CEN21LA047

NTSB accident investigation · Ercoupe 415 · Ardmore, OK · November 7, 2020

Accident · Serious injuriesClass 3 · LimitedFinal report
Date
November 7, 2020, 08:30 local (14:30 UTC)
Place
Ardmore, OK · 506 Concord Road, Ardmore, OK
Injuries
1 serious, 2 minor
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N331BWErcoupe 415
Defining event
Maneuvering-low-alt flying: Loss of engine power (partial)
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Central Region
Parties
FAA Will Rogers FSDO
FAA report
20201107021689A
Case key
102256

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

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Probable cause

The pilot’s improper decision to takeoff with 3 persons in a 2-place airplane and over maximum gross weight, and his failure to apply carburetor heat when the airplane’s engine experienced carburetor ice and a partial loss of 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.

Use of equip/info: use of equip/systemPersonnel issues › Task performance · PilotErcoupe 415-C: 2 casesAll aircraft: 1,391 casesProbable cause
Engine (reciprocating)Aircraft › Aircraft power plant · FailureErcoupe 415-C: 2 casesAll aircraft: 497 casesProbable cause
Temp/humidity/pressure: conducive to carburetor icingEnvironmental issues › Conditions/weather/phenomena · Effect on equipmentErcoupe 415-C: 1 caseAll aircraft: 435 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 performing a local flight with two passengers onboard the two-seat airplane. After flying two passes over a house, the pilot felt a “slight shudder” and thought the airplane had flown through its own propeller wash. The engine then started to vibrate, and the pilot was not able to control the vibration by adjusting the throttle. The pilot set the airplane up in a glide configuration at which time the airplane banked to the left. The pilot applied full right aileron control, but it did not stop the left turn. The pilot was attempting to land the airplane in a field when it contacted a tree and came to rest inverted. A postaccident examination revealed no preimpact mechanical malfunctions or failures with the airframe, including the flight controls, and engine that would have precluded normal operation. It was determined that the airplane was 48 pounds over its maximum gross weight when the pilot started the engine. A review of local area meteorological data showed that at the time of the accident, the airplane was likely operating in conditions conducive to the formation of serious icing conditions (at cruise power). The pilot reported he did not apply the carburetor heat when the engine began to lose power. It is likely the engine sustained a partial loss of engine power in flight due to the formation of carburetor icing, which resulted in the attempted forced landing.

Factual narrative

On November 7, 2020, about 0830 central standard time, an ERCO Ercoupe 415-C airplane, N331BW, sustained substantial damage when it was involved in an accident near Ardmore, Oklahoma. The commercial pilot sustained serious injuries and the two passengers sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The purpose of the flight was for the pilot to take the two passengers in the two-seat airplane on a local flight to photograph a home. The pilot reported the airplane departed with a full fuel load. The pilot was in the left seat while the two passengers shared the right seat . Both seats were equipped with lap belts. After the completing two passes by the house, the pilot felt a “slight shudder” and he announced to the passengers that he thought they were flying through the airplane’s own propeller wash. Immediately after that, the engine started “vibrating so bad” that the pilot thought the engine was going to separate from the airframe. The pilot attempted to control the vibration by adjusting the throttle to no avail. He did not apply carburetor heat. The pilot then set the airplane up in a glide configuration at which time the airplane banked to the left. The pilot applied full right aileron control, but it did not stop the left turn. The pilot was attempting to land the airplane in a field when it contacted a tree and came to rest inverted. The airplane sustained substantial damage to the fuselage, both wings, and the empennage. A postaccident examination of the engine and airframe, including the flight controls, revealed no preimpact mechanical malfunctions or failures with the airframe and engine that would have precluded normal operation. A review of local area meteorological data showed that at the time of the accident, the airplane was likely operating in conditions conducive to the formation of serious icing conditions (at cruise power) per the Federal Aviation Administration (FAA) Special Airworthiness Information Bulletin CE-09-35 Carburetor Icing Prevention. A review of weight and balance data showed that the airplane was 48 pounds over the maximum weight at the time of engine start. According to ERCO Ercoupe Information Letter Number 2, the model 415-C does not employ a flight manual, and none is available. According to FAA Type Certificate Data Sheet A-718 for the airplane, it is limited to two seats, but the data sheet does not address the topic of two passengers sharing a single seat together. The FAA has issued a clarification on the interpretation of the seat belt and seating requirements for general aviation flights and states in part: This clarification states that the use of a seat belt and/or seat by more than one occupant is permitted only if the seat usage conforms to the limitations contained in the approved portion of the Airplane Flight Manual (AFM). In addition, before multiple occupants use the same seat and/or seat belt, if the pertinentinformation is available, the pilot in command (PIC) must also check whether: The seat belt is approved and rated for such use; and the structural strength requirements for the seat are not exceeded. This clarification also emphasizes that, because it is safer for each individual person to have his or her own seat and seat belt, whenever possible, each person onboard an aircraft should voluntarily be seated in a separate seat and be restrained by a separate seat belt.

Aircraft

Registration
N331BW
Reported as
Ercoupe 415 (C)
Category
Airplane
Serial number
2091
Built
1946
Airframe hours
1,881.07
Engine
Continental Motors C-85-12, 85 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Airworthiness certificate
Standard, Normal
Last inspection
Annual · October 29, 2020 · 2.72 hours before
Departed
1FO · Ardmore, OK
Equipment
Handheld GPS

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
78
Injuries
Serious
Certificates
Sport Pilot, Commercial
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane, Helicopter
Last flight review
April 23, 2019
Seat
Left
Restraint
Lap only
Flight hours
2,405 total · 255 in this make and model · 1,992 as pilot in command · 8.4 in the last 90 days · 3.8 in the last 30 days · 0.5 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
140° at 3 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
55 °F, dew point 52 °F
Altimeter
30.13 inHg
Observed at
K1F0, 3 nm away
METAR
K1F0 071415Z AUTO 14003KT 10SM CLR 13/11 A3013 RMK AO2 T01300111

Docket · 4

The files NTSB released with the investigation on June 6, 2022, on NTSB’s docket system: statements, records, photos and specialists’ reports. 28.1 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.