Santa Fe, NM, USA
N92CG
Sukhoi SU-29
The Russian-built aerobatic airplane had taken off just prior to the start of the air show. The airplane held outside the show area for a T-33 jet, which was the show's first performance. The pilot then went into his routine. The airplane was approximately 1,500 feet above ground level (agl) when the pilot entered his second maneuver, a torque roll. On reaching its maximum height, the airplane was observed to tail slide and enter an inverted spin. A witness said, "The pilot attempted to recover but didn't make it. The airplane struck the ground upright, in a slight right bank and nose down attitude. On contact with the ground, the airplane exploded and was engulfed in a fireball." Another witness, also one of the air show's performers, described the torque roll. He said that in this maneuver, the airplane pulls up into a vertical climb at full throttle. As the airplane runs out of airspeed, torque from the engine and propeller turns the airplane. The airplane then falls off one direction or the other, nose down, and the pilot flies the airplane out of the dive. The witness said he saw the airplane come out the bottom of the smoke and enter an inverted flat spin. The witness said he saw the airplane make three revolutions. The witness said he thought the pilot had gone too far. "He came off the throttle, the rotation stopped, then the airplane yawed. I heard the engine come in. The airplane came around in a positive attitude. He was getting low. He was upright in a spin. He went to full power. He made a turn and a half and then hit [the ground]." An examination of the airplane revealed no anomalies. A former importer and dealer of SU-29's, who was also a pilot and mechanic who had flown and maintained SU-29's, stated that at the altitude the accident airplane was operating, the pilot cannot reduce power at all during the torque roll maneuver. He said," that if you do reduce power, the airplane will fall off wrong and you will not have enough altitude to recover." Examination of recorded video/images taken of the flight sequence through the ground impact showed the airplane come out of the torque roll into an inverted spin with full left rudder and slight upward elevator controls. The airplane descends in an inverted spin attitude for 3 revolutions before the airplane makes a clockwise roll around its longitudinal axis, placing it in an upright, nose down attitude. About 3.4 seconds prior to the airplane coming out of the inverted attitude, the rudder moves toward neutral. The airplane enters a left downward spiral. At this point, the airplane is less than 600 feet agl. The airplane makes 1.5 left-turning spirals. On completion of the first spiral, the rudder is deflected left and the elevator is deflected upward. At the end of 1.5 spirals, the airplane is approximately 150 feet agl. At this point, the airplane stops its spiral motion and falls straight down to the ground in a 47-degree nose down pitch attitude. On impact, the airplane's rudder shows full right deflection. The elevator is full up (full aft stick deflection).
HISTORY OF FLIGHT On October 2, 2004, at 1327 mountain daylight time, a Sukhoi, SU-29 aerobatic stunt airplane, N92CG, piloted by an airline transport pilot, was destroyed when it impacted terrain 500 feet west of runway 20 at the Santa Fe Municipal Airport (SAF), Santa Fe, New Mexico. A post-crash fire ensued. Visual meteorological conditions prevailed at the time of the accident. The aerobatic flight was being conducted under the provisions of Title 14 CFR Part 91 without a flight plan. The pilot was fatally injured. The local flight was the second performance in the 2004 Santa Fe Air Show. The flight originated at 1255. A Federal Aviation Administration (FAA) inspector spoke to the pilot before he took off. The inspector reviewed his certificates and his records. The inspector said the pilot looked fine, was talking, upbeat, and very cooperative. "He was willing to show us anything we wanted to see." The inspector was in the SAF Air Traffic Control Tower when the air show began. The inspector said that the airplane took off early and held outside the show area for a T-33 jet, which was the show's first performance. The inspector said the pilot then went into his routine. He said the airplane was really high, approximately 1,500 feet above ground level (agl), when he entered his second maneuver, an "inverted spin." He said, "The pilot attempted to recover but didn't make it. The wreckage struck flat in an upright, nose down attitude, and was engulfed in a fireball." A witness, also one of the air show's performers, said the pilot was performing a torque roll. In this maneuver, the airplane pulls up into a vertical climb at full throttle. As the airplane runs out of airspeed, torque from the engine and propeller turns the airplane. The airplane then falls off one direction or the other, nose down, and the pilot flies the airplane out of the dive. The witness he saw the airplane come out the bottom of the smoke and enter an inverted flat spin. The witness said he saw the airplane make three revolutions. The witness said he thought "the pilot had gone too far. He came off the throttle, the rotation stopped, then the airplane yawed. I heard the engine come in. The airplane came around in a positive attitude. He was getting low. He was upright in a spin. He went to full power. He made a turn and a half and then hit [the ground]." PERSONNEL INFORMATION The pilot held an airline transport pilot certificate dated May 14, 2004. The certificate listed privileges for airplane multi-engine land and type ratings for Boeing B-757 and B-767 airplanes. The certificate also listed commercial privileges for airplane single-engine land and sea, and L-188, and private privileges for gliders. The pilot was employed as a pilot for United Airlines. The pilot held a flight instructor certificate dated April 4, 2004. The certificate listed privileges for instruction in single and multi-engine land, and instrument airplanes. The pilot held a first-class medical certificate dated November 11, 2003. The pilot's medical certificate listed as limitations, "None" and "Not valid for any class after November 20, 2004." The pilot also possessed a Statement of Acrobatic Competency dated August 29, 2004, authorizing solo aerobatics in a SU-29 airplane and an altitude limitation [minimum floor] of 800 feet above ground level. According to the his logbook, as of September 27, 2004, the pilot had logged 11,550.4 total flying hours. Of that time, 222.2 hours were in the SU-29 airplane. According to United Airlines, the pilot completed a pilot proficiency checkride on July 28, 2004. His logbook also showed an entry for a "biennial flight review" dated June 23, 2003. The logbook entry for that day shows the pilot performed the flight review in an Extra 300L airplane. The flight duration was 1.0 hours, and covered the following areas: preflight, start, takeoff, traffic pattern entry and exit, 45-degree climbs, steep turns, multiple rolls, unusual attitudes, and landings. AIRCRAFT INFORMATION The airplane, serial number 74-02, was a tandem 2-seat training and aerobatic airplane manufactured by the Sukhoi Company at Omsk, Russia, in 1993. The airplane was one of several SU-29s exported to the United States, reassembled and sold to individual owners. The airplane was registered to the pilot on February 11, 2002, and was operating on an experimental airworthiness certificate. The airplane was owned and operated by the pilot and used for aerobatic competition and aerial demonstration at air shows. According to the airplane logbooks, the airplane underwent a conditional inspection on February 9, 2004. The engine tachometer time recorded at the annual inspection was 333.0 hours. Based on pilot records, the airplane's total airframe time at the accident was estimated as 388.5 hours. METEOROLOGICAL INFORMATION The Routine Aviation Weather Report for SAF at 1353, was clear skies, 10 miles visibility, temperature 64 degrees Fahrenheit (F), dew point 37 degrees F, winds of 100 degrees magnetic at 4 knots, and an altimeter of 30.38 inches. The density altitude was calculated as 7,771 feet. WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board's on scene investigation began October 2, 2004, at 2100. The accident site was located on the Santa Fe Municipal Airport, in flat desert terrain, approximately 500 feet west-northwest of runway 02-20 (8,342 feet by 150 feet, dry asphalt) and approximately 4,100 feet from the approach end of runway 20. The accident site consisted of the airplane main wreckage and a debris field that extended west from the main wreckage approximately 70 feet. The airplane main wreckage rested upright on its fuselage and right wing, and was oriented on a 333-degree magnetic heading. The airplane main wreckage consisted of the engine and propeller, the remains of the header fuel tank, the main landing gear, the left and right wings, the remains of the forward and aft cockpits, the remains of the aft fuselage, the empennage, and the tail wheel. The airplane's engine and cowlings were canted downward at a measured 47 degrees. The top cowling showed charring and paint blistering. The spinner was crushed and broken aft. One of the three propeller blades was broken aft at the hub and showed chordwise scratches. One propeller blade showed no damage. The bottom cowling was crushed upward. The engine was intact and showed some heat damage. The right main landing gear was bent aft and left underneath the front cockpit. The left main landing gear was broken aft. The left main wheel was broken aft at the wheel hub and brakes. The header tank was broken open, charred and melted. The forward cockpit floor was crushed upward. The metal tubing making up the walls and canopy frame was bent upward and twisted clockwise approximately 20 degrees. The fabric skin was charred and consumed. The front pilot seat was charred and consumed. The glare shield was crushed aft, charred, and melted. The front windscreen was broken out. The front cockpit instrument panel was broken to the right, crushed aft, charred, melted, and consumed. The front control stick was broken off near the base. The rear cockpit frame was twisted clockwise 50 degrees. The fabric skin was charred and consumed. The rear seat, instrument panel and aft cockpit glare shield were charred and consumed. The rear seat control stick was charred. The aft fuselage frame was bent downward. The fabric skin was charred and consumed aft to the empennage. The empennage was intact and broken downward just forward of the leading edge of the horizontal stabilizers. The vertical stabilizer and rudder were charred and showed paint blistering. The bottom fabric skin of the left horizontal stabilizer and left elevator was charred. The right horizontal stabilizer and elevator were intact. The bottom fabric skin of the horizontal stabilizer at the leading edge showed paint blistering. The tail wheel was undamaged. Flight control continuity to the elevator and rudder was confirmed. The airplane's left wing was intact but showed cracks in the top composite skin, cracks along the bottom leading edge, and upward crushing of the bottom wing skin near the root. The wing was broken downward 15 degrees. The outboard 14 inches of the wing at the tip was broken upward 3 degrees. The front inboard 15 inches of the wing leading edge was charred. The trailing portion of the left wing was partially separated from the fuselage. The left aileron was broken upward at the hinges. Flight control continuity to the left aileron was confirmed. The airplane's right wing was broken aft and upward approximately 15 degrees at the root. The wing tank was broken along the front. The top wing skin was charred and consumed. The bottom skin was crushed upward. The right aileron was charred and consumed. The smell of fuel prevailed in the area forward of the right wing, and front cockpit. Flight control continuity to the right aileron was confirmed. An impact crater, approximately 11 feet long, 11 feet wide, and 12 inches at its deepest point was located beneath the engine and front cockpit. Soil along the front of the right wing was pushed upward and forward. A debris field extended east from the main wreckage for approximately 70 feet. Within the debris field and approximately 55 feet east of the main wreckage was the canopy. The front seat portion of the canopy Plexiglas was broken out. The right forward canopy bottom frame was bent outward. The locking bayonets were extended. The canopy handles were in the open position. The remainder of the canopy was intact. Also within the debris field were pieces of broken clear Plexiglas, the pilot's headset, the aerobatic site, and small paint chips. An examination of the airplane's engine controls showed the following: Front Cockpit Throttle: Mid range Front Propeller Control: Destroyed Aft Cockpit Throttle: Mid range Aft Propeller Control: Full increase Aft Cockpit Mixture: Rich Magnetos (Aft Cockpit): Both An examination of the airplane's engine instruments showed the following: Left fuel gauge: Zero Right fuel gauge: Zero Oil temperature Zero Oil pressure Zero Cylinder head temperature: Zero Digital tachometer Destroyed An examination of the airplane's flight instruments showed the following: Altimeter: 6,800 feet Kollsman window: 30.30 inches Airspeed: Zero An examination of the airplane's navigation instruments showed the following: Transponder: Destroyed Magnetic compass Destroyed Comm/Nav radio Destroyed An examination of the airplane's systems showed no anomalies. The airplane's engine was retained for further examination. MEDICAL AND PATHOLOGICAL INFORMATION The New Mexico Office of the Medical Investigator, Albuquerque, New Mexico, conducted a post-mortem medical examination of the pilot on October 5, 2004. The results of the examination revealed no pre-existing medical conditions that could have contributed to the accident. FAA toxicology tests of specimens from the pilot were negative for all tests conducted. TESTS AND RESEARCH The airplane's engine was examined at Edgewood, New Mexico, on November 8, 2004. The propeller was still attached. On raising the engine, the bottom two of the engine's nine cylinders were broken aft. The bottom front of the engine housing at the sealing ring bushing and thrust bearing cover was broken aft. Rotational scoring was noted on the "airscrew shaft" at the broken housing. Rotational scoring was also observed on the rear side of the propeller flange. The accessory drive plate on the back of the engine was removed, An examination of the supercharger showed rotational scoring on the aft plate and the walls of the mixture collector. Rubs were observed on the leading edges of the impeller splines. A former importer and dealer of SU-29's, also a pilot and mechanic who had flown and maintained SU-29 airplanes stated that at the altitude the accident airplane was operating at, the pilot cannot reduce power at all during the torque roll maneuver. He said that if you do reduce power, the airplane will fall off wrong and you will not have enough altitude to recover. An aerobatic instructor in SU-29 airplanes for the International Aerobatics Club (IAC) described the torque roll maneuver as basically a "roll and tail slide." He stated the airplane is flown into a vertical climb until the airplane runs out of airspeed. During the vertical climb aileron inputs opposite to the direction of engine torque is applied. At the top of the maneuver the airspeed will be zero. The airplane will hang in the air under the propeller like a helicopter, and then begin to roll, because of the engine torque, around the engine crankshaft, hence where the maneuver gets its name, "torque roll". The airplane will then slide backwards because of gravity. As the airplane slides backwards, reverse airflow will cross the ailerons. The pilot will want to freeze the control stick either forward, neutral, or full aft to prevent a violent movement when the elevators begin to take effect. As airflow crosses the ailerons, the pilot will reverse his aileron input to get the airplane to roll and pitch over. When the airplane is pointing at the ground, the pilot recovers from the dive and continues on to set up for the next maneuver. Is critical that the airplane is flown perfectly vertical up the line. This requires small rudder adjustments and aileron opposing the engine torque. Once the airplane comes off the vertical line, it can fall any direction. To set up the maneuver, the pilot will accelerate the airplane at full power to gain much airspeed as possible. In the SU-29 airplane, this can be up to 300 knots. This entry allows the observing crowd to experience the airplane's speed, power, and noise generated. The pilot will fly the airplane down show center at roughly 250 to 300 feet agl. Then the pilot pulls the airplane up to the vertical and begins to roll opposite the torque in the vertical climb. The entry airspeed should put the airplane at least 2,000 feet agl when it reaches the top of the maneuver. At the top, engine torque turns the airplane. The pilot will look out to the horizon to determine the airplane's position and altitude. The airplane slides aft. The pilot puts in reverse aileron. After 2 to 3 turns, the airplane pitches over. The airplane should be at approximately 1,500 feet agl with the nose pointing at the ground. At this point, the maneuver is complete and the pilot recovers from the dive. Falling off into an inverted spin is not an uncommon occurrence when sliding backwards and rolling. When the airplane is on its back; however, the pilot needs to turn the airplane around quickly. The airplane is in a flat attitude and losing approximately 400 feet per second. The pilot needs to reduce power to idle, release back pressure on the stick, apply rudder opposite of the turn, and neutralize the ailerons. The airplane will recover in 2-1/2 turns. When the spin recovery is complete, the nose of the airplane will be about 60 degrees nose down and losing altitude fast. The airplane can recover on its own, if the pilot reduces the power to idle and releases the back pressure. The airplane will fly itself out, but will use about 2,500 feet to do so. A density altitude of 8,000 to 10,000 feet could make the maneuver recovery more disorienting. The Investigator-In-Charge (IIC) received two separate video recordings, a series of six digital images all taken from one digital still camera, and one digital image from another still camera, all of which captured the accident airplane during the accident and preceding maneuvers. The first videotape was recorded by hand held Digtial-8 format digital video camera. The tape contained approximately 06:28 (minutes: seconds) of recorded video and audio, of which about 01:10 was of the accident airplane. The video segment of the accident airplane was recorded continuously from the first time the airplane is visible until the accident occurs. The secon
the pilot's failure to maintain aircraft control resulting in the inverted spin, spiral, and subsequent impact with terrain. Factors contributing to the accident were the inadvertent stall spin, the spiral, low altitude, and the pilot's delayed attempt to recover from the spin and spiral.
Source: NTSB Aviation Accident Database
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