What is scud, anyway? Strictly speaking, it's those dark, low-altitude, ragged, patchy, sometimes fast-moving clouds that float beneath a stratus deck. The National Weather Service's official Cloud Code Chart puts scud in the "L7" category, meaning that it's a low-altitude (below 6,500 feet) cloud; the "7" is apparently just a designator. (The number 7 printed beneath a surface analysis chart's station model, however, refers to observed cloud height — which in this case would be 5,000 to 6,499 feet — far too high to meet scud standards.)
The terse descriptor on the chart calls scud "stratus fractus of bad weather or cumulus fractus of bad weather, usually below altostratus or nimbostratus." Fractus, of course, refers to the "fractured" nature of these dark blotches. The sky cover symbol for scud can be found on a surface analysis chart, beneath the central circle that shows the amount of sky cover.
Show of hands: How many of you look at surface analysis charts? How many know what the station model symbols mean?
The mention of fast movement, and the close association of scud with rain and low stratus layers, hints strongly at the involvement of warm or occluded frontal activity. Undoubtedly, the winds that blow scud are very often out of the southerly quadrants of the compass in the case of warm fronts, or the northerly or easterly quadrants in the case of occlusions.
What is scud-running? It's an informal term for a dimwitted navigation strategy. It's a technique that involves pressing on in the face of lowering ceilings, more clouds, and falling visibilities. The scud-running moniker may not directly correlate to warm front conditions. It's more of a colloquial term for any kind of ill-advised — or illegal — low-altitude foray around low clouds.
Mention of scud-running does, however, hint at a warm-front entrapment. Warm fronts have shallow frontal boundaries. Their cross sections slope gradually from the surface positions (which you'll see on surface analysis, weather depiction, and significant weather prognosis charts, among some others) to a point aloft some 300 or more miles ahead of the surface front. That's something to remember if you are approaching a warm front head-on. Lowering clouds and, yes, scud will be encountered as you fly toward and beneath an ever-so-slowly descending frontal boundary aloft. If you're instrument-rated, current on instrument flying, and on an IFR flight plan, you'll be fine — if you don't run into icing or an embedded thunderstorm or face weather below minimums at your destination.
But if you have no instrument rating or aren't proficient in instrument flying, you're setting yourself up for trouble.
Soon, you'll be flying in or among clouds and/or precipitation. In an attempt to fly clear of clouds you'll probably start weaving around them. Or, you'll freeze up in confusion, lock up mentally, and keep on trying to fly your heading. Or, you'll descend to progressively lower altitudes (as you fly closer to the front's surface position). Then you will have embraced the soul of scud-running.
"It will be better soon," the scud-runner convinces himself. "After this batch of clouds, or in a few minutes." The weather will improve, all right — when or if the scud-runner passes through the front! But scud-running isn't an approved method of traversing adverse weather.
Want to know another name for scud-running? This one comes from the National Transportation Safety Board, and it's called continued VFR into IMC (instrument meteorological conditions). It's the leading cause of fatal weather-related general aviation crashes. Many, many accident reports have a sentence that reads something like this: "Witnesses on the ground said that it was foggy and rainy. A park ranger said that he saw the airplane go by at treetop height and quickly disappear. Then, he said, he heard the sound of a collision. At the accident site visibility was reported as 200 feet ...."
There are four big problems with continuing VFR into scuddy, worsening weather. First off, there's the little problem of losing control of the airplane after a bout of spatial disorientation or vertigo. You also won't have a good grip on your position. You may have been using a sectional chart for navigation; but once in the clouds, you won't be able to tell where you are with respect to any nearby high terrain or obstacles. Another problem is low altitude: If you've been flying lower and lower to stay under the clouds, that strategy really falls apart if mountains are a factor. Finally, there's the psychological problem of coming up with a plan of action under these stressful conditions. Keeping your wits will be essential if the flight's to have a safe outcome.
To avoid scud-running, a.k.a. continuing VFR into IMC, use the following as common-sense guidelines:
- If you don't already have one, obtain an instrument rating. Any instrument experience or instruction you have will repay you in spades in critical situations like this.
- Obtain a good preflight weather briefing (Duh!). If you're a VFR-only pilot and lowering ceilings along your route are mentioned, call off the flight. If you're instrument-rated, set personal minimums for the ceiling and visibility forecast at your destination. A newly minted instrument pilot probably doesn't have any business flying ILS approaches in 200-foot ceilings and one-half-mile visibilities.
- Plan your flight well. Have alternate airports in mind, in case the weather goes down. Make good mental notes about the terrain along your route, plus the locations of any nearby navaids that could provide you with good cross-checks of your position as you fly. Better yet, write down this information on your flight log. You do use a flight log of some sort, don't you?
- Don't let yourself be forced into continually descending in order to stay clear of clouds. Consider an urge to descend as a warning to take action.
- Don't fly under Special VFR (SVFR) unless your destination is very near and the weather is significantly better than the one-mile, clear-of-clouds minimums for SVFR. SVFR is legalized scud-running.
If despite these precautions you encounter worsening weather, or can't safely remain clear of clouds, you'll want to be mentally prepared to:
- Climb to an altitude that will give you safe separation from terrain or obstacles.
- Perform a 180-degree turn. VFR or IFR, turning around has proven to be a sound way of avoiding adverse weather. Failing to make the decision to turn around, however, seems to be a big, big problem, according to accident statistics. If high terrain is near, then a climbing 180-degree turn is in order.
- Communicate with ATC or flight service, confess your predicament, and ask for help (vectors) to the nearest airport with better weather.
- Comply with the instructions or advice offered by controllers or specialists.
- Land at an airport or a suitable field close by — one that you can keep in sight and fly to at a safe altitude.
If the first four items sound familiar — remember climb, communicate, confess, and comply? — it's because these actions are the "lost procedures" that you learned in primary training.
You use them now because — guess what — you're probably not only lost, but you're also in the clouds and may not be up to instrument flying at all, let alone a climbing turn on the gauges. If you're not, then an off-airport landing is definitely the wisest move.
The mandate to climb almost guarantees that you'll be making a climb on instruments. That's why it's so important to tell controllers what has happened to you — or, more precisely, what you've allowed to happen to you. It's bad enough to illegally fly in instrument weather. It would be even worse if another pilot in another airplane, in the clouds, flying legally on an IFR flight plan, compounded your problem by ramming into you.
Some old salts are fond of doling out hair-raising stories about successfully scud-running those last 20 minutes to an airport that went below IFR minimums a minute after they landed. Sound smart to you?
Every scud-running situation is different. Sometimes the weather goes down fast, and complicating factors — like low fuel, system problems, and distant alternates — can make the options for a VFR-only pilot risky ones. How much better to have the option of climbing and air-filing an IFR flight plan to your destination.
E-mail the author at [email protected].
Confessions of a Scud-Runner
One pilot 'fesses up harrowing tales of scud running
BY JOHN R. HULL
Here are three of my most exciting scud-running adventures derived from my years of experience as a flight instructor and pilot-for-hire. But for the grace of God, any of these could have resulted in being summed up on an NTSB accident report as "Pilot continued VFR into adverse weather conditions."
Scud-running the Mississippi River
I sometimes scheduled two or three student pilots for long dual cross-country flights in one airplane over a weekend. Each of them took turns flying different legs of the flight. This quickly built their dual cross-country flight time, and the one riding in the backseat learned from the other.
Three students were with me on this planned flight from Fort Worth, Texas, to Miami, Atlanta, and return in a Piper PA-20 Pacer. All was going well until we neared the Mississippi River eastbound. The closer we came, the lower the visibility and ragged bottom of the stratus clouds became. I let the student pilot slowly descend with the clouds to about 200 feet agl before I took over the controls.
The weather on the other side of the river was supposed to be much improved from what it was on the west side. So, hoping to squeeze underneath the lowest scud hanging over the water, I let down to almost treetop level. While I was thinking, "We'll soon be flying in improved conditions," we suddenly were enveloped in clouds. Not daring to go any lower, or to fly the partially equipped instrument panel any more than necessary, I immediately started a 180-degree left climbing turn.
After gaining several hundred feet of altitude in the turn, we were on solid instruments flying west. Letting down very slowly, I searched diligently for a glimpse of anything through the clouds, hoping to see the tops of the pines instead of hitting them. After a very few long minutes, the treetops appeared through the scud about 100 feet below.
A few minutes later we were clear of the ragged clouds and able to gain a little more altitude. Soon we found the blacktop highway we had been following before getting swallowed by the scud. Following it, we soon came to a small town with an active crop-duster strip nearby. We landed and spent the night before continuing our journey.
Why did I continue into IFR conditions? Because I thought I could make it. Risk taking is an easy trap to fall into.
Scud-running the Oklahoma hills
This happened during the delivery flight of a Cessna 140 that I had sold to a pilot in Antioch, Illinois.
The weather was poor that morning in Fort Worth, but forecast to improve to mediocre VFR conditions by midday. Low and middle-altitude clouds covered the entire midsection of the country. The clouds lifted to above VFR minimums at Meacham Field about 10 a.m., so I took off.
Everything went well until I reached the Arbuckle Mountains in southern Oklahoma. The Arbuckles aren't very high. But, with the low ceiling, the tops were obscured by clouds. I decided to follow the main highway between Fort Worth and Oklahoma City through the mountains. As I approached the summit south of Ardmore, Oklahoma, the road seemed to disappear into the scud. Then, as I got closer, I could see a sliver of light on the other side of the pass. This raised my confidence level, so I flew through the narrow clearance between cloud and ground.
Going through the pass, I kept my eyes on the road. It was about 100 feet below and slightly to my left. Suddenly, my peripheral vision caught a glimpse of something going past the right cockpit window. "What was that?" I thought. "A bird? Another airplane?" I couldn't say. I was too low and hemmed in by the terrain to turn and look back.
A question flashed to mind that made chills run up my spine. "Is there a transmission tower in that pass?" As soon as there was safe maneuvering space between the clouds and the ground, I checked my sectional chart. Yes, there it was, just east of the highway. The obstruction light on top of the tower must have been in the clouds.
I've driven through that pass dozens of times since then. Each time, I've wondered how I could have flown that airplane between the tower and the highway without hitting it or one of its supporting guy wires.
Scud-running to home base
The weather had been exceptionally beautiful during the flight from Fort Worth to Cody, Wyoming, and back with a corpse in the cabin.
A few miles south of Wichita Falls, Texas, a weather update for Meacham Field surprised me. Reported conditions were below VFR minimums. I couldn't believe my ears. There was no mention of impending adverse weather in the forecast. I called and asked for a repeat of the Fort Worth weather. I had heard them right the first time. What's more, the ceiling and visibility were still going down.
It was only a hundred miles to Meacham Field, so I decided to keep going and ask the tower for a Special VFR clearance into Meacham when I got a little closer. There were several other airports north of Fort Worth that I could sneak into if they refused a Special VFR request.
The clouds associated with the unusually fast-moving warm front soon came into view. In a few minutes I had to descend to 300 or 400 feet agl to stay under them.
Within 25 miles of Meacham Field the clouds were so low that I had to fly around some hills. Funny, I flew over that area all the time and, until that day, I had thought of it as flatland.
When the little town of Decatur came into view off to my left, the courthouse dome protruded into the overcast. A light mist began to restrict my visibility. That's when I decided that it was time to quit. Guessing the approximate location of the small airport on the edge of Decatur, I headed for it.
Luckily, I was flying parallel to the runway when I spotted the airport in the darkening dusk and mist. To keep from losing sight of the runway, I immediately closed the throttle, slowed the airplane to flap speed, and pulled full flaps to make a short 180-degree turn and land.
The additional lift from the lowered flaps caused the airplane to balloon into the clouds. I couldn't see anything outside the cockpit and was no more than 100 feet above the ground. Leaving the power off, I gently eased the wheel forward until the ground appeared again. Then I made a quick 180-degree left turn. The runway had disappeared from view, but I quickly found it again and landed.
I hated to call the boss and tell him how close I had gotten to home but that I couldn't make it all the way. He called the funeral home, and its driver came to Decatur to pick us up.
When the ambulance arrived, I told the driver, "Sorry you had to drive an extra 25 miles to pick up the corpse."
"Oh, well," he said, "that's better than having to pick up two bodies."
Reflecting on these experiences is much more frightening than the actual occurrences. It's these reflections that shaped my maturation as a pilot. They changed my scud-running behavior. I avoided all intentional scud-running after that, lest my epitaph should read, "Pilot continued VFR into adverse weather conditions."
John R. Hull, AOPA 1316620, is a retired FAA FSDO manager and award-winning FAA writer. The commercial pilot and flight instructor has an instrument rating.
