# NTSB CHI93LA303: Schweizer G167B, N6637Q, Borup, MN, July 27, 1993

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 27, 1993, 18:30 local (23:30 UTC)
- Place: Borup, MN
- Coordinates: 47.180175, -96.500167 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=47.1802&lon=-96.5002&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report August 17, 1994
- Report: Approved by Office Director
- NTSB case key (mKey): 9268
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI93LA303
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/9268/pdf
- Page: https://openairdocs.org/ntsb/CHI93LA303

## Probable cause

the loss of engine power due to a cracked cylinder head.

## 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, maneuvering - aerial application
  - engine assembly,cylinder - cracked (cause)
- Forced landing, descent - emergency
- Nose over, landing - flare/touchdown
  - terrain condition - soft

## Analysis

THE PILOT REPORTED THE AIRPLANE LOST ENGINE POWER DURING AN AERIAL APPLICATION SPRAY RUN. HE MADE A FORCED LANDING ON A SOFT FIELD AND THE AIRPLANE NOSED OVER. EXAMINATION OF THE ENGINE REVEALED THAT THE NUMBER SEVEN CYLINDER HEAD WAS CRACKED BETWEEN THE SPARK PLUGS.

## Factual narrative

On July 27, 1993, about 1830 central daylight time, a Swizer G167B airplane, N6637Q, sustained substantial damage during a forced landing on a soft field near Borup, Minnesota.  The solo commercial pilot was not injured.  The aerial application flight operated under 14 CFR Part 137 without flight plan in visual meteorological conditions.  The flight departed Ada, Minnesota, about 1845.

The pilot reported a total loss of engine power during an approach to a field to begin aerial spraying.  He made a forced landing in the field and the airplane nosed over in the soft terrain.

An examination of the engine revealed the number seven cylinder head was cracked between the spark plugs.

## Aircraft

- Registration: [N6637Q](https://openairdocs.org/deregistered/N6637Q-2004-07-14), registration cancelled 2004-07-14, S/N 167B, built 1976 (OpenAirDocs)
- Reported make and model: Schweizer G167B
- Registry model: [Grumman Acft ENG Cor-Schweizer G-164B](https://openairdocs.org/model/grumman-acft-eng-cor-schweizer-g-164b) (registry code 3952802) (OpenAirDocs)
- Registry engine: [Pratt & Whitney R-985 series](https://openairdocs.org/engine/pratt-whitney-r-985-series) (registry code 52008, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 167
- Airframe hours: 8385
- Engines: P&W R1340 600 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: Robert M. Johnson
- Registered owner: Robert M. Johnson
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, May 10, 1993, 213 hours before
- Departed: ADA, MN

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 34; commercial, private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: front; flight hours: 3,500 total, 3,000 in this make and model, 185 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 110° at 5 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 90 °F, dew point 61 °F
- Altimeter: 30.00 inHg

## 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 19930727027329A](https://openairdocs.org/incident/19930727027329A), Jul 27, 1993: Scwzer G164B, Borup, MN, Substantial damage. Lost power during spray run force landed soft field. Nosed over. NR7 cylinder head cracked between plugs.

## Other investigations on N6637Q (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 ATL82DA230](https://openairdocs.org/ntsb/ATL82DA230), Aug 6, 1982: Grumman G164B (N6637Q), Opp, AL, 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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