# NTSB ERA21LA327: Let L-23 Super Blanik, N373BA, Sterling, MA, July 31, 2021 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 4 · Limited · Final report - Date: July 31, 2021, 12:58 local (16:58 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: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-flare/touchdown: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) - Highest injury: Serious injuries - Injuries: 1 serious, 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): 103704 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA21LA327 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103704/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103704 - Page: https://openairdocs.org/ntsb/ERA21LA327 ## Probable cause The flight instructor’s lack of remedial action, which resulted in an aerodynamic stall in the landing flare and a hard landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Action: lack of action](https://openairdocs.org/ntsb-findings/02041030): Personnel issues › Action/decision · Instructor/check pilot (probable cause); cases with it: [Let L-23 SUPER BLANIK, 2 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md?model=1360308), [All aircraft, 792 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md) - [Performance/control parameters: pitch control](https://openairdocs.org/ntsb-findings/01062022): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Let L-23 SUPER BLANIK, 1 case](https://openairdocs.org/ntsb-findings/01062022/cases.md?model=1360308), [All aircraft, 526 cases](https://openairdocs.org/ntsb-findings/01062022/cases.md) - [Performance/control parameters: angle of attack](https://openairdocs.org/ntsb-findings/01062042): Aircraft › Aircraft oper/perf/capability · Capability exceeded (probable cause); cases with it: [Let L-23 SUPER BLANIK, 5 cases](https://openairdocs.org/ntsb-findings/01062042/cases.md?model=1360308), [All aircraft, 990 cases](https://openairdocs.org/ntsb-findings/01062042/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-flare/touchdown: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) (defining event); cases with it: [Let L-23 SUPER BLANIK, 5 cases](https://openairdocs.org/ntsb-events/241/sequence.md?model=1360308), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md) - [Landing: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Let L-23 SUPER BLANIK, 3 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=1360308), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis The flight instructor reported that student pilot was flying the glider as it approached to land with the air brakes in the fully extended position. As the student pilot attempted to flare, the glider pitched up and stalled several feet above the runway, resulting in a hard landing. During the hard landing, the glider sustained minor damage and the student pilot was not injured; however, the flight instructor was seriously injured. The flight instructor added that there were no preimpact mechanical malfunctions with the glider and he should have had his hands in close proximity to the controls to be ready to prevent any abrupt inputs and take control if required. ## Aircraft - Registration: [N373BA](https://openairdocs.org/aircraft/N373BA), registered now, S/N 008713, built 2000 (OpenAirDocs) - Reported make and model: LET L-23 SUPER BLANIK - Registry model: [Let L-23 SUPER BLANIK](https://openairdocs.org/model/let-l-23-super-blanik) (registry code 1360308) (OpenAirDocs) - Registry engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000, none) (OpenAirDocs) - Category: Glider - Serial number: 008713 - Year built: 2000 - Airframe hours: 2545 - Damage: Minor damage - Flight: Instructional, Part 91 - Operator: Greater Boston Soaring Club - Registered owner: Greater Boston Soaring Club - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 17, 2020 - Airport: 3B3, Sterling Airport, runway 34, 3,086 × 40 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 76; injuries: serious; commercial; last flight review August 30, 2020; seat: rear; restraint: 4-point; flight hours: 733 total, 80 in this make and model, 695 as pilot in command, 11 in the last 90 days, 5 in the last 30 days, 0 in the last 24 hours - Student pilot; age 33; injuries: none; student; seat: front; restraint: 4-point; flight hours: 12 total, 2 in this make and model, 0 as pilot in command, 3 in the last 90 days, 1 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 270° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 46 °F - Altimeter: 29.93 inHg - Observed at: FIT, 10 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 20210731012279A](https://openairdocs.org/incident/20210731012279A), Jul 31, 2021: Let L-23 SUPER BLANIK, Sterling, MA, Minor damage. On July 31, while landing on runway 34 at Sterling Airport (3BE), glider N373BA, piloted by ip [privacy data omitted]and sp [privacy data omitted] made a hard… ## Docket (4 files) The files NTSB released with the investigation on January 13, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103704. 1.8 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12683253&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Interview summary (item 2, PDF, 1 page, 116 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12682832&FileExtension=pdf&FileName=Interview%20Summary-Rel.pdf - Photo array (item 3, PDF, 2 pages, 349 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12683425&FileExtension=pdf&FileName=Photo%20Array-Rel.pdf - Weather report (item 4, PDF, 1 page, 74 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12683027&FileExtension=pdf&FileName=Metars-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.