# NTSB DEN90DTK01: Piper PA-36-375, N3634E, Woonsocket, SD, May 8, 1990

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: May 8, 1990, 11:15 local (16:15 UTC)
- Place: Woonsocket, SD
- Location: 44.0542° N, 98.2717° W: Placed by OpenAirDocs: center of Woonsocket, SD, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=44.0542&lon=-98.2717&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal, 1 uninjured
- Status: Completed, report March 31, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 17803
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN90DTK01
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/17803/pdf
- Page: https://openairdocs.org/ntsb/DEN90DTK01

## Probable cause (aircraft 2)

FAILURE OF THE PILOT OF N3634E TO FOLLOW THE BRIEFED PLAN OF OPERATION, AND FAILURE OF BOTH PILOTS TO SEE-AND-AVOID EACH OTHER (INADEQUATE VISUAL LOOKOUT).

## Sequence of events

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

- Midair collision, maneuvering - aerial application
  - crew/group briefing - not followed, pilot in command (cause)
  - visual lookout - inadequate, pilot in command (cause)
  - visual lookout - inadequate, pilot of other aircraft (cause)
- In flight collision with terrain/water, descent - uncontrolled
- Midair collision, maneuvering - aerial application
  - crew/group briefing - not followed, pilot of other aircraft (cause)
  - visual lookout - inadequate, pilot in command (cause)
  - visual lookout - inadequate, pilot of other aircraft (cause)

## Analysis (aircraft 2)

THE PLTS OF TWO PA-36 AGRICULTURAL APPLICATION ACFT (N3634E & N6177A) WERE SPRAYING ADJACENT FIELDS.  THE ACFT WERE OWNED AND OPERATED BY A FATHER AND SON TEAM.  THE PLTS HAD PREBRIEFED TO SPRAY WITH EAST/WEST SWATH RUNS.  HOWEVER, DURING THE FLIGHT, THE PLT OF N3634E CHANGED TO NORTH/SOUTH RUN(S).  SUBSEQUENTLY, THE TWO ACFT CONVERGED AND COLLIDED AS EACH WAS PULLING UP AT THE END OF A SWATH RUN.

## Aircraft 1

- Registration: [N3634E](https://openairdocs.org/deregistered/N3634E-1991-04-10), registration cancelled 1991-04-10, S/N 367902042 (OpenAirDocs)
- Reported make and model: PIPER PA-36-375
- Registry model: [Piper PA-36-375](https://openairdocs.org/model/piper-pa-36-375) (registry code 7103620) (OpenAirDocs)
- Category: Airplane
- Serial number: 36-7902042
- Airframe hours: 1990
- Engines: LYCOMING IO-520 375 horsepower reciprocating
- Damage: Destroyed
- Flight: Aerial application, Part 137
- Registered owner: Emmett Hofer
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, March 17, 1990, 2 hours before
- Departed: WOONSOCKET, SD

## Aircraft 2

- Registration: [N6177A](https://openairdocs.org/deregistered/N6177A-1997-02-14), registration cancelled 1997-02-14, S/N 368102017 (OpenAirDocs)
- Reported make and model: PIPER PA-36-375
- Registry model: [Piper PA-36-375](https://openairdocs.org/model/piper-pa-36-375) (registry code 7103620) (OpenAirDocs)
- Category: Airplane
- Serial number: 36-8102017
- Airframe hours: 1574
- Engines: LYCOMING IO-520 375 horsepower reciprocating
- Damage: Minor damage
- Flight: Aerial application, Part 137
- Registered owner: Gary Hofer
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, January 16, 1990, 5 hours before
- Departed: NONE, WOONSOCKET, SD

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot, aircraft N3634E; age 60; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: center; toxicology performed; flight hours: 7,060 total, 2,005 in this make and model, 7,000 as pilot in command, 10 in the last 90 days, 10 in the last 30 days, 2 in the last 24 hours
- Pilot, aircraft N6177A; age 34; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 4,675 total, 1,600 in this make and model, 4,500 as pilot in command, 30 in the last 90 days, 30 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 310° at 10 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 64 °F, dew point 39 °F
- Altimeter: 29.00 inHg
- Observed at: HON, 16 nm away

## FAA reports on this event (2)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19900508014771A](https://openairdocs.org/incident/19900508014771A), May 8, 1990: Piper PA36375, Woonsocket, SD, Destroyed, 1 fatal. Was struck by son's PA36 N6177A during pull up from opposite direction spray run. Unknownly changed spray direction
- [Accident 19900508014772A](https://openairdocs.org/incident/19900508014772A), May 8, 1990: Piper PA36375, Woonsocket, SD, Minor damage. Collided with dads PA36 N3634F spray same field. Both on pullup. Unknown why his dad changed run direction.

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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