Weather--it's got to be the biggest challenge in aviation. Not only must you understand weather, but you must be able to read it in either written or pictorial form, digest what you've read, and apply the information to your route of flight, to your aircraft's capabilities, and to your own piloting skills. Then you must come up with a reasonable go/no-go decision.
When I began flying, I used to patiently read all the weather reports and forecasts, check all the pictorial charts--and then scratch my head, wondering what to do with all that data. The best ways to diagram the weather were often the simplest ones: First I'd draw a picture of my departure airport and the destination airport and then insert the terrain heights in between. I'd put in the ceiling, remembering it was above ground level (not above sea level) and then see how I'd fare if I kept 500 feet below the clouds, or 1,000 feet above and 2,000 feet away. (Honestly, I've never been able to determine what 2,000 feet away was, so I interpret that as lots of room and lots of time to see and avoid any airplane on an instrument flight plan that might pop out of that cloud.)
Drawing pictures is still a pretty good gauge, even with all the newfangled weather reports we now have available from the Internet, or Nexrad weather radar imagery--some light aircraft today even offer the ability to view current weather information and radar images in the cockpit while in flight. Many flight-planning programs, even older ones, offer depictions of actual weather (and terrain) along your route of flight. If you don't know what to do with the information, it's about as useful as yesterday's Lifted Index.
No pilot I know claims he's mastered the knowledge of weather, and few will admit to really understanding it. We read and study and review and then scratch our heads some more. What experienced pilots do is try to use the words of wisdom uttered by Capt. Robert Buck in his excellent book, Weather Flying: "Be skeptical and always have an alternative plan."
He talked about the importance of knowing the big picture, either from a good summary (often found online, on TV news, or on The Weather Channel) or by digging it out on your own. Being able to envision where the highs, lows, and various weather fronts are located is certainly the first step to understanding what's likely to occur both aloft and on the ground.
When I became an airline captain and became responsible for making weather decisions affecting more than 100 passengers--and not just me--I began to develop my intense weather skepticism, Buck's other critical component for pilots. Having an all-weather capability is a great advertisement for flying by commercial carrier, but in reality, we have many restrictions that can ground us when the Part 91 general aviation pilot is free to sally forth into the muck.
After reading Weather Flying, I began to look more closely at the temperature-dew point spread on the METARs. Our weather reports are purposely printed in a stacked format with the previous hour's weather shown directly below the current report. I knew, of course, that flights of any distance would need to be extrapolated into the future. That is, the METAR was for right now, or each previous hour, but I wasn't going to arrive there right now--I would arrive several hours in the future. What I saw now would not necessarily be the weather I'd find later.
The big question was, are things going to get better or worse? Fortunately, we still have weather briefers at 800-WXBRIEF to talk to about the situation, but most of us can learn the few keys of temperature and moisture, fronts, and pressure systems to help us decipher the general picture. A new online course from the AOPA Air Safety Foundation, Weather Wise: Air Masses and Fronts, can help you to get this important big-picture knowledge--and another free course, A Pilot's Guide to Flight Service, will help you to get the most from a telephone weather briefing.
Part of my weather skepticism comes from the fact that METARs and terminal aerodrome forecasts (TAFs) are issued only for airports, leaving enormous gaps in the weather information that we are able to acquire and interpret for the en route portion of a flight. Area forecasts help to fill those gaps, but they cover a large area and, as a result, generally are less precise.
Weather Tips
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If you fly between two coastal cities--as I frequently do between Santa Barbara and Monterey, California, which have mountainous terrain in between--you've got relatively good data for both ends of the flight and relatively little for the portion in between. You have to draw the route from A to B, insert the clouds at the ceiling(s) stated, and then see what happens to your terrain clearance when you're forced to stay 500 feet below the clouds to maintain VFR (area forecasts, unlike METARs and TAFs, describe ceiling in terms of height above sea level). A 7,000-foot overcast at a sea-level airport can become unflyable if the ground below you rises to 5,000 feet. Toss in a restricted area or two and now you've compounded your problem with airspace limitations.
Even an instrument rating can't fix the biggest problem which, after circumnavigating thunderstorms, is--for most pilots--in-flight structural icing. Since the light airplane I fly is not equipped for flight into known icing conditions, I watch the freezing level information very carefully so I can predict where the ice is likely to be located.
Clouds near or above the freezing level are usually the reason I'll cancel a flight, particularly during the winter months. I know I can't avoid them, given the altitudes that air traffic control assigns to aircraft operating under instrument flight rules, and trying to turn toward lower terrain only works at the beginning and end of my journey.
You can find a brief review of weather principles in any good weather text. You probably own a copy of the FAA's Aviation Weather or another good weather manual. I recommend that you find another practical weather guide like Buck's Weather Flying to help you put it all together, especially when you're wondering how to apply the information to your flights.
The new pilot needs to keep in mind that no airplane is going to get him there all the time. No instrument rating is going to solve the problem of weather. Time is the real solution. You always have time, and waiting out the weather is always the best solution when you have any doubts. Every time I've experienced weather delays at my airline, I've also benefited by that same delay because it allowed the worst of the weather to pass me by, thus rewarding me with much better flying conditions. Someone must be watching out for pilots on the ground, keeping us tethered until the bad stuff moves on.
Read all the reports and forecasts; correlate them with your route of flight, the time of day, your personal fitness, and the airplane's capabilities; and then be prepared to change your plan. Sometimes the quickest and safest way to your destination is not a straight line. Plan your flight to include alternate routes, fuel stops, and overnight stays, as well as an alternate destination airport. Consider taking the most weather-friendly route, even if it means more time and a possible fuel or overnight stop.
If nothing else, you'll figure out when you should drive or cancel the trip altogether. Not going is always an option high on my list if I don't think I can complete the flight safely. That decision varies with the time available to travel, the type of weather, the airplane and its equipment, and my experience level, as well as my personal readiness for flight. If you must get somewhere, your planning should consider alternative means of transportation such as driving or buying an airline ticket.
No matter how well you can read all the data, it can still seem to be a bit of a crapshoot, but fortunately you don't have to roll your dice. It's your decision. Just remember you're not alone when it comes to understanding weather. Many pilots don't really understand it, but we use our experience to bolster our two aces in the hole: skepticism and that invaluable alternative plan.
Capt. Karen Kahn is the author of Flight Guide for Success: Tips and Tactics for the Aspiring Airline Pilot and a career counselor. A Master CFI and 30-year airline pilot, she flies the Boeing 757/767 for a major U.S. carrier.
