# NTSB LAX93LA040: Cessna 172G, N6060R, Williams, AZ, November 15, 1992

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: November 15, 1992, 07:50 local (14:50 UTC)
- Place: Williams, AZ
- Coordinates: 35.369213, -112.260391 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.3692&lon=-112.2604&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 2 serious, 1 minor
- Status: Completed, report August 26, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 27865
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX93LA040
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27865/pdf
- Page: https://openairdocs.org/ntsb/LAX93LA040

## Probable cause

THE PARTIAL LOSS OF ENGINE POWER DUE TO A STUCK EXHAUST VALVE ON THE NUMBER TWO CYLINDER AND THE PILOT'S INABILITY TO CLIMB THE AIRCRAFT ABOVE THE TREES SURROUNDING THE AIRPORT.  A FACTOR IN THE ACCIDENT WAS THE EFFECTS OF THE HIGH DENSITY ALTITUDE ON THE AIRCRAFT CLIMB PERFORMANCE.

## 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, takeoff - initial climb
  - engine assembly,valve,exhaust - contamination (cause)
  - engine assembly,valve,exhaust - jammed (cause)
- In flight collision with object, takeoff - initial climb
  - object - tree(s)
  - weather condition - high density altitude (contributing factor)
  - climb - not possible, pilot in command (cause)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE PILOT, THE PILOT RATED PASSENGERS AND A MECHANIC GROUND WITNESS REPORTED THAT THE AIRCRAFT USED THE ENTIRE LENGTH OF THE RUNWAY TO BECOME AIRBORNE. THE AIRCRAFT WOULD NOT CLIMB, AND, WHILE FLYING IN GROUND EFFECT, COLLIDED WITH A TREE ABOUT ONE MILE OFF THE END OF THE RUNWAY. THE DENSITY ALTITUDE WAS COMPUTED TO BE JUST OVER 7,000 FEET. THE MECHANIC WITNESS SAID THE ENGINE SOUNDED LIKE THE CARBURETOR HEAT WAS ON DURING THE TAKEOFF GROUND ROLL. DETAILED EXAMINATION OF THE ENGINE REVEALED THAT THE EXHAUST VALVE ON THE NUMBER TWO CYLINDER WAS STUCK IN THE OPEN POSITION. A ENGINE OVERHAUL FACILITY REPORTED THAT THE VALVE WAS STUCK DUE TO 'A CONSIDERABLE AMOUNT OF CARBON' IN THE VALVE GUIDE.

## Aircraft

- Registration: [N6060R](https://openairdocs.org/aircraft/N6060R), registered now, S/N 17253729 (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: 17253727
- Airframe hours: 3549
- Engines: CONTINENTAL O-300D 145 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Rachel G. Bonzon
- Registered owner: Dorothy D. Limbach
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, June 10, 1992, 69 hours before
- Departed: P32
- Destination: PRC, PRESCOTT, AZ
- Airport: P32, Williams Muni, runway 18, 6,000 × 60 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 70; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 1,843 total, 1,000 in this make and model, 1,743 as pilot in command, 5 in the last 90 days, 5 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 340° at 3 knots
- Visibility: 30 statute miles
- Lowest ceiling: none
- Temperature: 39 °F
- Altimeter: 30.00 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 19921115046619A](https://openairdocs.org/incident/19921115046619A), Nov 15, 1992: Cessna 172G, Williams, AZ, Substantial damage. Unable to leave ground effect after long takeoff roll. Struck tree. NR2 cylinder exhaust valve stuck open.

## Other investigations on N6060R (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 LAX67F0339](https://openairdocs.org/ntsb/LAX67F0339), Mar 7, 1967: Cessna 172 (N6060R), Van Nuys, CA, 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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