# NTSB ANC83IA053: Cessna 401, N7864F, Bethel, AK, March 6, 1983

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: March 5, 1983, 20:00 local (Mar 6, 1983, 00:00 UTC)
- Place: Bethel, AK
- Coordinates: 60.809894, -161.850311 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=60.8099&lon=-161.8503&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 6 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 4082
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC83IA053
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/4082/pdf
- Page: https://openairdocs.org/ntsb/ANC83IA053

## Sequence of events

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

- Fire, cruise - normal
  - exhaust system,clamp - disconnected (cause)
  - aircraft preflight - inadequate, pilot in command (cause)
  - exhaust system,turbocharger - improper (cause)
  - maintenance,inspection - inadequate, other maintenance personnel (cause)

## Analysis

THE ACFT RIGHT ENGINE STARTED EMITTING SPARKS FROM THE COWLING DURING NORMAL CRUISE. THE PILOT NOTED A DROP IN MANIFOLD PRESSURE SO HE REDUCED POWER ON THAT ENGINE AND THE SPARKS STOPPED. THE ACFT WAS LANDED AT BETHEL. THE FIRE DEPT. USED A FIRE EXTINGUISHING AGENT ON THE ENGINE. THE DAMAGE WAS MINOR. INSPECTION OF THE RIGHT ENGINE REVEALED A BROKEN BOLT ONTHE EXHAUST CLAMP WHICH SECURED THE EXHAUST PIPE TO THE TURBOCHARGER. THE CLAMP WHICH SECURED THE PIPE TO THE ENGINE NACELLE HAD SLIPPED OFF THE BRACKET. THIS ALLOWED THE PIPE TO SLIP DOWN AND RELEASE HOT EXHAUST GASES INTO THE ENGINE NACELLE. THIS HEATED THE ENGINE EXCESSIVELY AND REMOVED THE WASTE GATE FROM THE OPERATIONAL SYSTEM OF THE ENGINE. THE BROKEN BOLT IS A PART OF THE CLAMP P/N MVT 68637-375M.

## Aircraft

- Registration: [N7864F](https://openairdocs.org/aircraft/N7864F), registered now, S/N 4010207, built 1968 (OpenAirDocs)
- Reported make and model: CESSNA 401
- Registry model: [Cessna 401](https://openairdocs.org/model/cessna-401) (registry code 207590C) (OpenAirDocs)
- Registry engine: [Continental TSIO-520-E](https://openairdocs.org/engine/continental-tsio-520-e) (registry code 17255, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 401-0207
- Engines: CONTINENTAL TSIO-520 300 horsepower reciprocating
- Damage: Minor damage
- Fire: In-Flight
- Flight: Business, Part 91
- Operator: Doug Bensing
- Registered owner: B.J. Matthews
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, March 1, 1982
- Departed: BET, BETHEL
- Destination: FAI, FAIRBANKS
- Flight plan: IFR
- Airport: BET, Bethel

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 29; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 1,454 total, 150 in this make and model, 1,197 as pilot in command, 79 in the last 90 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: 70° at 9 knots
- Visibility: 7 statute miles
- Lowest ceiling: 1,700 ft overcast
- Temperature: 28 °F, dew point 27 °F
- Altimeter: 29.00 inHg
- Observed at: BET

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Incident 19830305073509I](https://openairdocs.org/incident/19830305073509I), Mar 5, 1983: Cessna 401, Bethel, AK, Minor damage. Exhaust pipe slipped its securing bracket and came off the turbocharger. Caused a engine fire from the hot exhaust.

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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