# NTSB ERA21LA329: Alexander Schleicher ASW 27-18, N129MG, Sterling, MA, July 15, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: July 15, 2021, 16:00 local (20:00 UTC) - Place: Sterling, MA - Coordinates: 42.425917, -71.792861 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.4259&lon=-71.7929&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Loss of control on ground](https://openairdocs.org/ntsb-events/230) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Eastern Region Aviation - Parties: FAA FSDO - NTSB case key (mKey): 103721 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA21LA329 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103721/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103721 - Page: https://openairdocs.org/ntsb/ERA21LA329 ## Probable cause The pilot’s failure to maintain the glider’s stability in the roll axis during the takeoff roll, which resulted in a dragged wingtip and ground loop. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: lateral/bank control](https://openairdocs.org/ntsb-findings/01062023): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Alexander Schleicher ASW 27-18, 1 case](https://openairdocs.org/ntsb-findings/01062023/cases.md?model=3801538), [All aircraft, 390 cases](https://openairdocs.org/ntsb-findings/01062023/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Alexander Schleicher ASW 27-18, 2 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=3801538), [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: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Alexander Schleicher ASW 27-18, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=3801538), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) ## Analysis According to the pilot, there was a slight depression in the narrow, paved strip used for glider takeoffs, and that during the takeoff roll, the left wing “flexed” and “dipped” such that the wingtip contacted the turf which created the pivot point around which the glider “ground-looped” which fractured the empennage aft of the cockpit. The pilot added that there had been “3 weeks of heavy rain” prior to the day of the accident and that the grass on either side of the takeoff strip was longer than usual, which reduced his wingtip clearance. He stated that while he had successfully departed the strip earlier that day, a lower grass height would have lowered his risk exposure during the takeoff run. The pilot reported that there were no pre-accident mechanical malfunctions or anomalies that would have precluded normal operation. ## Aircraft - Registration: [N129MG](https://openairdocs.org/aircraft/N129MG), registered now, S/N 29081 (OpenAirDocs) - Reported make and model: ALEXANDER SCHLEICHER GMBH & CO ASW 27-18 - Registry model: [Alexander Schleicher ASW 27-18](https://openairdocs.org/model/alexander-schleicher-asw-27-18) (registry code 3801538) (OpenAirDocs) - Category: Glider - Serial number: 29081 - Year built: 2012 - Airframe hours: 472 - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, November 1, 2020 - Destination: Same as departure - Airport: 3B3, Sterling, runway 34, 2,800 × 10 ft, asphalt - Equipment: Unknown ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 70; injuries: none; private; airplane ratings: single-engine land; last flight review July 15, 2020; seat: single; restraint: 4-point; flight hours: 3,216 total, 435 in this make and model, 323 as pilot in command, 63 in the last 90 days, 21 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 88 °F, dew point 61 °F - Altimeter: 30.04 inHg - Observed at: KFIT, 8 nm away - METAR: KFIT 151952Z AUTO 23009KT 10SM CLR 31/16 A3004 RMK AO2 SLP171 T03060161 TSNO= ## 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 20210715010749A](https://openairdocs.org/incident/20210715010749A), Jul 15, 2021: Alexander Schleicher Gmbh & Co ASW 27-18, Sterling, MA, Substantial damage. Loss of directional control resulted in a ground loop while under tow during the takeoff roll. Ground loop resulted in substantial damage to the aircraft… ## Docket (4 files) The files NTSB released with the investigation on May 4, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103721. 7.0 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12906430&FileExtension=pdf&FileName=NTSB%20Form%206120_Redacted-Rel.pdf - Pilot's statement (item 2, PDF, 2 pages, 122 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12906168&FileExtension=pdf&FileName=Follow-up%20on%20Accident%20in%20N129MG%20on%20July%2015,%202021_Redacted-Rel.pdf - Memorandum for record a�� telephone interview, pilot (item 3, PDF, 1 page, 127 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12924982&FileExtension=pdf&FileName=Memorandum%20for%20Record%20Ira%20Bleiden%20Pilot-Rel.pdf - Photos (item 4, PDF, 2 pages, 4.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12906686&FileExtension=pdf&FileName=Docket%20Photo%20Array-Rel.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.