# NTSB WPR15LA232: Schleicher ASW 20B, N20YZ, Logan, UT, August 2, 2015 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: August 2, 2015, 15:00 local (21:00 UTC) - Place: Logan, UT - Coordinates: 41.800277, -111.75389 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.8003&lon=-111.7539&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Loss of lift](https://openairdocs.org/ntsb-events/500) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report November 5, 2015 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 91706 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR15LA232 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/91706/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=91706 - Page: https://openairdocs.org/ntsb/WPR15LA232 ## Probable cause The pilot’s failure to maintain glider control when it encountered a strong downdraft while maneuvering near a ridgeline. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause) - [Wind: downdraft](https://openairdocs.org/ntsb-findings/03034035): Environmental issues › Conditions/weather/phenomena · Effect on operation - [Object/animal/substance: tree(s)](https://openairdocs.org/ntsb-findings/03022020): Environmental issues › Physical environment · Not specified ## Analysis The pilot reported that he was participating in a mountain flying training course when the glider encountered a strong downdraft while maneuvering near a mountain ridge and lost lift. The pilot was unable to arrest the glider's descent rate, and the left wing impacted a tree. The pilot reported no preimpact malfunctions or failures with the glider that would have precluded normal operation. ## Factual narrative On August 2, 2015, about 1500 mountain daylight time, a Schleicher ASW 20B glider, N20YZ, experienced a loss of lift during cruise flight, and impacted terrain near Logan, Utah. The private pilot owned and operated the glider under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. The pilot was seriously injured. The glider sustained substantial damage throughout the fuselage and wings. Visual meteorological conditions prevailed for the local flight that departed the Logan-Cache Airport (LGU), Logan, at 1430. No flight plan had been filed. The pilot reported that he was participating in a mountain flying training course when the glider encountered a strong downdraft while maneuvering near a mountain ridge, and lost lift. The pilot was unable to arrest the glider's rate of descent, and the left wing impacted a tree. The pilot reported no preimpact malfunctions or failures that would have precluded normal operation of the glider. Postaccident examination of the wreckage revealed that the left wing was completely separated from the fuselage, and the right wing partially separated from the fuselage. The empennage forward of the vertical stabilizer was separated from the fuselage. ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Loss of lift](https://openairdocs.org/ntsb-events/500) (defining event) - [Emergency descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470) ## Aircraft - Registration: [N20YZ](https://openairdocs.org/deregistered/N20YZ-2018-03-21), registration cancelled 2018-03-21, S/N 20664, built 1984 (OpenAirDocs) - Reported make and model: SCHLEICHER ASW 20B - Registry model: [Schleicher ASW-20B](https://openairdocs.org/model/schleicher-asw-20b) (registry code 3801520) (OpenAirDocs) - Registry engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000, none) (OpenAirDocs) - Category: Glider - Serial number: 20664 - Year built: 1984 - Airframe hours: 1448 - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Abbott David H - Registered owner: Abbott David H - Airworthiness certificate: Special, Experimental (Special); Standard, Utility - Last inspection: Annual, March 22, 2015 - Departed: LGU, LOGAN, UT - Destination: LGU, LOGAN, UT - Airport: LGU, Logan-Cache - Equipment: Data recorder, Electronic flight bag or handheld device, Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; injuries: serious; last flight review July 18, 2015; seat: center; flight hours: 280 total, 280 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 360° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 93 °F, dew point 34 °F - Altimeter: 29.95 inHg - Turbulence: Unknown - Observed at: KLGU, 5 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 20150802012549A](https://openairdocs.org/incident/20150802012549A), Aug 2, 2015: Schleicher ASW-20B, Logan, UT, Substantial damage. Pilot participating in mountain flying event, released from tow aircraft, completed 3 figure 8S. Flew in between 2 peaks in mountainous area. Lost lift,… ## Docket (3 files) The files NTSB released with the investigation on October 16, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=91706. 736 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 569 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40432827&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Pilot's Statement (item 2, .PDF, 91 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40432828&FileExtension=.PDF&FileName=Pilot%27s%20Statement-Master.PDF - Accident Photo (Courtesy of FAA) (item 3, .PDF, 76 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40432830&FileExtension=.PDF&FileName=Accident%20Photo%20(Courtesy%20of%20FAA)-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.