by Susan Parson, FAA Safety Briefing Editor

Early bird gets the worm? I believe Commander Shelby erred. There is no evidence of avian or crawling vermicular lifeforms on Jouret IV. — Commander Data, Star Trek: The Next Generation

Thanks to tablets, apps, and panel-mounted avionics that make the bridge of even the more recent versions of Star Trek look outdated, GA pilots now have anytime, anywhere capability for all the weather data we could possibly want. But there are downsides. Data’s glossy appearance easily deludes us into taking it literally, rather than regarding it as raw material that requires refinement before we can safely use it. Second, the sheer volume of incoming bits and bytes can complicate even the most determined efforts at refining data into information — that is, data placed in some level of context or analysis.

Here’s where critical thinking becomes, well, critical. Like the human cliché that so puzzled Star Trek TNG’s android Commander Data, taking weather data without context distorts its meaning.

Ask, Answer, Analyze, Apply

The good news is that you don’t have to be a meteorologist to apply the context and analysis that transforms data into information. Weather observation and reporting technology have changed dramatically over the years, but nothing has changed the fundamental ways that weather can affect any aviator. So, Robert N. Buck’s Weather Flying is still one of the “go to” resources in my aviation library. Buck notes that weather can do three things: (1) Create wind or turbulence; (2) Reduce ceilings and visibility; and (3) Affect aircraft performance through conditions like icing, density altitude, or convection.

The process of transforming weather data into useful information requires asking and answering a few questions, then analyzing and applying the responses. For example:

Wind Direction and Velocity:

For takeoff or landing, analyze these numbers in terms of both the pilot and the airplane. If you aren’t comfortable with the crosswind component, or if it is beyond the airplane’s maximum demonstrated crosswind capability, apply that information by deciding whether to stay on the ground, hiring an instructor to help scrub the rust or, if already en route, diverting. For cruise, analyze and apply these numbers in terms of effect on groundspeed and fuel requirements.

Ceiling and Visibility:

Regardless of how it is equipped, the airplane itself is not affected by the presence of clouds and precipitation. Consequently, weather decision-making in this area most logically focuses on the pilot. Are you instrument rated, current, and proficient? Remember that maintaining just the legal minimums may not be enough for proficiency and confidence. If you haven’t flown in IMC recently, or if you have any doubts about your proficiency level, get some practice with a safety pilot or dual refresher training with an instrument instructor.

Performance:

Like all machines, airplanes have performance limits. Even the best pilots cannot overcome such performance-reducing elements as icing, high density altitude, or thunderstorm activity. Weather data provides facts about likely freezing level(s), temperatures and density altitudes, and location/likely intensity of convective activity. Ask yourself where these conditions exist in terms of your route. Can you avoid them? If not, does your airplane have the required capability? Since even newer airplanes may not make “book” numbers, analysis and application means taking your calculations with a big grain of salt and adding a safety margin.

Bottom line: it may be a “data-driven” world, but don’t let data drive you into trouble!

Susan K. Parson (susan.parson@faa.gov) is editor of FAA Safety Briefing and a Special Assistant in the FAA’s Flight Standards Service. She is a general aviation pilot and flight instructor.