while a little more difficult, isnt that hard either.

For non-instrument rated pilots, the first consideration is the pre-flight weather briefing. Despite the fact that a 1,000-foot ceiling and 3 miles visibility is legally VMC, it is not practical to attempt VFR flight beyond sight of the airport in such conditions.

Outside of the obvious problems of navigation and aircraft control, your ability to spot other traffic is severely degraded. Against a murky background, the average mostly white GA airplane is virtually impossible to spot more than a mile away, and difficult even then.

So the first step is to establish realistic weather minima for your VFR flying. Our flight school prohibits VFR solo operations outside the traffic pattern without at least 2,000 feet and 5 miles, and all VFR solo cross- countries require 3,000 feet and 5 miles.

When you get your weather briefing, go into it with a clear set of parameters based on your own skill level and the type of aircraft youre flying. You might do better in a Cub doing 60 knots in 3 miles visibility (able to see three minutes ahead) than in a Bonanza doing 170 knots in 5 miles visibility (less than two minutes flying time).

Low visibilities are almost always a bigger problem than low ceilings. Flying under a 1,500-foot ceiling with 8 miles vis gives you much better navigational and attitude references than flying under a 3,000-foot ceiling with only 3 miles.

If you dont have the weather mins you decided on ahead of time, be disciplined enough to take Nancy Reagans advice: Just say no.

Deadly Hat Trick
There are basically three ways the VFR pilot gets trapped by weather – deteriorating visibility, ceilings coming down and solidifying cloud decks underneath. Each has its own peculiar problems, warning signs and solutions.

Deteriorating visibility usually involves either precipitation or fog/haze. In unstable air, precipitation is usually visible from some distance away. In stable air, these obstructions to visibility are generally fairly widespread, but they develop rather insidiously.

With stable air, fog or haze and misty rain are the usual forms of visibility obstruction. Any time you find yourself planning a flight into a stable air mass with narrow temperature/dew point spreads, expect visibilities to be reduced by the milk bottle effect. The problems for VFR operations in these conditions include the inability to spot other traffic, reduced visual range to spot navigational checkpoints and loss of horizon attitude references.

This is especially a problem when you are flying into reducing visibility. Its natural to try very hard to maintain ground contact even as the apparent horizon gets closer. As this happens, the apparent horizon is also lower with respect to the horizontal axes of the aircraft, which makes it appear that the aircraft is pitched up. This can convince the pilot who is looking inside at the map and then out that the aircraft is either higher than it really is or in a serious nose-up attitude when it isnt.

In either case, there is a natural tendency to push the nose over, resulting in a sharp nose down attitude – dangerous at low altitude. The pilot who then reacts to the sudden upward rush of the ground by a sharp pull on the yoke is likely then to see nothing but a windshield full of gray, deteriorating airspeed and possibly an unusual attitude. At this point, theres little to do but transition to the instruments, climb straight ahead, and get on the radio with a Mayday call on 121.5 and a 7700 squawk.

Attempts to perform a 180 in this situation are not likely to succeed. The stability of the air makes it unlikely that you will find any better visibility where you came from, since the reduction in visibility is more likely to cover a large area than to be an isolated pocket into which you have just flown.

At the same time, the combination of the depressed apparent horizon and the perceived climb due to the increased g-force in the turn make it tempting to allow the nose to fall in order to keep a normal horizon position on the windshield and seat-of-the-pants weight feel.

This is a recipe for a spiral into the ground.

Clouds Above or Below
The second problem area is when the distance shrinks between clouds and ground. This can happen either because the ceiling is going down or the ground is coming up. Flying westward across the Great Plains is an excellent example of this effect as you watch the terrain elevation slowly rise from 3,000 feet or so in Nebraska to 6,000 feet in Eastern Wyoming over a couple of hundred miles, although it can be much more abrupt in mountainous terrain.

If theres a stratus layer at 6,000 msl, youre in great shape when you start, but the distance between cloud and dirt will decrease as you go, and eventually youll run out of options. If the visibility isnt bad, this is one place where you have a great advantage, as you have a reasonable expectation of better conditions behind you and pretty good horizon references to keep you in level flight.

If you get trapped down there, a 180 is generally a good option, although local weather and obstructions make it far from a sure thing. If turning around isnt an option, you have little choice but to squawk 7700, switch to 121.5 and climb.

The third problem is getting trapped on top of a scattered layer that becomes broken and then overcast. While its legal to operate VFR on top of such layers, it is most unwise unless you have either an instrument rating or a gold-plated VMC way out – and thats awful hard to find.

If you are in this situation, keep a good eye not only on the deck below and in front, but also behind you. Decks always seem to tighten up, leaving you fewer and smaller gaps to drop down through. Unfortunately, Murphy decrees that not only will the visibility be lower than expected below the deck, the bases will be closer than comfortable to the ground when you do decide to pop down.

If you dont have good, current weather data on the conditions below the deck, dont get on top of it in the first place. At least below the deck you can see the ground and may have more warning that its time to 180 or land where you are.

The only plus in the on-top situation is that you generally wont have visibility problems; horizon references are usually excellent. The one exception is getting trapped between layers, and in that case turn around before the layers merge. When trapped on top, you have another advantage over the reduced visibility or lowering ceiling situation: altitude. You are much more likely to be in radio range of an ATC facility to get help.

The Out Route
Probably the most important factor in avoiding these problems once youre in the air is keeping an out route behind you. If you are always thinking, If this doesnt work, I can always do that, you are keeping your options open. Whether its a good eyeball contact on a nearby airfield or a route back to better conditions, never fly on unless you know you have somewhere to go if things get worse in the direction in which youre going.

When you look ahead and realize that if you go another minute youll have no way back, its time to take the out. Dont ever press on if the only option left would be to press farther.

Given that, the question becomes how to read the sky in front of you to see when you are in immediate risk of getting boxed in. A number of factors come into play. For example, in summer weather, your highest priority concerns are low visibilities (murk) due to high humidity, especially around water, and thunderstorms. One of the most popular tactics to deal with this is getting up above the haze layer.

Doing so may take you up to 10,000 msl or so, but its worth it. Youll have to climb a couple of thousand feet above the bases to be above the main layer of puffy stuff, but you get several advantages: clear air with great visibility, a smooth ride, a long-range view of whats ahead, radio range, and radar coverage. You can see the tops of buildups that are turning into thunderstorms from 50 miles away and you can see the tops of mature thunderstorms up to 100 miles away.

If you can see a good clear path through to blue sky, youve got a good way to go, as long as you watch for signs that the gap is closing. If it is, or if theres only cloud behind that opening, stay out. Shooting the gap can lead you into box canyons of rapidly developing thunderstorms, which can close behind you in a heartbeat.

Always approach this situation with the thought that the opening wont last 10 seconds after you go through. Unless you can see a clear path between the buildups, youve got no way to get past them, and its time to find another way around the weather. Going below the deck is not a good idea in this case, since you stand a good chance of getting trapped either between showers or in a sudden downpour out of the clouds above you.

The two problems with this tactic are that the deck below you thickens during the day, and the visibility below the deck may be far less than youre comfortable with. You can get trapped on top or find when you arrive at your destination theres no way down through the clouds, or truly awful visibility once you slip down below even a scattered deck.

Know Your Enemy
How do you collect weather data while airborne? The most important tool in your kit is your eyesight – if it doesnt look good, it probably isnt.

When looking across the top of a deck, look for buildups to avoid, and blue sky to fly to. When looking underneath a deck, look for a definable horizon line. Compare the view straight ahead with that to the sides and behind. You want to run to daylight. Take a good look at the undersides of the clouds. If you see rain descending, stay away even if its evaporating before it hits the ground (virga). This is often a sign of the beginning of a thunderstorm, with serious downdrafts and turbulence below. Other signs of clouds you dont want to fly under are dark, roiling bases, including either lumpiness or swirls.

Your radio is probably the next best tool. You have a wide range of people you can talk to, including Flight Service, Flight Watch, Air Route Traffic Control Centers and Radar Approach Control facilities. Flight Watch is the best choice if youre in range of one of their sites, but those folks are sometimes difficult to reach.

First, youre sharing the single low-altitude frequency of 122.0 with the entire country. Since youre at altitude, you may find the reply from the ground is blocked by another aircraft even if the Flight Watch to which youre speaking cant hear it, and you cant hear the Flight Watch to which the other aircraft is speaking.

One solution to this is to try using the high altitude discrete frequencies for Flight Watch listed on the inside back cover of your Airport/Facility Directory. If youre near one of the sites as shown on the diagram there or are up fairly high, you may get through. When calling, remember that the Flight Watches are aligned with the Centers, so it helps if you know youre in Cleveland Centers airspace and can call Cleveland Flight Watch. This is another reason why carrying en route L-charts can be useful to the VFR pilot. Even if theyre not current theyll show the Center boundaries. Otherwise, call Any Flight Watch, this is Cessna 123, 40 north of Parkersburg, W.Va.

Flight Watch is a special position at a FSS, with extra weather displays and charts hung on the wall by the position, not at the Center. The specialist at that position is not doing anything but weather. As such, you can get a bit better information. However, you will not do much worse if you call a regular FSS frequency.

The specialists there can zoom in, animate, and do all those other good things to help read the development and movement of weather. The only drawback is that there is a wide range of experience among FSS specialists. While some are very good at reading the display to you, some are not. As with telephone briefings, sometimes its best to say thanks and hang up, then call again hoping to find another, more experienced, specialist.

Center controllers have limited weather capability on their primary displays, but they also have a big TV screen with the national radar on display in the room. If you get the my radar doesnt show weather very well response, ask him to look at the big radar picture. The weather display on their consoles is essentially a two-level system, showing precip and heavy precip. Suffice it to say if their display is showing Hs, you dont want to be there. However, what they show as precipitation may very well be flyable if its non-convective, and that they cant tell. If you have a sferics device aboard, and its showing electrical activity in the area in which center is showing precip, youve got a pretty good clue that area is bad news.

Approach control facilities have a very wide range of capability, depending on whether they have the new display systems. Some RAPCONs can do an excellent job of vectoring you around weather; some can not. Regardless, as a VFR pilot, you dont want to be in anything they show as precipitation since anything but the lightest precip will qualify as IMC.

Resorting to the Gauges
There are a number of situations into which you can put yourself in which the only choice is to get on the instruments, climb, and holler for help. This, along with the discussion surrounding the Kennedy accident, should be a wake-up call to all VFR pilots to get instrument work on a recurring basis (every six months or so) so youre proficient enough to make that life-saving move.

Get with an instructor, and either try flying with your eyes closed for a while, or close your eyes and have the instructor put you into an unusual attitude appropriate to an attempted 180 in the clouds. If you want some real serious training, get an instrument instructor to take you into the clouds on an IFR flight plan.

The first 15 seconds will probably be a true eye-opener. Foggles and hoods just dont give you the same feel as that murky grayness with no sun, shadows or peeks around the corner of the hood.

The final word is a discussion of night operations. Both the ICAO and FAA require only three hours of night training including 10 landings and one dual cross-country for the Private Pilot certificate, which may be inadequate to prepare you for a serious night cross-country flight. Witness the night flying requirements established at most FBOs. At night, you cannot see whats coming in the way of weather or visibility other than by exception. That is, its what you cant see thatll get you.

When flying on a clear night over populated land, you have an excellent view of the world ahead of you. You can see cities, airports and roads, and the moonlight is often enough to illuminate rivers and shorelines. The horizon is discernable as a border between the diffuse pattern of stars and the less regular but more sharply defined ground lighting. Clouds above you are bottom-lit by the ground lighting, and if youre on top, moonlight or even starlight makes the clouds minimally visible.

Throw in some weather, however, and life gets real tense real quick.

The first clue you get that youre headed into unsuitable weather is when things start disappearing. You no longer can see clouds many miles ahead, allowing time to work out an alternate plan. Lighted objects on the ground ahead of you are no longer coming visible as you proceed – the lights that were the farthest away is still the farthest thing you can see a couple of minutes later.

It might be rain, it might be fog, it might be a low cloud deck, but whatever it is, its something of which you want no part.

Unfortunately, these clues to unacceptable conditions for the VFR pilot are subtle at best and non-existent in many situations. Over sparsely populated areas there may be inadequate ground lighting to warn you that theres a curtain drawn across your route. Its all just a black hole ahead, and theres no way to tell if its just a lack of light or something obscuring the path.

Also in that situation, the widely scattered lights can be indistinguishable from the starry sky, eliminating your visual horizon line. A moonless night or a high overcast can take the lights from the sky completely. Either situation can eliminate the ability to see a cloud deck forming above or below you.

Open water below makes it even worse. If you want to know what its like to fly at night in VMC over open water on a moonless/starless night, pull your plane into a hangar, plug all the light leaks in the doors and walls, put blankets over all your windows and windshield just to be sure, and then turn on your instrument lights. What you see now is what youd get.

Yes, its legally VMC out there, but you have absolutely no usable attitude or navigational references, and you cannot see a cloud or reduced visibility condition ahead of you. Your first hint that you just went IMC will be when the inside of the cloud starts to flash with the intensely disorienting pulses of your own strobe lights.

The overall recommendation on night VFR is stick to the best conditions only – much better than the minimums youd go in day VFR – and slide into night VFR flying slowly and cautiously. Remember that your training in that area is at best minimal.

For the VFR-only pilot, weather is an implacable, ever-present and wily enemy lurking around every corner, waiting for you to venture into a blind alley with no exit. Treat it with great respect, always anticipating the worst.

Keep a good option open all the time, be looking ahead to see that theres another step available after the next one, and if you see that the next step has no way back, dont take it.

Also With This Article
Click here to view “What the Hell Was That?”

-by Ron Levy

Ron Levy, an ATP and CFI, is an assistant chief flight instructor at American Eagle Aeronautical Academy.


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