Boiling Trouble

Unsuspecting pilot gets caught in rip current between winds aloft and surface


Take an 80-degree summer afternoon, clear skies, high pressure and light winds. Add an airplane, a friend or spouse, and pick a destination a few hours away. While youre at it, throw in the family dog.

This is a scenario many general aviation pilots would consider the ultimate in personal aviation – the perfect time to embark on what may be the perfect trip. For one Colorado pilot, however, the prognosis wasnt so sunny.

The pilot had accumulated more than 14,500 hours, many of them as a Part 135 helicopter pilot. He had single and multi ratings and instrument ratings for both airplanes and helicopters. He had once been a flight instructor. Even though he was retired, he still held a second-class medical certificate.

His airplane was a 1965 Cessna P206. It had accrued less than 2,900 hours since new and its annual inspection had been only six weeks earlier. The pilot was planning a flight from Gunnison, Colo., to Oakley, Kan. He planned to depart at 2 p.m. on a flight that would take about three hours. Accompanying him would be his wife and dog.

About 20 minutes before departure, he called Flight Service for a weather briefing and to file his VFR flight plan. He selected a cruising altitude of 11,500 feet to stay below oxygen altitudes and selected a route of flight that, while not direct, would take him over lower terrain than flying direct. Going straight from Gunnison to Oakley would have meant overflying peaks southwest of Colorado Springs that climbed higher than 11,700 feet.

The briefer painted a rosy weather picture. He mentioned an earlier advisory for mountain obscuration that had expired. He spoke of good strong high pressure and said current observations were just some mid to high level scattered clouds, unrestricted.

The forecast for the pilots route of flight called for a few scattered clouds, unrestricted visibility and surface winds out of the southeast at 10 to 17 knots. The winds at 12,000 feet were tailwinds coming over the mountains at 15 to 20 knots.

Although the pilots and the airplanes FAA records showed a Galveston, Texas, address, the pilot told the briefer he was based at Gunnison. His retirement had been fairly recent, however, and many pilots FAA records take a while to get updated. In any case, it appears the pilot had at least some familiarity with mountain flying. Gunnison has a field elevation of 7,673 feet, but sits in a bowl with peaks over 13,000 feet within a few miles in nearly all directions.

He took off promptly at 2 p.m. and dutifully called Denver Radio to open his flight plan. Fifteen minutes later he was dead.

Although there is no radar record showing the airplanes track, its reasonable to conclude the pilot flew east and through Monarch Pass, which carries an elevation of 11,312 feet. He likely continued east past Salida before turning slightly to the southeast and his intermediate waypoint of Lamar.

To his left would be the Sangre de Cristo mountain range, a narrow line of peaks that exceeded 13,000 feet there.

Two witnesses in the small town of Howard were sitting on their deck when the 206 flew by. The husband was a student pilot and the wife a low-time private pilot, and so perhaps its not surprising their eyes went upward when he heard the sound of the 285-hp Continental churning overhead.

It was flying straight and level, they said, when suddenly it pitched up and went into a steep left descending spiral. They said it made two or three turns, but was definitely not in a spin. The airplane disappeared behind a mountain peak briefly, but then reappeared, laboring as it climbed. It then dropped its left wing again and rolled over. This time it did not reappear.

The witnesses said there were thunderstorms to the north of the area and that, although the airplane was close to them, it was in an area clear of clouds.

An analysis of WSR-88D doppler weather radar installed at Pueblo, Colo., some 60 miles away, showed what an NTSB meteorologist called weak weather echoes in the vicinity of the site at the time of the accident. The storms were moving from northwest to southeast, with tops of about 33,000 feet. Images from weather satellites show cloud cover in the area and cloud tops of about 29,000 feet.

High-Speed Impact
The aircraft struck a boulder head-on while on a southwest heading and slid down the face of the rock, coming to rest 30 feet lower at about 8,160 feet. The airplane was going fast enough at the time of impact that the right wing ripped off and flipped over the rock. The wing was found ahead and to the left of the wreckage, while the strut was found ahead and to the right.

The shattered airplane made it impossible for investigators to verify control continuity. The panel was destroyed and no readings could be obtained from any of the instruments. The only cockpit determination they were able to make was that the fuel selector was on both. A 15-inch stub of one blade was all that remained of the propeller assembly, and it showed evidence that the engine was operating a high power at the time of impact.

Because of the condition of the remains, pathologists were unable to perform an autopsy to see if pilot incapacitation may have been a factor in the initial loss of control.

Investigators concluded that turbulence from the thunderstorms was a factor in the pilots loss of control, despite the fact that witnesses put him clear of the storms. Thats not a contradiction, given the dynamics of thunderstorms, particularly in the mountains.

Thunderstorms can influence the air around them enough that light plane pilots should stay well clear, at least 10 miles for weak storms and 20 miles for strong ones. In the mountains, the up- and down-drafts can become even more severe.

Recall that the winds aloft were from the southwest, about 240 to 260, according to the pilots preflight briefing. At the same time, however, surface winds were from the southeast.

Here was a situation where you had strong winds coming over the mountains and crashing into air coming at it and rising up the mountainside. The pilot, perhaps blinded by what he saw out the window, didnt make the connection.

Another troubling aspect is that the thunderstorms reported by the witnesses, the Pueblo radar and the satellite images did not find their way into the pilots briefing from FSS.

The briefer used the current conditions report from 16:53 UTC to 17:35 UTC. (The pilot took off at 18:00 UTC.) The forecast reports were valid from 12:00 UTC June 5 to 12:00 UTC June 6 – six hours before takeoff to 18 hours after takeoff. The winds aloft data was valid from 17:00 UTC to 21:00 UTC.

The difference between the reported weather and the weather the pilot ran into less than a half-hour later points to some of the shortcomings of weather briefings – especially those done by telephone and not augmented by pictures or charts. In addition, a standard briefing usually leaves it unclear just when the observations were taken or when the forecast expires, though briefers will tell you if you ask.

Finally, it illustrates that even a highly experienced pilot can get lulled into believing everything is as it seems. A quick look out the window shows a glory day. A quick briefing does nothing to quell that notion. The pilot could see the storms, but believed he was giving them a wide enough berth.

Unfortunately, a snarling spit of air that should have been anticipated gave the pilot a surprise of the most unwelcome kind.


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