ERA20LA295

NTSB accident investigation · Aeronca 11AC · Nebo, NC · August 22, 2020

Accident · No injuriesClass 3 · LimitedFinal report
Date
August 22, 2020, 17:35 local (21:35 UTC)
Place
Nebo, NC
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N86002Aeronca 11AC
Defining event
Enroute: Fuel related
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Eastern Region Aviation
Parties
FAA/FSDO
FAA report
20200822013149A
Case key
101847

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

A leak in the main fuel tank that resulted in a total loss of engine power due to fuel starvation.

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.

Fluids: fuelAircraft › Fluids/misc hardware · Fluid levelAeronca 11AC: 4 casesAll aircraft: 1,695 casesProbable cause
Fuel system: fuel storageAircraft › Aircraft systems · FailureAeronca 11AC: 1 caseAll aircraft: 60 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 was hired to transport the airplane to another state. Prior to departure, both the main and auxiliary fuel tanks were topped with fuel (minus 1 gallon) and the pilot departed using fuel from just the main tank. About 45 minutes into the flight, the engine began to run rough, and the pilot reported smelling a strong odor of fuel in the cockpit. The pilot was unable to maintain altitude and performed a forced landing to a highway. The airplane was substantially damaged during the landing. Postaccident examination of the airplane’s fuel system revealed the main tank, which was gravity-fed from the aft fuel tank, was intact and empty of fuel. About 3.5 gallons of fuel was emptied from the aft tank. When fuel was added to the main tank, fuel was immediately observed to be leaking from the lower left-hand seam of the tank. Blue fuel stains were also observed around the area of the leak. The accident is consistent with the engine losing power due to fuel starvation as a result of a leak in the main fuel tank.

Factual narrative

On August 22, 2020, about 1735 eastern daylight time, N86602, an Aeronca 11AC airplane, was substantially damaged when it was involved in an accident near Nebo, North Carolina. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot was hired to transport the airplane to another state. In preparation for the long flight, he topped the main and auxiliary fuel tanks with fuel (though a gallon of fuel was spilled in the overall fueling process). He then departed utilizing fuel from the 15-gallon main tank. About 45 minutes into the flight, the engine began to run rough, and the pilot said he could smell a strong odor of fuel in the cockpit. He applied carburetor heat and pumped the throttle several times, but to no avail. The pilot was unable to maintain altitude and made a forced landing to a busy highway, during which time the engine lost total power. After the airplane touched down on the highway it impacted a guardrail resulting in substantial damage to the airframe. Examination of the airplane’s fuel system revealed the main fuel tank was intact and empty of fuel and about 3.5 gallons of fuel was drained from the aft tank. The fuel system was configured so that the aft fuel tank gravity fed to the forward tank through the cockpit fuel selector valve. The forward tank fed directly to the engine without flowing through the fuel selector valve. Therefore, when the fuel selector valve was placed to the ON position, it allowed fuel to flow from the aft tank to the forward tank by gravity. The inside of the main tank, which was located between the cockpit and engine firewall, was visually inspected with a flashlight, and no obvious anomalies were noted. The fuel finger screen was clean. Fuel was added to the tank to check for leaks. A considerable fuel leak was immediately observed at the lower left-hand seam of the tank. Blue fuel stains were also observed around the area of the leak. Examination of the rest of the fuel system revealed no anomalies that would have precluded normal operation.

Aircraft

Registration
N86002
Reported as
Aeronca 11AC (No Series)
Category
Airplane
Serial number
11AC-421
Built
1946
Airframe hours
2,054
Engine
Continental Motors A65-8, 65 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Airworthiness certificate
Standard, Normal
Last inspection
Annual · May 3, 2020
Departed
SVH · Statesville, NC
Destination
GLY · Clinton, MO
Equipment
Unknown

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
Minor
Certificates
Flight instructor, Commercial
Airplane ratings
Single-engine sea, Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 2, Without waivers/limitations
Last flight review
February 21, 2020
Seat
Left
Flight hours
3,500 total · 5 in this make and model · 3,000 as pilot in command · 60 in the last 90 days · 20 in the last 30 days · 5 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
180° at 6 knots
Visibility
10 statute miles
Temperature
84 °F, dew point 68 °F
Altimeter
30.04 inHg
Observed at
MRN, 20 nm away

Docket · 6

The files NTSB released with the investigation on September 15, 2022, on NTSB’s docket system: statements, records, photos and specialists’ reports. 68.3 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.