# NTSB DEN83LA121: Piper PA-22-150, N9975D, Ennis, MT, May 27, 1983

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: May 26, 1983, 23:30 local (May 27, 1983, 05:30 UTC)
- Place: Ennis, MT
- Coordinates: 45.28001, -111.709289 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.2800&lon=-111.7093&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 16080
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN83LA121
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16080/pdf
- Page: https://openairdocs.org/ntsb/DEN83LA121

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise - normal
  - lubricating system - undetermined (cause)
  - lubricating system - chafed (cause)
  - lubricating system - leak (cause)
  - fuselage,crew compartment - smoke (contributing factor)
  - window,flight compartment window/windshield - dirty(foggy) (contributing factor)
- In flight collision with terrain/water, landing - flare/touchdown
  - light condition - night (contributing factor)
  - terrain condition - high obstruction(s) (contributing factor)
  - maneuver - performed, pilot in command (contributing factor)
  - terrain condition - ditch (contributing factor)
- Gear collapsed, landing - flare/touchdown
  - landing gear - overload (contributing factor)
- On ground/water collision with object, landing
  - object - fence (contributing factor)
- Nose over, landing

## Analysis

DURING A NIGHT FLIGHT, OIL BEGAN SPREADING OVER THE WINDSHIELD & HEAVY SMOKE CAME IN THE COCKPIT THROUGH THE CABIN HEATER. THE PLT OPENED THE CABIN WINDOWS, REDUCED POWER & TURNED BACK TOWARD THE ARPT. THE OIL PRESSURE DROPPED TO 5 PSI & THE PLT DESCENDED TO LAND ON A ROAD WHICH COULD BE SEEN ON THE MOONLIT NIGHT. REPORTEDLY, THE ENGINE BEGAN TO 'RATTLE' AS THE ACFT NEARED THE GROUND. THE PLT LINED UP WITH THE ROAD, BUT LOST SIGHT OF IT MOMENTARILY DUE TO CLOUDS OBSCURING THE MOON. JUST BEFORE LANDING, HE SAW A GUY WIRE & MANEUVERED THE PLANE TO AVOID A COLLISION. THE ACFT STALLED & HIT A DITCH, THEN THE NOSE & LEFT MAIN GEAR SHEARED OFF. THE ACFT CONTINUED THRU BUSHES, HIT A FENCE & NOSED OVER. AN INVESTIGATION REVEALED THAT 2 OIL LINES HAD RUBBED TOGETHER UNTIL 1 HAD WORN THRU. THE OIL LINES SHOULD HAVE BEEN PROTECTED BY A RUBBER SPACER & A CLAMP. EITHER THE CLAMP HAD FAILED OR HAD NOT BEEN INSTALLED. SUBSEQUENTLY, THE RUBBER SPACER HAD MOVED & ALLOWED THE LINES TO RUB TOGETHER.

## Aircraft

- Registration: [N9975D](https://openairdocs.org/deregistered/N9975D-2020-07-10), registration cancelled 2020-07-10, S/N 22-6766 (OpenAirDocs)
- Reported make and model: PIPER PA-22-150
- Registry model: [Piper PA-22-150](https://openairdocs.org/model/piper-pa-22-150) (registry code 7102210) (OpenAirDocs)
- Category: Airplane
- Serial number: 22-6766
- Airframe hours: 1597
- Engines: LYCOMING O-320 150 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Delane M. Hall
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, June 3, 1982, 50 hours before
- Departed: BZN, BOZEMAN, MT
- Destination: VOI, AMERICAN FALLS, ID

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 54; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 1,084 total, 60 in this make and model, 1,029 as pilot in command, 14 in the last 90 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Night/bright
- Wind: 150° at 10 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 55 °F, dew point 43 °F
- Altimeter: 29.00 inHg
- Observed at: BZN, 32 nm away

## 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 19830526021929A](https://openairdocs.org/incident/19830526021929A), May 26, 1983: Piper PA22150, Ennis, MT, Substantial damage. Engine quit from lack of oil after oil lines to oil cooler broke. Crash occurred during night emergency landing.

## Other investigations on N9975D (1)

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.

- [NTSB WPR17LA088](https://openairdocs.org/ntsb/WPR17LA088), Apr 21, 2017: Piper PA 22-150 (N9975D), Kernville, CA, substantial damage. Probable cause: The pilot’s exceedance of the airplane's critical angle of attack, which resulted in an aerodynamic stall/mush.

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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