ERA10LA504

NTSB accident investigation · Aeronca 11AC · Mocksville, NC · August 28, 2010

Accident · No injuriesLimited investigationFinal report
Date
August 28, 2010, 12:00 local (16:00 UTC)
Place
Mocksville, NC
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Approach
Aircraft
N85929Aeronca 11AC
Defining event
Approach-VFR pattern downwind: Loss of engine power (total)
Weather
Visual (VMC) · Day
Status
Completed · report June 20, 2011
Report
Approved by Office Director
NTSB office
Eastern Region Aviation
Parties
FAA/FSDO
FAA report
20100828049799A
Case key
77419

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

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

Findings · 2

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Temp/humidity/pressure: conducive to carburetor icingEnvironmental issues › Conditions/weather/phenomena · Effect on equipmentAeronca 11AC: 5 casesAll aircraft: 435 casesProbable cause
Action: incorrect action performancePersonnel issues › Action/decision · PilotAeronca 11AC: 2 casesAll aircraft: 1,386 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

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
Reported as
Aeronca 11AC
Category
Airplane
Serial number
11AC-349
Airframe hours
1,085
Engine
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

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
60
Injuries
None
Certificate
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

Docket · 4

The files NTSB released with the investigation on May 9, 2011, on NTSB’s docket system: statements, records, photos and specialists’ reports. 1.1 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.