# NTSB ERA13LA320: Thompson Bruce D Sonerai II, N788T, Pulaski, TN, July 16, 2013 - Type: NTSB accident investigation - Classification: Accident · Fatal · Limited investigation · Final report - Date: July 16, 2013, 08:05 local (13:05 UTC) - Place: Pulaski, TN - Coordinates: 35.159721, -87.066947 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.1597&lon=-87.0669&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) - Highest injury: Fatal - Injuries: 1 fatal - Status: Completed, report July 30, 2014 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 87490 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA13LA320 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/87490/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=87490 - Page: https://openairdocs.org/ntsb/ERA13LA320 ## Probable cause The pilot's failure to maintain airspeed during a near-vertical climb after takeoff, which resulted in an aerodynamic stall and subsequent collision with terrain. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: airspeed](https://openairdocs.org/ntsb-findings/01062010): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Thompson Bruce D SONERAI II, 1 case](https://openairdocs.org/ntsb-findings/01062010/cases.md?model=05659N9), [All aircraft, 1,681 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Thompson Bruce D SONERAI II, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=05659N9), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) (defining event); cases with it: [Thompson Bruce D SONERAI II, 1 case](https://openairdocs.org/ntsb-events/241/sequence.md?model=05659N9), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md) - [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Thompson Bruce D SONERAI II, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=05659N9), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis Witnesses reported seeing the airplane stop on the runway and the engine stop producing power during the takeoff. The private pilot/owner subsequently deplaned and hand propped the engine, which was not equipped with an electric starter, to restart it. The pilot continued the takeoff in tailwind conditions on the 2,500 feet of remaining up-sloping runway. The airplane lifted off the runway in a near-vertical climb and traveled about 2,900 feet before it rolled left and descended vertically to the ground. Flight control continuity was established during postaccident examinations; however, the engine could not be examined due to fire and impact damage. The airplane's previous owner described the airplane's design as inherently unstable and stated that higher airspeeds were required to maintain stability in all phases of flight and that the wing would dip very quickly in a stall. ## Factual narrative On July 16, 2013, about 0805 central daylight time, an experimental amateur-built Thompson Sonerai II, N788T, was destroyed during collision with terrain and a post-crash fire following an uncontrolled descent after takeoff from Abernathy Field Airport (GZS), Pulaski, Tennessee. The certificated private pilot/owner was fatally injured. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight, which was operated under the provisions of Title 14 Code of Federal Regulations Part 91. Witnesses reported to a Federal Aviation Administration (FAA) inspector that they watched as the airplane came to a stop on Runway 34, with the propeller stopped, after having taxied out from the parking area. They watched the pilot deplane, walk to the front of the airplane, restart the engine, then climb back into the cockpit. According to the witnesses, the airplane began its takeoff roll from that point, where approximately 2,500 feet of the 5,310-foot-long runway remained. The airplane departed downwind, and used the entire up-sloping runway that remained before it rotated "steeply." The airplane travelled 2,900 feet beyond the departure end of the runway before it descended "vertically," impacted a state highway in a nose-down attitude, and subsequently caught fire. A witness who was travelling on the state highway noticed the airplane because it was lower than typical departing traffic. Just prior to the airplane crossing over the roadway, it "pulled straight up…like a crop duster…about 70 –75-degree angle" before it rolled to the left and descended straight down to ground contact. Witnesses stated that they heard the engine "sputtering" and running roughly during taxi and takeoff. Examination of photographs revealed the engine compartment, cockpit, left wing, and empennage were completely consumed by fire. The right wing was largely intact, and the leading edge was crushed uniformly across the leading edge, consistent with a near-vertical, nose-down impact. Control continuity was established from the cockpit to all flight control surfaces. The right-side engine cylinder heads were separated from the engine by impact, and the internal components were exposed. An examination of the engine was not completed due to extensive impact and fire damage. The pilot held a private pilot certificate with a rating for airplane single-engine land. His most recent FAA third-class medical certificate was issued February 10, 2012. A review of the pilot's logbook revealed that he had logged 120 total hours of flight experience, of which 9 hours were in the accident airplane. He had logged 3 hours in the 90 days prior to the accident, and 28 hours in the year previous to the accident. The airplane was manufactured in 1982, and was purchased by the pilot/owner on March 31, 2013. The maintenance logbooks were not recovered, but according to the FAA inspector, an annual inspection was completed in May 2012. The inspector added that the enginewas not equipped with an electric starter. In an interview with an FAA inspector, the previous owner explained the flight characteristics of the accident airplane. He detailed the inherent instability of the airplane's design, the speeds necessary to maintain stable takeoffs and landing approaches, and the airplane's stall characteristics. The previous owner stated that the airplane required "lots of airspeed" to be stable. He stated 100 mph was his preferred airspeed in the airport traffic pattern, as well as in a climb to facilitate engine cooling. He stated that the airplane had no dihedral in the wing, which lessened its lateral stability, and added that the wing would dip very quickly in a stall. He indicated that a 1,000-foot altitude loss would be normal for a recovery from the resultant spin. The airplane also exhibited adverse yaw tendencies, which required "lots of rudder attention." The previous owner stated he had entered an inadvertent spin on several occasions while practicing aerodynamic stalls.At 1621, the weather reported at GZS included clear skies and wind from 140 degrees at 3 knots. The temperature was 26 degrees C, the dew point was 23 degrees C, and the altimeter setting was 30.31 inches of mercury. The computed density altitude was 2,040 feet. ## Aircraft - Registration: [N788T](https://openairdocs.org/deregistered/N788T-2018-03-06), registration cancelled 2018-03-06, S/N 788, built 1982 (OpenAirDocs) - Reported make and model: THOMPSON BRUCE D SONERAI II - Registry model: [Thompson Bruce D SONERAI II](https://openairdocs.org/model/thompson-bruce-d-sonerai-ii) (registry code 05659N9) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 788 - Engines: AMA/EXPR UNKNOWN ENG reciprocating - Damage: Destroyed - Fire: On-Ground - Flight: Personal, Part 91 - Operator: Cliff J. Rosa - Registered owner: Cliff J. Rosa - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, May 30, 2012 - Departed: GZS, Pulaski, TN - Destination: GZS, Pulaski, TN - Airport: GZS, Abernathy Fielld, runway 34, 5,310 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 24; injuries: fatal; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review March 28, 2013; seat: front; toxicology performed; flight hours: 120 total, 9 in this make and model, 3 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Wind: 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 79 °F, dew point 73 °F - Altimeter: 30.30 inHg - Observed at: GZS ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20130716016259A](https://openairdocs.org/incident/20130716016259A), Jul 16, 2013: Thompson Bruce D SONERAI II, Pulaski, TN, Destroyed, 1 fatal. The accident aircraft had a reported rough running engine. It taxied to rwy 34. Winds reported at kgzs were 140 at 3 knots. The engine quit and the pilot got… ## Docket (6 files) The files NTSB released with the investigation on April 17, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=87490. 1.0 MB in all. - FAA Inspector’s Statement Allen (item 1, .PDF, 44 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40411300&FileExtension=.PDF&FileName=FAA%20Inspector%E2%80%99s%20Statement%20Allen-Redacted.PDF - FAA Inspector’s Statement Standifur (item 2, .PDF, 364 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40411301&FileExtension=.PDF&FileName=FAA%20Inspector%E2%80%99s%20Statement%20Standifur-Redacted.PDF - Witness Interview Transcripts (THP) (item 3, .PDF, 187 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40411302&FileExtension=.PDF&FileName=Witness%20Interview%20Transcripts%20(THP)-Master.PDF - Photo 1 – View of Main Wreckage as Found (Photo Courtesy of FAA) (item 4, .PDF, 170 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40411303&FileExtension=.PDF&FileName=Photo%201%20%E2%80%93%20View%20of%20Main%20Wreckage%20as%20Found%20(Photo%20Courtesy%20of%20FAA)-Master.PDF - Photo 2 – View of Main Wreckage from Right Wingtip (item 5, .PDF, 168 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40411304&FileExtension=.PDF&FileName=Photo%202%20%E2%80%93%20View%20of%20Main%20Wreckage%20from%20Right%20Wingtip-Master.PDF - Toxicological Report (item 6, .PDF, 113 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40411305&FileExtension=.PDF&FileName=Toxicological%20Report-Master.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.