# NTSB SEA86LA107: Cessna 172, N70040, Bonners Ferry, ID, April 20, 1986

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: April 20, 1986, 06:45 local (14:45 UTC)
- Place: Bonners Ferry, ID
- Coordinates: 48.749599, -116.510581 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=48.7496&lon=-116.5106&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 2 serious, 2 minor
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 40390
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA86LA107
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/40390/pdf
- Page: https://openairdocs.org/ntsb/SEA86LA107

## Sequence of events

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

- In flight encounter with weather, climb
  - terrain condition - mountainous/hilly (contributing factor)
  - weather evaluation - inadequate, pilot in command (cause)
  - weather condition - mountain wave (contributing factor)
  - clearance - misjudged, pilot in command (cause)
  - weather condition - clouds (contributing factor)
  - vfr flight into imc - inadvertent, pilot in command (cause)
- In flight collision with terrain/water, descent - uncontrolled
  - terrain condition - mountainous/hilly (contributing factor)

## Analysis

THE PLT UTILIZED UPDRAFTS TO CLIMB TO 7800 FT TO CLEAR A MOUNTAIN RIDGE WHICH WAS COVERED WITH 'CAP CLOUDS'. ON THE LEE SIDE OF THE RIDGE A DOWNDRAFT WAS EXPERIENCED AND THE ACFT DESCENDED INTO THE 'FOG'. THE PLT REPORTED THE ACFT INSTRUMENTS WERE USED TO MAINTAIN A NOSE UP ATTITUDE BUT THE ACFT CONTINUED DESCENDING TO GROUND IMPACT.

## Aircraft

- Registration: N70040 (not matched to a registry record)
- Reported make and model: CESSNA 172
- Category: Airplane
- Serial number: 17267181
- Airframe hours: 1940
- Engines: LYCOMING O-320-ED2 150 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Registered owner: Charles C. Chamberlin
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, April 20, 1985, 97 hours before
- Departed: 65S, BONNERS FERRY, ID
- Destination: ELN, ELLENSBURG, WA
- Flight plan: VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 27; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 161 total, 109 in this make and model, 127 as pilot in command, 2 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 0° at 15 knots
- Visibility: 15 statute miles
- Lowest ceiling: 1,200 ft overcast
- Temperature: 36 °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 19860420037629A](https://openairdocs.org/incident/19860420037629A), Apr 20, 1986: Cessna 172M, Bonners Ferry, ID, Destroyed. Tried to cross a ridge line but encountered downdrafts on the lee side and impacted mountain. Cap clouds present.

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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