Aviation Accident Summaries

Aviation Accident Summary DEN08LA017

Salida, CO, USA

Aircraft #1

N36LB

Schempp-Hirth Ventus B/16.6

Analysis

The glider was towed by an airplane to an altitude of 11,800 feet mean sea level (msl) approximately 7 miles south of the departure airport. The glider was released from the tow airplane, and the tow airplane returned to the airport to tow another glider to join the accident glider. Approximately 15 minutes later when the tow airplane returned with the other glider, the tow airplane and other glider attempted to contact the accident glider via radio. The attempts to contact the accident glider were unsuccessful. The glider was located in mountainous tree-covered terrain the next day. The weather at the time of the accident was reported as clear sky and light winds. Examination of the glider wreckage revealed the damage was consistent with a nose-low, vertical impact. No anomalies were noted with glider that would have precluded normal operations.

Factual Information

HISTORY OF FLIGHT On October 26, 2007, approximately 1340 mountain daylight time, a Schempp-Hirth Ventus B/16.6 glider, N36LB, was destroyed when it impacted terrain while maneuvering near Salida, Colorado. The private pilot, who was the sole occupant and registered owner of the glider, sustained fatal injuries. Visual meteorological conditions prevailed, and a flight plan was not filed for the Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. The local flight departed the Harriet Alexander Field (ANK), Salida, Colorado, approximately 1314. According to local authorities, the glider was towed by an airplane from ANK to an altitude of 11,800 feet mean sea level (msl) approximately 7 miles south of Salida. At 1327, the glider released from the tow airplane, and the tow airplane returned to ANK to tow another glider that was to join the accident glider. At 1339, when the tow airplane returned with the other glider, the tow airplane and other glider attempted to contact the accident glider via radio. The attempts to contact the accident glider were unsuccessful. The weather at the time of the accident was reported as sky clear and light winds. At 2215, an Alert Notice was issued by the Prescott Flight Service Station, Prescott, Arizona, for the accident glider. On October 27th at 2100, the Civil Air Patrol located the glider wreckage in tree-covered mountainous terrain approximately 7 miles south of Salida. PERSONNEL INFORMATION The pilot, age 53, held a private pilot certificate with a glider rating. The pilot did not hold a current Federal Aviation Administration (FAA) issued medical certificate. According to CFR Part 61.23 (b), Operations Not Requiring a Medical Certificate, a person is not required to hold a valid medical certificate if they are exercising the privileges of a pilot certificate with a glider category or balloon class rating. A review of the pilot records provided by the pilot's insurance company revealed that as of June 2007, the pilot had accumulated 621.0 total glider flight hours, and 180.0 total hours in the accident glider. The pilot's most recent flight review was completed on September 30, 2006. According to the insurance records, on June 23, 2007, the pilot was involved in an off-airport landing in the accident glider. The forced landing was performed because the pilot was "unable to locate sufficient lift to remain airborne." During the landing to a field, the left wing tip contacted vegetation and the glider ground-looped. The glider sustained minor damage, and the repairs were completed on June 30, 2007. AIRCRAFT INFORMATION The Schempp-Hirth Ventus B/16.6, serial number 239, was a single-seat, high performance, flap-equipped, T-tail glider. The glider was registered to the pilot on February 7, 2003. A review of the most recent glider logbook revealed that a conditional inspection was conducted on March 24, 2007, at a total airframe time of 1,637.2 hours. The total airframe time of the glider at the time of the accident could not be determined. The glider was 21.59 feet in length. The four-piece wing had a triple trapezoid planform. The wingspan was 54.46 feet and the wing area was 107.21 square feet, which equated to an aspect ratio of 27.7. The trailing edge airbrakes were a combination of flaps and spoilers. The glider's maximum gross weight was 948 pounds. The glider flight manual stated that the stall speed in straight flight was between 33 and 48 knots (kts) dependent upon the configuration and weight. A stall warning occurs "2 or 3 kt above stalling speed and is indicated by a slight buffeting and increasing vibration in the control system when pulled further back. Ailerons get spongy and the sailplane tends to slight pitching motions." METEOROLOGICAL INFORMATION At 1328, the Monarch Pass (MYP) automated weather observing system (AWOS), located approximately 10 miles west of the accident site, reported the wind from 260 degrees at 14 knots, gusting to 20 knots, visibility 10 miles, sky clear, temperature 8 degrees Celsius, dew point minus 10 degrees Celsius, and an altimeter setting of 30.54 inches of Mercury. WRECKAGE AND IMPACT INFORMATION The accident site was located in mountainous tree-covered terrain at 38 degrees 27.332 minutes north latitude and 106 degrees 01.338 minutes west longitude, at an elevation of approximately 11,550 feet. According to a Federal Aviation Administration inspector, who responded the accident site, the forward fuselage and both wings were fragmented and destroyed. The glider "appeared to have entered the trees in a nose-low vertical attitude." A flight data recorder was recovered from the wreckage and sent to the manufacturer for data downloading. Upon receipt of the recorder, the manufacturer informed the NTSB investigator-in-charge (IIC) that the data on the recorder had been erased during the accident and was not retrievable. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was conducted on the pilot by the El Paso County Coroner's office on October 30, 2007. According to the autopsy report, the probable cause of death was from "multiple injuries." Specimens were retained for toxicological analysis by the FAA Civil Aeromedical Institute's (CAMI) Forensic and Accident Research Center, Oklahoma City, Oklahoma. The toxicological analysis results were negative for all screened drug substances. Tests revealed 54, 74, and 5 (mg/dL, mg/hg) ethanol were detected in the liver, muscle, and blood, respectively. TESTS AND RESEARCH On November 14, 2007, the glider wreckage was examined by the NTSB IIC at the facilities of Beegles Aircraft Services, Greeley, Colorado. Control continuity was established from the cockpit to the flight control surfaces. No anomalies were noted that would have precluded normal operation.

Probable Cause and Findings

The pilot's failure to maintain aircraft control while maneuvering resulting in an inadvertent stall and impact with terrain.

 

Source: NTSB Aviation Accident Database

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