# NTSB MKC82DA068: Beech M35, N313Z, Ottumwa, IA, May 2, 1982

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Final report
- Date: May 2, 1982, 15:25 local (20:25 UTC)
- Place: Ottumwa, IA
- Coordinates: 41.009109, -92.409683 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=41.0091&lon=-92.4097&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor, 2 uninjured
- Status: Completed, report May 2, 1983
- Report: Approved by Office Director
- NTSB case key (mKey): 72123
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC82DA068
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/72123/pdf
- Page: https://openairdocs.org/ntsb/MKC82DA068

## 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 - normal
  - engine assembly,valve,intake - worn (cause)
  - fluid,oil - leak (cause)
  - fluid,oil - exhaustion (cause)
- Forced landing, landing - flare/touchdown
- In flight collision with terrain/water, landing - flare/touchdown
  - window,flight compartment window/windshield - dirty(foggy) (contributing factor)
  - terrain condition - high obstruction(s) (contributing factor)
  - maneuver - performed, pilot in command
  - wheels up landing - performed, pilot in command

## Analysis

DURING FLIGHT, THE ENGINE RPM EXCEEDED ITS MAXIMUM LIMIT. THE PILOT ATTEMPTED TO REDUCE THE RPM BY USING THE PROPELLER CONTROL, BUT THIS HAD NO EFFECT. THE PILOT WAS IN THE PROCESS OF SHUTTING DOWN THE ENGINE WHEN ENGINE OIL SPRAYED OUT THE COWLING AND ONTO THE WINDSHIELD. UNABLE TO GLIDE TO AN AIRPORT, HE ELECTED TO LAND IN A CORN FIELD. AS HE APPROACHED THE FIELD, HE SAW POWERLINES IN HIS GLIDE PATH, THEN LANDED HARD WITH THE GEAR RETRACTED AFTER MANEUVERING TO AVOID THE LINES. A TEARDOWN OF THE ENGINE REVEALED THAT THE NO. 3 CYLINDER EXHAUST VALVE GUIDE WAS WORN WELL BEYOND ITS SERVICE LIMIT AND ALLOWED EXCESSIVE BLOWBY FROM THE CRANKCASE. THE OIL SUPPLY HAD BEEN DEPLETED AND THERE WAS DETERIORATION OF METAL TO METAL PARTS DUE TO LOSS OF LUBRICATION. THE VALVE GUIDE, PN 631496, HAD BEEN OUT OF PRODUCTION FOR ABOUT 8 OR 9 YEARS.

## Aircraft

- Registration: [N313Z](https://openairdocs.org/deregistered/N313Z-2012-09-25), registration cancelled 2012-09-25, S/N D-6465, built 1960 (OpenAirDocs)
- Reported make and model: BEECH M35
- Registry model: [Beech M35](https://openairdocs.org/model/beech-m35) (registry code 1151526) (OpenAirDocs)
- Registry engine: [Continental I0-470 series](https://openairdocs.org/engine/continental-i0-470-series) (registry code 17027, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: D-6465
- Engines: CONTINENTAL IO-470-C 250 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Gerald G. Boneson
- Registered owner: Gerald G. Boneson
- Departed: ALO, WATERLOO, IA
- Destination: HRO, HARRISON, IA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 35; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; flight hours: 446 total, 98 in this make and model, 348 as pilot in command, 46 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 220° at 8 knots
- Visibility: 10 statute miles
- Lowest ceiling: 6,500 ft broken
- Temperature: 151 °F
- Altimeter: 30.00 inHg
- Observed at: OTM

## 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 19820502015119A](https://openairdocs.org/incident/19820502015119A), May 2, 1982: Beech 35BEECH, Ottumwa, IA, Substantial damage. Excess blow by from worn valve guides caused engine blow up from lack of oil. Stalled clearing wires on landing.

## Other investigations on N313Z (3)

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 MIA76FLA41](https://openairdocs.org/ntsb/MIA76FLA41), Apr 13, 1976: Beech M35 (N313Z), Jacksonville, FL, substantial damage
- [NTSB FTW70FPG11](https://openairdocs.org/ntsb/FTW70FPG11), Mar 27, 1970: Beech M35 (N313Z), Hope, AR, substantial damage
- [NTSB MKC66D0185](https://openairdocs.org/ntsb/MKC66D0185-175700), Aug 20, 1965: Beechcraft M-35 (N313Z), Osage Beach, MO, 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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