# NTSB ANC89LA053: Aeronca 15AC, N4433N, Fairbanks, AK, March 16, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: March 16, 1989, 13:00 local (17:00 UTC)
- Place: Fairbanks, AK
- Coordinates: 64.809478, -147.719665 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=64.8095&lon=-147.7197&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report September 28, 1990
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5173
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC89LA053
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5173/pdf
- Page: https://openairdocs.org/ntsb/ANC89LA053

## Probable cause

THE STUDENT PILOT'S INPROPER USE OF CARBURETOR HEAT AND THE INSTRUCTORS FAILURE TO PROPERLY SUPERVISE THE STUDENT ACTIONS WITHIN THE AIRPLANE.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Loss of engine power(total) - nonmechanical, cruise
  - carburetor heat - improper use of, dual student (cause)
  - fuel system,carburetor - ice (cause)
  - supervision - inadequate, pilot in command(cfi) (cause)
  - weather condition - carburetor icing conditions
- Forced landing, descent - emergency
- Nose over, landing - roll
  - terrain condition - rough/uneven

## Analysis

THE FLIGHT INSTRUCTOR STATED THAT DURING CRUISE FLIGHT THE ENGINE BEGAN TO RUN ROUGH AND SUBSEQUENTLY QUIT. EMERG PROCEDURES WERE FOLLOWED AND THE ENG REGAINED POWER. THE THROTTLE WAS REDUCED TO 2000 RPM IN ORDER TO ALLOW FOR EXTRA TIME TO FIGURE OUT WHAT FAILED. WITH THE THROTTLE REDUCED, THE ENGINE QUITE ONCE AGAIN. THE CFI APPLIED CARB HEAT AND THE STUDENT SUBSEQUENTLY REMOVED CARB HEAT. THIS HAPPENED SEVERAL TIMES WITH SUBSEQUENT LOSSES AND GAINS IN POWER. THE POWER EVENTUALLY COULD NOT BE REGAINED AND A FORCED LANDING WAS MADE ON A FROZEN SWAMP AREA WHICH WAS COVERED BY 2 1/2 FEET OF SNOW. THE ACFT NOSED OVER DURING THE LANDING.

## Aircraft

- Registration: [N4433N](https://openairdocs.org/deregistered/N4433N-2018-03-14), registration cancelled 2018-03-14, S/N 15AC-322, built 1949 (OpenAirDocs)
- Reported make and model: AERONCA 15AC
- Registry model: [Aeronca 15AC](https://openairdocs.org/model/aeronca-15ac) (registry code 0191202) (OpenAirDocs)
- Registry engine: [Continental C145 series](https://openairdocs.org/engine/continental-c145-series) (registry code 17012, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 15AC322
- Engines: CONTINENTAL O-300 145 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Registered owner: Clester Graham
- Airworthiness certificate: Standard, Normal
- Departed: HRR, HEALY, AK
- Destination: FAI, FAIRBANKS, AK
- Flight plan: VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 28; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 560 total, 15 in this make and model, 450 as pilot in command, 10 in the last 90 days, 5 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 20° at 3 knots
- Visibility: 60 statute miles
- Lowest ceiling: none
- Temperature: 19 °F, dew point 9 °F
- Altimeter: 30.00 inHg

## 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 19890316004419A](https://openairdocs.org/incident/19890316004419A), Mar 16, 1989: Aronca STC15, Fairbanks, AK, Substantial damage. Rough engine finally quit. CFI applied carb heat several times but student kept turning it off. Crashed in swamp.

## Other investigations on N4433N (1)

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.

- [NTSB ANC04CA089](https://openairdocs.org/ntsb/ANC04CA089), Aug 7, 2004: Aeronca 15AC (N4433N), Big lake, AK, substantial damage. Probable cause: The pilot's inadequate evaluation of the weather conditions and subsequent collision with high vegetation during the initial climb after takeoff, which resulted in a collision with the ground.…

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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