# NTSB ERA10LA504: Aeronca 11AC, N85929, Mocksville, NC, August 28, 2010

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: August 28, 2010, 12:00 local (16:00 UTC)
- Place: Mocksville, NC
- Coordinates: 35.914722, -80.456665 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.9147&lon=-80.4567&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Defining event: [Approach-VFR pattern downwind: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report June 20, 2011
- Report: Approved by Office Director
- NTSB office: Eastern Region Aviation
- Parties: FAA/FSDO
- NTSB case key (mKey): 77419
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA10LA504
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/77419/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=77419
- Page: https://openairdocs.org/ntsb/ERA10LA504

## Probable cause

The pilot’s failure to attain the proper touchdown point, following a loss of engine power due to carburetor icing.

## Findings

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

- [Temp/humidity/pressure: conducive to carburetor icing](https://openairdocs.org/ntsb-findings/03031030): Environmental issues › Conditions/weather/phenomena · Effect on equipment (probable cause); cases with it: [Aeronca 11AC, 5 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md?model=0191102), [All aircraft, 435 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md)
- [Action: incorrect action performance](https://openairdocs.org/ntsb-findings/02041015): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Aeronca 11AC, 2 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md?model=0191102), [All aircraft, 1,386 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md)

## Sequence of events

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

- [Approach-VFR pattern downwind: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Aeronca 11AC, 4 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=0191102), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)
- [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Aeronca 11AC, 5 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=0191102), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)
- [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Aeronca 11AC, 13 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=0191102), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md)
- [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Aeronca 11AC, 7 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=0191102), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md)

## Analysis

The pilot reported that the airplane was on the downwind leg of the traffic pattern, when it experienced a complete loss of engine power. He was able to glide the airplane onto the runway; however, he subsequently realized that he would not be able to stop before the end of the runway, and elected to turn right into bushes, rather than encounter the down-sloping terrain located beyond the runway. The airplane contacted the bushes, and flipped over, prior to coming to rest, which resulted in substantial damage to the right wing, fuselage, and empennage. A postaccident examination of the airplane and engine did not reveal any mechanical malfunctions which would have resulted in a loss of engine power. The pilot stated that he believed the loss of engine power was due to carburetor icing, and that he had applied carburetor heat, just prior to the loss of engine power. Review of a carburetor icing envelope chart revealed that the temperature and dew point reported at an airport located about 11 miles southeast of the accident site, at the time of the accident, was within the "serious icing (glide power)" area of the chart.

## Factual narrative

On August 28, 2010, about 1200 eastern daylight time, an Aeronca 11AC, N85929, operated by a private pilot, was substantially damaged during a forced landing, after experiencing a loss of engine power during approach to the Twin Lakes Airport (8A7), Mocksville, North Carolina. The certificated private pilot was not injured. Visual meteorological conditions prevailed and no flight plan had been filed for the personal flight that was conducted under the provisions of 14 Code of Federal Regulations Part 91. According to pilot, the airplane was on the downwind leg of the traffic pattern for runway 27, a 2,943-foot-long, 50-foot-wide, asphalt runway, at an altitude of 1,000 feet above ground level, when it experienced a complete loss of engine power. The pilot made an immediate turn toward the runway to ensure that the airplane would clear an area of tall trees. The pilot was able to glide the airplane onto the runway; however, he subsequently realized that he would not be able to stop before the end of the runway. The terrain beyond the runway sloped downward steeply and he elected to turn into bushes located off the right side of the runway. The airplane contacted the bushes, and flipped over, prior to coming to rest, which resulted in substantial damage to the right wing, fuselage, and empennage. Examination of the airplane by a Federal Aviation Administration (FAA) inspector did not reveal any preimpact malfunctions. The pilot stated that he believed that the loss of engine power was due to carburetor icing, and that he had applied carburetor heat, just prior to the loss of engine power. According to FAA records, the airplane was manufactured in 1946 and equipped with a Teledyne Continental Motors A-65-8 series, 65-horsepower engine. It had been operated for about 10 hours, since its most recent annual inspection, which was performed on March 20, 2010. The reported weather at an airport located about 11 miles southeast of the accident site, at 1159, was: wind calm; visibility 10 statute miles; scattered clouds at 3,200 feet; temperature 28 degrees Celsius (C); dew point 19 degrees C; altimeter 30.22 inches of mercury. Review of an FAA carburetor icing envelope chart revealed that the reported temperature and dew point at the time of the accident was within the "serious icing (glide power)" area of the chart.

## Aircraft

- Registration: [N85929](https://openairdocs.org/aircraft/N85929), registered now, S/N 11AC-349 (OpenAirDocs)
- Reported make and model: AERONCA 11AC
- Registry model: [Aeronca 11AC](https://openairdocs.org/model/aeronca-11ac) (registry code 0191102) (OpenAirDocs)
- Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs)
- Category: Airplane
- Serial number: 11AC-349
- Airframe hours: 1085
- Engines: TCM A-65-8 65 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, March 20, 2010, 10 hours before
- Departed: 8A7, Mocksville, NC
- Destination: 8A7, Mocksville, NC
- Airport: 8A7, Twin Lakes, runway 09, 2,943 × 50 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 60; injuries: none; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review February 14, 2009; seat: left; flight hours: 327 total, 220 in this make and model, 327 as pilot in command, 4 in the last 90 days, 4 in the last 30 days, 0 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 82 °F, dew point 66 °F
- Altimeter: 30.21 inHg
- Observed at: EXX, 11 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 20100828049799A](https://openairdocs.org/incident/20100828049799A), Aug 28, 2010: Aeronca 11AC, Mocksville, NC, Substantial damage. Pilot states his engine quit at the 180 degree position downwind of runway 27 at Twin Lakes (8A7). Pilot elected to use carb heat just before this event…

## Docket (4 files)

The files NTSB released with the investigation on May 9, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=77419. 1.1 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 757 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40344581&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Personell Statements (item 2, .PDF, 113 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40344729&FileExtension=.PDF&FileName=Personell%20Statements-Redacted.PDF
- Weather Observations (item 3, .PDF, 22 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40344728&FileExtension=.PDF&FileName=Weather%20Observations-Master.PDF
- FAA Carburetor Icing Envelope (item 4, .PDF, 253 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40344730&FileExtension=.PDF&FileName=FAA%20Carburetor%20Icing%20Envelope-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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