Incident Overview
On February 13, 2010, at approximately 0830 mountain standard time, a Cessna 680 airplane, registration N606CS, was substantially damaged during a turbulence encounter while in cruise flight near Eagle, Colorado. The aircraft was operated by Citationshares Management, LLC and owned by DEC Leasing, LLC. The two airline transport pilots were not injured. Visual meteorological conditions prevailed, and an instrument flight rules (IFR) flight plan had been filed for the 14 Code of Federal Regulations Part 91 repositioning flight.
Flight Sequence
The airplane departed Centennial Airport (APA) in Denver, Colorado, around 0819, en route to Eagle County Airport (EGE) in Eagle, Colorado. Initially cruising at 16,000 feet mean sea level (MSL) in clear air above lower clouds, the flight crew encountered light to moderate turbulence. They requested and were cleared to climb to 18,000 feet MSL. While leveling off at 18,000 feet, the airplane encountered extreme turbulence, causing the autopilot to disengage. For a brief period lasting less than a minute, the flight crew struggled to maintain wings level, altitude, and airspeed. Following the turbulence encounter, the crew executed an uneventful descent and landing at EGE.
Damage Assessment
A postflight inspection revealed overstress damage, including wrinkling and debonding of portions of the top skin on both wings.
Weather Conditions
Surface stations near the mountain range recorded high sustained winds with significant gusts during the event, with wind speeds approaching 40 knots and gusts reaching 50 knots. Wind directions were generally perpendicular to the mountain range orientation. An Airmen's Meteorological Information (AIRMET) in-flight weather advisory, issued at 0145, was active for moderate turbulence, icing, and mountain obscuration at the upset location and altitude. Low Level Significant Weather charts, valid for the time surrounding the accident, advised of moderate or greater turbulence below 20,000 feet in the region. Numerous aircraft in the area relayed turbulence information indicating a significantly turbulent atmosphere over central Colorado. Pilot reports near the time indicated moderate turbulence above 10,000 feet.
Preflight Weather Briefing
The operator provided a copy of the preflight weather briefing accessed via FlightPlan.com. This briefing included winds aloft estimates, surface observations, station forecasts, NOTAMs, and pilot reports (PIREPS) for selected sites. However, it did not include available information about active AIRMETS, recent PIREPS, or Low Level Significant Weather (SIGWX) charts.