# NTSB ERA14CA420: Mooney M20K, N231MN, Vero Beach, FL, August 23, 2014

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Data collection · Final report
- Date: August 23, 2014, 10:20 local (14:20 UTC)
- Place: Vero Beach, FL
- Coordinates: 27.651666, -80.416389 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=27.6517&lon=-80.4164&mi=10
- Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping)
- Defining event: [Standing-engine(s) start-up: Fire/smoke (non-impact)](https://openairdocs.org/ntsb-events/150)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report January 12, 2015
- Report: Approved by Office Director
- NTSB office: Eastern Region Aviation
- Parties: FAA/FSDO
- NTSB case key (mKey): 89998
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA14CA420
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/89998/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=89998
- Page: https://openairdocs.org/ntsb/ERA14CA420

## Probable cause

The failure of the pilot and personnel from the fixed base operator to assure the correct ground power unit was utilized to provide external power, resulting in damage to the aircraft's electrical wiring and subsequent damage to structure adjacent to the aircraft's battery.

## Findings

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

- [Electrical power system: dC power distribution system](https://openairdocs.org/ntsb-findings/01022460): Aircraft › Aircraft systems · Incorrect service/maintenance (probable cause); cases with it: [Mooney M20K, 1 case](https://openairdocs.org/ntsb-findings/01022460/cases.md?model=5870220), [All aircraft, 13 cases](https://openairdocs.org/ntsb-findings/01022460/cases.md)
- [Personnel issues](https://openairdocs.org/ntsb-findings/02060000): Personnel issues › Task performance · Other (probable cause); cases with it: [Mooney M20K, 1 case](https://openairdocs.org/ntsb-findings/02060000/cases.md?model=5870220), [All aircraft, 137 cases](https://openairdocs.org/ntsb-findings/02060000/cases.md)
- [Planning/preparation](https://openairdocs.org/ntsb-findings/02061000): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Mooney M20K, 2 cases](https://openairdocs.org/ntsb-findings/02061000/cases.md?model=5870220), [All aircraft, 113 cases](https://openairdocs.org/ntsb-findings/02061000/cases.md)

## Sequence of events

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

- [Standing-engine(s) start-up: Fire/smoke (non-impact)](https://openairdocs.org/ntsb-events/150) (defining event); cases with it: [Mooney M20K, 1 case](https://openairdocs.org/ntsb-events/150/sequence.md?model=5870220), [All aircraft, 504 cases](https://openairdocs.org/ntsb-events/150/sequence.md)

## Analysis

The pilot stated that when attempting the start the engine for an intended flight, the batteries were dead. As a result he asked the fixed base operator (FBO) for an external power cart to provide an external power source for his aircraft, which was a 12 volt system. He completed a waiver, but indicated he did not recall having a conversation with personnel of the FBO about the aircraft voltage requirement. Personnel of the FBO indicated the external power cart they used has a minimum voltage of 28 volts, and they asked the pilot if his aircraft's electrical system was 28 volts, to which he replied yes. A passenger remained outside the airplane, while the pilot was inside the airplane and a ground power unit (GPU) with a minimum of 28 volts was connected to the external power receptacle. The pilot indicated that he told the line service person to turn on power and he noticed that the alternator circuit breaker tripped. An individual from the (FBO) heard a bang and saw smoke coming from the airplane. The passenger who was outside the airplane later told the pilot that the line service person was frozen, but he was able to disconnect the (GPU) from the airplane, and in doing so noted arcing. The pilot reported that he saw smoke at the rear of the airplane, and the passenger who was outside the airplane reported that when he came off the wing an explosion occurred and fire and smoke was coming from the top of the airplane. The pilot exited the airplane and using a fire extinguisher from it, extinguished the fire. Fire department personnel responded however the fire had been extinguished before their arrival. Postaccident inspection of the airframe revealed structural damage above a battery. Following the accident, the (FBO) added a line to their liability release indicating, "Aircraft voltage system is _____________ volts."

## Factual narrative

The pilot stated that when attempting the start the engine for an intended flight, the batteries were dead. As a result he asked the fixed base operator (FBO) for an external power cart to provide an external power source for his aircraft, which was a 12 volt system. He completed a waiver, but indicated he did not recall having a conversation with personnel of the FBO about the aircraft voltage requirement. Personnel of the FBO indicated the external power cart they used has a minimum voltage of 28 volts, and they asked the pilot if his aircraft's electrical system was 28 volts, to which he replied yes. A passenger remained outside the airplane, while the pilot was inside the airplane and a ground power unit (GPU) with a minimum of 28 volts was connected to the external power receptacle. The pilot indicated that he told the line service person to turn on power and he noticed that the alternator circuit breaker tripped. An individual from the (FBO) heard a bang and saw smoke coming from the airplane. The passenger who was outside the airplane later told the pilot that the line service person was frozen, but he was able to disconnect the (GPU) from the airplane, and in doing so noted arcing. The pilot reported that he saw smoke at the rear of the airplane, and the passenger who was outside the airplane reported that when he came off the wing an explosion occurred and fire and smoke was coming from the top of the airplane. The pilot exited the airplane and using a fire extinguisher from it, extinguished the fire. Fire department personnel responded however the fire had been extinguished before their arrival. Postaccident inspection of the airframe revealed structural damage above a battery. Following the accident, the (FBO) added a line to their liability release indicating, "Aircraft voltage system is _____________ volts."

## Aircraft

- Registration: [N231MN](https://openairdocs.org/aircraft/N231MN), registered now, S/N 25-0717 (OpenAirDocs)
- Reported make and model: MOONEY AIRCRAFT CORP. M20K
- Registry model: [Mooney M20K](https://openairdocs.org/model/mooney-m20k) (registry code 5870220) (OpenAirDocs)
- Registry engine: [Continental TSIO-360 series](https://openairdocs.org/engine/continental-tsio-360-series) (registry code 17019, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 25-0717
- Year built: 1982
- Airframe hours: 3160.4
- Engines: CONT MOTOR TSIO-520 305 horsepower reciprocating
- Damage: Substantial damage
- Fire: On-Ground
- Flight: Personal, Part 91
- Operator: Surgical Pain Consulting LLC
- Registered owner: Surgical Pain Consulting LLC
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, August 1, 2014, 2 hours before
- Departed: VRB, Vero Beach, FL
- Destination: SUA, Stuart, FL
- Airport: VRB, Vero Beach Municipal

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; injuries: none; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review October 26, 2012; seat: left; restraint: 3-point; flight hours: 673.4 total, 351.7 in this make and model, 633.4 as pilot in command, 7.3 in the last 90 days, 1.8 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 260° at 5 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 84 °F, dew point 73 °F
- Altimeter: 29.98 inHg
- Observed at: VRB

## 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 20140823021679A](https://openairdocs.org/incident/20140823021679A), Aug 23, 2014: Mooney Aircraft Corp. M20K, Vero Beach, FL, Substantial damage. Attemped to start aircraft with gpu set at the wrong voltage. Line crew said they could not determine the current setting voltmeter was inop.

## Docket (7 files)

The files NTSB released with the investigation on December 17, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=89998. 11.4 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40420135&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Weather Report and Record (item 2, .PDF, 101 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40420136&FileExtension=.PDF&FileName=Weather%20Report%20and%20Record-Master.PDF
- Record of Conversations (item 3, .PDF, 89 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40420137&FileExtension=.PDF&FileName=Record%20of%20Conversations-Redacted.PDF
- Documents from Sun Aviation, Inc. (item 4, .PDF, 107 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40420138&FileExtension=.PDF&FileName=Documents%20from%20Sun%20Aviation,%20Inc.-Redacted.PDF
- Photo 1 - External Power Receptacle (Photo Courtesy of Insurance Adjuster) (item 5, .PDF, 2.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40420139&FileExtension=.PDF&FileName=Photo%201%20-%20External%20Power%20Receptacle%20(Photo%20Courtesy%20of%20Insurance%20Adjuster)-Master.PDF
- Photo 2 - Electrical Wiring (Photo Courtesy of Insurance Adjuster) (item 6, .PDF, 3.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40420140&FileExtension=.PDF&FileName=Photo%202%20-%20Electrical%20Wiring%20(Photo%20Courtesy%20of%20Insurance%20Adjuster)-Master.PDF
- Photo 3 - Airframe Adjacent to Battery (Photo Courtesy of Insurance Adjuster) (item 7, .PDF, 4.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40420141&FileExtension=.PDF&FileName=Photo%203%20-%20Airframe%20Adjacent%20to%20Battery%20(Photo%20Courtesy%20of%20Insurance%20Adjuster)-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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