CEN10FA115

The failure of both pilots to see and avoid the other resulting in a midair collision. Contributing to the accident was the lack of perceived visual relative motion of the Piper and the Cirrus to the pilot of each airplane, the terrain background, and the overcast weather conditions making it difficult for either pilot to visually acquire the other aircraft.

While conducting glider-tow operations, the right wing of a Piper PA-25 was struck at a 90 degree angle by a Cirrus SR20. Analysis of the radar information, the flight condition of both airplanes, and the pilots' visibility in their respective cockpit configurations, suggests that until just prior to the impact, the Piper would have been located below the horizon and against the background of the surrounding terrain and city, between the 10 and 11 o’clock position of the Cirrus pilot. The Piper remained in this same relative position in the windscreen of the Cirrus pilot for the entire duration of its 7 minute flight. The Cirrus would have been above the horizon, against the white overcast sky, in about the 1 to 2 o’clock position of the Piper pilot. The Cirrus would have only appeared in this position after the Piper pilot completed the last turn and was headed to the west, which would have been (at most) the last 3 minutes of the flight. Visual meteorological conditions existed at the time of the accident with an overcast layer and visibility of 8 miles. The overcast sky conditions likely made it difficult for the Piper pilot to detect the primarily white-colored Cirrus. The lack of maneuvering, as observed by the glider pilot prior to the accident, suggests that neither the pilot of the Cirrus nor the pilot of the Piper observed the other airplane prior to the accident. If the Piper pilot had observed the Cirrus prior to the impact, his ability to maneuver to avoid an impact would have been severely limited due to the glider in tow. A postaccident examination of the engine and flight control systems on both airplanes revealed no mechanical anomalies that would have prevented either pilot from maneuvering to avoid an impact. Medical and pathological examination of both pilots revealed no medical or toxicological issues that would have precluded either pilot from operating their airplane in a safe manner prior to the accident.

HISTORY OF FLIGHT On February 6, 2010, at 1327 mountain standard time, a Cirrus SR20 airplane, N825BC, collided with a Piper PA-25-235 airplane, N8718L, while the Piper was conducting glider tow operations with a Schweizer SGS 2-32 glider, N2472W, near Boulder, Colorado. Both the Cirrus and the Piper were substantially damaged. The Schweizer was not damaged. The Cirrus was owned and piloted by a private individual. Mile High Gliding, Inc., operated both the Piper and the Schweizer. Visual meteorological conditions prevailed at the time of the accident. All three flights were being conducted under the provisions of 14 Code of Federal Regulations Part 91 without flight plans. The commercial pilot aboard the Piper and the private pilot and passenger aboard the Cirrus were all fatally injured. The commercial pilot and two passengers aboard the Schweizer were not injured. The Cirrus departed Erie Municipal Airport (KEIK), Erie, Colorado, as a local flight approximately 1245. The Piper and Schweizer departed Boulder Municipal Airport (KBDU), Boulder, Colorado, as a glider tow flight approximately 1320. According to a statement taken from the pilot of the Schweizer, the purpose of the flight was a scenic glider flight for a birthday party. The tow flight departed runway 8, performed a 360-degree turn for altitude on the east end of the airport, and then continued to a west/northwest heading. He stated that during this portion of the flight he was pointing out various landmarks in Boulder, and other aircraft in the vicinity, to the two passengers. The pilot of the Schweizer remarked that at 8,000 feet the tow rope was tight, they were climbing at 70 miles per hour, and that the air was smooth. At this approximate time and altitude, he observed a Cirrus airplane off the right side of his glider, less than 500 feet away. He was immediately concerned that the Cirrus was going to fly between the tow plane and the glider, and impact the tow line. He reached for the towline release, at which time the Cirrus impacted the forward right side of the tow plane at nearly a 90 degree angle. The Schweizer flew through a ball of fire and was able to return to KBDU shortly thereafter. The pilot of the Schweizer and one passenger on board the glider stated that they did not observe either the Piper or the Cirrus maneuver prior to the collision. The pilot of the Schweizer stated that prior to the impact there were no control movements or turbulence induced by control movements of the tow plane. He commented that the flight was extremely smooth and that normally he can feel control movements or inputs from the tow plane. He elaborated that he felt that the tow pilot would have tried to correct or make an evasive maneuver had he seen the Cirrus airplane prior to the impact. Multiple witnesses heard the collision between the two airplanes and observed the post collision state of both airplanes. The Cirrus was observed to descend under the canopy of the Cirrus Airframe Parachute System (CAPS) while on fire. Debris from both airplanes was spread over a 1.5-mile area with components of the Piper at the northern most end of the debris field, and the main wreckage of the Cirrus at the southern most end of the debris field. Radar data, provided by Denver Air Route Traffic Control Center (ZDV) in National Track Analysis Program (NTAP) format, identified and depicted the Cirrus flight from the time of departure from KEIK to the time of the accident. The encoded altitude of the Cirrus ranged from 6,800 feet to 8,800 feet mean sea level (msl). The flight track proceeded north from KEIK, maneuvered, and then reversed course back toward the south. Just prior to the accident the Cirrus was tracking an approximate course of 180 degrees. Radar data, provided by ZDV in NTAP format, identified and depicted the Piper flight from the time of departure from KBDU to the time of the accident. The altitude of the Piper was intermittent with only two altitudes recorded during the accident flight. The first was reported at 1320:58 at an encoded altitude of 5,500 feet. The second was recorded at 1322:57 at an encoded altitude of 6,500 feet. The Piper performed one turn in the vicinity of KBDU. Just prior to the accident the Piper was tracking an approximate course of 270 degrees. The radar data for the Cirrus depicted the airplane at a consistent altitude of 8,400 and 8,300 feet within the last minute of flight. There was no continuous altitude information associated with the radar data for the Piper tow flight; however, according to a statement from the glider pilot, they were climbing from the time of departure until the collision. He estimated the altitude at the time of the accident to be 8,000 feet. Neither the Cirrus pilot or the Piper pilot were receiving radar flight following services, nor were they in voice communications with air route traffic control. There was no requirement for them to be in voice communications with air route traffic control. PERSONNEL INFORMATION Cirrus Pilot The pilot of the Cirrus, age 58, held a private pilot certificate with an airplane single engine land rating. He was issued a third class airman medical certificate on December 4, 2008. The certificate contained the limitation “must wear corrective lenses.” The charred remains of the Cirrus pilot’s flight logbook was located with the wreckage of the Cirrus airplane. The pilot of the Cirrus had logged no less than 640 hours of total time; 359 hours of which were logged in the accident airplane make and model. He had completed the requirements for a flight review on May 15, 2009, and had received an endorsement to operate high performance airplanes on October 10, 2003. Piper Pilot The pilot of the Piper, age 25, held a commercial pilot certificate with airplane single and multiengine land, and instrument ratings. In addition, he held a certified flight instructor certificate with airplane single and multiengine ratings. He was issued a first class airman medical certificate, with no limitations, on February 12, 2009. Mile High Gliding submitted a completed Pilot/Operator Aircraft Accident/Incident Report form. On this form they reported that the pilot of the Piper had completed the requirements for a flight review on October 24, 2009. He had logged 1,110 hours total time; 260 hours of which were in the accident airplane make and model. Schweizer Pilot The pilot of the Schweizer, age 39, held a commercial pilot certificate with a glider rating, and an airplane single engine land, and instrument rating. In addition, he held a certified flight instructor certificate with airplane single engine, and instrument ratings. He was issued a third class airman medical certificate, with no limitations, on March 15, 2006. The pilot of the Schweizer submitted a completed Pilot/Operator Aircraft Accident/Incident Report form. On this form he reported that he had completed the requirements for a flight review on June 7, 2009. The pilot had logged 2,044 hours total time; 3 hours of which were in the make and model of the glider. AIRCRAFT INFORMATION Cirrus The Cirrus Design Corporation SR20 (serial number 20-1655) low wing airplane, predominately white in color with blue striping, was manufactured in May of 2006. It was registered with the Federal Aviation Administration (FAA) on a standard airworthiness certificate for normal operations. A Teledyne Continental Motors engine, IO-360-ES(6), rated at 210 horsepower at 2,700 rpm, powered the airplane. The engine was equipped with a three-blade, constant speed, Hartzell propeller. The Cirrus was registered to and operated by the Cirrus pilot, and was maintained under an annual inspection program. A review of the maintenance records indicated that Vector Air – Aircraft Inspection & Repair, Erie, Colorado, had completed an annual inspection on April 8, 2009, at a Hobbs hour reading of 319.0 hours. The engine