# NTSB DEN84LA034: Cessna 172N, N4818D, Helena, MT, December 2, 1983

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: December 1, 1983, 22:30 local (Dec 2, 1983, 05:30 UTC)
- Place: Helena, MT
- Coordinates: 46.530101, -112.210258 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=46.5301&lon=-112.2103&mi=10
- Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious, 1 uninjured; on the ground: 1 serious
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 16297
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN84LA034
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16297/pdf
- Page: https://openairdocs.org/ntsb/DEN84LA034

## Analysis

THE ACFT PROPELLER STRUCK A PASSENGER WHO WAS ATTEMPING TO SWEEP SNOW OFF THE ACFT. THE PLT'S AND PASSENGER'S VERSION OF MISHAP VARY. THE PLT STATED HE INSTRUCTED THE PASSENGER TO STAY AWAY FROM THE ACFT. THE PASSENGER STATED THE PLT TOLDHIM TO SWEEP THE SNOW OFF THE ACFT AND THAT THE NEXT THING HE REMEMBERS 'IS HOLDING MY ARM AFTER IT HAD BEEN HIT.'

## Sequence of events

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

- Propeller/rotor contact to person, standing - engine(s) operating
  - passenger briefing - inadequate, pilot in command (cause)

## Aircraft

- Registration: [N4818D](https://openairdocs.org/aircraft/N4818D), registered now, S/N 17272367, built 1979 (OpenAirDocs)
- Reported make and model: CESSNA 172N
- Registry model: [Cessna 172N](https://openairdocs.org/model/cessna-172n) (registry code 2072434) (OpenAirDocs)
- Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 17272367
- Airframe hours: 1141
- Engines: LYCOMING O-320-H2AD 160 horsepower reciprocating
- Damage: Minor damage
- Flight: Personal, Part 91
- Registered owner: Marathon Aviation Company
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, January 4, 1983, 282 hours before
- Departed: BTM, BUTTE, MT
- Flight plan: VFR
- Airport: HLN, Helena

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 55; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 395 total, 170 in this make and model, 281 as pilot in command, 19 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: 350° at 5 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 3 °F, dew point 5 °F
- Altimeter: 29.00 inHg
- Observed at: HLN

## 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 19831201061299A](https://openairdocs.org/incident/19831201061299A), Dec 1, 1983: Cessna 172N, Helena, MT, Minor damage. Pilot started engine for warm up while passenger was outside using a broom to clear snow. Prop hit passengers arm.

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.

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