# NTSB DEN93LA064: Schempp-Hirth Nimbus II, N173, Buena Vista, CO, May 30, 1993

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: May 30, 1993, 10:30 local (16:30 UTC)
- Place: Buena Vista, CO
- Coordinates: 38.830924, -106.139938 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.8309&lon=-106.1399&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed, report November 3, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 18292
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN93LA064
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18292/pdf
- Page: https://openairdocs.org/ntsb/DEN93LA064

## Probable cause

FAILURE TO FOLLOW PROCEDURES AND DIRECTIVES WHEN OPERATING THE FLAPS.

## Sequence of events

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

- Loss of control - in flight, takeoff - initial climb
  - flight controls - improper use of, pilot in command (cause)
- In flight collision with terrain/water, descent - uncontrolled
  - terrain condition - runway

## Analysis

DURING THE TAKEOFF ROLL THE PILOT WENT FROM NEGATIVE TO POSITIVE FLAPS AFTER THE CONTROLS BECAME EFFECTIVE.  THE FLAP TRANSITION WAS RAPID AND THE GLIDER BEGAN TO OSCILLATE IN PITCH.  THE OSCILLATIONS BECAME DIVERGENT AND THE GLIDER ROLLED OFF ON A WING AND COLLIDED WITH THE GROUND SHORTLY AFTER THE SAFETY ROPE PARTED.  THE PILOT STATED THAT HE WENT FROM NEGATIVE TO POSITIVE FLAPS TOO QUICKLY RESULTING IN LOSS OF CONTROL.

## Aircraft

- Registration: [N173](https://openairdocs.org/deregistered/N173-1996-05-16), registration cancelled 1996-05-16, S/N 27 (OpenAirDocs)
- Reported make and model: SCHEMPP-HIRTH NIMBUS II
- Registry model: [Schempp-Hirth K. G NIMBUS II](https://openairdocs.org/model/schempp-hirth-k-g-nimbus-ii) (registry code 3801925) (OpenAirDocs)
- Category: Glider
- Serial number: 27
- Airframe hours: 2073
- Engines: unknown
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Kile, R. L.
- Registered owner: Kile, R. L. And Crowl, C.L.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, January 12, 1993, 5 hours before
- Departed: 7V1
- Destination: 7V1
- Airport: 7V1, Buena Vista Municipal, runway 15, 9,000 × 48 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 47; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, valid medical--no waivers/lim.; seat: center; flight hours: 1,617 total, 20 in this make and model, 1,434 as pilot in command, 10 in the last 90 days, 6 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 360° at 5 knots
- Visibility: 30 statute miles
- Lowest ceiling: none
- Temperature: 52 °F, dew point 30 °F
- Altimeter: 30.00 inHg
- Observed at: LXV, 30 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 19930530016129A](https://openairdocs.org/incident/19930530016129A), May 30, 1993: Sphrth NIMBUS2, Buena Vista, CO, Substantial damage. Misused flaps on glider tow. Porpoised and oscillate. Broke tow rope. Wing hit ground. Glider cartwheeled.

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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