# NTSB CEN17LA328: Beech A36, N48TZ, Gonzales, LA, August 17, 2017

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: August 17, 2017, 09:27 local (14:27 UTC)
- Place: Gonzales, LA
- Coordinates: 30.153888, -90.937774 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=30.1539&lon=-90.9378&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Defining event: [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report March 18, 2019
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: Continental Motors, Flight Standards District Office
- NTSB case key (mKey): 95883
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN17LA328
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/95883/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=95883
- Page: https://openairdocs.org/ntsb/CEN17LA328

## Probable cause

A partial loss of engine power due to inadequate maintenance, including worn spark plugs and a leaking fuel hose fitting.

## Findings

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

- [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Beech A36, 13 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=1151604), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md)
- [Maintenance](https://openairdocs.org/ntsb-findings/02062000): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Beech A36, 1 case](https://openairdocs.org/ntsb-findings/02062000/cases.md?model=1151604), [All aircraft, 143 cases](https://openairdocs.org/ntsb-findings/02062000/cases.md)
- [Ignition system: spark plugs/igniters](https://openairdocs.org/ntsb-findings/01057421): Aircraft › Aircraft power plant · Fatigue/wear/corrosion (probable cause); cases with it: [Beech A36, 1 case](https://openairdocs.org/ntsb-findings/01057421/cases.md?model=1151604), [All aircraft, 38 cases](https://openairdocs.org/ntsb-findings/01057421/cases.md)
- [Fuel system](https://openairdocs.org/ntsb-findings/01022800): Aircraft › Aircraft systems · Damaged/degraded (probable cause); cases with it: [Beech A36, 6 cases](https://openairdocs.org/ntsb-findings/01022800/cases.md?model=1151604), [All aircraft, 181 cases](https://openairdocs.org/ntsb-findings/01022800/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 (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Beech A36, 7 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=1151604), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md)
- [Landing: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Beech A36, 7 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=1151604), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md)

## Analysis

During the initial climb on an instructional flight, the private pilot and instructor noticed a partial loss of engine power. The pilot performed a forced landing into a hay field and the airplane nosed over. Following the accident, the mechanic who normally performed maintenance removed and discarded all twelve spark plugs, as several were worn. A subsequent examination and test run of the engine revealed a leaking fuel hose due to a loose B-nut. The loss of engine power was consistent with an inadequate fuel supply due to a fuel line leak. Further, it is likely that the worn spark plugs would also have contributed to the loss of engine power.

## Factual narrative

On August 17, 2017, about 0927 central daylight time, a Beech A36 airplane, N48TZ, was substantially damaged during a forced landing after departing from the Louisiana Regional Airport (REG), Gonzales, Louisiana. The pilot and flight instructor were not injured. The airplane was registered to and operated by Gulf Central Aviation LLC under the provisions of Title 14 Code of Federal Regulations Part 91 as an instructional flight. Day visual meteorological conditions prevailed for the local flight, which departed without a flight plan about 0926. According to the pilot, he departed from Runway 17, following a normal engine run up and takeoff roll. After reaching about 150 ft agl, the pilot noticed the airplane was no longer climbing and lowered the airplane's nose. Based on his perceptions of a partial engine power loss, the pilot checked the throttle and mixture lever positions, both of which were full forward. After maneuvering to avoid trees, the pilot initiated a forced landing into a hay field. During the landing roll, the airplane impacted a small ridge and nosed over, which damaged the engine firewall. Examination at the recovery location revealed the ignition harness connecting the magnetos to each of the top sparkplugs had been disconnected from the sparkplugs. All twelve sparkplugs appeared new, with no combustion deposits noted. Without authorization, a mechanic who normally performed maintenance on the airplane stated he had removed and discarded the spark plugs due to several having a worn-out condition. Not realizing the airplane should not be disturbed during the investigation, the mechanic had also removed the fuel screen. Examination of the throttle and mixture control cables revealed proper attachment to their respective control arms. Borescope inspection of piston domes, cylinder wall surfaces, and intake and exhaust valves revealed normal wear patterns and combustion signatures, except for the No. 5 cylinder exhaust valve, which had a green crescent-shaped discoloration on the bottom of the valve face. After the fuel screen was returned by the mechanic, an engine test run was performed. The engine rotated and ran on the first attempt but stopped after several seconds. A fuel leak was observed adjacent to the fuel pump, with a flexible fuel hose leaking at a B-nut. The nut was tightened about ¼ turn, which seated the nut onto the fitting. The engine driven fuel pump and the adjacent oil filter adapter were stained with a blue color. A second fuel leak was observed at the throttle body/metering unit, with the fuel mixture arm and shaft bent in a manner consistent with impact damage. A second engine test run was conducted, during which power was not increased above 1,100 rpm, due to a damaged propeller. The engine was operated at varying speeds and a magneto check was accomplished, with no anomalies. The throttle was reduced to idle power and the engine ran smoothly. The oil on the oil rod was very dark in color. A logbook reviewrevealed the engine had accumulated 163.7 hours since the last oil and oil filter change. The manufacturer recommends oil change intervals of 50 hours for an engine equipped with external filters installed.

## Aircraft

- Registration: [N48TZ](https://openairdocs.org/aircraft/N48TZ), registered now, S/N E-1804 (OpenAirDocs)
- Reported make and model: BEECH A36
- Registry model: [Beech A36](https://openairdocs.org/model/beech-a36) (registry code 1151604) (OpenAirDocs)
- Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: E-1804
- Year built: 1980
- Airframe hours: 6184
- Engines: Continental IO-520 285 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: Gulf Central Aviation LLC
- Registered owner: Gulf Central Aviation LLC
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, August 8, 2016, 163 hours before
- Departed: REG, GONZALES, LA
- Destination: REG, GONZALES, LA
- Airport: REG, Louisiana Rgnl, runway 17, 5,003 × 100 ft, asphalt
- Equipment: Satellite tracking device, Stall warning system, Auto-pilot, Onboard weather, Electronic multifunction display

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 43; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review September 19, 2016; seat: left; restraint: 3-point; flight hours: 302 total, 165 in this make and model, 148 as pilot in command, 18 in the last 90 days, 11 in the last 30 days, 3 in the last 24 hours
- Flight instructor; age 58; injuries: none; flight instructor, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review May 12, 2017; seat: right; restraint: 3-point; flight hours: 18,100 total, 3,000 in this make and model, 17,200 as pilot in command, 100 in the last 90 days, 25 in the last 30 days, 0 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 230° at 6 knots
- Visibility: 10 statute miles
- Temperature: 86 °F, dew point 79 °F
- Altimeter: 30.09 inHg
- Observed at: KREG, 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 20170817015829A](https://openairdocs.org/incident/20170817015829A), Aug 17, 2017: Beech A36, Gonzales, LA, Substantial damage. Aircraft departed Gonzales Regional Airport (reg) for an instrument training flight. On-board were the private pilot [privacy data omitted] and the flight…

## Docket (3 files)

The files NTSB released with the investigation on September 12, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=95883. 2.0 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 950 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466576&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF
- Correspondence with Federal Aviation Administrator Inspector (item 2, .PDF, 84 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466577&FileExtension=.PDF&FileName=Correspondence%20with%20Federal%20Aviation%20Administrator%20Inspector-Master.PDF
- Photos (item 3, .PDF, 12 photos, 943 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466578&FileExtension=.PDF&FileName=Photos-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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