# NTSB ERA12CA454: Let L-23 Super Blanik, N273BA, Benton, TN, June 28, 2012

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Data collection · Final report
- Date: June 28, 2012, 11:30 local (16:30 UTC)
- Place: Benton, TN
- Coordinates: 35.222499, -84.584442 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.2225&lon=-84.5844&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing: Landing area undershoot](https://openairdocs.org/ntsb-events/370)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report October 4, 2012
- Report: Approved by Office Director
- NTSB office: Eastern Region Aviation
- Parties: FAA Nashville FSDO
- NTSB case key (mKey): 84328
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA12CA454
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/84328/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=84328
- Page: https://openairdocs.org/ntsb/ERA12CA454

## Probable cause

The pilot's inadvertent extension of the wing airbrakes, which resulted in a loss of lift and subsequent landing prior to the runway.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Performance/control parameters: descent/approach/glide path](https://openairdocs.org/ntsb-findings/01062040): 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/01062040/cases.md?model=1360308), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/01062040/cases.md)
- [Flight control system: drag control system](https://openairdocs.org/ntsb-findings/01022760): Aircraft › Aircraft systems · Incorrect use/operation (probable cause); cases with it: [Let L-23 SUPER BLANIK, 1 case](https://openairdocs.org/ntsb-findings/01022760/cases.md?model=1360308), [All aircraft, 10 cases](https://openairdocs.org/ntsb-findings/01022760/cases.md)
- [Action: incorrect action performance](https://openairdocs.org/ntsb-findings/02041015): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Let L-23 SUPER BLANIK, 1 case](https://openairdocs.org/ntsb-findings/02041015/cases.md?model=1360308), [All aircraft, 1,386 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Approach-VFR pattern final: Altitude deviation](https://openairdocs.org/ntsb-events/282); cases with it: [Let L-23 SUPER BLANIK, 1 case](https://openairdocs.org/ntsb-events/282/sequence.md?model=1360308), [All aircraft, 104 cases](https://openairdocs.org/ntsb-events/282/sequence.md)
- [Landing: Landing area undershoot](https://openairdocs.org/ntsb-events/370) (defining event); cases with it: [Let L-23 SUPER BLANIK, 2 cases](https://openairdocs.org/ntsb-events/370/sequence.md?model=1360308), [All aircraft, 201 cases](https://openairdocs.org/ntsb-events/370/sequence.md)
- [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Let L-23 SUPER BLANIK, 3 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=1360308), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)
- [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Let L-23 SUPER BLANIK, 10 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=1360308), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)

## Analysis

The pilot was landing the glider at the conclusion of her third solo flight. She stated that on the base leg of the traffic pattern, the glider was lower and farther away from the runway than she intended. She "set" the wing airbrakes, turned onto the final leg of the traffic pattern, and the glider began to sink. The glider subsequently impacted the ground short of the runway, resulting in substantial damage to the left wing spar and rear cockpit bulkhead. A postaccident examination of the glider revealed no evidence of preexisting mechanical anomalies that would have precluded normal operation. The airbrakes were found fully deployed after the accident, and the pilot reported that she actually extended the airbrakes when she meant to stow them.

## Factual narrative

The pilot was landing the glider at the conclusion of her third solo flight. She stated that on the base leg of the airport traffic pattern, the glider was “lower and further away” from the runway than she intended. She "set" the airbrakes, turned onto the final leg of the traffic pattern, and the glider began to sink. The glider subsequently impacted terrain short of the runway, resulting in substantial damage to the left wing spar and rear cockpit bulkhead. A postaccident examination of the glider revealed no evidence of preexisting mechanical anomalies that would have precluded normal operation. The airbrakes were found fully deployed after the accident.

## Aircraft

- Registration: [N273BA](https://openairdocs.org/deregistered/N273BA-2013-11-08), registration cancelled 2013-11-08, S/N 948118, built 1994 (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: 948118
- Airframe hours: 1401
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Airworthiness certificate: Standard, Utility
- Last inspection: Annual, May 18, 2012
- Departed: 92A, Benton, TN
- Destination: 92A, Benton, TN
- Airport: 92A, Chilhowee Gliderport, runway 21, 2,600 × 200 ft, grass/turf

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 59; injuries: minor; commercial, private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review May 11, 2011; seat: front; flight hours: 499 total, 3 in this make and model, 313 as pilot in command, 5 in the last 90 days, 0 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: variable at 4 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 97 °F, dew point 55 °F
- Altimeter: 30.04 inHg
- Observed at: KMMI, 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 20120628016099A](https://openairdocs.org/incident/20120628016099A), Jun 28, 2012: Let L-23 SUPER BLANIK, Benton, TN, Substantial damage. Pilot was low and slow on downwind glider landed short of runway in cornfield. Landing was hard damaging landing gear attachment and wings.

## Docket (7 files)

The files NTSB released with the investigation on August 3, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=84328. 4.6 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40374363&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Pilot Interview Summaries and Statement (item 2, .PDF, 223 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40374398&FileExtension=.PDF&FileName=Pilot%20Interview%20Summaries%20and%20Statement-Redacted.PDF
- Instructor Interview Summary (item 3, .PDF, 242 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40373208&FileExtension=.PDF&FileName=Instructor%20Interview%20Summary-Master.PDF
- Excerpt from Aircraft Log Book (item 4, .PDF, 70 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40374375&FileExtension=.PDF&FileName=Excerpt%20from%20Aircraft%20Log%20Book-Redacted.PDF
- Chilhowee (MMI) Meteorological Observations (item 5, .PDF, 34 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40373469&FileExtension=.PDF&FileName=Chilhowee%20(MMI)%20Meteorological%20Observations-Master.PDF
- Photo 1 - View of Left Wing (Courtesy of FAA) (item 6, .PDF, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40374316&FileExtension=.PDF&FileName=Photo%201%20-%20View%20of%20Left%20Wing%20(Courtesy%20of%20FAA)-Master.PDF
- Photo 2 - Damage to Cockpit Rear Bulkhead (Courtesy of FAA) (item 7, .PDF, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40374317&FileExtension=.PDF&FileName=Photo%202%20-%20Damage%20to%20Cockpit%20Rear%20Bulkhead%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.