February 2001 Volume 44 / Number 2
Following the fronts
ASF SkySpotter Program
The AOPA Air Safety Foundation is cooperating with the Aviation Weather Center (AWC) and the FAA's flight service system to greatly expand the number of pireps filed below 10,000 feet where most of us fly. All pilots are asked to file pireps on every flight. A complete guide on how to file can be found in the Aeronautical Information Manual (AIM) or on ASF's Web site. However, the exact phraseology is less important than passing along your weather observation. FSS will ask any questions it needs for clarification.
The most certain way for a pirep to reach AWC is to file it through a local FSS or flight watch on 122.0 MHz (a national frequency), although they can be filed with ATC, particularly if they're urgent. If workload prevents an in-flight report, please call FSS at 800/WX-BRIEF right after landing and pass along the information. Areas of particular interest are turbulence, cloud bases, cloud tops, icing conditions encountered, and in-flight visibility. This will help AWC and FSS determine the true nature of the weather. Multiple reports are valuable because they confirm a particular condition, where an isolated report may be an anomaly.
For example, the forecasts sometimes state that "VFR is not recommended" when there is little threat, or it is localized. IFR and VFR pilots should pass along what they find. If good weather is encountered, the reports should be disseminated so that the forecast can be corrected. Conversely, if bad weather is a fact, it should be verified so that VFR pilots getting weather briefs understand that the forecast is correct. The same concept applies to turbulence and icing. By increasing the pirep flow, we can improve the utility of light aircraft and save lives by letting our fellow pilots know what's happening in the weather department. Be a SkySpotter on every flight!
Last winter I wrote about a trip that wasn't taken because of a single negative pilot report. The following journey last fall was possible because other pilots took the time to file pireps that either vindicated or nullified the forecast. Without pireps, we are limited to official guesstimates that can over- or underestimate the nature of the weather we're likely to encounter. We've all been skunked too many times by an overly conservative forecast and occasionally surprised by something nasty that the forecast models didn't predict. Pireps help the decision-making process and are used by the National Weather Service to amend forecasts—and by flight service to help pilots come to the safe conclusion about starting a flight.
A business trip took me from the East Coast to Kansas City, Missouri; southern Nebraska; Wichita; and back. Cold air was moving in to start winter in earnest. The trip planning and execution became a fascinating exercise. One can always find an excuse not to fly, but I don't sacrifice myself to row 26 of an Airbus without a legitimate reason. Knowing when to bail out is the million-dollar question. Flying light aircraft without deicing equipment during the fall/winter changeover adds new meaning to the word flexibility.
The outbound leg was to Kansas City International (MCI) with a fuel stop in Terre Haute, Indiana. A cold front across my route trailed behind a strong low-pressure system to the north. The Weather Channel showed tightly packed isobars and snow on the back side of the low, but MCI was just on the southern edge. After half an hour of defrosting the Beech Bonanza, I launched into gorgeous VFR conditions. Working westward, gathering weather along the way, an IFR clearance seemed appropriate, and just west of Cincinnati an undercast formed. Then the rain and fog began, and by the time I landed at Terre Haute, the ceiling dropped from 2,500 feet in light rain to 1,000 feet overcast and just over mile in moderate rain.
The ability at most FBOs to look at weather radar, while getting TAFs and METARs is wonderful. There was a band of heavy rain just west of Terre Haute, then an open area, and then another, more diffuse band east of Kansas City. This first batch of weather was the warm sector ahead of the low, and the second was clearly the cold front. The temperature and the wind shift to the northwest marked the frontal boundary. Flight service was very helpful in getting some pireps on the ride ahead and convinced me that the rain band near Terre Haute was not convective, just heavy.
You can feel sorry for yourself when checking the fuel caps and sumping the tanks as the rain comes down, but procedures are there for a reason. A wise man once said there is no such thing as inclement weather, just inadequate clothing. I carry a poncho to keep the focus on a good, unhurried preflight. The challenge is not to let more water into the tanks than you're trying to extract.
At 6,000 feet there was plenty of rain but not much turbulence. Twenty minutes later the rain stopped, and the clouds became layered. Another call into flight watch about an hour later confirmed that there was more rain ahead, but no particular problems were reported. It got darker, and I asked Mizzou Approach near Columbia, Missouri, for a little insight from their radar. The controller was apologetic that the weather circuits were down and said that I'd have to work this on my own.
A twin some miles ahead with weather radar started asking for deviations around some heavy cells. Hmmm. It was not the time to be shy, so after the controller permitted them to deviate as necessary I asked where the twin was and what it was encountering.
Without radar, sometimes you can get some help from someone else who is equipped. This won't work if the frequency is jammed, and there is a calculated risk in letting strangers possibly lead you into temptation—or worse.
The twin pilot allowed that he was looking at level three, four, and five cells! Only 10 minutes had passed since I had spoken to flight watch, and it seemed unlikely that it would have built that quickly. It is possible, of course, but the nature of this system was for the flash-bang stuff to be much farther south. There had been nothing convective anywhere near my proposed route. A view of the sky ahead did not seem to support bad news of this magnitude, and the Stormscope showed no activity. The twin pilot decided to reverse course and then the controller popped the question: What were my intentions?
I've read and written about pilots who make the destination a holy grail only to come to grief along the way.
The twin's report just did not jibe with anything else, and if his tilt control was misadjusted he could have been looking at the ground and thinking it was convective activity. I've done it myself. So I cinched up the belt, slowed way down below maneuvering speed, and told the controller that I would take a look and keep him advised. It got dark with a few moderate bumps and a narrow area of moderate rain. That was the cold front.
I advised the controller what I had not found and proceeded on to Kansas City, which had a bucking crosswind from the west and some stratus behind the front. The ceilings were running about 800 feet overcast with low tops.
The following two days in the Heartland were aeronautically uneventful, but the departure back to the East Coast coincided with a strong low coming up from the southwest. Everyone has a favorite TV show. Some people watch Oprah, some watch football or the soaps, but I watch The Weather Channel when I need to get the big picture of how a trip might turn out meteorologically. TWC had the northern edge just brushing Wichita with some light snow and strong thunderstorms out ahead of the front. DUATS updates and a call to FSS fleshed out the picture.
I planned to leave at 8 a.m., but flying into the back of a November low without deicing is asking for trouble. Convective sigmets were being issued hourly, and the radar showed that a hundred miles west of my planned refueling stop in Evansville, Indiana, there was a line only 20 miles wide but almost eight miles high. It was clearly going to be a leisurely morning. Let the storm move on ahead, let the tops behind the low get lower, and let the convection move to the northeast. There was freezing drizzle in Springfield, Missouri, that needed to be avoided. I started collecting pireps hourly to get a picture of where the tops were and the actual temperatures aloft compared to the winds aloft forecast temps. Without the pireps there is usually only widespread pessimism in the icing forecast and unless one chooses to be a big risk-taker, without additional information from pireps, the best course is to wait.
Around 1:30 p.m. I launched from Wichita under bright sunshine and a steady northwest breeze. Moving east, the clouds built under the Bonanza again, but this time the front was ahead and moving away rather than toward me as it had been on the outbound trip. At 5,000 feet, there was an inversion and the temperature was about 5 degrees Celsius. The clouds continued to build, and I asked for 7,000.
The inversion kept the water streaming back over the windshield. The temperature started to drop and being close to the tops, which is frequently where ice is the heaviest, it was now time to move. Climbing to 9,000 feet I looked up, and just ahead there was a flock of geese, at 12 o'clock and less than a mile, coming out of another cloud. The flight leader called for the avians to break right, as did I, and they passed under the left wing. I didn't think geese flew in the clouds, but they were there and the controller hadn't called it so they were without a clearance—or we'd clearly had a loss of separation. I did not file a near-miss report.
The airspeed dropped 5 knots and rime was forming on the wings. There were no top reports in the area, but it looked like 11,000 might just do it. Only 80 miles to go to Evansville. Ten knots gone now and a bit more ice, but the Bonanza was mostly on top and flying well. The temperature was just below freezing, and I advised the controller of the flight conditions. "Wait and see" is not a good strategy with ice. Up, down, or out are options to be exercised before the wings and tail cease to function as designed.
Shortly after that came a broadcast of convective sigmets and airmets Zulu (ice), Tango (turbulence), and Sierra (IMC) for most of the world east of the Mississippi. It wasn't a fit night out for small aircraft. No wonder the geese were headed west! The sky was ominous and the Stormscope was active. If I'd received the same pilot radar report that was provided on the westbound trip, it clearly would have been time for a diversion. That strategic five-hour delay on leaving Wichita was paying off, though, because all the big action was northeast of Evansville.
The ILS for Evansville's Runway 22 provided the guidance and the approach was uneventful, although the airplane was a little light on its feet during taxi because of 25-knot winds. Time to call it a night and fire up TWC again to see how the storm would progress through the night. I was only three hours' flight time from home, but it could easily be another day or two before I got there.
It was raining lightly in Evansville the next morning, with two reports of moderate ice at low altitude by departing regional carriers. Time to wait and learn the tops and ice situation. At times like these, one longs for turbine—or at least turbocharged—power and a deicing system. A two-hour delay and several more pireps showed that the ice was gone and tops were at 4,000 feet. Good to go.
I headed eastbound in bright sun at 7,000 feet with a blanket of white stratus below and a deep blue sky above. Upon reaching the Appalachians, the clouds began to build, but my inversion was holding up well, with temperatures staying around 10 degrees C. Now the issue turned from ice to turbulence. The Bonanza was getting a 20-kt push with 40-kt winds. The ride down low could be miserable and the stratus deck began to show wave forms. I opted for 11,000 to stay above the clouds and the bumps.
All good things must come to an end, and Washington Center called for a descent to 7,000 feet with 65 miles to go. The clouds were fractured and there were some lenticulars. Time to slow down and go down—something Bonanzas don't do well. I canceled the IFR out of 5,000 feet with the airport in sight, put the gear out to act as a speed brake, and hung on for the last few minutes. After landing, I called flight service to file another pirep on the last 200 miles of the trip, to help someone else along the way. This weather week was interesting and serious. The dozens of pilot reports that other pilots had put into the system made it easier to make the right go/no-go or delay decision. Will you help pass the word?
See also the index of "Safety Pilot" articles, organized by subject. Bruce Landsberg is executive director of the AOPA Air Safety Foundation.