Pilots who do a lot of reading - particularly accident reports and the articles that analyze them - have an advantage when it comes to knowing which questions to ask. Since the same missed cues are repeated over and over, learning to be suspicious can help you immensely when it comes to using weather data wisely.
Several years ago I had a good demonstration of the "weather or not" principle when I returned from one of my airline trips early - ironically, because the weather in Denver was so bad that in order to expedite our airline's traffic flow our flight from San Francisco to Denver was cancelled. The rest of the crew flew home on an earlier flight, and I, living just an hour to the south of SFO by airline, bid them goodbye and came straight home, almost nine hours earlier than planned. How nice that for once, bad weather had brought me good fortune.
On my way home from the airport, I stopped at the local FBO and noticed a friend of mine sitting in her car in the parking lot. I stopped by to say hello, and she immediately told me about her go/no-go dilemma. An experienced instrument and multiengine pilot, she had planned to fly her daughter to southwestern Colorado for a week of skiing. She was ready, her Beech Baron was ready, but the weather...now there was a problem that presented itself in varying shades of gray.
As she described her quandary I thought to myself how fortunate it was that I happened to come along at a time when we were both victims of weather situations. Mine, of course, brought me some extra time off; hers was giving her acute pangs of indecision, what I jokingly call PWP (pilot's weather paralysis).
As an FAA aviation safety counselor I rarely get a chance to influence a pilot's decision-making process or her subsequent courses of action before they occur. Mostly we find ourselves talking to pilots after something goes wrong, wishing that we could have altered the often-negative outcome with some preflight educational input. This was a good opportunity to help her learn about the weather and how to make her own informed decision
I suggested we telephone the flight service station, but she wisely proposed that we walk over to the local (now sadly closed) FSS to look at the weather charts she'd been combing through earlier that day. "You know," she said, "I've already been there four times this morning. They're going to be sick of me!" I chuckled and pointed out that I hadn't been there even once, and besides, weather briefings are their stock in trade. Perhaps we could elicit some additional information as my questions would likely be different ones.
While still in the car, we took a look at her low altitude en route charts to familiarize ourselves with her planned route of flight. It would take her across southern California, Nevada, Arizona, Utah, and up into Colorado. We noted which VORs she'd cross, their three-letter identifiers, and the MEAs (minimum en route altitudes) on the different route segments. Then, taking her charts with us, we headed for the FSS.
As we walked across the parking lot, I complimented her for wanting to check the charts in person. "One picture is worth 1,000 words," particularly when it comes to weather interpretation. To get an accurate picture of the situation, I asked her for the details of her vacation plans. When she told me the room reservations at the resort hotel were nonrefundable, I pointed out that hotel rooms were the least of her concerns. The airfare by commercial airline was $800 each for her 9-year-old daughter and her (another nonfactor, as far as I was concerned).
"I'm back," my friend said to the flight service specialist. I joined in with, "But I'm new and interested to see it all." As he pulled out the prognostic or prog charts and route forecasts along with the current weather, I spread out our low altitude charts and began to circle the VORs she would cross along the way. I also circled the MEAs along the route so that we could relate the freezing levels and ceilings to her cruising altitude of 15,000 feet mean sea level.
Speaking of MEAs, I pointed out that since she would be flying mostly at the MEA rather than several thousand feet above it (as is more common in the flatlands), her ability to climb higher into colder air to escape icing conditions - should she encounter them - was seriously in doubt. And as for going lower to find warmer air, that certainly would not be an option for her and is a real concern for pilots of nonturbocharged airplanes when flying in high mountainous terrain.
As we looked at the route forecasts, I listed a few other important considerations. If the forecast contained any ceilings of 2,000 feet or less (from one hour before her ETA to one hour after her ETA), she would need to designate an alternate airport on her IFR flight plan and carry the fuel to fly there. Alternate or not, to conduct the flight IFR she would also have to carry 45 minutes' additional reserve fuel on board - more than the 30 minutes required for VFR flight. That extra required fuel might limit her range, change her route plans, and possibly require a fuel stop that would necessitate a descent and climb through additional ice-laden clouds.
Because her destination was in a valley, the reports and forecasts she received would give her an unrealistic picture of the true en route flight conditions. Telluride, at an elevation of 9,086 feet msl, might well have visual conditions or even a 5,000-foot ceiling, but the MEAs leading into the area were 16,200 feet. So a 5,000-foot overcast (C50 OVC) could easily translate to a cloud cover at her cruising altitude (9,086 plus 5,000 feet makes for a cloud base of 15,000 feet) with a high probability of icing in those clouds. Since her airplane wasn't pressurized, I mentally noted that oxygen would be necessary for most of the three-and-one-half-hour trip, and planned to ask her about this if she made a "go" decision.
With pen in hand we began to annotate the FSS charts. The first four-panel prog chart the briefer showed us gave the 12- and 24-hour forecasts for the surface and aloft. Right on the chart I drew her route of flight, which would take her over the high terrain of southern Nevada, Utah, and southwestern Colorado. Next we looked at the legends shown on the prog charts and carefully noted the symbol for the freezing level at the surface: a continuous jagged line (or series of continuous V's) that looked like the teeth I used to draw on Halloween pumpkins when I was a child.
The 12-hour significant prog chart, the first in a series of four, showed that zigzag line starting at the Canadian border in north-central Washington state, continuing due south until it hit the "angle" at Nevada's western border, about abeam the SFO area, and then curving through southern Nevada and southern Utah. It continued from just northeast of the Four Corners area (where Utah, Colorado, Arizona, and New Mexico meet at right angles, hence the name) on a straight line to Amarillo, encompassing most of the Texas panhandle before it moved north into southeastern Oklahoma.
We had clearly defined where the surface temperatures were 32 degrees Fahrenheit or 0 degrees C. Flying anywhere over or north of this line would definitely put my friend in sub-zero temps (exactly how cold is something that you can determine by using lapse rates to figure the approximate outside air temperature at your planned cruising altitude). If she flew inside a moisture-laden cloud deck, she'd almost surely encounter in-flight icing conditions.
The first part of her route, which would take her from Santa Barbara to Las Vegas via the high desert country of Southern California, looked OK. The third panel of the prog chart, the 12-hour surface forecast, showed a cold front stretching from offshore central California, swinging back up through south-central Nevada and up in to Utah, crossing over Salt Lake City.
No problem there, as the weather that was forecast was located to the north of her route. It looked like an easy trip as far as Las Vegas - at least on paper. Later, when we looked out the window we saw a row of towering cumulus clouds building over the mountains immediately to the north of us. So much for the "no sweat on the first leg" plans.
The second part of the flight was what concerned her, and wisely so. Leaving Las Vegas, the forecasts were for clouds covering most of her route through southern Utah. The forecast area of precipitation showed large globs of shaded areas indicating some kind of moisture, a bit north of her course and extending farther east, covering the Continental Divide.
Although the forecast moisture didn't cover her destination, her IFR routing would take her right along the leading edge of that cold front we saw running through central California up into Utah. There it met a stationary front that stretched from southern Idaho to southeastern New Mexico. The stationary front changed to a cold front over her destination, blanketing the Midwest with a forecast for snow. Ugh!
We read through each of the route forecasts, starting at the top and eliminating most of those that were definitely not along her route of flight. The applicable forecasts got special attention from my gaudy pink pen. I read and underlined the ceiling data first. Then we found the same area on the en route charts and noted the MEAs. We compared the two numbers to see if her cruising altitude would put her in the clouds and make her vulnerable to in-flight icing. With climbing higher to avoid the ice-laden clouds unlikely and descending to warmer air not possible, we began to discuss her other options.
She could fly over to Las Vegas and wait for conditions to improve, but a comparison of the previous days' prog charts with what was currently happening showed that the forecast areas of weather had actually enlarged and moved farther south than predicted. Not good.
Since the weather wasn't likely to improve, leaving the airplane in a strange place and going on by airline wasn't particularly appealing, especially with a 9-year-old child in tow. Hangar space was likely unavailable for a transient airplane parked for a week or more, and valuable avionics might be appealing targets for thieves.
Until now, we hadn't really discussed the go/no-go decision aspect, as I was waiting to see how the weather briefing had affected her planning. As we walked away from the FSS, I was about the bring up the oxygen factor for her consideration - plus the fact that her copilot wouldn't be much help - when she volunteered that perhaps the best plan was to forget the whole thing. That much worry, work, and weather-dodging would definitely take the fun out of a skiing vacation.
I was glad when she said she wasn't interested in becoming a statistic. To ease the disappointment for her daughter, I suggested a trip to Disneyland, a mere 40-minute hop to the east of us. With VFR weather prevailing, she nodded enthusiastically. I breathed a sigh of relief and congratulated her on making a wise decision.
As I left my friend and her daughter at the airport, I remembered how comforting it was to share a weather decision with an experienced pilot I trusted. Many years earlier I'd spent the night sleeping in a chair at the Wichita FSS, checking its weather radar each hour for any change in the position of a line of thunderstorms that blocked our return home to Tulsa. If my experienced partner wasn't interested in pushing for home, I certainly wasn't going to argue the point. A few more winks in that uncomfortable chair sounded like a good idea to me.
The next time you encounter a "weather or not" situation that leaves you wondering, ask for advice from someone whose judgment you trust. That person can help you to clarify the information and hopefully make the decision a bit easier. Just remember that when the flight becomes more work than fun, take the safe way out and head for home or the motel. It's a decision that you'll never regret.
Karen Kahn is a captain for a major U.S. airline and author of the book Flight Guide for Success - Tips and Tactics for the Aspiring Airline Pilot. Type-rated in the MD-80 and Lockheed JetStar, she's an FAA aviation safety counselor who holds ATP and Gold Seal CFI certificates. Kahn is rated in gliders, seaplanes, and helicopters. Visit her Web site ( www.AviationCareerCounseling.com ).
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