# NTSB CHI94LA328: Mooney M20E, N6944U, Plymouth, MI, September 14, 1994

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: September 14, 1994, 18:25 local (22:25 UTC)
- Place: Plymouth, MI
- Coordinates: 42.369323, -83.459373 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=42.3693&lon=-83.4594&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report February 24, 1995
- Report: Approved by Office Director
- NTSB case key (mKey): 9683
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI94LA328
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/9683/pdf
- Page: https://openairdocs.org/ntsb/CHI94LA328

## Probable cause

the pilot's improper (maintenance) modification and his initiating an operation with known deficiencies in equipment

## 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
  - maintenance,modification - improper, pilot in command (cause)
  - operation with known deficiencies in equipment - initiated, pilot in command (cause)
- Forced landing, descent - emergency
- On ground/water collision with object, landing
  - object - fence

## Analysis

THE PILOT STATED THAT HE NOTED THAT THE AIRPLANE HAD DEVELOPED AN OIL LEAK IN THE OIL COOLER.  HE ISOLATED THE LEAK BY CAPPING THE OIL LINES FROM THE ENGINE TO THE COOLER AND INITIATED A FLIGHT.  HE REPORTED THAT AFTER ABOUT TEN MINUTES OF FLIGHT THE OIL PRESSURE DROPPED TO ZERO AND HE WAS ATTEMPTING A FORCED LANDING WHEN THE ENGINE BEGAN RUNNING ROUGH AND SHORTLY THEREAFTER SUFFERED A TOTAL LOSS OF POWER.

## Factual narrative

On September 14, 1994, at 1825 eastern daylight time, a Mooney M20E, N6944U, registered to Earl R. Sobeck of Dearborn Heights, Michigan, and operated by a private pilot, struck a fence during a forced landing following a total loss of engine power.  The accident occurred in an industrial area about seven miles east- northeast of the intended destination of Canton, Michigan.  The airplane sustained substantial damage.  The pilot reported no injuries.  The personal 14 CFR Part 91 flight was operating in visual meteorological conditions.  No flight plan was on file.  The flight departed Detroit, Michigan, at 1815.

The pilot stated that he had made a modification to the accident airplane, which included isolating the oil cooler which was leaking.  He accomplished this by capping off the engine fittings to the oil cooler hoses which blocked the lubricating oil between the engine and the oil cooler.  He then departed for another airport where he intended to obtain maintenance to repair the leaking oil cooler.  He stated that while enroute the engine oil pressure dropped to zero and while he was conducting a forced landing the engine began to run rough and a total power loss soon followed.

## Aircraft

- Registration: [N6944U](https://openairdocs.org/deregistered/N6944U-1995-08-17), registration cancelled 1995-08-17, S/N 314 (OpenAirDocs)
- Reported make and model: MOONEY M20E
- Registry model: [Mooney M20E](https://openairdocs.org/model/mooney-m20e) (registry code 5870212) (OpenAirDocs)
- Category: Airplane
- Serial number: 314
- Airframe hours: 3151
- Engines: LYCOMING IO-360-A1A 200 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Sobeck, Earl R.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, April 19, 1994, 40 hours before
- Departed: DET, DETROIT, MI
- Destination: 1D2, CANTON, MI

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 57; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 1,004 total, 355 in this make and model, 901 as pilot in command, 25 in the last 90 days, 6 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 120° at 7 knots
- Visibility: 6 statute miles
- Lowest ceiling: 8,000 ft overcast
- Temperature: 77 °F, dew point 73 °F
- Altimeter: 30.00 inHg
- Observed at: DTW, 10 nm away

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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