# NTSB FTW89LA144: Cessna 172G, N4377L, Mckinney, TX, August 5, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: August 4, 1989, 22:30 local (Aug 5, 1989, 03:30 UTC)
- Place: Mckinney, TX
- Coordinates: 33.18003, -96.590263 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.1800&lon=-96.5903&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 4 uninjured
- Status: Completed, report March 29, 1991
- Report: Approved by Office Director
- NTSB case key (mKey): 22902
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW89LA144
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/22902/pdf
- Page: https://openairdocs.org/ntsb/FTW89LA144

## Probable cause

TOTAL FAILURE OF THE ENGINE ASSEMBLY/ROCKER ARM/TAPPET SHAFT.

## 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,rocker arm/tappet - failure,total (cause)
- Forced landing, descent - emergency
  - light condition - dark night (contributing factor)
- In flight collision with object, descent - emergency
  - object - tree(s) (contributing factor)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

DURING A NIGHT CROSS-COUNTRY FLIGHT, THE ENGINE LOST POWER AND DURING THE FORCED LANDING, THE AIRPLANE IMPACTED TREES AND THEN THE TERRAIN. DURING A PARTIAL TEARDOWN OF THE ENGINE, IT WAS FOUND THAT THE NUMBER 3 CYLINDER EXHAUST VALVE ROCKER ARM SHAFT HAD BROKEN. THERE WAS ALSO A LARGE GAP BETWEEN THE ROCKER ARM AND THE EXHAUST VALVE STEM.

## Aircraft

- Registration: [N4377L](https://openairdocs.org/deregistered/N4377L-1991-08-28), registration cancelled 1991-08-28, S/N 17254455 (OpenAirDocs)
- Reported make and model: CESSNA 172G
- Registry model: [Cessna 172G](https://openairdocs.org/model/cessna-172g) (registry code 2072420) (OpenAirDocs)
- Category: Airplane
- Serial number: 17254455
- Airframe hours: 3573
- Engines: CONTINENTAL O-300-D 145 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Gary R. Swain
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, December 30, 1988, 137 hours before
- Departed: MLC, MCALESTER, OK
- Destination: HQZ, MESQUITE, TX
- Airport: TKI, Municipal

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 600 total, 550 in this make and model, 510 as pilot in command, 50 in the last 90 days, 28 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: 160° at 12 knots
- Visibility: 12 statute miles
- Lowest ceiling: none
- Temperature: 84 °F, dew point 72 °F
- Altimeter: 29.00 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 19890804027369A](https://openairdocs.org/incident/19890804027369A), Aug 4, 1989: Cessna 172G, Mc Kinney, TX, Substantial damage. Engine failed en route. Struck trees on the night forced landing. Exhaust valve rocker arm shaft had broken.

## Other investigations on N4377L (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 FTW81FQG36](https://openairdocs.org/ntsb/FTW81FQG36), Jun 6, 1981: Cessna 172G (N4377L), Shallowater, TX, 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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