Incident Overview
A pilot on a fire assignment departed Grand Junction, Colorado (GJT) to support the Coal Seam Fire in Garfield County, near Glenwood Springs. The pilot reported encountering low-level wind shear and varying degrees of turbulence—light, moderate, and severe—shortly after takeoff and continuing throughout the flight to the operational area.
Fire Operations and Return
After conducting a reconnaissance of the fire, the pilot climbed to approximately 5,000 feet above ground level to mitigate turbulence and await favorable wind conditions for tanker aircraft that were dropping fire suppressant chemicals. Once conditions improved, tanker operations commenced and were completed without incident. The pilot then returned to GJT.
Turbulence Encounter on Descent
While in the vicinity of the Book Cliffs, about 10 nautical miles northeast of GJT, the pilot was at approximately 2,000 feet agl in a low power descent at an indicated airspeed of 150-160 knots. At that point, he experienced a single significant event of severe turbulence. Winds at the time were reported from the southwest at 20 knots with gusts to 29 knots. The aircraft continued to GJT and landed uneventfully.
Post-Flight Discovery
The damage was noted the following morning during a routine preflight inspection. Examination revealed that the top skin of the left wing, between the fuselage and the left engine nacelle, was buckled. No other anomalies were found.
Weather Conditions
The reported winds at GJT, 34 minutes before the turbulence encounter, were from 180 degrees at 20 knots with gusts to 28 knots.