Aviation Accident Summaries

Aviation Accident Summary LAX05LA239

Sparks, NV, USA

Aircraft #1

N9276Y

As+ Ltd AC4

Analysis

The glider stalled and impacted level terrain on final approach to landing. The pilot returned to the gliderport about 20 minutes after release from the tow plane. The pilot made no radio transmissions to indicate the reason for the return to the gliderport. Airborne and ground witnesses reported that they saw the accident glider enter the downwind leg at a high altitude. After turning onto the final approach leg, the glider began to make S-turns to lose altitude. Witnesses indicated that on the third S-turn, about 200 feet above the ground, the glider stalled and descended in a near vertical nose down attitude and impacted the ground short of the runway. No evidence of a preimpact mechanical malfunction or failure was found during post accident examination of the glider. Chlorpheniramine, an over-the-counter sedative antihistamine, was detected on toxicology testing of the pilot's blood at a level several times higher than that expected with the dosage described in the pilot's most recent application for airman medical certificate.

Factual Information

HISTORY OF FLIGHT On July 19, 2005, about 1250 Pacific daylight time, an As+ Ltd. AC4 (glider), N9276Y, impacted level terrain at Air Sailing Gliderport (NV23), Sparks, Nevada. The private glider pilot/owner operated the glider under the provisions of 14 CFR Part 91. The glider was destroyed. The pilot, the sole occupant, sustained fatal injuries. Visual meteorological conditions prevailed for the local area flight that departed NV23 about 1230. No flight plan had been filed. A deputy from the Washoe County Sheriff's Department interviewed the certified flight instructor (CFI) of the accident pilot. The CFI reported that the accident pilot had been at NV23 for the past 10 days and had participated in a 5-day beginning cross-country glider pilot course. He observed her glider takeoff about 10-15 minutes prior to the accident. The tow was normal and the release was estimated about 7,100 feet. He overheard a partial radio transmission where the pilot reported that she was returning to the airport for landing. The CFI reported that the glider was about 500 feet above the ground, which he stated was high for a landing at this airport. He then saw the glider begin to make S-turns to lose altitude. The CFI observed that the airbrakes on the wings were "about half open." On the second or third S-turn, about 200 feet above the ground, the glider made a steep left turn, and the left wing dropped. The nose of the glider dropped and descended in a nose down attitude where it impacted the ground and came to rest inverted. The Federal Aviation Administration (FAA) accident coordinator interviewed several witnesses to the accident, which included the tow plane pilot and another glider pilot that was airborne at the time of the accident. The witnesses reported that the glider entered the downwind leg for runway 21 about 20 minutes after it had been released from the tow plane. They all observed the accident glider high and to the left of the runway on short final approach, and while on a "very short final approach," the pilot had initiated S-turns. On the third S-turn the glider turned to the left and pitched nose down. The glider continued in a nose down (almost vertical) flight profile until it impacted the ground. The witnesses reported that the pilot transmitted over the Common Traffic Advisory Frequency (CTAF) that she was entering the downwind leg for runway 21. No further radio transmissions were heard from the accident pilot. According to the Airport/Facility Directory NV23 was at an elevation of 4,300 feet mean sea level (msl). Runway 21 was 3,000 feet long and 60 feet wide, and the runway surface was comprised of dirt. PERSONNEL INFORMATION A review of the FAA Airman records revealed that the pilot held a private pilot certificate with ratings for airplane single engine land and sea, and glider. The pilot also held an advanced ground instructor certificate. The pilot held a second-class medical certificate issued on February 1, 2005. It contained the limitations that the pilot must wear corrective lenses. The pilot reported on her medical application a total flight time of 1,200 hours with 54 hours logged in the last 6 months. The accident pilot was a member of the Willamette Valley Soaring Club, Portland, Oregon, for several years. The soaring club's operational base was located at the North Plains Gliderport (1OR4), North Plains, Oregon, at an elevation of 210 feet msl. AIRCRAFT INFORMATION The glider was an AS+ LTD AC4, serial number 13. It had an experimental airworthiness certificate for the exhibition/racing category. METEOROLOGICAL INFORMATION The closest official weather observation station was Reno, Nevada (RNO), located 22.6 nautical miles (nm) south of the accident site. The elevation of the weather observation station was 4,404 feet msl. An aviation routine weather report (METAR) for RNO issued at 1256 reported winds from 040 degrees at 9 knots; visibility 10 miles; few clouds at 10,000 feet; temperature 96 degrees Fahrenheit; dew point 41 degrees Fahrenheit; altimeter 29.97 InHg. The density altitude calculated for the area based on Reno's METAR information was 7,884 feet. WRECKAGE AND IMPACT INFORMATION Inspectors from the FAA examined the wreckage at the accident scene, which included all of the glider components within the impact area. The FAA inspectors verified flight control continuity from the cockpit to the flight control surfaces. The FAA inspectors reported that the glider came to rest inverted and sustained extensive compression damage to the cockpit area. The upper wing spoilers were deployed. The aluminum elevator control tube had separated from the control stick where the cockpit area had disintegrated. The T-tail assembly had almost entirely separated from the fuselage. A small portion of fiberglass and the rudder cable remained attached to the aft end of the fuselage. According to the FAA inspectors, the left wing had twisted in the leading edge "D" tube area, and the inboard aileron rib had broken loose, punctured the wing skin, and was protruding upward. The right wing remained intact with minor skin damage. MEDICAL AND PATHOLOGICAL INFORMATION The Washoe County Coroner, Reno, completed an autopsy on July 19, 2005. The FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicological testing of specimens obtained from the pilot. Analysis of the specimens contained no findings for carbon monoxide, cyanide, and volatiles. The report contained the following positive finding for tested drugs: 0.024 (ug/ml, ug/g) chlorpheniramine detected in blood. Chlorpheniramine, an over-the-counter sedative antihistamine, was detected on toxicology testing of the pilot's blood at a level several times higher than that expected with the dosage described in the pilot's most recent application for airman medical certificate.

Probable Cause and Findings

the pilot's failure to maintain an adequate airspeed while performing S-turns on final approach, which resulted in a stall and uncontrolled descent into terrain. A contributing factor in the accident was the pilot's impairment due to ingestion of an over-the-counter sedating antihistamine.

 

Source: NTSB Aviation Accident Database

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