# NTSB SEA86LA024: Cessna 421C, N124RS, Idaho Falls, ID, November 16, 1985

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: November 16, 1985, 14:45 local (21:45 UTC)
- Place: Idaho Falls, ID
- Coordinates: 43.500518, -111.889083 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=43.5005&lon=-111.8891&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 5 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 40334
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA86LA024
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/40334/pdf
- Page: https://openairdocs.org/ntsb/SEA86LA024

## Analysis

DURING INITIAL APCH INFLIGHT ICING WAS ENCOUNTERED. THE WINDSCREEN FAILED TO HEAT DUE TO AN INOPERATIVE INVERTER. A SMALL AREA ON THE RIGHT BOTTOM PORTION OF THE WINDSCREEN DE-ICED DUE TO DEFROST HEAT. THE PLT ELECTED TO LAND USING THE SMALL CLEAR AREA OF THE WINDSCREEN FOR OUTSIDE REFERENCE. A HARD LANDING RESULTED FROM A LOSS OF DEPTH PERCEPTION.

## Sequence of events

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

- In flight encounter with weather, approach - iaf to faf/outer marker (ifr)
  - weather evaluation - disregarded, pilot in command (cause)
- Airframe/component/system failure/malfunction, approach - iaf to faf/outer marker (ifr)
  - anti-ice/deice system,windshield - inoperative (cause)
- Hard landing, landing - flare/touchdown
  - window,flight compartment window/windshield - ice (contributing factor)
  - visual/aural perception, pilot in command (cause)

## Aircraft

- Registration: [N124RS](https://openairdocs.org/deregistered/N124RS-1989-08-31), registration cancelled 1989-08-31, S/N 421C0673 (OpenAirDocs)
- Reported make and model: CESSNA 421C
- Registry model: [Cessna 421C](https://openairdocs.org/model/cessna-421c) (registry code 2076016) (OpenAirDocs)
- Category: Airplane
- Serial number: 421C0673
- Airframe hours: 1170
- Engines: CONTINENTAL GTSIO-520-L 375 horsepower reciprocating
- Damage: Substantial damage
- Flight: Executive/Corporate, Part 91
- Registered owner: Recreational Sports & Imports
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, April 1, 1985, 30 hours before
- Departed: BFI, SEATTLE, WA
- Destination: IDA, IDAHO FALLS, ID
- Flight plan: IFR
- Airport: IDA, Idaho Falls, runway 20, 9,000 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 32; commercial, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, invalid medical for flight; seat: left; flight hours: 2,675 total, 180 in this make and model, 2,500 as pilot in command, 75 in the last 90 days, 8 in the last 24 hours

## Weather

- Conditions: Instrument (IMC), Day
- Wind: calm
- Visibility: 1 statute miles
- Lowest ceiling: 1,200 ft
- Temperature: 28 °F, dew point 25 °F
- Altimeter: 30.00 inHg
- Observed at: IDA

## 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 19851116057639A](https://openairdocs.org/incident/19851116057639A), Nov 16, 1985: Cessna 421C, Idaho Falls, ID, Substantial damage. Electric windscreen heat made inoperative by failed inverter. Windscreen covered by ice. Flared high,landed hard.

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.