CEN21LA338

NTSB accident investigation · Aeronca 7AC · Harrah, OK · July 23, 2021

Accident · Minor injuriesClass 3 · LimitedFinal report
Date
July 23, 2021, 15:20 local (20:20 UTC)
Place
Harrah, OK
Injuries
2 minor
Damage
Substantial damage
Phase of flight
Initial climb
Aircraft
N83365Aeronca 7AC
Defining event
Initial climb: Fuel related
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Central Region
Parties
Federal Aviation Administration
FAA report
20210723020409A
Case key
103559

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 decision to fly the airplane without a carburetor heat control in atmospheric conditions conducive to the development of serious carburetor icing, which resulted in a partial loss of engine power.

Findings · 3

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 7AC: 5 casesAll aircraft: 435 casesProbable cause
Engine fuel and control: fuel control/carburetorAircraft › Aircraft power plant · Damaged/degradedAeronca 7AC: 1 caseAll aircraft: 195 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 and pilot-rated-passenger departed in an airplane that did not have a carburetor heat control installed. After takeoff, the engine surged several times and then lost partial power. The pilot completed a forced landing to a field and nosed over; the airplane sustained substantial damage to the horizontal stabilizer and rudder. The atmospheric conditions at the time of the accident were conducive to the development of serious carburetor icing at glide and cruise power. Given the available evidence, it is likely that carburetor ice accumulated during the flight and resulted in a loss of engine power. It is likely that use of carburetor heat would have prevented the accident.

Factual narrative

On July 23, 2021, about 1520 central daylight time, an Aeronca 7AC airplane, N83365, was substantially damaged when it was involved in an accident near Harrah, Oklahoma. The pilot and pilot-rated-passenger sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The pilot-rated-passenger stated that, during the preflight inspection, he and the pilot noted that the carburetor heat control was not installed. They completed a short ground taxi and engine runup with no anomalies noted. Shortly after takeoff, the engine rpm surged then decreased such that the airplane was unable to maintain altitude. The pilot made a forced landing to a field and the airplane nosed over. The passenger reported that he had experienced carburetor ice many times in the past and believed that the loss of engine power was the result of carburetor ice. The pilot, who was also the airplane owner, stated that, about 150 ft above ground level after takeoff, the airplane was sluggish and the engine surged between 2,000 and 2,400 rpm, then experienced a loss of power. They made a forced landing to a field of tall grass and soft soil and the airplane nosed over. The pilot reported that there were no mechanical malfunctions or anomalies that would have precluded normal operation. The pilot provided photos that showed substantial damage to the horizontal stabilizer and rudder. The atmospheric conditions at the time of the accident were conducive to the development of serious carburetor icing at glide and cruise power. Postaccident photos of the airplane revealed that the carburetor heat control was missing.

Aircraft

Registration
N83365
Reported as
Aeronca 7AC
Category
Airplane
Serial number
7AC-2032
Built
1946
Airframe hours
4,240
Engine
Cont Motor O-200, 65 horsepower, reciprocating
Damage
Substantial damage
Flight
Instructional · Part 91
Registered owner
Jonathan Wise & Associates Inc
Airworthiness certificate
Standard, Normal
Last inspection
Annual · July 23, 2021
Airport
1OL2 · Steciak Strip, runway 17/35, 2,375 × 60 ft, grass/turf

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 · 2

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
65
Injuries
Minor
Certificates
Commercial, Flight instructor
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 2, Waiver time limited special
Last flight review
August 1, 2021
Seat
Rear
Restraint
Lap only
Flight hours
2,475 total · 165 in this make and model · 2,242 as pilot in command · 130 in the last 90 days · 40 in the last 30 days · 0 in the last 24 hours
Role
Pilot-rated passenger
Injuries
Minor
Airplane ratings
Single-engine land
Seat
Front
Restraint
Lap only

Weather

Conditions
Visual (VMC) · Day
Wind
180° at 12 knots
Visibility
10 statute miles
Temperature
90 °F, dew point 68 °F
Altimeter
30.05 inHg
Observed at
KSNL, 14 nm away
METAR
METAR KSNL 232115Z AUTO 18012KT 10SM SCT040 SCT049 SCT060 32/20 A3005 RMK AO2 T03230199=

Docket · 3

The files NTSB released with the investigation on November 7, 2022, on NTSB’s docket system: statements, records, photos and specialists’ reports. 12.8 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.

Other investigations on N83365 · 1

Matched to the same aircraft by N-number and date.