# NTSB FTW89LA165: Cessna 172N, N738BB, Waxahachie, TX, September 17, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: September 16, 1989, 19:55 local (Sep 17, 1989, 00:55 UTC)
- Place: Waxahachie, TX
- Coordinates: 32.399826, -96.849769 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=32.3998&lon=-96.8498&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report June 26, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 22918
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW89LA165
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/22918/pdf
- Page: https://openairdocs.org/ntsb/FTW89LA165

## Probable cause

FAILURE OF THE #3 EXHAUST VALVE DUE TO EXPOSURE TO OVERTEMPERATURE OPERATING CONDITIONS.

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, cruise - normal
  - engine assembly,valve,exhaust - overtemperature (cause)
  - engine assembly,valve,exhaust - failure,partial (cause)
- Forced landing, descent - emergency
- On ground/water encounter with terrain/water, landing - roll
  - terrain condition - soft (contributing factor)

## Analysis

THE AIRPLANE EXPERIENCED A PARTIAL POWER LOSS, WHILE IN CRUISE FLIGHT AT 2,500 MSL OVER AN AIRPARK. AFTER REDUCING POWER AND APPLYING CARBURETOR HEAT, THE PILOT ATTEMPTED TO EXECUTE A FORCE LANDING TO THE AIRPARK. HOWEVER, SHE OVERSHOT AND LANDED IN A WET PLOWED FIELD BEYOND THE END OF THE RUNWAY. DURING ROLL OUT, THE GEAR DUG INTO THE SOFT TERRAIN AND THE AIRPLANE FLIPPED OVER. EXAMINATION OF THE ENGINE REVEALED THAT A PIECE OF THE #3 EXHAUST VALVE HAD SEPARATED AND HAD BEEN INGESTED. METALLURGICAL EXAMINATION OF THE FAILED VALVE INDICATED THAT IT HAD BEEN EXPOSED TO HIGH TEMPERATURE OPERATION. HOWEVER, THE EXACT ORIGIN OF THE SEPARATION WAS NOT DETERMINED DUE TO MASKING OF THE FRACTURE SURFACES, ACCUMULATION OF EXHAUST DEPOSITS AND POST-SEPARATION MECHANICAL DAMAGE.

## Aircraft

- Registration: [N738BB](https://openairdocs.org/deregistered/N738BB-1995-05-03), registration cancelled 1995-05-03, S/N 17269839 (OpenAirDocs)
- Reported make and model: CESSNA 172N
- Registry model: [Cessna 172N](https://openairdocs.org/model/cessna-172n) (registry code 2072434) (OpenAirDocs)
- Category: Airplane
- Serial number: 17269839
- Airframe hours: 1492
- Engines: LYCOMING O-320-H2AD 160 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Frances P. Casey
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, November 18, 1988, 69 hours before
- Departed: TE06, LEONARD, TX
- Destination: ERV, KERRVILLE, TX
- Airport: T25, O'Brien Airpark, runway 36, 2,000 × 25 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 635 total, 600 in this make and model

## Weather

- Conditions: Visual (VMC), Dusk
- Wind: 110° at 10 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 66 °F, dew point 59 °F
- Altimeter: 30.00 inHg
- Observed at: RBD, 15 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 19890916035179A](https://openairdocs.org/incident/19890916035179A), Sep 16, 1989: Cessna 172N, Waxahachie, TX, Substantial damage. Rough engine,overshot runway on forced landing. Nosed over in soft field. Broken exhaust valve. Engine run too lean.

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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