Lone Pine, CA, USA
N71DA
Schempp-Hirth Standard Cirrus
The glider collided with power lines shortly after the pilot released from the tow airplane. Prior to departure, the pilot assembled the glider by himself. During the initial climb out, the tow airplane's climb performance was poor, and the tow pilot noticed that the glider's spoilers were in the deployed position. The tow pilot opted to return back to the airport and while in the turn, the glider pilot released from the towline. The glider pilot announced over the radio that he was having problems with the spoilers and planned to attempt to maneuver back to the airport. The glider turned and then continued on a flight path until impacting high-tension power lines. The glider's service manual states that prior to departure the pilot should check the function of the control surfaces, and ensure that the spoilers are operating properly. A post accident examination of the spoiler control rods inside the fuselage revealed that the inboard sections of both control rods were not connected to their corresponding bell crank. The glider is designed in such a way that to assemble the spoilers, the person performing the assembly must access the control rods from the cockpit, by going through the aft bulkhead. While connecting the spoilers, it is not possible to visually assess how to make the assembly. The assembly must be done by feeling the parts and connecting them without any visual reference.
HISTORY OF FLIGHT On September 19, 2003, at 1503 Pacific daylight time, a Schempp-Hirth Standard Cirrus glider, N71DA, collided with power lines shortly after departing Lone Pine Airport, Lone Pine, California. The pilot/owner was operating the glider under the provisions of 14 CFR Part 91. The private pilot, the sole occupant, received fatal injuries; the glider sustained substantial damage. The local area personal flight originated about 1440 from Lone Pine via a tow plane. Visual meteorological conditions prevailed, and a flight plan had not been filed. During a telephone conversation with a National Transportation Safety Board investigator, the Federal Aviation Administration (FAA) inspector who responded to the accident reported that the pilot was a member of a glider organization, which was traveling around the country flying their gliders in various locations. Other members of the glider organization reported to the FAA inspector that the pilot arrived at the airport about 1030, and, as he had done many times prior, assembled his glider by himself. The FAA inspector further stated that he interviewed the pilot who was flying the airplane, which had the glider in tow. The tow plane pilot reported that during the initial climb out, the airplane's climb performance was poor, leading him to suspect that something was wrong with the glider. As he glanced out the window, he visually examined the glider in an effort to ascertain if the glider was indeed having a problem. He noticed that the glider's spoilers (which the manufacturer refers to as airbrakes) were configured in the up position, corresponding to the deployed position. He made a radio transmission informing the glider pilot about the spoilers, but did not here a response. The tow pilot continued to maneuver the airplane in a climbing configuration, despite the glider flying erratically behind him. Upon reaching what he determined to be a sufficient altitude, the tow pilot turned the airplane toward the airport, in an effort to make an immediate landing. While in the turn, the glider pilot released from the towline and announced over the radio that he was having problems with the glider's spoilers and planned to attempt a maneuver back to the airport. The glider turned and then continued on a flight path directly toward high tension power lines. The right wing impacted the power lines, and the glider made a flat spin into terrain. PERSONNEL INFORMATION The pilot's personal flight records were not provided to the Safety Board investigator for examination. According to the FAA records, the pilot held a private pilot certificate, with a glider rating, issued on June 21, 1980. AIRCRAFT INFORMATION The Schempp-Hirth Standard Cirrus glider, serial number 145, was manufactured in 1971. The pilot purchased the glider on December 26, 1983. The Standard Cirrus service manual, under the "assembly" section states that, "control connections of the ailerons and airbrakes are to be made in the back of the spar root. It is advisable to get familiar with the ball-spring safety couplings of the pushrods before doing the wing assembly." It further indicates that in an effort to connect the airbrakes, the push rods must be connected to the bell crank with the right hand, while simultaneously holding the control stick in the neutral position with the left hand. Under the "before take-off" section in the service manual's checklist, the manufacturer states to check the function of the control surfaces and ascertain if the controls reach the limit of their travels with "sufficient ease." It also advises for the pilot to ensure that the airbrakes are operating properly, verifying that they are locked after testing them. Excerpts of the service manual are in the public docket. WRECKAGE AND IMPACT The global positioning system (GPS) coordinates for the accident site were 36 degrees 35.372 minutes north latitude by 118 degrees 01.038 west longitude, which equates to being about 1.6 nautical miles east of the airport. The accident site was in desert terrain comprised of sand and sagebrush, located below two parallel power lines and in the vicinity of several power line stanchions. In a written statement, a mechanic who examined the wreckage, reported that the glider remained nearly intact, with only the outboard section of the right wing and its corresponding aileron separated. The glider's right wing revealed that the glider had impacted the wires twice, once on the inboard section and the other further outboard. The mechanic located a ground scar next to the wreckage, which he attributed to be the impact from the left wing; he did not see any other ground scars. The landing gear was in the retracted position. The FAA inspector added that the pilot's seat belt harness was loose and did not appear to be tightly strapping him into the seat. MEDICAL AND PATHOLOGICAL INFORMATION The Inyo County Coroner's Office completed an autopsy on the pilot, which disclosed the immediate cause of death to be "multiple traumatic injuries with exsanguinations with bilateral hemothorax from lacerations of the heart and lungs and multiple fractures including the lower extremities." TESTS AND RESEARCH In a written statement, the mechanic who examined the wreckage stated that both spoilers were in the extended position. During the examination he pressed the right wing's spoiler in a downwardly direction with ease, as it only required a slight amount of pressure to pass the counter balance point. The left wing's spoiler required more pressure to deflect it downward and upward, and he noted more friction present in the control. He inspected the spoiler control rods inside the fuselage, and noted that the inboard section of both control rods were not connected to the corresponding bell crank. From the control rods' ends he manipulated the disconnected spoilers independently and found them to be functioning normally. He added that the friction felt previously from the left spoiler appeared to be a result of the rod end contacting the bell crank. The mechanic's full account of the examination is in the public docket. The FAA inspector conducted a post accident examination of the glider, which disclosed that the spoilers had not been connected prior to flight. He stated that the glider is designed in such a way that to assemble the spoilers, the person performing the assembly must access the pushrods from the cockpit, by going through the aft bulkhead. While connecting the spoilers, it is not possible to visually assess how to make the assembly. The assembly must be done by feeling the parts and connecting them without any visual reference.
the pilot's inadequate assembly of the glider and improper preflight inspection, which resulted in an inadvertent deployment of the spoilers. Also causal was the pilot's failure to maintain obstacle clearance. His diverted attention to the control problems presented by the deployed spoilers was a contributing factor.
Source: NTSB Aviation Accident Database
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