# NTSB CEN16LA033: Cessna 120, N2942N, Gonzales, LA, November 6, 2015

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: November 6, 2015, 12:05 local (18:05 UTC)
- Place: Gonzales, LA
- Coordinates: 30.240554, -90.915275 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=30.2406&lon=-90.9153&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Defining event: [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed, report January 21, 2016
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: FAA FSDO
- NTSB case key (mKey): 92298
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN16LA033
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/92298/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=92298
- Page: https://openairdocs.org/ntsb/CEN16LA033

## Probable cause

Maintenance personnel’s improper installation of the carburetor during recent maintenance, including the omission of a required cotter pin, which resulted in a total loss of engine power.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Maintenance/inspections](https://openairdocs.org/ntsb-findings/01010500): Aircraft › Aircraft handling/service · Incorrect service/maintenance (probable cause); cases with it: [Cessna 120, 1 case](https://openairdocs.org/ntsb-findings/01010500/cases.md?model=2071402), [All aircraft, 103 cases](https://openairdocs.org/ntsb-findings/01010500/cases.md)
- [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Cessna 120, 2 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=2071402), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md)
- [Maintenance/inspections](https://openairdocs.org/ntsb-findings/01010500): Aircraft › Aircraft handling/service · Incorrect service/maintenance (probable cause); cases with it: [Cessna 120, 1 case](https://openairdocs.org/ntsb-findings/01010500/cases.md?model=2071402), [All aircraft, 103 cases](https://openairdocs.org/ntsb-findings/01010500/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Cessna 120, 4 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2071402), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)
- [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna 120, 10 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2071402), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)

## Analysis

The pilot reported that the airplane was on final approach to the airport when the engine started to lose power. He applied carburetor heat and switched fuel tanks, but engine power was not restored, so he made a forced landing to a field near the airport. An examination of the wreckage found that the castellated nut that connects the throttle arm to the carburetor had backed off, which allowed the engine to go to idle, and that the nut's associated cotter pin was missing. The pilot reported that the carburetor had been replaced the day before the accident flight. The accident is consistent with the throttle arm becoming disengaged from the carburetor as a result of a missing cotter pin and the accompanying nut subsequently backing off.

## Factual narrative

On November 6, 2015, about 1205 central standard time, a Cessna 120 airplane, N2942N, impacted terrain shortly after departing the Louisiana Regional Airport (L38), Gonzales, Louisiana. The commercial rated pilot was seriously injured and the airplane was substantially damaged during the accident. The airplane was registered to and operated by Graham Aviation LLC, Baton Rouge, Louisiana, under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed at the time. The pilot reported that he had been airborne about 25 minutes and was on final approach to the runway. The engine began to lose power, so he applied carburetor heat and switched fuel tanks. The engine did not recover, so he made a forced landing in a field. The pilot added that the engine's carburetor had been replaced the day prior. The responding Federal Aviation Administration (FAA) inspector reported that the airplane had crashed in a field near the airport. A visual examination of the engine noted that fuel was present on site. The airplane came to rest upright, with the main landing gear collapsed. Heavy impact damage was noted to the airplane's fuselage. After the airplane was recovered, an examination of the wreckage was conducted by the FAA inspector. The examination found that the castellated nut holding the carburetor's throttle arm had backed off, allowing the engine to go to idle. Additionally, the nut was missing the associated cotterpin.

## Aircraft

- Registration: [N2942N](https://openairdocs.org/deregistered/N2942N-2018-05-03), registration cancelled 2018-05-03, S/N 13203, built 1947 (OpenAirDocs)
- Reported make and model: CESSNA 120
- Registry model: [Cessna 120](https://openairdocs.org/model/cessna-120) (registry code 2071402) (OpenAirDocs)
- Registry engine: [Continental C85 series](https://openairdocs.org/engine/continental-c85-series) (registry code 17008, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 13203
- Year built: 1947
- Engines: CONT MOTOR C85 SERIES 85 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Graham Aviation LLC
- Registered owner: Graham Aviation LLC
- Airworthiness certificate: Standard, Normal
- Departed: L38, Gonzales, LA
- Destination: L38, Gonzales, LA
- Airport: L38, Louisiana Regional Airport

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 56; injuries: serious; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review May 15, 2015; seat: left; restraint: lap only; flight hours: 16,000 total, 220 in this make and model, 15,200 as pilot in command, 150 in the last 90 days, 30 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 130° at 3 knots
- Visibility: 10 statute miles
- Lowest ceiling: 1,100 ft broken
- Temperature: 81 °F, dew point 77 °F
- Altimeter: 30.06 inHg
- Observed at: KL38, 3 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 20151106018349A](https://openairdocs.org/incident/20151106018349A), Nov 6, 2015: Cessna 120, Gonzales, LA, Substantial damage. On approach to landing the pilot stated he lost power and conducted an emergency landing in an open field.

## Other investigations on N2942N (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 MIA76FKG57](https://openairdocs.org/ntsb/MIA76FKG57), Apr 20, 1976: Cessna 120 (N2942N), St Simon Is, GA, substantial damage

## Docket (3 files)

The files NTSB released with the investigation on December 1, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=92298. 4.3 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40434358&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF
- Wreckage Exam (item 2, .PDF, 403 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40434359&FileExtension=.PDF&FileName=Wreckage%20Exam-Master.PDF
- Maintenance Record (Page) (item 3, .PDF, 152 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40434360&FileExtension=.PDF&FileName=Maintenance%20Record%20(Page)-Master.PDF

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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