# NTSB SEA92LA098: Schweizer SGS-1-35C, N2739H, Big Timber, MT, May 20, 1992

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: May 20, 1992, 16:20 local (22:20 UTC)
- Place: Big Timber, MT
- Coordinates: 45.96088, -109.850494 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.9609&lon=-109.8505&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report June 30, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 41676
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA92LA098
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41676/pdf
- Page: https://openairdocs.org/ntsb/SEA92LA098

## Probable cause

AIRSPEED WAS NOT MAINTAINED.  FACTORS TO THE ACCIDENT WERE: NO THERMAL LIFT AND INADEQUATE REMEDIAL ACTION.

## Sequence of events

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

- Miscellaneous/other, cruise
  - weather condition - no thermal lift (contributing factor)
- Forced landing, descent - emergency
- Hard landing, landing - flare/touchdown
  - airspeed - not maintained, pilot in command (cause)
  - remedial action - inadequate, pilot in command (contributing factor)

## Analysis

DURING A CROSS COUNTRY FLIGHT, THE GLIDER WAS UNABLE TO MAINTAIN ALTITUDE DUE TO A LOSS OF LIFT. THE PILOT INITIATED A FORCED LANDING TO AN OPEN FIELD. WHEN APPROXIMATELY 30 FEET AGL, THE GLIDER ENTERED A HIGH SINK RATE. THE PILOT REDUCED THE ANGLE OF ATTACK AND RETRACTED THE FLAPS, HOWEVER, THE GLIDER CONTINUED TO SINK AND LANDED HARD.

## Aircraft

- Registration: [N2739H](https://openairdocs.org/deregistered/N2739H-2013-04-18), registration cancelled 2013-04-18, S/N 69, built 1976 (OpenAirDocs)
- Reported make and model: SCHWEIZER SGS-1-35C
- Registry model: [Schweizer SGS 1-35C](https://openairdocs.org/model/schweizer-sgs-1-35c) (registry code 8050151) (OpenAirDocs)
- Registry engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000, none) (OpenAirDocs)
- Category: Glider
- Serial number: 69
- Engines: unknown
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Ridge Runners Inc.
- Registered owner: Ridge Runners Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, January 2, 2000
- Departed: BZN, BOZEMAN, MT

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 29; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: front; flight hours: 2,300 total, 75 in this make and model, 1,900 as pilot in command, 120 in the last 90 days, 35 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 270° at 15 knots
- Visibility: 50 statute miles
- Lowest ceiling: none
- Temperature: 70 °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 19920520015539A](https://openairdocs.org/incident/19920520015539A), May 20, 1992: Scwzer SGS135C, Big Timber, MT, Substantial damage. Unable to make destination due to loss of thermals. Selected a field. High sink rate on final,unable to correct.

## Other investigations on N2739H (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 DEN79DTE38](https://openairdocs.org/ntsb/DEN79DTE38), May 13, 1979: Schweizer SGS135 (N2739H), Colorado Spr, CO, 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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