History of Flight
On May 8, 2008, at approximately 1545 mountain daylight time, a single-engine Cessna 182H, registration N8553S, sustained substantial damage after impacting terrain near Black Hawk, Colorado, following a partial loss of engine power. The private pilot was fatally injured, and the passenger sustained serious injuries. The aircraft was operated by Winkmaggair, LLC under 14 CFR Part 91 as a personal cross-country flight. Instrument meteorological conditions were reported by the passenger, and an instrument flight plan had been filed. The flight originated from Glenwood Springs Airport (GWS), Glenwood Springs, Colorado, at about 1508, with a destination of Boulder Municipal Airport (BDU), Boulder, Colorado.
According to the passenger, after passing Eagle County Airport (EGE) at approximately 16,000 feet mean sea level (MSL), the airplane entered clouds with light snow persisting throughout the remainder of the flight. While en route, the engine began to sputter, and the pilot indicated a mixture problem while adjusting the mixture control. The airplane entered a right turn and continued descending as the pilot attempted to troubleshoot the engine malfunction. Air traffic controllers queried the heading change and provided altitude warnings. The passenger observed the pilot manipulating all engine controls, primarily the mixture. The passenger could not confirm whether carburetor heat was activated. The engine repeatedly sputtered and then briefly regained power. When the engine sputtered, the airplane would nose over. Once visual contact with the ground was established, the pilot maneuvered to avoid mountainous terrain until the airplane collided with a mountain at 10,400 feet MSL. The passenger exited the wreckage, freed the pilot, called for emergency services, and attempted to provide medical assistance.
Personnel Information
The pilot, aged 47, held a private pilot certificate with single-engine land and instrument ratings. A valid third-class medical certificate was issued on October 2, 2006. The last logbook entry was on January 13, 2008, for 3.6 hours of single-engine flight time. Additionally, a tachometer time log maintained by the aircraft's co-owners recorded 3.5 hours on April 23, 2008, which was the last flight before the accident.
Aircraft Information
The 1965 Cessna 182H, serial number 18256653, was a four-seat, high-wing, fixed-gear airplane powered by a 230-horsepower Teledyne Continental Motors O-470-R engine. The last annual inspection was completed on June 13, 2007, at which time the tachometer read 2800.9 hours and the airframe had 4652.9 hours. At the accident, the tachometer indicated 2868.4 hours.
Meteorological Information
A detailed weather study was conducted by an NTSB Senior Meteorologist. As the airplane passed near Eagle County Regional Airport at approximately 15,600 feet MSL (about 9,000 feet AGL), the automated weather station reported wind from 220° at 10 knots gusting to 16 knots, few clouds at 3,800 feet AGL, scattered at 4,400 feet AGL, ceiling broken at 6,000 feet AGL, temperature 48°F, dew point 36°F. At 1532 MDT, near Copper Mountain, the KCCU station reported wind from 310° at 16 knots gusting to 32 knots, visibility ½ mile in moderate snow, ceiling broken at 400 feet, overcast at 700 feet, temperature 27°F, dew point 18°F, with lightning in the distance. Upper air sounding near Denver indicated at 16,000 feet wind from 300° at 22 knots, temperature 7°F, dew point 5°F, yielding relative humidity of 94% and a 50% chance of moderate clear icing. Base reflectivity showed the flight path through echoes of 15 to 25 dBZ, corresponding to very light precipitation. There was no record of the pilot receiving a weather briefing from Flight Service or DUATS; he logged into www.fltplan.com to file his flight plan but did not check weather, and no weather information was found in the wreckage.
Wreckage and Impact Information
The wreckage came to rest on a heavily wooded mountainside. The impact heading was estimated at 140° magnetic, with a shallow descending path indicated by splintered trees. Both wing leading edges showed accordion-style crushing, and bark deposits on the left wing and left horizontal stabilizer indicated tree strikes. The left side of the engine and cabin compartments sustained greater crushing. The engine was found buried in snow and soil. Control continuity was established for the left aileron, elevator, and rudder; the right aileron control cable showed overload failure. The flap handle was set at 10°, fuel selector at BOTH (unobstructed), and the firewall fuel strainer was clear. Fuel from both tanks tested negative for water. The carburetor heat control knob was full forward (off), throttle full forward (full), and propeller and mixture controls at mid-travel. No abnormalities precluding safe operation were noted.
Medical and Pathological Information
Forensic toxicology on pilot specimens by the FAA Bioaeronautical Sciences Research Laboratory found no carbon monoxide, cyanide, ethanol, or drugs. An autopsy by the Gilpin County Coroner determined the cause of death as closed head injuries due to blunt force trauma.
Tests and Research
The engine was recovered and examined at Teledyne Continental Motors. Impact damage to cylinders #4 and #6 was noted, but no pre-impact anomalies were found. Magneto leads were damaged but tested conductive. Damaged components (oil sump, cap, screen, and the affected cylinders and leads) were replaced for a test run. The engine started normally and produced power; no anomalies preventing normal operation were identified. Data from a Garmin GPSMAP 496 revealed the flight maintained 16,000 feet MSL for about 14.5 minutes, then descended at an average of 1,100 feet per minute over 4.5 minutes. Four zoom maneuvers—altitude increases with airspeed decay—were recorded, corresponding to terrain avoidance.