# NTSB WPR09LA130: Toland S/Thornburgh J Twin 503SL, N426MT, Torrance, CA, February 27, 2009 - Type: NTSB accident investigation - Classification: Accident · Fatal · Limited investigation · Final report - Date: February 26, 2009, 21:00 local (Feb 27, 2009, 05:00 UTC) - Place: Torrance, CA - Coordinates: 33.803333, -118.339447 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.8033&lon=-118.3394&mi=10 - Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping) - Defining event: [Standing-engine(s) operating: Miscellaneous/other](https://openairdocs.org/ntsb-events/900) - Highest injury: Fatal - Injuries: 1 fatal, 1 serious - Status: Completed, report March 23, 2010 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 73397 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR09LA130 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/73397/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=73397 - Page: https://openairdocs.org/ntsb/WPR09LA130 ## Probable cause The passenger’s inadvertent activation of the engine throttle. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Action: incorrect action performance](https://openairdocs.org/ntsb-findings/02041015): Personnel issues › Action/decision · Passenger (probable cause); cases with it: [Toland S/Thornburgh J TWIN 503SL, 1 case](https://openairdocs.org/ntsb-findings/02041015/cases.md?model=05606EY), [All aircraft, 1,386 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md) - [Engine controls: power lever](https://openairdocs.org/ntsb-findings/01057603): Aircraft › Aircraft power plant · Unintentional use/operation (probable cause); cases with it: [Toland S/Thornburgh J TWIN 503SL, 1 case](https://openairdocs.org/ntsb-findings/01057603/cases.md?model=05606EY), [All aircraft, 95 cases](https://openairdocs.org/ntsb-findings/01057603/cases.md) - [Performance/control parameters](https://openairdocs.org/ntsb-findings/01062000): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Toland S/Thornburgh J TWIN 503SL, 1 case](https://openairdocs.org/ntsb-findings/01062000/cases.md?model=05606EY), [All aircraft, 1,269 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Standing-engine(s) operating: Miscellaneous/other](https://openairdocs.org/ntsb-events/900) (defining event); cases with it: [Toland S/Thornburgh J TWIN 503SL, 1 case](https://openairdocs.org/ntsb-events/900/sequence.md?model=05606EY), [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md) - [Takeoff: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Toland S/Thornburgh J TWIN 503SL, 1 case](https://openairdocs.org/ntsb-events/240/sequence.md?model=05606EY), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Toland S/Thornburgh J TWIN 503SL, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=05606EY), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The owner/pilot said that the pilot-rated passenger, who was seated in the front seat, had been shown the function of the steering bar, the pedals, the brake, and the throttle. After engine start and while performing the pre-taxi checklist, the steering control bar was tied to the glider's frame tube with a bungee cord. The pilot performed a brake check from the rear seat and then asked the passenger to perform the brake check from the front seat. The glider foot controls are similar to airplane controls, except when the top of the left pedal is depressed it activates the nosewheel brake. When the top of the right pedal is depressed it activates the throttle instead of activating the brake. After the pilot asked the passenger to perform the brake check, the glider engine accelerated to full power and the glider became airborne. Because the control bar was tied to the main frame of the glider the pilot was unable to attain control before the glider stalled. The owner/pilot indicated that the glider did not have a mechanical malfunction or failure. ## Factual narrative HISTORY OF FLIGHT On February 26, 2009, about 2100 Pacific standard time, an experimental homebuilt Toland/Thornburgh Twin 503SL weight-shift-control power glider, N426MT, impacted terrain following an unintentional takeoff at Zamperini Field Airport (TOA), Torrance, California. The owner/pilot was operating the glider under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The airline transport pilot sustained serious injuries; the private pilot passenger was killed. The glider sustained substantial damage to the frame and to both wings. The planned local personal flight was in the pre-taxi stage when the accident occurred. Night visual meteorological conditions prevailed, and no flight plan had been filed. According to witnesses the glider was parked facing runways 11R/29L, between two hangars on the south side of the airport. Witnesses reported that the owner/pilot was seated in the rear seat, and the pilot-rated passenger was seated in the front seat. After the engine was started, witnesses heard the engine accelerate to full throttle and saw the glider speeding toward a row of parked airplanes. The glider became airborne in a nose up pitch attitude, and nearly struck the parked airplanes. After missing the parked airplanes, when the glider was about 75 to 100 feet above the ground, the glider appeared to stall and impacted the ground between the two runways. The owner/pilot submitted a Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2). The pilot stated that the airplane and engine had no mechanical failures or malfunctions during the flight. The pilot stated that after preflight, the passenger was seated in the front seat and was shown the function of the steering bar, the pedals, the brake, and the throttle. After the engine was started the pilot tested the brakes by depressing the top of the left pedal; the pilot then asked the passenger to perform a brake check. Suddenly the glider engine increased rpm to what appeared to the pilot, to be full power. The pilot stated the glider accelerated to takeoff speed and flew off the tarmac. Approximately 150 feet north of the glider were several rows of airplanes tied down on the ramp. The glider lifted off and climbed so quickly that it flew over the rows of tied down airplanes. However, since the glider had not completed the pre-taxi checklist and the control bar was still bungee-tied to the down tube, the pilot was unable to maneuver the wing. The glider climbed to approximately 100 feet, stalled, and descended back to the ground impacting nose first. The glider hit the ground in the middle of the airport, between the two runways. PERSONNEL INFORMATION The owner/pilot, holds multiple ratings, which includes a weight-shift-control flight instructor rating, with night flying authorization. The purpose of the flight was to maintain his night flight qualification. The pilot rated passenger in the front seat was not receiving instruction, he had never before flown in theaccident glider before, and was along for the flight as a passenger. AIRCRAFT INFORMATION In his written report, the pilot described the systems of the weight-shift-control power glider, which he referred to as a “trike.” The accident glider is steered by two foot pedals in front of each pilot. The foot controls are similar to airplane controls, except when the top of the left pedal is depressed it activates the nose wheel brake. When the top of the right pedal is depressed, it activates the throttle, instead of activating the brake. The glider is controlled in pitch and roll by a "control bar" in front of the front-seated pilot, which maneuvers a large hang-glider wing. The instructor in the back has "extension bars" that allow him to maneuver the control bar. When the control bar is bungee-tied to the down tube the wing is "locked," comparable to the control locks on the ailerons, rudder, and elevator of an airplane. WRECKAGE AND IMPACT INFORMATION The Federal Aviation Administration (FAA) accident coordinator inspected the wreckage at the accident scene prior to the recovery and verified control continuity to all of the flight controls and the throttle linkage. A bungee cord was noted to be located near the control bar and near the airframe down tube. MEDICAL AND PATHOLOGICAL INFORMATION The Los Angeles County Coroner completed an autopsy on the passenger. The cause of death was determined to be a result of blunt force trauma. Analysis of the specimens for the passenger contained no findings for volatiles or tested drugs. They did not perform tests for carbon monoxide or cyanide. ADDITIONAL INFORMATION In the pilot’s written statement he stated the following items are highly recommended to prevent such an accident from occurring again: Trike pilots should be aware that the engine could experience uncommanded full power at any time after the engine is running. This could occur during taxi, during the magneto check in the run-up area, or even after landing. 1. Before the engine is started, and at all times thereafter, the bungee-tie should be removed from the control bar/down tube. In other words, from the time that the engine is started the trike pilot should be able to fully manipulate the control bar without interference from the bungee so that he can immediately start flying the trike in the event of an uncommanded full power causes the trike to unexpectedly take off and become airborne. 2. Both the front and rear pilots should have immediate and unimpeded access to a "kill switch” that would stop the engine in the event of an uncommanded power increase. According to FAA Advisory Circular AC 20-27F, Certification and Operation of Amateur-Built Aircraft, "Amateur builders are free to develop their own designs or build from existing designs. We do not approve these designs and it would be impractical to develop design standards for the wide variety of design configurations, created by designers, kit manufacturers, and amateur builders." ## Aircraft - Registration: [N426MT](https://openairdocs.org/deregistered/N426MT-2013-04-29), registration cancelled 2013-04-29, S/N 95, built 1999 (OpenAirDocs) - Reported make and model: TOLAND S/THORNBURGH J TWIN 503SL - Registry model: [Toland S/Thornburgh J TWIN 503SL](https://openairdocs.org/model/toland-s-thornburgh-j-twin-503sl) (registry code 05606EY) (OpenAirDocs) - Registry engine: [Rotax 503 series](https://openairdocs.org/engine/rotax-503-series) (registry code 55564, 2 cycle) (OpenAirDocs) - Category: Weight-shift, amateur-built - Serial number: 95 - Airframe hours: 318 - Engines: ROTAX 503 52 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, February 21, 2009, 2 hours before - Departed: TOA, Torrance, CA - Destination: TOA, Torrance, CA - Flight plan: Unknown - Airport: TOA, Zamperini Field Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 64; injuries: serious; commercial, private, airline transport; airplane ratings: single-engine land, multi-engine land, single-engine sea, multi-engine sea; instrument ratings: airplane, helicopter; medical: class 2, with waivers/limitations; last flight review June 8, 2007; seat: rear; flight hours: 17,000 total, 300 in this make and model, 10,000 as pilot in command, 70 in the last 90 days, 20 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night - Wind: 220° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: 1,600 ft overcast - Temperature: 57 °F, dew point 52 °F - Altimeter: 30.12 inHg - Observed at: HHR, 7 nm away ## 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 20090226008599A](https://openairdocs.org/incident/20090226008599A), Feb 26, 2009: Toland TWIN503SL, Torrance, CA, Destroyed, 1 fatal. (-23) On February 26, 2009 at 2105 N426MT Toland s/thornburgh twin 503SL aircraft was positioned between hangars at ktoa. While preparing the aircraft during… ## Docket (4 files) The files NTSB released with the investigation on December 21, 2009, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=73397. 2.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40320863&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - FAA Interview- Thornburgh (item 2, .PDF, 855 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40322685&FileExtension=.PDF&FileName=FAA%20Interview-%20Thornburgh-Redacted.PDF - Witness Statement- Mishra (item 3, .PDF, 73 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40322683&FileExtension=.PDF&FileName=Witness%20Statement-%20Mishra-Redacted.PDF - Google Map Diagram of Accident Site (item 4, .PDF, 286 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40322684&FileExtension=.PDF&FileName=Google%20Map%20Diagram%20of%20Accident%20Site-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.