# NTSB LAX98LA084: Let Blanik L-13, N3463, Prescott Valley, AZ, January 25, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: January 25, 1998, 12:00 local (19:00 UTC) - Place: Prescott Valley, AZ - Coordinates: 34.619026, -112.420982 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.6190&lon=-112.4210&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 15, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 30031 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX98LA084 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/30031/pdf - Page: https://openairdocs.org/ntsb/LAX98LA084 ## Probable cause The failure of the ground crew to correctly attach the tow bridle, which resulted in the pilot's loss of directional control. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - on ground/water, takeoff - roll/run - glider launch/tow equipment - disconnected (cause) - glider/tow release - improper, ground personnel (cause) - directional control - not possible, pilot in command - On ground/water collision with object, takeoff - roll/run - object - vehicle - object - pole ## Analysis The glider uses two attachment points on its bridle, one on either side of the fuselage, and has a single retractable wheel in the center of the fuselage. The left side bridle attachment point for the glider became unattached as the glider began the winch tow. The asymmetrical force then pulled the glider to the left, and the left wing struck a parked truck. The glider then proceeded in a sharp angle away from the runway towards the windsock pole, still under tow on only the right side and still accelerating. The glider launched into the air and struck the top of the windsock pole with the inboard portion of the right wing. The pilot reported that he then pulled the release to disconnect the tow wire from the glider. The right wingtip then struck the ground and the glider swung around approximately 270 degrees as the fuselage and tail struck the ground and came to a stop. According to an FAA inspector, the bridle was incorrectly attached at the time of the accident by the ground crew. ## Factual narrative On January 25, 1998, at 1200 hours mountain standard time, a Let Blanik L-13, N3463, veered off the runway and collided with parked vehicles during a winch launch at the Coyote Run Gliderport, Prescott Valley, Arizona. The glider sustained substantial damage and the commercial pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed at the time of the accident and no flight plan was filed for the intended local area personal flight. In his report, the pilot explained that the Blanik L-13 uses two attachment points on its tow bridle, instead of the usual single attachment point, with one attach point on either side of the fuselage about half way up the side. The glider has a single retractable wheel in the center of the fuselage. He reported that during this particular launch, the left hook of the bridle became unattached almost immediately as the glider lurched forward under the winch tow. With only the right hook attached, "the one attachment point now worked as a lever, rotating the glider about the center wheel, and resulting in the glider being pulled off to the left side of the runway as it shot forward." The pilot further stated that before he had time to react and pull the release, the left wingtip of the glider struck the tailgate of a pickup truck parked off the left side of the runway, and approximately 6 feet of the outer portion of the wingtip separated at the leading edge. The glider then proceeded in a sharp angle away from the runway towards the windsock pole still under tow on only the right side and still accelerating. The glider then launched into the air and struck the top of the windsock pole with the inboard portion of the right wing. The pilot reported that at that time he pulled the release to disconnect the tow wire from the glider. The right wingtip then struck the ground and the glider swung around approximately 270 degrees as the fuselage and tail struck the ground and came to a stop. According to a Federal Aviation Administration inspector from the Scottsdale Flight Standards District Office, the bridle was incorrectly attached at the time of the accident by the ground crew. ## Aircraft - Registration: [N3463](https://openairdocs.org/deregistered/N3463-2018-01-18), registration cancelled 2018-01-18, S/N 173921, built 1969 (OpenAirDocs) - Reported make and model: Let BLANIK L-13 (BLANIK L-1) - Registry model: [Let BLANIK L-13](https://openairdocs.org/model/let-blanik-l-13) (registry code 1360306) (OpenAirDocs) - Registry engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000, none) (OpenAirDocs) - Category: Glider - Serial number: 173921 - Airframe hours: 2017 - Engines: unknown - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Prescott Soaring Association - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 1, 1997, 85 hours before - Airport: Coyote Run Glider Port, runway 21, 2,500 × 10 ft, dirt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 39; commercial; medical: unknown; seat: front; flight hours: 223 total, 19 in this make and model, 199 as pilot in command, 1 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Wind: 290° at 5 knots - Visibility: 50 statute miles - Temperature: 61 °F - Altimeter: 29.00 inHg ## 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 19980125003549A](https://openairdocs.org/incident/19980125003549A), Jan 25, 1998: Let L13BLANIK, Prescott, AZ, Substantial damage. During winch tow. Veered off runway. Collided with parked vehicles. Let side bridle unhooked. No time to release tow. (-23) during the winch launch, the… ## Other investigations on N3463 (1) 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. - [NTSB LAX76DUQ30](https://openairdocs.org/ntsb/LAX76DUQ30), Feb 28, 1976: Let-Np-K L-13 (N3463), California Cty, CA, substantial damage 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.