Flying Seasons

The Risky Business of Scud Running

September 1, 2007

There's no shame in not launching into marginal conditions

Scud running has been described as the delicate balancing act of maintaining visual contact with the ground so as to avoid physical contact with it. Pilots who scud run on a regular basis seem to be from the same gene pool as golfers who continue playing as a thunderstorm sweeps across the golf course. Continuing these risky practices automatically increases the odds of a fatal outcome. Successfully completing a scud-running flight depends on many factors such as weather, familiarity with the route, aircraft performance, and pilot skills. Unfortunately the margins between success and failure are extremely fluid and can change rapidly, often within minutes.

A review of the AOPA Air Safety Foundation Web site data of fatal scud-running accidents points at three distinct causes. We'll label them: It can't happen to me, or I'm too experienced; I don't have far to go, or it's just a few miles farther; and I've got to get home now! None of these mantras is ever etched on a tombstone, but they often are the reason the tombstone is needed.

Tower support cables and high tension wires

"Examination of the engine found high-tension cable wrapped around the crankshaft between the prop and engine case." — NTSB report

The pilot of a Grumman F6F Hellcat held an airline transport pilot certificate. On the day of the flight the pilot was heard saying that he planned to follow Interstate 40 from Sevierville, Tennessee, to Little Rock, Arkansas, a distance of approximately 438 nm. He took off VFR. According to the NTSB report, the pilot encountered weather estimated at five miles' visibility in mist while flying under a 500-foot overcast. The flight came to an abrupt and tragic end when the airplane was flown into multiple high-tension power lines. The chances of seeing and avoiding guy wires and high-tension lines during good visibility conditions are slim; throw in mist and the flat light that's typical below an overcast and the odds of seeing these hazards decrease to near zero.

Take the advice

"During the preflight weather briefing, the pilot was advised numerous times about the adverse weather conditions along his route of travel. He was also advised that visual flight rules could not be maintained from Jacksboro, TN, to Rome, GA, and that there were active tornado watches. The pilot stated that he would still be departing shortly after the phone call with the Anniston Flight Service Station." — NTSB report

The pilot was instrument-rated but chose to scud run VFR from Jackson, Tennessee, to Geneva in southern Alabama during the early afternoon in May. An IFR flight plan was filed and the pilot told flight service station personnel that he would activate the IFR portion of the route when he got to Rome, Georgia. He never got that far. The airplane hit the side of Horn Mountain near Calhoun, Georgia. An aerial search for the wreckage was delayed for three days because of poor weather in the area.

It's possible that the pilot decided that scud running would provide enough ground clearance for him to see and avoid the thunderstorm bases that were forecast along his route of flight and would be a better risk than flying into imbedded thunderstorms while IFR. The fact that the pitot-static/altimeter certification was two years out of date also may have been a factor in the decision to fly VFR instead of IFR.

When severe weather and tornado activity is forecast along a route of flight, it's always wise to live by the adage, "I'd rather be down here wishing I was up there instead of up there wishing I was down here."

Frosty days

"The pilot got in the airplane as another lineman brushed frost off the wing. According to an FBO employee interviewed by the NTSB, 'He seemed to be neglecting every sign of danger. He didn't even get the frost off the wing before he left.'" — NTSB report

The pilot took off from the Salt Lake City airport even though an FBO employee questioned the pilot's decision by pointedly asking why getting to work was so important and then took the pilot into the FBO — no record of the pilot requesting a formal weather briefing was found — and showed him computer weather depictions of the winter storm that was moving across the area. The reported weather near the accident scene didn't sound too bad: wind, 130 degrees at 7 knots; visibility, 10 statute miles; sky condition, 1,200 feet scattered; ceiling, 1,600 feet broken, 2,300 feet broken; temperature, 1 degree Celsius; dew point, minus 2 degrees C; altimeter, 29.71. The pilot took off, headed for his destination less than an hour's flight away. Instead of proceeding in a southeasterly direction and following a prominent highway that led to his destination, the pilot turned east and flew up a box canyon. Radar tracks showed that the pilot was able to make four turns in a circling climb before radar contact was lost. This accident suggests that scud running distorts the visual clues pilots are used to navigating by when flying at normal cruise altitudes. Somewhat surprisingly, witnesses quoted throughout various NTSB reports said that often the accident pilots didn't even go through a normal run-up procedure before launching off on what turns out to be their last flight.

Finding granite

"A search of recorded radar data for air traffic was performed, which had been flying between 1620 and 1645 on a southerly course between Chico [California] and the accident site. The search profile was limited to include only aircraft exhibiting a Mode C altitude readout, reversing course south of the Sutter Buttes, and then disappearing off radar in the vicinity of the Sutter Buttes." — NTSB report

The pilot of this airplane had departed from an airport located at 238 feet msl for an afternoon VFR flight to his home airport, which is at 356 feet msl, a flight of approximately 285 miles down the central valley of California. Three calls were made before the flight for weather along the route. When the pilot took off, the weather at the takeoff airport was reported as a broken layer of clouds at 800 feet with an overcast layer at 9,000 feet. The pilot said he would take a look and if it looked bad he would return. He had already flown approximately 40 miles from the departure airport and had turned around to return when the airplane hit one of the Sutter Buttes at 780 feet msl. The Sutter Buttes are a series of three peaks, the tallest reaching 2,117 feet msl, which stand alone and isolated in the vast expanse of the 365-mile-long-by-40-mile-wide central valley of California.

This accident may look more like a case of bad luck than a scud-running miscue. The pilot turned toward and hit the only rock at his altitude within hundreds of square miles. Based on the reported broken cloud layer and the impact altitude, it's likely that he was temporarily in the clouds when he turned back. The lesson this accident teaches is that even a route that appears to be benign has hazards that can snare scud-running pilots. Had the pilot spent some time before taking off locating no-go zones along his proposed route of flight on a current sectional chart, he would have taken steps to steer clear of the Sutter Buttes.

Zero-zero. Do the math

"The airplane impacted trees and terrain about 1 minute after takeoff, and pieces of angularly cut wood were found along the 400-foot wreckage path." — NTSB report

It's perfectly legal, although not too wise, for a private pilot to begin an IFR flight from an airport where the weather is so bad that the forward visibility is zero and the ceiling is zero. Although the decision to proceed with a zero-zero takeoff doesn't usually fall under the scud-running label, the elements are very similar in that the pilot has the full responsibility to avoid flying into terrain.

"The accident pilot responded, 'I'm at the river, starting up Marsh Creek. It's pretty low in here.' The second pilot called back asking if the accident pilot could turn around. The accident pilot responded 'no,' followed by, 'There's fog clear to the ground." — NTSB report

The pilot who died in this accident in mountainous terrain had logged more than 15,000 hours. His airplane was one of a flight of two that was returning to the air service home base after a flight to drop off cargo at a remote strip.

Scud running, or contact flying as it's sometimes called, is often the only way to complete flights in remote areas. Experienced bush pilots, who specialize in contact flying, still crash with some regularity when unusual weather patterns close off their normal escape routes.

Scud running doesn't always mean zooming along under an overcast layer down at lower altitudes. The airplane in this accident hit the terrain at 8,700 feet msl. Aircraft climb performance is always compromised at high density altitudes unless the engine is turbo-charged or turbonormalized.

In addition to the accidents identified above, two other factors from the NTSB reports were conspicuous because of their absence — a number of pilots who died in scud-running accidents had not bothered to get a weather briefing nor had they filed a flight plan. This seems to indicate that these pilots had already determined that they were going to take off no matter what the weather was. It's possible that these pilots either didn't think the rules applied to them, or that they had successfully scud run so many times that they had come to believe that they could always find a way through. There's another possibility. A study of 1,301 male and female U.S. Air Force pilots by Joseph D. Callister revealed that these students described themselves as achievement oriented, highly competent, responsible, and capable of handling high levels of stress. All good traits, but these traits can turn from assets to liabilities during a scud-running flight when the desire to complete a flight (achievement) overrides a pilot's ability to assign the correct weight to all the factors involved.

Scud-running accidents are listed under the controlled flight into terrain (CFIT) heading in accident Web sites. CFIT accidents continue to be general aviation's biggest avoidable headache. VFR minimums have been established to provide a measure of safety — follow these guidelines to utilize the wisdom of the thousands of flyers that have gone before. There's no shame in not launching into marginal conditions or in telling your passengers at any time during any flight that the weather is too poor to continue. The weather will move on. And you will live to fly another day.

E-mail the author at steve.ells@aopa.org.