Training and Safety
Fly like a fighter: Predicting the weather based on patterns
When I moved to Bitburg, Germany, to fly the F-15 there I had to learn a few new Air Force regulations. One of them seemed a bit crazy. Normally, to file IFR to a destination required the forecast weather to be at or above approach minimums. In Europe, we could file to a destination below approach minimums as long as there were two alternates at least 35 miles apart whose forecast was at least a 700-foot ceiling with 1 mile visibility (700/1). I wondered why anyone would ever attempt to fly to a location if the weather was forecast to be below minimums. I found out a couple of years later.
I was on a deployment to Italy, and it was time for me to rotate back to Germany. Maintenance needed to send two jets home, to be replaced by two other jets. Poor weather in Italy delayed our departure, which put the whole day’s mission under a time crunch. The two returning jets needed to get back to Italy before the field closed. Naturally, Bitburg had been below minimums all morning, with all of Germany IFR. We launched with our dual alternates, and for 90 percent of the flight, I was not a happy camper as I kept wondering why I was doing a mission I deemed crazy two years earlier. My 100-mile-out ATIS check showed the weather still below minimums. As I coordinated for our diversion, approach control informed me that Bitburg was now at approach minimums. We made it in.
It was only a month later that we had a week of daily déjà vous—W0X0F every morning (ceiling and visibility zero) that rose to about ¼ mile visibility around 11 a.m., and then fell back to W0X0F by 1 p.m. I realized then that local weather patterns can be predictable enough such that the dual alternates rule wasn’t as crazy as I initially thought. Europe sees a lot of IFR in the winter, but weather at 700/1 normally didn’t fall down to unflyable minimums.
Just recently I launched in my Cessna P210 with 25 knots of crosswind for some proficiency flying. I intended to do an approach and a couple of patterns at Colorado Springs Municipal, only 10 miles to the southwest. After getting airborne, I heard the airport’s ATIS: “An Embraer and Cessna 172 both reported a 50-knot gain in airspeed on short final to runways 17 Left and 17 Right.” I had to listen again to be sure it said “5-0” and not “1-5” knots. That had to be an exciting ride for them, not in a good way, so I headed north. The ATIS for Denver’s Front Range Airport, 50 miles away, was calling the winds calm.
These three different reports were a little surprising, but not unbelievable. With a slight ridgeline both to the south and north of my home airport, I have seen winds from different directions in each sector. Over time, I have learned the local geography so I was not totally caught off guard. In addition, even on days I am not going to fly I keep track of the local aviation weather reports just to see what is happening. The more exposure I have, the better prepared I will be to interpret the weather.
What are you doing to learn your local weather patterns?
Larry Brown of Colorado Springs, Colo., is a retired Air Force F-15 pilot who is using the lessons he learned as a fighter pilot as a GA pilot in his Cessna P210. Brown, who has 2,700 hours total time during his 33 years of flying, also was an instructor pilot and flight examiner in the Air Force T-38 and instructor pilot in the T-52, the military’s version of GA’s Diamond DA40. See previous installments of “Fly like a fighter.”
March 1, 2013