Wx Watch: The Rolling Go/No-Go

All too often, pilots seem to think of the go/no-go decision as something that happens only at the very beginning of a flight, as part of the preflight weather briefing. Once you've made up your mind, this line of thinking goes, you're off and running, confident that the weather will hold up as promised and you'll have no dangerous surprises.

Of course, we all know that forecasts can go bust. We also know that alternate airports and plans of action should be established ahead of time if fore-casts indicate weather beyond our capabilities or those of our airplane. But as accident statistics show, it can be all too easy to slip into another mindset once en route. Focused on the mission at hand, and maybe feeling pressure to get home or make that business appointment, some pilots pressed on into worsening conditions even though they knew that there would be a strong chance of adverse weather from their preflight weather briefing.

This is how the continued VFR-into-IMC accident so often happens. Or, in the case of instrument pilots getting in over their heads, what we could call the "continued IFR into hard instrument meteorological conditions" accident. These kinds of scenarios account for most of general aviation's fatal accidents (see " Ounce of Prevention: Shades of Gray," page 137). Mind you, these accidents happen to the sanest of us. It's just that as high-achieving optimists, pilots are mentally geared to completing a mission successfully. Throw in the towel? Well, maybe, but let's see how things are in 10 minutes….

Here's what happened to me on a recent flight. I was flying AOPA's Sweepstakes Bonanza — a 300-horsepower turbonormalized fire-breather with a great big restriction to day-VFR flight (the primary flight and navigation displays have yet to be certified). (See " AOPA Sweepstakes Bonanza: The Cabin — An Aerial Entertainment Center," page 105.) I was flying from Cincinnati's Lunken Field to Houston's Southwest Airport and had to negotiate my way — VFR, remember — through a stormy, fast-moving cold front that was coming down from the west.

During my preflight briefing, I decided that an end run would be the best strategy. That way, I'd stay ahead of the storms, rain, and clouds. For a more detailed, colorful story of this flight, visit AOPA Online ( www.aopa.org/pilot/bonanza/010606commentary.html). The airplane's Goodrich WX-500 Stormscope plots on the V35's Garmin GNS 530 and 430 would help greatly with storm avoidance, and so I felt confident I could cross the front with a minimum of fuss.

I took off and within an hour I was seeing lightning on the Garmins. I had to descend from 8,500 to 6,500 feet to stay out of the clouds, and then I avoided rain shafts visually as I watched lightning bolts make ground strikes just off my right wing about 25 or more nautical miles away. That Stormscope sure is accurate.

The ride was smooth, but the cloud bases were forcing me lower. By the time I reached the Birmingham, Alabama, area I was down to 4,500 feet, but not for long. A descent to 3,000 feet became necessary, and for the first time visibility was turning lousy. By Jackson, Mississippi, I was down to 2,000 feet and the visibility was definitely marginal. I'd passed some breaks in the overcast a few minutes ago. Still I pressed on, thinking that I could land at Jackson.

Then it hit me. "This is plumb crazy," I thought to myself. Any landing in Jackson would involve an instrument procedure, and I couldn't legally do that. The weather had been worse than forecast for the past hour, and it sure looked like it would continue that way. I was being lulled, trancelike, into pressing on when my airplane definitely wasn't up to the task.

That "plumb crazy" thought snapped me out of it. New thinking came into play. What was I doing down there at 2,000 feet when I had the power of a 300-hp turbonormalized engine and cloud breaks behind me? I reversed course, found the breaks, and climbed to VFR-on-top conditions at 8,500 feet. Back at Birmingham a VFR climb to VFR-on-top was out of the question (a VFR landing at Birmingham was not), but now it made perfect sense. I spent the rest of the flight in clear blue skies.

Back to the preflight briefing. Flight service said it would be VFR — with stretches of marginal VFR — all along my route. Up to Birmingham they were right, so I thought that I'd, well, see how things would be in 10 minutes. When the time was up, I did the only prudent thing and turned around. Still, it was tempting to press on to Jackson. It helped me realize the very real temptation to stick with the current plan and helped me understand how some continued-VFR-into-IMC accidents progress.

This experience inspired me to come up with some guidelines for coping with and evaluating the weather's behavior while en route. Here's the list of main points:

• Get an instrument rating. If you already have one, make sure that you stay current and proficient. The instrument rating is a huge antidote to the continued-VFR-into-IMC scenario.
• Pay attention to forecasts, but be skeptical. Forecasts are becoming more and more accurate, but any mention of VFR or MVFR weather in or around fronts should serve as a warning — things can and will go downhill fast in such volatile atmospheric environments.
• Watch the clouds. I mean really watch them. This sounds like an obvious recommendation, but I've seen several pilots act oblivious in the face of building cumulus or expanding stratus layers. The air was unstable, and becoming more so (first case), and a front was moving in (second case) — but these pilots couldn't put two and two together.
• Beware of early mornings and sunset. That's when surface temperatures fall. If the temperature falls to the dew point temperature, dense fog can form.
• Don't get trapped on top — especially if you don't have an instrument rating. You may have to descend through the layer for your landing and that means flying on the gauges.
• Know if you're in a frontal complex's "warm sector." This is the area ahead of a cold front and behind a warm front. This is where thunderstorms are most likely to form. A rough rule: If winds aloft are out of the southerly quadrant of the compass, you're probably there. Surface heating is at a maximum in this territory, and so is the air's moisture content.
• Don't let yourself be forced into descending. Terrain and obstacles await, airports will be more difficult to locate visually, and without a good VFR "out" or an instrument rating, disaster waits.
• Monitor AWOS, ATIS, or ASOS frequencies as you fly. This keeps you up to date on surface conditions, and lets you compare actual with forecast weather. Also, remember that the combination of high temperatures and high dew points (above 70 degrees Fahrenheit) is a recipe for thunderstorms.
• File IFR, or get VFR advisories from air traffic control. Valuable help is available from ATC, so why not use it for weather information along your route?
• Check in with flight watch (122.0 MHz). Do it often if conditions are changing, however subtly.
• Tune in to HIWAS (hazardous in-flight weather advisory service) frequencies. Collocated with certain VOR stations and formerly identified on VFR charts by a blue square in the corner of the station's identification box, they're now marked with an H in a blue circle. (If the VOR broadcasts an ASOS/AWOS, the circle contains an A; T denotes a transcribed weather broadcast.)
• Finally, if the weather is making you ask yourself, "Am I plumb crazy?" do something about it — now. This is where the "rolling go/no-go" strategy comes into play. Yes, your preflight briefer may have guaranteed acceptable weather. But you're the expert once you're on your way. When the weather takes a turn for the worse, any briefer's reassuring words become empty indeed.

Think of your flight in 10-minute intervals, keep tabs visually and electronically, and always have a comfortable way out of trouble. It's up to you to make sure that you have one — so make rolling go/no-go decisions as you fly. Just make sure that you act on them.

E-mail the author at [email protected].