# NTSB LAX91LA349: Let L-13, N53AS, Byron, CA, August 4, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: August 4, 1991, 13:45 local (20:45 UTC)
- Place: Byron, CA
- Coordinates: 37.849338, -121.619758 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=37.8493&lon=-121.6198&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report January 25, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 27320
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX91LA349
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27320/pdf
- Page: https://openairdocs.org/ntsb/LAX91LA349

## Probable cause

THE ON GROUND COLLISION WITH A HIDDEN DITCH NOT VISIBLE TO THE PILOT DURING THE LANDING ROLL OUT PHASE OF A FORCED LANDING.

## Sequence of events

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

- Undershoot, approach - vfr pattern - final approach
  - precautionary landing - performed, pilot in command
  - terrain condition - high vegetation
  - terrain condition - hidden obstruction(s) (cause)
- In flight collision with terrain/water, landing

## Analysis

THE PILOT SAID HE WAS RETURNING TO THE GLIDER PORT AFTER A LOCAL SOARING FLIGHT DUE TO A LACK OF LIFT. DURING THE FLIGHT BACK TO THE AIRPORT THE PILOT BECAME AWARE THAT THE RATE OF DESCENT WAS TOO HIGH AND THE GLIDER WOULD NOT MAKE THE AIRPORT RUNWAY. THE PILOT SET UP TO LAND IN A VACANT FIELD COVERED WITH MEDIUM HEIGHT GRASS. THE GLIDER COLLIDED WITH A DITCH DURING THE LANDING ROLL OUT IN THE FIELD. THE DITCH WAS NOT VISIBLE TO THE PILOT UNTIL THE LATTER STAGES OF THE LANDING ROLL OUT.

## Aircraft

- Registration: [N53AS](https://openairdocs.org/deregistered/N53AS-2021-10-30), registration cancelled 2021-10-30, S/N 027057, built 1977 (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)
- Registry engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000, none) (OpenAirDocs)
- Category: Glider
- Serial number: 027057
- Engines: unknown
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: Ames Soaring Club
- Registered owner: Ames Soaring Club
- Last inspection: Unknown, January 2, 2000

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; student; flight hours: 29 total, 23 in this make and model, 14 as pilot in command, 5 in the last 90 days, 3 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 270° at 10 knots
- Visibility: 15 statute miles
- Lowest ceiling: none

## 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 19910804061919A](https://openairdocs.org/incident/19910804061919A), Aug 4, 1991: Let L13BLANIK, Byron, CA, Substantial damage. Ran out of thermals,began return. Unable. Landed in field with tall weeds and struck a ditch.

## Other investigations on N53AS (2)

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 LAX04CA220](https://openairdocs.org/ntsb/LAX04CA220), May 24, 2004: Let Blanik L-13 (N53AS), Sparks, NV, substantial damage. Probable cause: the student pilot's misjudged altitude, distance, and speed, and failure to attain the proper touchdown point, resulting in an overshoot of the runway.
- [NTSB LAX81FVD19](https://openairdocs.org/ntsb/LAX81FVD19), Apr 12, 1981: Blanik L-13 (N53AS), Fremont, CA, 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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