Accident Details
On November 17, 2016, at approximately 1430 central standard time, a Schweizer SGS 1-26E glider, registration N65968, was substantially damaged when it impacted trees and terrain while maneuvering in the airport traffic pattern at Hawks Nest Airport (4TN3) in Moscow, Tennessee. The airline transport pilot sustained serious injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight, which was conducted under 14 CFR Part 91.
Witness Account
After an aerial tow to 3,000 feet above ground level (agl), the glider disconnected from the tow plane and the pilot flew for approximately 20 minutes between 2,500 and 3,000 feet agl. A tow plane pilot who witnessed the accident from the ground observed the glider flight for about 20 minutes. He saw the glider enter a normal left downwind approach to runway 18. He further observed the glider execute a 360-degree right turn while on the base leg at about 300 feet agl. After the 360-degree turn, the glider made another 180-degree right turn, which appeared to "develop into a slow spin" from about 100 feet agl; the glider then descended into the trees.
Pilot Information
The pilot held an airline transport pilot certificate with ratings for airplane single-engine land, multiengine land, and glider. His most recent FAA first-class medical certificate was issued on September 6, 2016. He reported a total flight experience of 8,500 hours, with 17.4 hours in gliders and 1.6 hours in this make and model. He stated he could not recall the left base turn and had no recollection of the accident. He offered the possibility of wind shear as a cause and indicated he might have made the turn to lose altitude. He also stated there were no mechanical irregularities or anomalies with the glider.
Aircraft Information
The single-seat, mid-wing glider, serial number 608, was manufactured in 1974. Its most recent annual inspection was completed on December 15, 2015, at which time the airframe had accumulated approximately 2,709 total hours. The glider's flight manual detailed stalling speeds: 28 mph in level flight, 29 mph at a 20-degree bank, 30 mph at 30 degrees, and 33.4 mph at 45 degrees.
Post-Accident Examination
Post-accident examination by an FAA inspector revealed the glider was upright and level on flat ground with both wing leading edges pushed against trees in an area about one quarter mile northeast of runway 18. Both wings were partially detached from the fuselage. Four feet of the left outboard wing was crumpled, and the right wing was crumpled and nearly severed mid-span. The empennage and rudder remained attached, and the cockpit sustained minor damage.
Weather Conditions
The William L Whitehurst Field Airport (M08) in Bolivar, Tennessee, located about 17 miles south of the accident site, recorded weather at 1425: wind from 170 degrees at 7 knots, gusting to 14 knots, clear sky, temperature 27°C, dew point 6°C, and altimeter 29.97 inHg. Winds remained steady from 170 degrees at 7 knots with gusts up to 15 knots from an hour before to an hour after the accident.