# NTSB NYC91DGT02: Kolb Twinstar, N94MW, Williamsport, PA, May 5, 1991

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Final report
- Date: May 5, 1991
- Place: Williamsport, PA
- Coordinates: 41.229541, -77.030029 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=41.2295&lon=-77.0300&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor
- Status: Completed, report May 5, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 36751
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC91DGT02
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/36751/pdf
- Page: https://openairdocs.org/ntsb/NYC91DGT02

## Probable cause

AN ENGINE SEIZURE AS THE RESULT OF OVERHEATING.

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, cruise
  - powerplant - overtemperature (cause)
- In flight collision with terrain/water, descent - emergency
  - terrain condition - ravine

## Analysis

THE HOMEBUILT AIRPLANE COLLIDED WITH THE GROUND IN A HEAVILY WOODED RAVINE AFTER ITS ENGINE QUIT DURING CRUISE FLIGHT.  THE FAA REPORTED THAT 'THE NUMBER TWO CYLINDER WAS SCORED' AND THE 'ENGINE SEIZED AFTER IT OVERHEATED.'

## Aircraft

- Registration: [N94MW](https://openairdocs.org/deregistered/N94MW-2013-10-28), registration cancelled 2013-10-28, S/N A-1, built 1985 (OpenAirDocs)
- Reported make and model: Kolb Company TWINSTAR
- Registry model: [Welch Marshal JR KOLB TWINSTAR](https://openairdocs.org/model/welch-marshal-jr-kolb-twinstar) (registry code 05613SG) (OpenAirDocs)
- Registry engine: [Bombardier ROTAX (ALL)](https://openairdocs.org/engine/bombardier-rotax-all) (registry code 09050, reciprocating) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: A-1
- Airframe hours: 410
- Engines: Rotax 503 3561619 47 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Marshall Welch, Jr.
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, October 10, 1990, 28 hours before
- Departed: TROUT RUN, PA
- Airport: NONE, Finkhaven

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 62; private; airplane ratings: single-engine land, single-engine sea; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: left

## Weather

- Conditions: Visual (VMC), Day
- Lowest ceiling: none
- Temperature: -0 °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 19910505014269A](https://openairdocs.org/incident/19910505014269A), May 5, 1991: Amtrkb TWINSTAR, Williamsport, PA, Substantial damage. Engine lost power. Crash landed in trees.

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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