Aviation Accident Summaries

Aviation Accident Summary IAD04LA022

Alexandria, PA, USA

Aircraft #1

N12PX

Masak Scimitar

Analysis

The accident pilot was attempting to fly over a ridge, in the fold in a ridgeline, during a national soaring competition. The glider descended about 1,400 feet in about 6 minutes, and 350 feet "in a very small space" before striking a large tree. According to a nationally known, locally based glider instructor, if the accident pilot had been successful in crossing the ridgeline, "he would have been the only pilot to do so, and probably would have easily won the day." The instructor also noted that as he retraced the accident flight in a motorglider, "I could not help believe I would have done the same thing in the same circumstances," and further observed that there was a good landing field at the base of the ridge, and the valley was wide enough to make shallow turns, but that the accident pilot probably "tried to fly a sharp 180-degree turn to return to the lifting air he just passed." The accident pilot had first flown from the instructor's airport in 1979, and was "an accomplished pilot" who had logged numerous cross country flights and international competitions. Winds aloft would have resulted in turbulence and downdrafts in the vicinity of the crash site.

Factual Information

HISTORY OF FLIGHT On May 22, 2004, at 1641 eastern daylight time, a homebuilt Scimitar, N12PX, was destroyed when it impacted a tree in mountainous terrain near Alexandria, Pennsylvania. The certificated private pilot was fatally injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the flight, which departed Mifflin County Airport (RVL), Reedsville, Pennsylvania, about 1425. The competition flight was conducted under 14 CFR Part 91. According to a member of the Soaring Society of America, the accident pilot was participating in the 15 Meter Nationals competition. The competition consisted of a "Modified Assigned Task" (MAT), with a 2.5-hour minimum time aloft constraint. The task area included a "start cylinder" with a 5-statute-mile radius and 5,000-foot agl top centered about 6 statute miles southeast of Mifflin County Airport, one mandatory 1-mile-radius turn point at Mill Creek, Pennsylvania, about 19 statute miles southwest of the airport, 34 additional 1-mile-radius turn points, and a finish line at the airport, about 3,000 feet northwest of the mid-point of runway 06-24. According to MAT rules, after a pilot passed the mandatory turn point, he could visit other turn points of his choice within the task area, with an objective of returning to the finish line at Mifflin County 2 1/2 hours or greater after starting. The pilot could return and finish in less than 2 1/2 hours, but his score would be penalized. A pilot could not repeat a turn point unless at least two other turn points had been reached in the interim, and a maximum of 11 turn points was permitted, not counting the start and finish. If the pilot returned to the airport for a valid finish, he would be scored on time and distance achieved. The task area extended approximately 50 statute miles to the north, east, and south of the airport, and 90 statute miles to the southwest. Within the task area, there was a ridgeline running from southwest to northeast, about 035 degrees magnetic, which peaked at 2,350-foot Tussey Mountain. The ridgeline then turned back on itself, to the southwest, about 240 degrees magnetic for approximately 2 statute miles, and varied in elevation between approximately 1,900 and 2,000 feet. The ridgeline then peaked again, about 2,100 feet, and turned back toward the north, heading 020 degrees magnetic, while maintaining about 1,900 feet of elevation. To the northeast of the ridgeline, the terrain flattened out to an elevation of about 950 feet. Each glider had an onboard, GPS-based flight recorder, and the accident glider's recorder was subsequently forwarded to the Safety Board for download. The investigating engineer's Special Study revealed that the flight began at 1425, and the glider flew first to Jack's Mountain, "a well defined southwest to northeast running ridgeline approximately 1,600 feet msl in elevation." The glider then "thermal-soared" Jack's Mountain for approximately 1 hour, while executing multiple climbs from approximately 2,900 feet msl to 4,800 feet msl, and passing into the start cylinder several times. The glider subsequently proceeded down-ridge, to the southwest, to "momentarily" enter the mandatory turn point cylinder about 1534. The glider then proceeded up-ridge, and momentarily entered a turn point near the airport about 1556. The glider then proceeded down-ridge once again, turned to the west and crossed over Stone Mountain, then proceeded over the northern end of Huntingdon, Pennsylvania, at 3,300 feet msl. The glider subsequently entered the "complex ridge line" of Tussey Mountain, heading south, between the eastern ridge fold and the western ridge fold, about 1,900 feet msl. The eastern fold of the ridge system, abeam where the glider entered, extended up to approximately 2,250 feet. The "pocket" of the fold, southwest the pilot's entry point, extended up, to about 2,000 feet msl, while the ridgeline west of the pilot’s entry point extended up to approximately 1,500 feet msl. The recording stopped at 1641:20, with the glider at 1,932 feet, and a groundspeed of 28.3 mph. A review of the graphical presentation of information revealed that during the last 6 minutes of flight, the glider descended about 1,400 feet. The accident occurred at 40 degrees, 29.94 minutes north latitude, 78 degrees, 08.49 minutes west longitude. PERSONNEL INFORMATION The accident pilot held a private pilot certificate, with airplane single engine land, and glider ratings based on a Canadian pilot license. The pilot was not required to have a medical certificate for glider operations; however, on his latest FAA second class medical certificate, issued June 7, 1999, the pilot indicated 1,743 hours of flight time. As of March 27, 2004, the pilot had recorded 1961.1 hours in his logbook; however, the pilot had skipped many of the lines near the end of the entries. The pilot also recorded, in the glider's aircraft logbook between May 14, 2000, and May 24, 2003, 104 hours of flight time. In addition, the pilot recorded his participation in numerous cross country flights and international competitions. METEROLOGICAL INFORMATION Weather, reported at an airport about 15 miles to the southwest, about the time of the accident, included winds from 280 degrees true at 12 knots, 10 miles visibility, a few clouds at 6,000 feet, temperature 81 degrees F, dew point 64 degrees F, and a barometric pressure of 29.91 inches of mercury. In the Special Study, the investigating engineer calculated GPS-derived thermal drift to be 270 degrees at 16 mph, between 1,800 feet msl and 3,000 feet msl, at nearby Huntingdon. According to the engineer's report, "This eastward-flowing air would have created an area of turbulence and downdrafts...in the region of the crash site." WRECKAGE AND IMPACT INFORMATION The wreckage was located on the southeast side of a canyon "pocket" formed by the ridgelines, about 290 degrees, 1/2 statute mile from the peak of Tussey Mountain, at a 1,750-foot elevation. According to a Federal Aviation Administration (FAA) inspector, the majority of the fuselage was located in a "V" of a tree, and all flight control surfaces were accounted for at the accident scene. Photographs provided by the inspector revealed that the glider's right wing extended vertically, down along the trunk of the tree, and the tip was in contact with the ground. A part of the left wing, estimated to be about 10 feet in length, was leaning against the other side of the tree, with the leading edge along the ground and the trailing edge up against the tree. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot at J.C. Blair Memorial Hospital, Huntingdon, Pennsylvania, under the auspices of the Huntingdon County, Pennsylvania, Coroner. Toxicological testing was subsequently performed at the FAA Bioaeronautical Research Laboratory, Oklahoma City, Oklahoma. ADDITIONAL INFORMATION A glider instructor pilot/designated pilot examiner, who was also a world record holder, flight safety counselor, and the author of numerous instructional books on the subject, subsequently flew over the area in a motor glider. According to a newsletter email he published, he retraced the accident flight, and while crossing the valley leading to the Tussey ridgeline, noted that "it would have been easily seen [that the accident pilot] would need to find some lift in order to clear the top of the mountain. It would [also] be obvious [that the accident pilot] would need to try ridge soaring another ridge in order to gain altitude." The instructor also noted that the accident pilot "was obviously planning to fly to, and over Tussey Ridge, into ridge lift and then south to a turn point. If he were successful, he would have been the only pilot to do so, and probably would have easily won the day. Only two other pilots flew to a nearby turn point (Spruce Creek) and then returned towards the contest site." The instructor further stated: "There is a very good landing field at the base of the ridge, and I am sure [that the accident pilot] was not concerned at all about being able to abort the attempt and land in this or any of several other fields nearby. As...I retraced his flight, I could not help believe I would have done the same thing in the same circumstances. The valley he was in was wide enough that a rather shallow turn could have been made, and I am also sure [the accident pilot's] confidence was buoyed by his slight gain in altitude. He could not fly further into the V-shaped valley, as terrain was rising in front of him. He would have tried to fly a sharp 180-degree turn to return to the lifting air he just passed. The flight track shows the glider losing 350 feet of altitude in a very small space, which can only be caused by a spin. It is in a heavily wooded area, and the glider hit a large tree." The instructor also stated that the accident pilot had first flown from the instructor's airport in 1979, and that "he was an accomplished pilot. Why the glider spun probably won't be answered. Although the glider was called a Scimitar, it really was a Ventus after [the accident pilot] replaced his owned designed wings with Ventus wings a couple of years ago." In addition, the accident pilot was "instrumental in designing winglets for gliders, and even tried a sound-generated boundary device. I am unaware of any other modifications he might have made on his glider." On June 2, 2004, the wreckage was released to a representative of the owner' insurance company, with the exception of the flight data recorder. The recorder was subsequently forwarded to the owner's family directly from the Safety Board Vehicle Recorders Division.

Probable Cause and Findings

The pilot's failure to maintain airspeed, which resulted in an inadvertent stall/spin. A factor was the turbulent wind conditions.

 

Source: NTSB Aviation Accident Database

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