|Narrative Type: NTSB FINAL NARRATIVE (6120.4)
|According to radar data, the airplane climbed to an initial altitude of about 2,700 feet mean sea level on a southerly heading. Over the span of the flight, the airplane reversed course toward the north, reversed course again to the south, and then reversed course a third time to the north. Several witnesses observed the accident airplane in a spin approximately 800 feet above the ground. Ground scars and damage to the airplane were consistent with a 70-degree nose down attitude at the time of impact. A postaccident examination of the airframe, airplane systems, and engine revealed no mechanical anomalies that would have precluded normal operation; however, a mechanic’s work light was discovered in the tail section of the airplane. Score marks on the body of the work light were consistent with the work light having been jammed in the tail of the airplane underneath the stabilator control tube. Due to the distortion of the wreckage components, it was not possible to establish if the work light interfered with proper movement of the stabilator control tube.
|Narrative Type: NTSB PRELIMINARY NARRATIVE (6120.19)
|HISTORY OF FLIGHT
On January 23, 2010, at 1158 central standard time, a Costruzioni Aeronautiche Tecnam P2002 Sierra special light sport airplane, N145AG, was substantially damaged when it impacted terrain following an uncontrolled descent near Waxahachie, Texas. The certified flight instructor (CFI) and student pilot sustained fatal injuries. The airplane was owned by U S Aviation Group, LLC, and was operated by CRP Future Pilots Flight School, Inc. Visual meteorological conditions prevailed at the time of the accident and a flight plan had not been filed for the 14 Code of Federal Regulations Part 91 instructional flight. The flight departed the Dallas Executive Airport (RBD), Dallas, Texas, at 1139.
One witness observed the airplane in “slow vertical spin” approximately 800 feet above the ground. The airplane made one and a half to two turns before it disappeared behind a row of trees. Another witness observed the airplane pointed nose down and moving in a circular motion “like the blades of a ceiling fan”.
Radar data, provided by the Federal Aviation Administration (FAA), identified and depicted the accident flight from the time of departure until the time of the accident. The airplane climbed to an initial altitude of about 2,700 feet mean sea level (msl) on a southerly heading. Over the span of the flight, the airplane reversed course towards the north, reversed course again to the south, and then reversed course a third time to the north. The last recorded position of the airplane was at 1158.
Certified Flight Instructor
The CFI, age 36, held a commercial pilot certificate with airplane single and multiengine land, and instrument airplane ratings. In addition, he held a flight instructor certificate with airplane single and multiengine, and instrument airplane privileges. He was issued a first class airman medical certificate, without limitations, on January 13, 2010.
A review of the CFI’s logbook indicated that he had logged 1,162 hours of flight experience; 59 of which were logged in the same make and model as the accident airplane.
The student pilot, age 15, did not hold a student pilot certificate or an airman medical certificate. A review of the student pilot’s logbook indicated that he had logged 3.3 hours of flight experience; all of which had been flown in the same make and model as the accident airplane.
The two-seat, low-wing, fixed-gear airplane, serial number (s/n) 316, was manufactured in 2007. It was powered by a Rotax 912 ULS 100-hp engine and equipped with a GT Tonini model GT-2/173/VRR-FW 101 SRTC fixed-pitch wood and composite propeller.
A review of the aircraft maintenance records indicated that the FAA had issued a special airworthiness certificate for light sport airplane on May 12, 2008 at an aircraft total time of 3.3 hours. Another logbook entry showed that a “conformity” inspection had been completed on June 14, 2009 at a total airframe time of 75.3 hours. At the accident scene the hobbs meter was observed as 00117.77 hours. The airplane had flown about 114.4 hours since the initial condition inspection, and about 42.4 hours since the June 14, 2009 inspection.
The closest official weather observation station was Mid-Way Regional Airport, Midlothian, Texas (JWY), located 3 nautical miles (nm) southwest of the accident site. The elevation of the weather observation station was 713 feet msl. The routine aviation weather report (METAR) for JWY, issued at 1204, reported, calm wind, visibility of 10 miles, overcast clouds at 7,000 feet above ground level (agl), temperature 16 degrees Celsius (C), dew point temperature 7 degrees C, with an altimeter setting of 29.57 inches of mercury.
The airplane was equipped with an Advanced Flight Systems AF-3400EF cockpit display capable of displaying Electronic Flight Instrument System (EFIS) information to the pilot. The unit contained an Attitude/Heading Reference System (AHRS) to provide the pilot with attitude and heading information and an internal Air Data System (ADS) to provide the pilot with altitude and airspeed information. The unit also had the capability to store flight data. The AFS-3400EF recording contained approximately 14 hours of data over 20 power cycles. The accident flight was the last flight of the recording and its duration was approximately 25 minutes.
A review of the data points over the last minute of the flight showed the airplane was northbound and at an average altitude around 2,300 feet msl with recorded airspeeds ranging from a maximum of 52.9 knots to the minimum of 39.5 knots. A data point at 1157:44 showed the airplane was at an altitude of 2,260 feet msl, or about 1,625 feet agl, with an airspeed of 39.5 knots, when it began to bank to the left and pitch nose down. The last data point at 1157:59 showed the airplane was descending through an altitude of 1,240 feet msl, or about 605 feet agl, in a 33.4 degree bank to the left and a nose down pitch of 45.27 degrees.
WRECKAGE AND IMPACT INFORMATION
The airplane wreckage was located in a flat open farm field approximately 3 miles northeast of JWY. The wreckage was oriented on a heading of 190 degrees. The elevation of the accident site was estimated from map data to be 635 feet msl.
The main wreckage consisted of the left and right wing, empennage, fuselage, engine and propeller. The airplane came to rest in an approximate 40-degree nose down attitude. The cockpit canopy separated from the airframe and was located about 15 feet forward of the main wreckage.
The engine was partially embedded in the ground directly beneath the wreckage. The propeller hub remained attached to the engine. One blade had fractured but remained attached to the hub. The other blade had separated from the hub and was observed about five feet forward of the main wreckage.
Both wings exhibited aft accordion crushing along their leading edges and there were corresponding impact scars on the ground. The forward portion of the fuselage was crushed aft, reducing the occupiable space in the cabin. The instrument panel was fragmented and partially separated. The fuselage aft of the cabin exhibited forward to aft accordion crushing and remained attached to the empennage.
Both wings remained attached to the fuselage except that the left wing aft spar attach point was broken off at the bolt hole. The left and right ailerons remained attached and control continuity to both ailerons was confirmed. The left wing flap was hanging loose at a 45-degree angle with the flap pushrod attach point separated from the flap inboard rib. The right flap was retracted and remained attached.
The stabilator, vertical tail, and rudder remained attached to the empennage which was bent over the top portion of the fuselage. The stabilator trim tab and the electric actuator were observed in the neutral position. Rudder control continuity was confirmed. Stabilator control continuity was confirmed from the stabilator to the forward clevis end at the center control yoke. A red battery operated work light was observed in the rear fuselage area underneath the stabilator control tube and just aft of the half length flange.
The clevis rod end was broken at the forward end of the stabilator control tube in the threaded portion. The bearing potion of the clevis rod end was still secured in the center control yoke. In the cabin area, the control yoke assembly and the left and right control sticks were observed to be deformed, but still intact with the aileron control cables attached.
The auto pilot pitch and trim servo actuators had free motion of the control arms. The actuators measured an arm turning radius of 2-1/16 inches from center of the servo to the rod end attach center point, this allowed 4-1/4 inches of linear movement of the push rods at the pitch and roll servo in a 180-degree arc. The aileron roll servo attach point below the right control stick at the aileron cable attach bolt had a total linear movement of 3 inches while the pitch servo rod end attach point at the top of the mixing assembly measured 1-3/16 inches of linear movement. With mechanical connections to the servos disconnected, and with no electrical power applied, the servos had 360 degrees of free rotation.
An examination of the engine was performed. No preimpact damage was noted. During partial disassembly the impact damaged engine’s internal ignition coil, internal alternator, and trigger coil were found jamming the flywheel hub and preventing rotation.
After removing the propeller hub, gear reduction housing and the trigger coil, the propeller shaft had a full 360 degrees of free rotation. All gears and keepers where found in their respective positions. The valve train for each cylinder moved through each of the four cycles with normal mechanical continuity. Thumb compression was confirmed to all cylinders. All spark plugs exhibited normal wear when compared to the Champion Check-A-Plug comparison card.
The left and right carburetors were inspected; all control arms and cables were found attached and in place. The right carburetor bowl was damaged and no fuel was noted in the bowl. The left carburetor bowl contained approximately 3/16 of an inch of fuel. A small amount of fine, black debris was noted in both carburetor bowls that appeared to be the same material as the carburetor floats.
Portions of the stabilator control tube, bottom piece of fuselage tail section including stabilator control tube pass-through plate mounting braces, stabilator control tube pass-through plate, rubber grommet, and the work light were removed and sent to the Safety Board materials laboratory for examination.
MEDICAL AND PATHOLOGICAL INFORMATION
Certified Flight Instructor
The Southwestern Institute of Forensic Sciences, Dallas, Texas, performed the autopsy on the certified flight instructor on January 24, 2010. The autopsy concluded that the cause of death was the result of “multiple blunt force injuries” and the report listed the specific injuries.
The FAA’s Civil Aerospace Medical Institute, Oklahoma City, Oklahoma, performed toxicological tests on specimens that were collected during the autopsy. Results were negative for carbon monoxide, cyanide, and ethanol. Testing of the blood revealed 0.159 ug/ml diphenhydramine. Diphenhydramine is a sedating antihistamine which is commonly used in the treatment of allergies and the common cold.
The Southwestern Institute of Forensic Sciences, Dallas, Texas, performed the autopsy on the student pilot on January 24, 2010. The autopsy concluded that the cause of death was the result of “multiple blunt force injuries” and the report listed the specific injuries.
The FAA’s Civil Aerospace Medical Institute, Oklahoma City, Oklahoma, performed toxicological tests on specimens that were collected during the autopsy. Results were negative for all tests conducted.
TESTS AND RESEARCH
Safety Board materials laboratory staff examined portions of wreckage which had been removed from the airplane. The stabilator control tube was bent and buckled at two places along its length. The forward clevis rod was fractured and separated. The fracture features and thread damage indicate that the rod end fractured in ductile overstress due to downward cantilever bending. The forward control mixing unit had three areas of bending overstress fracture. A bend in the linkage was also indicated. The half length flange pass-through plate was bent in the forward direction. The edge of the hole in the pass-through plate was deformed in a manner consistent with forward sliding contact with the stabilator control tube. The rubber grommet in the half length flange pass-through plate hole, had a radial through-thickness cut in the wall. The radial cut in the grommet was consistent with the application of lateral force applied between the stabilator control tube and the pass-through plate.
The surface of the stabilator push pull tube had a thin, greasy residue in the area of the pass-through plate. In this same area, the surface of the stabilator control tube exhibited features consistent with scoring and galling. Excrescence features due to galling were consistent with forward sliding contact between the stabilator control tube and the edge of the pass-through plate hole.
The black transfer marks present on the inner bottom surface of the fuselage tail section were consistent with marks made by the rubber handle grip on the work light. Due to the distortion of the wreckage components, it was not possible to establish if the work light interfered with proper movement of the stabilator control tube.
|Narrative Type: NTSB PROBABLE CAUSE NARRATIVE
|A loss of aircraft control while maneuvering for undetermined reasons.