# NTSB CEN12LA389: Hoyle Fighter Escort Wings, N2051P, Pueblo, CO, June 23, 2012 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 23, 2012, 08:30 local (14:30 UTC) - Place: Pueblo, CO - Coordinates: 38.289165, -104.496391 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.2892&lon=-104.4964&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Electrical system malf/failure](https://openairdocs.org/ntsb-events/332) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 13, 2012 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Federal Aviation Administration - Denver FSDO - NTSB case key (mKey): 84069 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN12LA389 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/84069/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=84069 - Page: https://openairdocs.org/ntsb/CEN12LA389 ## Probable cause An internal failure of one of the electrical system’s two batteries combined with the inadequate electrical system design, which resulted in a total loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Electrical power system: battery/charger](https://openairdocs.org/ntsb-findings/01022432): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Hoyle Clifford L FIGHTER ESCORT WINGS, 1 case](https://openairdocs.org/ntsb-findings/01022432/cases.md?model=05630TB), [All aircraft, 37 cases](https://openairdocs.org/ntsb-findings/01022432/cases.md) - [Electrical power system: dC power distribution system](https://openairdocs.org/ntsb-findings/01022460): Aircraft › Aircraft systems · Design (probable cause); cases with it: [Hoyle Clifford L FIGHTER ESCORT WINGS, 1 case](https://openairdocs.org/ntsb-findings/01022460/cases.md?model=05630TB), [All aircraft, 13 cases](https://openairdocs.org/ntsb-findings/01022460/cases.md) - [Landing gear system: gear extension and retract sys](https://openairdocs.org/ntsb-findings/01023230): Aircraft › Aircraft systems · Not used/operated; cases with it: [Hoyle Clifford L FIGHTER ESCORT WINGS, 1 case](https://openairdocs.org/ntsb-findings/01023230/cases.md?model=05630TB), [All aircraft, 416 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Electrical system malf/failure](https://openairdocs.org/ntsb-events/332) (defining event); cases with it: [Hoyle Clifford L FIGHTER ESCORT WINGS, 1 case](https://openairdocs.org/ntsb-events/332/sequence.md?model=05630TB), [All aircraft, 182 cases](https://openairdocs.org/ntsb-events/332/sequence.md) - [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Hoyle Clifford L FIGHTER ESCORT WINGS, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=05630TB), [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: [Hoyle Clifford L FIGHTER ESCORT WINGS, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=05630TB), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Landing gear not configured](https://openairdocs.org/ntsb-events/095); cases with it: [Hoyle Clifford L FIGHTER ESCORT WINGS, 1 case](https://openairdocs.org/ntsb-events/095/sequence.md?model=05630TB), [All aircraft, 584 cases](https://openairdocs.org/ntsb-events/095/sequence.md) ## Analysis The pilot reported that there was an electrical system failure during the cruise portion of the test flight, which resulted in insufficient voltage to maintain engine operation using either the primary or secondary battery circuits. Following the total loss of engine power, the pilot elected to perform a wheels-up landing on a gravel road. The non-certificated automobile engine that was installed in the airplane was equipped with a computer-controlled electronic ignition system and high-pressure fuel pumps. According to the pilot/builder, the airplane incorporated two 12-volt batteries wired in parallel to supply voltage to the main power bus to power the engine systems. Postaccident examination revealed that the primary battery had an internal short and would not take a charge. The secondary battery was found below normal service voltage, but could be recharged. Postaccident testing revealed that the two batteries were not isolated from each other; as a result, an internal short of one of the two batteries could drain the other battery’s charge. No anomalies were found with the remaining electrical system components or wiring paths. ## Factual narrative On June 23, 2012, at 0830 mountain daylight time, an experimental amateur-built Hoyle model Fighter Escort Wings airplane, N2051P, was substantially damaged during a forced landing near Pueblo, Colorado. The commercial pilot was not injured. The airplane was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91. Day visual meteorological conditions prevailed for test flight, which was operated without a flight plan. The local area flight departed Pueblo Memorial Airport (KPUB), Pueblo, Colorado about 0810. The accident occurred during a phase-one test flight of the 2/3 scale P-51 Mustang airplane replica. The pilot reported that there was an electrical system failure during cruise flight, which resulted in insufficient voltage to maintain engine operation using the primary or secondary battery circuits. Following the total loss of engine power, the pilot elected to perform a wheels-up landing on a gravel road, during which the airplane was substantially damaged. The non-certificated engine, a 350-horsepower Chevrolet model LS1 automobile engine, serial number 12550592, was equipped with a computer-controlled electronic ignition system and high-pressure fuel pumps. According to the pilot/builder, the airplane incorporated two 12-volt batteries wired in parallel to supply voltage to the main power bus. A postaccident examination revealed that the primary battery had an internal short and would not take a charge. The secondary battery was found below normal service voltage, but was able to be recharged. No anomalies were found with remaining electrical system components or wiring paths. The alternator functioned as designed during a bench test. The two battery circuits were protected by contactors and bridge diodes on the main power bus; however, postaccident testing revealed that they were not isolated from each other, and as such, an internal short of one of the two batteries could draw-down the charge of the other battery. The closest weather observing station was at KPUB, located about 8 miles north of the accident site. At 0853, the KPUB automated surface observing system reported the following weather conditions: wind 220 degrees at 3 knots; visibility 10 miles; clear sky conditions; temperature 29 degrees Celsius; dew point -2 degrees Celsius; altimeter setting 29.91 inches of mercury. ## Aircraft - Registration: [N2051P](https://openairdocs.org/aircraft/N2051P), registered now, S/N T-035 (OpenAirDocs) - Reported make and model: Hoyle Fighter Escort Wings - Registry model: [Hoyle Clifford L FIGHTER ESCORT WINGS](https://openairdocs.org/model/hoyle-clifford-l-fighter-escort-wings) (registry code 05630TB) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: T-035 - Airframe hours: 12 - Engines: Chevrolet LS1 350 horsepower reciprocating - Damage: Substantial damage - Flight: Flight test, Part 91 - Operator: Clifford L. Hoyle - Registered owner: Clifford L. Hoyle - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, May 30, 2012 - Departed: KPUB, Pueblo, CO - Destination: KPUB, Pueblo, CO ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 73; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review January 23, 2012; seat: single; flight hours: 1,985 total, 12 in this make and model, 1,850 as pilot in command, 11 in the last 90 days, 8 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 220° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 84 °F, dew point 28 °F - Altimeter: 29.90 inHg - Observed at: KPUB, 8 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 20120623010669A](https://openairdocs.org/incident/20120623010669A), Jun 23, 2012: Hoyle Clifford L FIGHTER ESCORT WINGS, Avondale, CO, Substantial damage. At 0830 local in the [privacy data omitted] road in Avondale, Colorado in VMC N2051 experimental aircraft, fighter escort wing, experienced substantial damage… ## Docket (3 files) The files NTSB released with the investigation on July 6, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=84069. 1.1 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 840 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372077&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Summary of Postaccident Examination and Testing (item 2, .PDF, 92 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372078&FileExtension=.PDF&FileName=Summary%20of%20Postaccident%20Examination%20and%20Testing-Redacted.PDF - Weather Reports (item 3, .PDF, 126 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372079&FileExtension=.PDF&FileName=Weather%20Reports-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. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.