# NTSB ANC90LA104: Cessna 170B, N8054A, Anchorage, AK, June 30, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: June 30, 1990, 13:05 local (21:05 UTC)
- Place: Anchorage, AK
- Coordinates: 69.219619, -146.790756 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=69.2196&lon=-146.7908&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report February 22, 1994
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5394
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC90LA104
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5394/pdf
- Page: https://openairdocs.org/ntsb/ANC90LA104

## Probable cause

A POWER LOSS DUE TO A FATIGUE FAILURE OF THE #5 EXHAUST ROCKER ARM.

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, cruise - normal
  - engine assembly,rocker arm/tappet - fatigue (cause)
- Forced landing, descent - emergency
- Nose over, landing - roll

## Analysis

THE PILOT REPORTED A LOSS OF ENGINE POWER AND A SUBSEQUENT FORCED LANDING. INVESTIGATION REVEALED THAT THE #5 EXHAUST ROCKER ARM HAD FAILED DUE TO FATIGUE.

## Aircraft

- Registration: [N8054A](https://openairdocs.org/aircraft/N8054A), registered now, S/N 20906, built 1952 (OpenAirDocs)
- Reported make and model: CESSNA 170B
- Registry model: [Cessna 170B](https://openairdocs.org/model/cessna-170b) (registry code 2072306) (OpenAirDocs)
- Registry engine: [Continental C145 series](https://openairdocs.org/engine/continental-c145-series) (registry code 17012, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 20906
- Engines: CONTINENTAL O-300A 145 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Thomas A. Dalrymple
- Airport: NONE

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 34; student; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; flight hours: 52 total, 45 in this make and model, 15 as pilot in command, 27 in the last 90 days, 4 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 315° at 5 knots
- Visibility: 40 statute miles
- Lowest ceiling: none
- Temperature: 64 °F, dew point -0 °F

## 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 19900630026699A](https://openairdocs.org/incident/19900630026699A), Jun 30, 1990: Cessna 170B, Anchorage, AK, Substantial damage. Engine misfired and quit. Landed in a swamp and nosed over. Aircraft not recovered.

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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