NTSB Identification: CEN13LA356
14 CFR Part 91: General Aviation
Accident occurred Saturday, June 08, 2013 in Golden, CO
Probable Cause Approval Date: 02/10/2014
Aircraft: ULTRAMAGIC N-250, registration: N753ZF
Injuries: 1 Serious,2 Minor,8 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The pilot reported that, before the flight, he and the other balloon pilots flying that day reviewed the forecast weather, which indicated that a cold front was north of the departure location. Before takeoff, there was some surface wind, but it subsided around the time the balloons were ready to take off. The balloons took off about 0730. The plan was to drift eastward, but once airborne, the pilot noted that the balloons were being pushed to the south. About 20 to 30 minutes into the flight, the wind increased and was accompanied by updrafts and downdrafts. The pilot reported that the balloons were moving fast and that the bottom of his balloon envelope was becoming concave, which was causing heat and air to spill out of the balloon. The pilot looked toward the ground and saw the trees rustling and he realized that the wind speed was faster than he had expected. After seeing another balloon land and then get dragged by the wind, the pilot decided that he needed to land his balloon immediately, so he located the "biggest place" he could find before he reached power lines south of his location. When the balloon touched down, the basket tipped over and was immediately dragged. The pilot pulled in the vent line to spill the air from the envelope. He reported that, after half of the air was out, the balloon was still moving quickly across the ground but that he finally got the balloon to stop after it had moved about 200 yards. One passenger sustained a serious injury.
A review of meteorological data available at the time of the preflight briefing indicated, in part, that wind from the west existed at 10 knots or less before takeoff. The National Weather Service (NWS) terminal area forecast expected easterly wind shifting to the northwest at 13 knots during the anticipated flight with wind from the north gusting to 23 knots after 1000 mountain daylight time. The NWS area forecast did not expect any high wind across Colorado. The NWS Aviation Forecast Center had no advisories current for low-level turbulence or high winds over Colorado surrounding the anticipated flight. However, shortly after takeoff, a sudden increase in wind speed occurred across the region with wind gusts from 20 to 38 knots. The NWS misjudged the timing and underestimated the magnitude of the frontal boundary moving across the region. It is likely that, if the pilot had known about the gusting wind at the time of takeoff, he may not have chosen to fly that day.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The balloon's encounter with unforecast strong gusting wind, which resulted in a high-wind landing. Contributing to the accident was the National Weather Service's misjudgment of the timing and underestimation of the magnitude of the frontal boundary moving across the region. Full narrative available
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