May 1, 2000
By Bruce Landsberg
How many times have you gotten right up to the point of launching on a cross-country trip, and then had one thing tip the balance to no-go? In my early flying years, this happened quite a bit. With more experience and sometimes more aircraft capability, go became the more common option. However, there are days when it looks like it all ought to work but something says, "No."
NASA conducted a meeting in late January on some important aviation safety initiatives. I really needed to be there, so it was fly or find an alternative mode of transportation. Flight time was an hour by Beech Bonanza from Frederick, Maryland, to Newport News, Virginia. As far as deicing equipment, the Bonanza's heated pitot tube relates just about how fast you're getting into trouble if ice is the problem.
My first hope, looking at the weather outlook the night before, was that it would be VFR. The next morning the sky had that milky look to it and, according to the local METARs, visibility was running about four miles with a 2,800-foot ceiling. Marginal. As the day wore on, the weather improved. A mid-morning DUAT check showed good ceilings and visibility to the north, but there was a developing low along the south Atlantic Coast. It was supposed to track off of the coast and away from the mainland; however, the leading edges were affecting the Norfolk/Newport News area, with ceilings at 900 feet overcast and two miles' visibility in drizzle.
That was still flyable, but IFR was the only way, and that would add about 20 minutes to the trip to accommodate the preferred route. I went into a meeting, intending to get an update just prior to my 3 p.m. departure. The call to flight service started positively enough, but then went downhill rapidly. There were no airmets or sigmets for ice, but a recent pirep by a Boeing 737 reported light ice at 1,000 feet. Nuts. Was there anything else? The briefer allowed that the surface temperature was just a few degrees above freezing, so for operational purposes it might as well be at the surface. (An airmet for ice was subsequently issued.)
It was drizzling at Norfolk, 20 miles to the southeast of Newport News, and the ceiling was 200 feet lower at 700 feet agl. The wind was northeast at 15, gusting to 23 knots; temperature and dew point were 36 degrees Fahrenheit. Was there anything else? Well, yes, said the briefer. The possibility of freezing rain or drizzle did have to be considered. Tilt. Freezing precipitation does bad things, even to aircraft approved for flight into icing conditions.
At this point, there was one positive report of ice and the possibility (not probability) of some other nasty things. My desire to fly was strong, as it is for most pilots, and I understand how people can rationalize any decision — that capacity is endless. In retrospect, I really didn't need any more information; but having been burned by overly conservative forecasts in the past, especially where ice is concerned, a bit more verification would reinforce the decision not to fly. This no-go was not satisfying because I wasn't convinced beyond reasonable doubt.
The briefer and I discussed the scarcity of pilot reports. It would have been most helpful to know how many other aircraft in the area had encountered ice, what the tops were, and if there was a temperature inversion — the precursor for freezing rain or drizzle. The briefer was required to solicit pireps under these conditions, but he wasn't talking to many aircraft and the pilots apparently weren't volunteering. I suspect that the Norfolk Tracon was talking to many aircraft. It was impossible to know if they were talking about the weather.
This points out a real weakness in our weather dissemination system. Over the past several years, the FAA has been studying the weather accident problem with industry members and the AOPA Air Safety Foundation. The unanimous conclusion was that there should be many more pireps. But when pilots are busy, very few leave ATC frequencies to talk with flight service. The 737 crew did a good deed by passing along the icing report. It could have been relayed by ATC, and if they took the time to forward it along, then thanks is due there as well. But the reality is that pireps are pretty low on ATC's priority list and probably fewer than half make it into the FSS distribution system.
The ATC system can work really well for passing along weather to those who are on the party line and know how to use it. High- and mid-altitude sectors are replete with ride reports and sometimes ice or convective weather concerns. This isn't the long, formal report format of the Aeronautical Information Manual. It could be as simple as "Light ice from 2,000 to 4,000." Everybody in the sector hears it, and occasionally somebody will ask the location of the reporting aircraft. Controllers generally pass the information on to new crews checking on the frequency. The airlines put it into their own dispatch systems. But in general aviation, not many reports make it into the flight service system or back to the National Weather Service (NWS).
If you think of flight service as GA's dispatch system, merely reading the weather from the NWS is not enough. Sometimes the forecasts that flight service gets from NWS are not accurate. Sometimes it is more art than science. Many briefers do an outstanding job of interpretation, but some will not stray from the printed forecast word and METARs. There are briefers and controllers with a flair for understanding the weather situation. They search out information, and you can hear the enthusiasm in their voices. Pireps are gold nuggets to be mined and passed along, either encouraging or discouraging one to fly on that particular day. As always, though, the decision must rest with us.
In the perfect world of the future, we'll have weather in the cockpit and electronic pireps, where sensors on board the aircraft will datalink temperature, moisture, winds aloft, and perhaps even visibility and turbulence to the ground. Some of this is already being done on a few air carrier and cargo aircraft. The last two items are a big stretch for present technology, but in five years, who knows? For now, however, it needs to be done the old-fashioned way. A pilot has to call on the radio, provide a subjective view of what's happening, and a controller or flight service specialist has to transcribe it into the distribution system. It's low-tech and cumbersome.
Could we handle pireps better in the short term? It would probably require a relatively small investment in personnel and hardware — both in short supply in this day of government surplus. There are controllers who would prefer to just separate aircraft and leave weather to flight service. There are other controllers who do accommodate weather requests and my hat is off to them, because they have helped many of us complete more flights safely; but there is no systemic mandate to make this work.
If I were the National Weather Service, it would be great to know whether my forecast hit the mark or not. In addition to saving lives, a minor reward in itself, there is nothing quite so satisfying as to be able to see the immediate results of a prediction and make mid-course corrections. Adding a few thousand observation points each day would update the forecast models, improve air traffic flow, and help the nation as a whole to be better prepared for weather. Sounds like a win-win situation to me. The NWS would likely endorse such a solution.
I decided, with some uncertainty, to make the 3.5-hour drive, because I had more uncertainty about flying. The icing conditions were potentially severe, and there were relatively few convenient alternatives. From Washington, D.C., to Richmond, the skies were clear with light winds. Drat — foxed by a pessimistic briefer. About 20 miles east of Richmond it started to deteriorate, and by the time I arrived at Newport News the ceiling was down, it was 34 degrees on the surface, and the winds were honking out of the northeast. The briefer had helped me make the right decision.
The next morning a full-fledged nor'easter had blown up with moderate snow and winds in excess of 60 knots. The forecast said nothing about this. The storm raged all day and shut down the East Coast. The drive home the following day was in clear sunshine.
It is as important to report something that isn't there as what is. No turbulence, no ice, good visibility, etc. will help all of us make better decisions. If the forecast calls for bad weather and we can verify that it's safe to fly, that information should be widely distributed. When it is as bad or worse than forecast, it is vital for other pilots to know that the NWS nailed it. When they miss, both the pilot community and the NWS need to know.
Visit ASF's Web site for Safety Advisors on weather decision making. We'd also like your opinions and comments regarding the current state of forecasting and whether a more robust pirep system would help. E-mail us at [email protected]; call 800/USA-AOPA; or write ASF, 421 Aviation Way, Frederick, Maryland 21701, Attn: Pireps. See also the index of "Safety Pilot" articles, organized by subject. Bruce Landsberg is executive director of the AOPA Air Safety Foundation.
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