LAX05LA014

the pilot's likely inadvertent entry into instrument meteorological conditions created by the rapidly changing cloud conditions that resulted in his spatial disorientation and exceeding the glider's ultimate design loads while in a spiral dive, which resulted in the overload failure of the wings.

The motorized glider broke apart during a personal flight. The pilot told an acquaintance at the airport that he intended only a short flight. The acquaintance noted that the pilot did not have oxygen and offered to loan the pilot some; however, the pilot reiterated that he only intended on doing a short local flight. The glider was not equipped with gyroscopic flight attitude reference instruments. Witnesses reported hearing an engine rev up and down prior to hearing a loud bang. Several of the witnesses observed the aircraft falling from the base of the clouds with separated wings and debris following behind. Review of the weather in the area of the accident revealed there were unstable wave conditions that were reported as rapidly changing by another glider pilot. The pilot witness said the wave conditions were not very strong, nor was the mountain wave very well established. The air gap between the mountain cap cloud and the downwind lenticular clouds was rapidly closing and opening, creating an area that one moment was free of clouds and the next moment completely obscured. There were also reports of moderate turbulence in the accident area and freezing levels were reported above 9,200 feet in clouds and precipitation. The cloud tops were reported to be between 15,000 and 16,000 feet, while the bases were between 8,000 and 9,000 feet. Review of the glider's radar data revealed it was flying along a southerly heading at 14,600 feet mean sea level (msl). The glider's radar track then depicted the glider making a turn toward the northeast and enter two spiraling right turns with a rapid descent. The glider descended from 14,600 feet to 9,200 feet in 1 minute, which was the last radar return received. Post-accident examination of the composite wings revealed the right wing spar failed in two locations while the left spar failed in four locations. All of the fractures were consistent with an overload failure and were not associated with any obvious manufacturing defects. No preimpact anomalies were noted with the flight controls. The never exceed and maneuvering speeds of the glider were 135 and 100 knots, respectively. The limit load factor was established at +5.3/-2.65. The pilot did not wear a parachute due to previous back injuries and pain. He had not had a current medical certificate for more than 7 years prior to the accident, and review of his medical history revealed he had a number of medical conditions that could have resulted in an incapacitation event; however, the autopsy results were inconclusive in determining the likelihood of this possibility. He was also taking some potentially impairing medications such as brompheniramine and diazepam; however, no blood samples were available, and it was not possible to determine precisely when the drugs might have been used nor the level of potential impairment at the time of the accident.

HISTORY OF FLIGHT On October 23, 2004, approximately 1240 Pacific daylight time, an AMS Flight Carat A motorized glider broke apart in flight and impacted terrain near Minden, Nevada. The glider was registered to, and operated by, the pilot. The airline transport pilot, the sole occupant, was fatally injured. The glider was destroyed. Visual meteorological conditions prevailed, and a flight plan was not filed for the local flight. The flight departed the Minden-Tahoe Airport, Minden, Nevada, approximately 1220. According to an acquaintance of the pilot, who was also a glider pilot, the accident pilot spoke with him while they were on the ramp area at the Minden-Tahoe Airport. The pilot indicated he was going flying and the acquaintance stated that the waves were closing up. The pilot said it would be a short flight. The acquaintance was familiar with the pilot and his aircraft, and was aware that his oxygen tank was not filled. He offered his oxygen, but the pilot declined, again indicating that it was going to be a short flight. The acquaintance further stated that the pilot did not have a parachute with him. The acquaintance additionally noted that he observed a gap between the wave clouds, which was opening and closing at a noticeably rapid rate. A review of the aircraft's radar data obtained from Reno's Airport Surveillance Radar (ASR-9) revealed the glider initially flew northbound, parallel to, but west of, U.S. route 395 [route 395 is a north-south route that runs between Minden and Carson City, Nevada]. As the glider reached the southern end of Carson City, it reversed course and traveled southbound on the east side of route 395 for about 3.5 nautical miles. The glider's radar track then shifted west until it was over route 395. The track continued south over route 395 for about 1.5 nautical miles before it veered to the east-northeast. The last 10 radar returns depicted an aircraft track consisting of two, right, 360-degree spiraling turns with the following associated altitudes: 1. 1244:45 14,600 feet 2. 1245:04 14,200 feet 3. 1245:09 13,700 feet 4. 1245:14 12,800 feet 5. 1245:18 12,100 feet 6. 1245:23 12,100 feet 7. 1245:28 12,100 feet 8. 1245:32 11,400 feet 9. 1245:37 10,400 feet 10. 1245:42 9,200 feet Douglas County sheriff's office personnel interviewed seven witnesses regarding their observations of the accident. Three of the witnesses mentioned hearing an engine rev up and down prior to hearing a loud bang. All of the witnesses heard a loud bang. Four looked up and observed an airplane falling out of the base of the clouds. One of the witnesses estimated the cloud height to be approximately 5,000 feet. This same witness indicated that as the fuselage fell out of the cloud, one of the wings remained attached until approximately 3,000 feet. All of the witnesses described seeing debris flutter to the ground following the impact of the fuselage. PERSONNEL INFORMATION The pilot held an airline transport pilot certificate with single engine land, multiengine land, and instrument airplane ratings. Under the airline transport pilot certificate, the pilot also acquired type ratings in Boeing 737, 757, and 767 transport category airplanes. In addition, he had commercial pilot privileges for gliders. The pilot's family was unable to locate his logbooks. He was a retired pilot for United Airlines, and according to an insurance application dated July 9, 2004, he had accumulated a total of 12,000+ hours of flight time. His application indicated he accrued a total of 202 glider flight hours, of which 169 hours were listed as motorglider. According to acquaintances of the pilot, he accumulated about 85 hours in the accident glider make and model [totaling approximately 254 motorglider hours]. The pilot did not hold a current Federal Aviation Administration (FAA) issued medical certificate. His last medical was a first-class medical certificate, which was issued on July 17, 1995. According to 14 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. The FAA defines a glider as a heavier-than-air aircraft, that is supported in flight by the dynamic reaction of the air against its lifting surfaces and whose free flight does not depend principally on an engine. AIRCRAFT INFORMATION The single-seat, motorized, composite glider, serial number CA012, was type certificated in Germany as a motorglider. However, since it has not yet been approved for a standard certification in the U.S., the pilot obtained a special airworthiness certificate in the form of an experimental (glider) designation from an FAA designated airworthiness representative (DAR) for the purpose of "exhibition/air racing." According to a letter written by the pilot, dated September 7, 2004, the glider was "intended to be flown in pursuit of Soaring Society of America (SSA) and Federation Aeronautique International (FAI) records and sponsored contests. In addition, the glider will be flown for proficiency and practice for these events. Also, as a new type of factory built motor glider, the machine will be statically displayed at air shows and aircraft conventions." The letter terminated by indicating, "all flights in this glider will be operated in day VFR [visual flight rules] under Visual Flight Rules." There are 11 registered AMS Flight Carat A gliders in the U.S. as of this report's writing. The AMS Flight Carat A glider is constructed from fiber reinforced plastic (FRP) composites, featuring aileron, airbrake, elevator, and rudder flight controls in a T-tail configuration (with fixed horizontal stabilizer and two-piece elevator). The manufacturing process uses a lay-up of composite material plies and epoxy resins. The flight controls are all push-pull tubes except for the rudder, which is controlled via cables. The airbrakes are a single panel mounted aft of the main spar, but inboard of each aileron. The airbrakes consist of a red metal panel that when deployed disrupts the flow of air over the wings thereby inducing drag. When stowed, the airbrakes are hidden beneath the surface of the wings by a composite cover that fairs the slot opening for the airbrake with the upper surface of the wing. During deployment the airbrakes extend above the surface of the wing; an action controlled by push/pull tubes that are connected to the cockpit controls. The glider utilizes two composite wings that are interconnected by a wing pin located under the seat pan. The wing roots slide into slots located on the bottom sides of the glider. The root of each spar contains a stainless steal pin (oriented parallel to the lateral axis of the glider) that slides into a cylindrical fitting located in the opposite wing. When those wing root pins are inserted into the other wing, the stainless steal locking pin (oriented along the longitudinal axis of the glider) can then slide into both wing spars, locking them together in the center of the glider. In addition, there is a fore and aft lift pin for each wing (also oriented parallel to the lateral axis of the glider) that slide into receptors located in the fuselage. With the wings connected to each other and the fuselage, the aileron and spoiler flight controls are automatically connected and engaged via a roller and roller adapter connection (no additional flight control connection is required). The glider's wingspan equated to 49.2 feet and the total wing area amounted to 114 square feet. Information provided by the manufacturer indicated that the airfoil had an aspect ratio of 21.3. The wing loading was 7.5 to 9.1 pounds per square foot and the limit maneuvering load factor was +5.3 g and -2.65 g. The glider's maneuvering speed was 100 knots wit