Kolb Twinstar Mark III, Donald Thompson (rgd. owner & pilot), N408K: Accident occurred September 08, 2010 in Elkhart, Indiana
NTSB Identification: CEN10LA526
14 CFR Part 91: General Aviation
Accident occurred Wednesday, September 08, 2010 in Elkhart, IN
Probable Cause Approval Date: 07/21/2011
Aircraft: Thompson Kolb Twinstar Mark, registration: N408K
Injuries: 1 Fatal.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The accident occurred during the amateur-built airplane’s first flight. According to the pilot, the purpose of the flight was to determine the stall speed and handling characteristics of the airplane during the flight. After departure, the pilot circled the airport at an altitude of about 3,000 feet, and then requested a return for landing with air traffic control. A video of the accident showed the airplane in a steep descent toward a grassy area between the runway and taxiway. As the airplane neared the ground, the nose of the airplane oscillated pitching up, down, and up again prior to the nose dropping and the airplane impacting the ground. A witness reported the engine sounded normal during the flight and while the airplane was on final approach. A postaccident examination of the airframe did not reveal any failure or malfunction that would have resulted in the loss of control.
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The pilot’s failure to maintain control of the airplane during the landing approach.
HISTORY OF FLIGHT
On September 8, 2010, at 1958 eastern daylight time, an amateur-built Thompson Kolb Twinstar Mark III, N408K, impacted the terrain following a loss of control while landing on runway 36 at the Elkhart Municipal Airport (EKM), Elkhart, Indiana. The pilot was fatally injured and the airplane was substantially damaged. The flight was being conducted under the provisions of 14 Code of Federal Regulations Part 91. The local flight was operating in visual meteorological conditions without a flight plan. The flight departed from EKM about 1938.
The accident occurred on the first flight following completion of the airplane’s construction. According to personnel at the EKM air traffic control tower, the pilot went to the control tower to speak with the controllers. He stated he was going to make the airplane’s first flight and that after takeoff he wanted to orbit the airport at 3,000 feet so he could get a feel for the airplane. He stated he needed to figure out the stall speed and handling characteristics of the airplane.
There were several witnesses who saw the airplane during the flight. An air traffic controller stated the airplane took off and circled the airport for 10 to 12 minutes. The pilot then radioed that he was ready to return to land. The controller cleared the pilot for the option to land, go-around, make a low pass, a touch and go, or a stop and go. He stated he was not sure if the airplane ever touched down on the runway, but he saw the airplane nose down and impact the ground off the side of the runway.
Another witness, a pilot, reported seeing the airplane takeoff. He stated the airplane climbed to an altitude of 50 feet above the runway where it leveled off and flew parallel to the runway prior to climbing. The airplane then climbed to an altitude he estimated to be about 2,500 feet. The airplane circled the airport about 3 times before turning onto final approach for runway 36. The witness stated the airplane made a “very steep descent” onto final approach. He then lost sight of the airplane as it traveled behind the trees. The witnesses reported the engine sounded normal during the flight and while the airplane was on final approach.
The accident portion of the flight was captured on video. The video showed the airplane descending at what appeared to be a steep angle toward the airport in front of a tree line. The airplane appeared to be lined up with the grass between the runway and the taxiway, and not with the runway. As the airplane neared the ground, the nose of the airplane pitched up, down, and up again prior to the nose dropping and the airplane impacting the ground.
The pilot, age 48, held a sport pilot certificate, issued on August 31, 2009. The pilot did not hold a Federal Aviation Administration (FAA) medical certificate.
The pilot’s logbook indicated that as of September 5, 2010, the pilot had accumulated a total of 76 hours of flight time. The pilot had logged about 49 hours in an Allegro light sport airplane (LSA). The pilot had a total of 8 hours of dual flight instruction in a Kolb Twinstar Mark III LSA, having logged 3 hours in May 2005 and 5 hours in June 2010. The pilot had not logged any pilot-in-command time in Kolb Twinstar Mark III airplanes.
The airplane was an amateur-built Kolb Twinstar Mark III, serial number M3X6-4-00083, which was built and owned by the accident pilot. The Twinstar Mark III is a two-place tailwheel configured airplane designed with short takeoff and landing (STOL) capabilities. The airplane’s tail and wings are designed to fold for transporting and storage of the airplane. The wings are strut-braced, fabric covered, with steel tubing and aluminum sub-structure. The flight controls are operated with control cables and push/pull tubes. The airplane was powered by a 100 horsepower, pusher mounted Rotax 912. The engine is mounted on the aft portion of the fuselage and partially above the height of the wing. The airplane met the limitations to be operated as a light sport aircraft.
The aircraft registration was issued to the pilot on April 5, 2010. An Experimental category Special Airworthiness Certificate and the Experimental Operating Limitations were issued on July 24, 2010. The accident occurred during the first flight of the airplane.
A friend of the pilot who was familiar with Kolb Twinstar Mark III airplanes stated that because the pusher engine is mounted high, these airplanes tend to nose up when engine power is removed and to nose down when power is added.
At 1855, the automated weather observing system at EKM, reported wind from 360 degrees at 7 knots, 10 statute miles visibility, clear sky conditions, temperature 17 degrees Celsius, dew point 8 Celsius, and a barometric pressure setting of 30.10 inches of Mercury.
WRECKAGE AND IMPACT INFORMATION
The airplane impacted a grass field located between runway 36 and the parallel taxiway. The wreckage was located approximately 1,000 feet from the approach end of runway 36 and about 30 feet west of the runway. A review of the video showed the airplane impacted the ground in a nose down, slight right wing low attitude. The airplane then rolled tail over nose prior to coming to rest in an upright position.
The instrument panel was pushed back into the cockpit area. The left wing remained attached to the fuselage, and the right wing detached from the fuselage with the wing strut still attached to the wing and fuselage. The tailboom style aft fuselage was fractured near the fuselage. All of the flight control surfaces remained attached to their respective airplane surfaces. Flight control continuity was established from the cockpit to all of the flight controls. All three propeller blades were broken. The engine remained attached to the engine mounts.
Examination of the airframe did not reveal any failure/malfunction that would have resulted in the loss of control.
MEDICAL AND PATHOLOGICAL INFORMATION
An autopsy on the pilot was performed on September 9, 2010, at the South Bend Medical Foundation. The autopsy findings included “multiple blunt force injuries.”
The FAA, Civil Aerospace Medical Institute, conducted toxicological testing on the pilot. The toxicology report stated Amlodipine was detected in the liver and blood, Atropine was detected in the heart and blood, and Diphenhydramine was detected in the liver along with 0.164 (ug/ml, ug/g) detected in the blood. Ibuprofen and Naproxen were also detected in blood.
Friends say Scott Thompson was an expert plane builder. He often helped out at a senior aeronautics class at Notre Dame. He was a member of the Experimental Aircraft Association and the South Bend Radio Control Club.