# NTSB CHI90LA274: Burkhart Grob 109A, N912G, Waukesha, WI, September 26, 1990

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: September 26, 1990, 15:00 local (20:00 UTC)
- Place: Waukesha, WI
- Coordinates: 43.009742, -88.229286 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=43.0097&lon=-88.2293&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor, 1 uninjured; on the ground: 1 minor
- Status: Completed, report November 9, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 14783
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI90LA274
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/14783/pdf
- Page: https://openairdocs.org/ntsb/CHI90LA274

## Probable cause

THE PILOT'S FAILURE TO MAINTAIN ADEQUATE CLEARANCE AND VISUAL LOOKOUT FOR THE MOVING TRACTOR.

## Sequence of events

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

- On ground/water collision with object, landing - roll
  - object - vehicle
  - visual lookout - inadequate, pilot in command (cause)
  - clearance - not maintained, pilot in command (cause)

## Analysis

THE STUDENT PILOT REPORTED THAT HE WAS LANDING TO THE NORTH AT AN UNCONTROLLED AIRPORT WHEN THE LEFT WING OF THE MOTOR GLIDER AIRPLANE HE WAS FLYING STRUCK A TRACTOR TYPE LAWM MOWER. HE SAID THAT WHEN HE INITIALLY SAW THE MOWER IT WAS ABOUT 80 FEET FROM THE RUNWAY. THE NEXT TIME THAT HE SAW IT, IT WAS APPROXIMATELY 3 FEET FROM THE RUNWAY'S LEFT EDGE. THE OPERATOR OF THE MOWER SAID THAT HE WAS DRIVING THE MOWER ON THE WEST SIDE OF THE RUNWAY WITH HIS BACK TO THE APPROACHING AIRPLANE. HE DID NOT SEE OR HEAR THE AIRPLANE UNTIL IT HIT THE MOWER.

## Aircraft

- Registration: [N912G](https://openairdocs.org/deregistered/N912G-2019-03-04), registration cancelled 2019-03-04, S/N 6143, built 1982 (OpenAirDocs)
- Reported make and model: Burkhart Grob 109A
- Registry model: [Burkhart Grob Flugzeugbau G109](https://openairdocs.org/model/burkhart-grob-flugzeugbau-g109) (registry code 1660204) (OpenAirDocs)
- Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs)
- Category: Airplane
- Serial number: 6143
- Engines: LIMBACH L2000EB1M 80 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Registered owner: Arthur L. Daun, Jr.
- Departed: HXF, HARTFORD, WI
- Airport: O26, Capital Drive, runway 3, 3,500 × 45 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 41; student; medical: class 3, valid medical--w/ waivers/lim; flight hours: 87 total, 76 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 130° at 8 knots
- Visibility: 8 statute miles
- 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 19900926042479A](https://openairdocs.org/incident/19900926042479A), Sep 26, 1990: Grob G109, Brookfield, WI, Substantial damage. Motor glider struck a mowing machine and driver on landing roll. Driver was mowing too close to an active runway.

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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