# NTSB SEA91LA147: Let L-13, N711KR, Driggs, ID, July 1, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 1, 1991, 16:00 local (22:00 UTC)
- Place: Driggs, ID
- Coordinates: 43.729766, -111.219024 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=43.7298&lon=-111.2190&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report December 4, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 41462
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA91LA147
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41462/pdf
- Page: https://openairdocs.org/ntsb/SEA91LA147

## Probable cause

THE PILOT MISJUDGED HIS DISTANCE AND ALTITUDE TO THE RUNWAY DURING THE APPROACH AND FAILED TO ATTAIN THE PROPER TOUCHDOWN POINT FOR LANDING.  HIS LACK OF EXPERIENCE IN THE MAKE AND MODEL OF GLIDER WAS A RELATED FACTOR.

## Sequence of events

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

- Undershoot, approach
  - distance - misjudged, pilot in command (cause)
  - altitude - misjudged, pilot in command (cause)
  - proper touchdown point - not attained, pilot in command (cause)
  - lack of total experience in type of aircraft, pilot in command (contributing factor)
- On ground/water collision with object, landing
  - object - fence

## Analysis

DURING A SOLO INSTRUCTIONAL FLIGHT, THE PILOT ALLOWED THE GLIDER TO GET LOW ON FINAL APPROACH.  UNABLE TO REACH THE AIRPORT, HE LANDED THE GLIDER SHORT OF THE RUNWAY. DURING THE LANDING ROLL, IT COLLIDED WITH THE AIRPORT BOUNDARY FENCE.

## Aircraft

- Registration: [N711KR](https://openairdocs.org/deregistered/N711KR-2012-06-28), registration cancelled 2012-06-28, S/N 175127, built 1972 (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: 175127
- Engines: unknown
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: James Ball & Eric Soyland, doing business as Grand Valley Aviation
- Registered owner: James Ball & Eric Soyland
- Airport: U59, Teton Peaks, runway 21, 5,200 × 75 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 55; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; flight hours: 294 total, 5 in this make and model, 218 as pilot in command, 27 in the last 90 days, 19 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 30 statute miles
- Lowest ceiling: none
- Temperature: 81 °F, dew point -0 °F

## 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 19910701025229A](https://openairdocs.org/incident/19910701025229A), Jul 1, 1991: Let L13BLANIK, Driggs, ID, Substantial damage. Too low on final approach. Landed short of runway and collided with a fence.

## Other investigations on N711KR (3)

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 NYC02LA092](https://openairdocs.org/ntsb/NYC02LA092), May 5, 2002: Blanik L-13 (N711KR), Saratoga Spring, NY, substantial damage. Probable cause: The glider encountering an unanticipated downdraft, which resulted in insufficient altitude to reach a suitable landing area.
- [NTSB LAX84LA091](https://openairdocs.org/ntsb/LAX84LA091), Dec 3, 1983: Let L-13 (N711KR), Jacumba, CA, substantial damage
- [NTSB FTW73AF016](https://openairdocs.org/ntsb/FTW73AF016), Nov 5, 1972: Blanik L-13 (N711KR), Friendswood, TX, 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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