# NTSB DEN85FA131: Consolidated-Vultee PBY-5A, N84857, Lewistown, MT, May 9, 1985

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: May 9, 1985, 08:44 local (14:44 UTC)
- Place: Lewistown, MT
- Coordinates: 47.009155, -109.339569 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=47.0092&lon=-109.3396&mi=10
- Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal, 2 minor
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 16538
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN85FA131
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16538/pdf
- Page: https://openairdocs.org/ntsb/DEN85FA131

## Sequence of events

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

- Miscellaneous/other, standing - pre-flight
  - fluid,hydraulic - inadequate (contributing factor)
  - aircraft preflight - inadequate, pilot in command (cause)
  - acft/equip inadequate,visual restriction, copilot/second pilot (contributing factor)
  - hydraulic system,reservoir - low level (contributing factor)
  - aircraft service - improper, copilot/second pilot (cause)
  - window,inspection/observation - blocked(partial) (contributing factor)
  - crew/group coordination - poor, pilot in command (contributing factor)
  - anti-ice/deice system,propeller - unmarked (contributing factor)
  - supervision - poor, pilot in command (cause)
- Airframe/component/system failure/malfunction, taxi - to takeoff
  - hydraulic system,pump - failure,total
  - brakes(normal) - selected, pilot in command
  - hydraulic system - pressure too low (cause)
  - brakes(emergency) - not used, pilot in command (cause)
  - safety system(other) - not engaged (cause)
  - emergency procedure - not followed, pilot in command (cause)
- Loss of control - on ground/water, taxi - to takeoff
  - ground loop/swerve - attempted, pilot in command
- On ground/water encounter with terrain/water, other
  - terrain condition - ditch

## Analysis

DURING TAXI TO TAKEOFF THE BRAKES FAILED. THE PLT ATTEMPTED TO GROUNDLOOP THE ACFT. THE ACFT ROLLED DOWN HILL AND COLLIDED WITH A GULLY. THE PLT WAS FATALLY INJURED. DURING PREFLIGHT THE CO-PLT INADVERTENTLY ADDED HYDRAULIC FLUID IN THE ALCOHOL TANK. THE HYDRAULIC PUMP CAVITATED. THE PLT FAILED TO USE THE HYDRAULIC EMERGENCY HAND PUMP OR THE A.C. ELECTRIC PUMP.

## Aircraft

- Registration: [N84857](https://openairdocs.org/aircraft/N84857), registered now, S/N 1522, built 1943 (OpenAirDocs)
- Reported make and model: Consolidated-Vultee PBY-5A
- Registry model: [Consolidated Vultee PBY-5A](https://openairdocs.org/model/consolidated-vultee-pby-5a) (registry code 2421208) (OpenAirDocs)
- Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs)
- Category: Airplane
- Serial number: 1522
- Airframe hours: 1481
- Engines: P&W R1830-94-M2 1350 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial observation, Part 91
- Operator: Government Of Israel
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, January 1, 1985, 35 hours before
- Destination: RNO, RENO, NV
- Airport: LWT, Lewistown, runway 25, 7,984 × 100 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 52; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: right; toxicology performed; flight hours: 6,838 total, 19 in this make and model, 24 in the last 90 days, 18 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 120° at 3 knots
- Visibility: 30 statute miles
- Lowest ceiling: 8,000 ft broken
- Temperature: 55 °F, dew point 45 °F
- Altimeter: 29.00 inHg
- Observed at: LWT

## 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 19850509016259A](https://openairdocs.org/incident/19850509016259A), May 9, 1985: Cvac PBY5A, Lewistown, MT, Substantial damage. Mistakenly put hydraulic fluid into alcohol tank. Lost brakes because of low brake fluid, taxied into a gully.

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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