# NTSB CHI92FA066: Piper PA-31P, N500BH, Mosinee, WI, January 2, 1992

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: January 2, 1992, 13:05 local (19:05 UTC)
- Place: Mosinee, WI
- Coordinates: 44.779926, -89.68003 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=44.7799&lon=-89.6800&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report March 24, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 15280
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI92FA066
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/15280/pdf
- Page: https://openairdocs.org/ntsb/CHI92FA066

## Probable cause

AN INFLIGHT FIRE WITH THE CABIN HEATER AS THE ORIGIN, AND UNSUITABLE TERRAIN IN WHICH TO MAKE A FORCED LANDING.  A FACTOR RELATED TO THE ACCIDENT WAS THE SOFT TERRAIN.

## Sequence of events

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

- Airframe/component/system failure/malfunction, maneuvering
  - air cond/heating/pressurization - fire (cause)
  - maintenance - inadequate, other maintenance personnel (contributing factor)
- Forced landing, descent - emergency
  - terrain condition - none suitable (cause)
  - terrain condition - soft (contributing factor)
- Fire, other

## Analysis

PILOT WAS CLEARED FOR AN ILS APPROACH AT HIS DESTINATION, AND REQUESTED TO REPORT ALTITUDE OF 3,000 FEET ON THE APPROACH.  THIS WAS THE LAST RADIO TRANSMISSION RECEIVED FROM THE PILOT.  AIRCRAFT WAS FOUND IN SOFT FIELD SIX MILES FROM THE AIRPORT.  LANDING GEAR WAS UP, FLAPS WERE DOWN. FISHERMAN NEARBY REPORTED HEARING THE AIRCRAFT MANEUVERING AT LOW ALTITUDE.  HE REPORTED THAT THE ENGINES SOUNDED FINE, BUT THE SOUND WAS CHANGING IN PITCH AND INTENSITY.  HE REPORTED THAT GOT QUIET JUST A FEW SECONDS BEFORE HE HEARD THE IMPACT.  THE INVESTIGATION REVEALED THAT THERE WAS EVIDENCE OF A FIRE IN THE NOSE BAGGAGE COMPARTMENT.  THE CABIN HEATER IS LOCATED IN THE NOSE BAGGAGE COMPARTMENT, AND HAD A RECENT HISTORY OF DISCREPANCIES.

## Aircraft

- Registration: [N500BH](https://openairdocs.org/deregistered/N500BH-2014-12-02), registration cancelled 2014-12-02, S/N 31P-7530024, built 1975 (OpenAirDocs)
- Reported make and model: PIPER PA-31P
- Registry model: [Piper PA-31P](https://openairdocs.org/model/piper-pa-31p) (registry code 7103120) (OpenAirDocs)
- Registry engine: [Lycoming TIGO-541SER](https://openairdocs.org/engine/lycoming-tigo-541ser) (registry code 41539, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 31P-7530024
- Airframe hours: 3520
- Engines: LYCOMING TIGO-541-E1A 425 horsepower reciprocating
- Damage: Destroyed
- Fire: Both
- Flight: Business, Part 91
- Operator: Becher Hoppe Engineers, Inc., doing business as Becher Hoppe Engineers, Inc.
- Registered owner: Becher Hoppe Engineers, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: Continuous airworthiness, October 25, 1991, 15 hours before
- Departed: MSP, MINNEAPOLIS, MN
- Destination: CWA, MOSINEE, WI
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 59; private; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: left; toxicology performed; flight hours: 8,150 total, 1,500 in this make and model, 15 in the last 90 days, 5 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Instrument (IMC), Day
- Wind: 140° at 4 knots
- Visibility: 1 statute miles
- Lowest ceiling: 500 ft overcast
- Temperature: 32 °F, dew point 30 °F
- Altimeter: 30.00 inHg
- Observed at: CWA, 6 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 19920102000049A](https://openairdocs.org/incident/19920102000049A), Jan 2, 1992: Piper PA31P, Mosinee, WI, Destroyed, 1 fatal. Lost control and crashed on ILS approach. Sound heard indicates spiral. Gasoline heater showed overtemp.

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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