# NTSB GAA15CA028: Let L23 - NO Series, N381BA, Los Alamitos, CA, March 29, 2015

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Data collection · Final report
- Date: March 29, 2015, 12:45 local (19:45 UTC)
- Place: Los Alamitos, CA
- Coordinates: 33.789722, -118.059165 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.7897&lon=-118.0592&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Defining event: [Initial climb: Loss of lift](https://openairdocs.org/ntsb-events/500)
- Highest injury: Minor injuries
- Injuries: 1 minor, 1 uninjured
- Status: Completed, report June 1, 2015
- Report: Approved by Office Director
- NTSB office: General Aviation Accidents
- Parties: Federal Aviation Administration
- NTSB case key (mKey): 90962
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA15CA028
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/90962/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=90962
- Page: https://openairdocs.org/ntsb/GAA15CA028

## Probable cause

The inadvertent deployment of the air brakes during initial climb, resulting in a loss of lift. Contributing to the accident was the pilot's failure to identify and remediate the cause.

## Findings

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

- [Performance/control parameters: configuration](https://openairdocs.org/ntsb-findings/01062017): Aircraft › Aircraft oper/perf/capability · Incorrect use/operation (probable cause); cases with it: [Let L-23 SUPER BLANIK, 1 case](https://openairdocs.org/ntsb-findings/01062017/cases.md?model=1360308), [All aircraft, 80 cases](https://openairdocs.org/ntsb-findings/01062017/cases.md)
- [Use of equip/info: use of equip/system](https://openairdocs.org/ntsb-findings/02063015): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Let L-23 SUPER BLANIK, 2 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md?model=1360308), [All aircraft, 1,391 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md)
- [Info processing/decision: identification/recognition](https://openairdocs.org/ntsb-findings/02041510): Personnel issues › Action/decision · Instructor/check pilot (probable cause); cases with it: [Let L-23 SUPER BLANIK, 1 case](https://openairdocs.org/ntsb-findings/02041510/cases.md?model=1360308), [All aircraft, 559 cases](https://openairdocs.org/ntsb-findings/02041510/cases.md)

## Sequence of events

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

- [Initial climb: Glider tow event](https://openairdocs.org/ntsb-events/510); cases with it: [Let L-23 SUPER BLANIK, 1 case](https://openairdocs.org/ntsb-events/510/sequence.md?model=1360308), [All aircraft, 45 cases](https://openairdocs.org/ntsb-events/510/sequence.md)
- [Initial climb: Loss of lift](https://openairdocs.org/ntsb-events/500) (defining event); cases with it: [Let L-23 SUPER BLANIK, 5 cases](https://openairdocs.org/ntsb-events/500/sequence.md?model=1360308), [All aircraft, 252 cases](https://openairdocs.org/ntsb-events/500/sequence.md)
- [Uncontrolled descent: 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 glider instructor was giving an introduction flight. During the tow-plane assisted launch, the glider's air brakes were inadvertently deployed. The tow plane was unable to obtain a positive rate of climb, so the tow-plane pilot signaled for a glider disconnect. The glider pilot released the glider from the tow plane, about 175 feet above the ground. After the release the pilot made a 125 degree right turn to land on an adjacent taxiway and touched down with a high descent rate. During the landing the glider sustained substantial damage to the right wing, right aileron, and fuselage. The pilot sustained minor injuries. The passenger was not injured. The pilot reported no mechanical malfunctions or failures with the glider prior to the accident that would have resulted in abnormal operation of the glider. In addition, he reported that he accomplished a pre-launch checklist prior to the flight and that the launch was more turbulent than normal. He remarked that the accident could have been prevented if he would have landed straight ahead instead of making the right turn. Witnesses on the ground reported seeing the air brakes deploy during the launch.

## Factual narrative

The glider instructor was giving an introduction flight. During the tow-plane assisted launch, the glider's air brakes were inadvertently deployed. The tow plane was unable to obtain a positive rate of climb, so the tow-plane pilot signaled for a glider disconnect. The glider pilot released the glider from the tow plane, about 175 feet above the ground. After the release the pilot made a 125 degree right turn to land on an adjacent taxiway and touched down with a high descent rate. During the landing the glider sustained substantial damage to the right wing, right aileron, and fuselage. The pilot sustained minor injuries. The passenger was not injured. The pilot reported no mechanical malfunctions or failures with the glider prior to the accident that would have resulted in abnormal operation of the glider. In addition, he reported that he accomplished a pre-launch checklist prior to the flight and that the launch was more turbulent than normal. He remarked that the accident could have been prevented if he would have landed straight ahead instead of making the right turn. Witnesses on the ground reported seeing the air brakes deploy during the launch.

## Aircraft

- Registration: [N381BA](https://openairdocs.org/deregistered/N381BA-2020-05-01), registration cancelled 2020-05-01, S/N 018801, built 2001 (OpenAirDocs)
- Reported make and model: LET L23 - NO SERIES (NO SERIES)
- 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: 018801
- Year built: 2001
- Airframe hours: 391.1
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: Los Alamitos Glider Training Sqaudron 41
- Registered owner: Civil Air Patrol Inc
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, October 30, 2014, 8 hours before
- Departed: SLI, Los Alamitos, CA
- Destination: SLI, Los Alamitos, CA
- Flight plan: Military VFR
- Airport: SLI, Los Alamitos Aaf, runway 22R, 5,900 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 70; injuries: minor; flight instructor, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review August 7, 2013; seat: rear; restraint: 3-point; flight hours: 30,681 total, 19 in this make and model, 21,876 as pilot in command, 25 in the last 90 days, 19 in the last 30 days, 0.3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 220° at 8 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 70 °F, dew point 59 °F
- Altimeter: 30.04 inHg
- Observed at: KSLI

## 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 20150329005289A](https://openairdocs.org/incident/20150329005289A), Mar 29, 2015: Let L-23 SUPER BLANIK, Los Alamitos, CA, Substantial damage. During take off using normal aerotow operations on runway 22R at approximately 150 to 200 AGL tow aircraft waved wings signalling immediate release. Pilot of…

## Other investigations on N381BA (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 LAX06TA234](https://openairdocs.org/ntsb/LAX06TA234), Jul 11, 2006: Let Super Blanik L-23 (N381BA), Los Alamitos, CA, substantial damage. Probable cause: failure of the winch operator to maintain an adequate winch tow speed, resulting in a stall and hard landing.

## Docket (3 files)

The files NTSB released with the investigation on May 21, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=90962. 6.2 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40426783&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Photo 1 – Rear View of Right Wing and Aileron (Photo Courtesy of CAP) (item 2, .PDF, 2.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40426784&FileExtension=.PDF&FileName=Photo%201%20%E2%80%93%20Rear%20View%20of%20Right%20Wing%20and%20Aileron%20(Photo%20Courtesy%20of%20CAP)-Master.PDF
- Photo 2 – View of Fuselage-Tail Damage (Photo Courtesy of CAP) (item 3, .PDF, 2.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40426785&FileExtension=.PDF&FileName=Photo%202%20%E2%80%93%20View%20of%20Fuselage-Tail%20Damage%20(Photo%20Courtesy%20of%20CAP)-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.

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