# NTSB FTW86LA141: Cessna 150H, N50101, Bartlesville, OK, July 31, 1986

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: July 31, 1986, 09:20 local (14:20 UTC)
- Place: Bartlesville, OK
- Coordinates: 36.730472, -96.070549 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=36.7305&lon=-96.0705&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 22068
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW86LA141
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/22068/pdf
- Page: https://openairdocs.org/ntsb/FTW86LA141

## 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, climb
  - maintenance,annual inspection - improper, other maintenance personnel (cause)
  - engine assembly,valve,intake - incorrect (cause)
  - maintenance,replacement - improper, other maintenance personnel (cause)
  - engine assembly,valve,intake - movement restricted (cause)
  - engine assembly,cylinder - failure,total (cause)
- Forced landing, descent - emergency
- In flight collision with object, landing - flare/touchdown
  - terrain condition - none suitable (contributing factor)
  - terrain condition - high vegetation (contributing factor)
  - object - tree(s) (contributing factor)

## Analysis

THE PLT TOOK OFF ON A TEST FLT AFTER AN ANNUAL INSPN OF THE ACFT & A TOP OVERHAUL OF THE ENG HAD BEEN COMPLETED. WHILE CLIMBING THRU ABOUT 1200 TO 1300 FT AGL, THE ENG STARTED RUNNING ROUGH, THEN QUIT. THE PLT ATTEMPTED TO RETURN TO THE ARPT, BUT WAS UNABLE. SUBSEQUENTLY, SHE LANDED THE ACFT IN AN AREA OF DENSE BRUSH & TREES. AN INV REVEALED THAT THE ROCKER ARM SUPPORT STRUCTURE ON THE #3 CYLINDER HAD FAILED, RELEASING THE ROCKER ARM SHAFT & BOTH ROCKER ARMS. TEARDOWN OF THE ENG REVEALED THAT THE #3 EXHAUST VALVE GUIDE WAS AN INCORRECT PART & WAS OVERSIZE IN LENGTH BY 0.165 INCH. THE OVERSIZE GUIDE WOULD NOT ALLOW FULL VALVE MOVEMENT & THE RESIDUAL MOVEMENT RESULTED IN FAILURE OF THE ROCKER ARM SUPPORT STRUCTURE.

## Aircraft

- Registration: [N50101](https://openairdocs.org/deregistered/N50101-2006-04-06), registration cancelled 2006-04-06, S/N 15069063, built 1968 (OpenAirDocs)
- Reported make and model: CESSNA 150H
- Registry model: [Cessna 150H](https://openairdocs.org/model/cessna-150h) (registry code 2071818) (OpenAirDocs)
- Registry engine: [Continental 0-200 series](https://openairdocs.org/engine/continental-0-200-series) (registry code 17020, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 15069063
- Airframe hours: 4343
- Engines: CONTINENTAL O-200-A 100 horsepower reciprocating
- Damage: Substantial damage
- Flight: Part 91
- Registered owner: Jean F. Cox
- Airworthiness certificate: Standard, Utility; Standard, Normal
- Last inspection: Annual, July 31, 1986

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 67; private; airplane ratings: single-engine land; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 357 total, 80 in this make and model, 254 as pilot in command, 8 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 360° at 10 knots
- Visibility: 5 statute miles
- Lowest ceiling: 2,000 ft broken
- Temperature: 88 °F, dew point 73 °F
- Altimeter: 29.00 inHg
- Observed at: BVO, 1 nm away

## 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 19860731036729A](https://openairdocs.org/incident/19860731036729A), Jul 31, 1986: Cessna 150H, Bartlesville, OK, Substantial damage. The engine failed shortly after takeoff. A cylinder rocker arm shaft failed from improper valve components.

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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