# NTSB SEA91FA131: Piper PA-18-150, N4090Z, Nephi, UT, June 15, 1991

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: June 15, 1991, 15:10 local (21:10 UTC)
- Place: Nephi, UT
- Coordinates: 39.680553, -111.82917 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.6806&lon=-111.8292&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed, report February 8, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 41321
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA91FA131
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41321/pdf
- Page: https://openairdocs.org/ntsb/SEA91FA131

## Probable cause

POOR INFLIGHT PLANNING AND DECISIONS.  FACTORS TO THE ACCIDENT WERE:  AN UNCONTROLLED STALL/SPIN, AND INADEQUATE AIRSPEED.

## Sequence of events

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

- Loss of control - in flight, maneuvering
  - stall/spin - uncontrolled, pilot in command (contributing factor)
  - airspeed(vmc) - inadequate, pilot in command (contributing factor)
  - in-flight planning/decision - poor, pilot in command (cause)
- In flight collision with terrain/water, descent - uncontrolled
  - terrain condition - mountainous/hilly

## Analysis

DURING A FLIGHT FOR THE PURPOSE OF INSPECTING POWER LINES AT A LOW ALTITUDE IN HILLY TO MOUNTAINOUS TERRAIN, THE AIRPLANE COLLIDED WITH THE TERRAIN IN AN UNCONTROLLED ATTITUDE.

## Aircraft

- Registration: N4090Z (not matched to a registry record)
- Reported make and model: PIPER PA-18-150
- Category: Airplane
- Serial number: 18-8105
- Engines: LYCOMING O-320 150 horsepower reciprocating
- Damage: Destroyed
- Fire: On-Ground
- Flight: Other work use, Part 91
- Operator: Earl H. Moore, doing business as Mercury Aviation Services
- Registered owner: Earl H. Moore
- Departed: RIF, RICHFIELD, UT
- Destination: TVY, TOOELE, UT

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 48; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; toxicology performed; flight hours: 2,267 total, 90 in this make and model, 2,160 as pilot in command, 92 in the last 90 days, 60 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 30 statute miles
- Lowest ceiling: none
- Temperature: 81 °F, dew point -0 °F

## 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 19910615021849A](https://openairdocs.org/incident/19910615021849A), Jun 15, 1991: Piper PA18150, Nephi, UT, Destroyed, 2 fatal. Struck trees,crashed and burned while patrolling powerline in rough terrain at low AGL in high density altitude.

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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