# NTSB SEA97LA194: Let Blanik L-13, N52AS, Hamilton, MT, August 19, 1997 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 19, 1997, 16:30 local (22:30 UTC) - Place: Hamilton, MT - Coordinates: 46.160072, -114.14083 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=46.1601&lon=-114.1408&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report May 4, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 42679 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA97LA194 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42679/pdf - Page: https://openairdocs.org/ntsb/SEA97LA194 ## Probable cause The pilot's excessive speed taxispeed and failure to maintain wing clearance from a taxiway sign. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - On ground/water collision with object, landing - roll - taxispeed - excessive, pilot in command (cause) - clearance - not maintained, pilot in command (cause) - object - airport sign/marker ## Analysis Eyewitnesses observed the glider turn off the runway at an excessive speed after landing. The glider then impacted a taxiway sign near the turnoff. The pilot stated that a gust of wind 'slammed down' the left wing of the glider onto the sign. The eyewitnesses reported that the winds were light and variable with no gusts or crosswinds. ## Factual narrative On August 19, 1997, about 1630 mountain daylight time, N52AS, a Blanik L-13 glider, operated by the Hellgate Soaring Society, struck a taxiway sign during landing rollout and was substantially damaged near Hamilton, Montana. The private pilot and his passenger were not injured. Visual meteorological conditions prevailed and no flight plan had been filed. The personal flight departed Hamilton and was conducted under 14 CFR 91. According to an eyewitness (statement attached) who is a representative of Hamilton Aviation, Inc., the glider turned off of "...runway 34 at the A-1 exit at high speeds, estimated at thirty miles an hour. The winds favored [runway 34] at light and variable. At that time the wing of the glider missed the runway lights, but impacted with the exit A-1 sign...." According to a certified flight instructor (statement attached) who was in the traffic pattern behind the glider, no corrections were necessary for a cross wind, and there was a "slight breeze...no more than five knots..." from the northeast as indicated by the wind sock. The certified flight instructor also stated that as he observed the glider land on runway 34, he expected the glider pilot to continue his landing roll out to the end of the runway. Instead, he observed that the glider had turned off onto a taxiway well before the end of the runway. In a written statement to the Safety Board, the pilot stated: "... [I] landed properly and safely. While taxiing to tie down area a wind gust slammed down my left wing which struck down the airport [runway] signs.... " The pilot also reported that there were no preimpact mechanical malfunctions. ## Aircraft - Registration: [N52AS](https://openairdocs.org/aircraft/N52AS), registered now, S/N 027056, built 1977 (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: 027056 - Airframe hours: 90 - Engines: unknown - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Hellgate Soaring Society - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 12, 1996, 90 hours before - Departed: 6S5 - Airport: 6S5, Ravalli County Airport, runway 34, 4,200 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 65; private; medical: unknown, unknown; flight hours: 1,000 total, 1,000 in this make and model, 900 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 330° at 8 knots, gusting 12 - Visibility: 50 statute miles - Lowest ceiling: none - Temperature: 81 °F ## 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 19970819023189A](https://openairdocs.org/incident/19970819023189A), Aug 19, 1997: Let L13BLANIK, Hamilton, MT, Substantial damage. Sailplane struck a taxiway sign while turning off the runway at a high speed. (.4)eyewitnesses observed the glider turn off the runway at an excessive speed… ## Other investigations on N52AS (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 SEA93LA216](https://openairdocs.org/ntsb/SEA93LA216), Sep 26, 1993: Let Blanik L-13 (N52AS), Clinton, MT, substantial damage. Probable cause: TOTAL FAILURE OF THE TOW EQUIPMENT. 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.