# NTSB MIA92LA122: Let L-13, N99946, Boynton Beach, FL, May 4, 1992

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: May 4, 1992, 16:00 local (20:00 UTC)
- Place: Boynton Beach, FL
- Coordinates: 26.509868, -80.149116 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=26.5099&lon=-80.1491&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report August 26, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 33089
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA92LA122
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/33089/pdf
- Page: https://openairdocs.org/ntsb/MIA92LA122

## Probable cause

PREMATURE EXTENSION OF THE SPOILERS BY THE PILOT DURING APPROACH TO LAND. CONTRIBUTING TO THE ACCIDENT WAS HIS LACK OF TOTAL EXPERIENCE IN THE TYPE OF AIRCRAFT AND IN-FLIGHT ENCOUNTER WITH A DOWNDRAFT.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- In flight encounter with weather, approach - vfr pattern - final approach
  - weather condition - downdraft (contributing factor)
  - spoiler extension - premature, pilot in command (cause)
  - lack of total experience in type of aircraft, pilot in command (contributing factor)
- In flight collision with object, descent
  - object - tree(s)

## Analysis

THE FLT TURNED BASE WITH PARTIAL SPOILERS EXTENDED THEN TURNED FINAL, & ENCOUNTERED A 'SEVERE DOWNDRAFT.'  THE PLT RETRACTED THE SPOILERS BUT THE DESCENT CONTINUED UNTIL IMPACT WITH TREES APPROXIMATELY 300 FT SHORT OF THE RWY.  HE HAD ACCUMULATED 3 HRS TOTAL TIME MAKE & MODEL DURING 8 DUAL & 12 SOLO FLIGHTS IN THE PRECEDING 30 DAYS.

## Aircraft

- Registration: [N99946](https://openairdocs.org/deregistered/N99946-2018-04-06), registration cancelled 2018-04-06, S/N 025822 (OpenAirDocs)
- Reported make and model: LET L-13
- Registry model: [Let BLANIK L-13](https://openairdocs.org/model/let-blanik-l-13) (registry code 1360306) (OpenAirDocs)
- Category: Glider
- Serial number: 025822
- Airframe hours: 2754
- Engines: unknown
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: Willis, B.N.
- Registered owner: Willis, B.N.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, April 2, 1992, 18 hours before
- Airport: 1X4, Willis Gliderport

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; flight instructor, commercial, airline transport; airplane ratings: multi-engine land, single-engine land, multi-engine sea, single-engine sea; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: front; flight hours: 9,171 total, 3 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 260° at 10 knots, gusting 17
- Visibility: 7 statute miles
- Lowest ceiling: none
- Temperature: 88 °F, dew point 52 °F
- Altimeter: 29.00 inHg
- Observed at: PBI, 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 19920504013299A](https://openairdocs.org/incident/19920504013299A), May 4, 1992: Let L13BLANIK, Boynton Beach, FL, Substantial damage. Downdraft on landing approach. Unable to recover. Struck trees short of runway.

## Other investigations on N99946 (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 MIA87LA199](https://openairdocs.org/ntsb/MIA87LA199), May 31, 1987: Let L-13 (N99946), Plymouth, FL, substantial damage

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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