# NTSB CHI91DER11: Piper OA25-235, N9599P, Clinton, MN, June 29, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Final report
- Date: June 28, 1991, 20:15 local (Jun 29, 1991, 01:15 UTC)
- Place: Clinton, MN
- Coordinates: 45.459197, -96.439376 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.4592&lon=-96.4394&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report September 28, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 14857
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI91DER11
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/14857/pdf
- Page: https://openairdocs.org/ntsb/CHI91DER11

## Probable cause

THE PILOT'S FAILURE TO MAINTAIN ADEQUATE CONTROL OF THE AIRCRAFT WHILE MANEUVERING IN AERIAL APPLICATION OPERATIONS. RELATED FACTORS ARE WAKE TURBULENCE AND LOW ALTITUDE.

## Sequence of events

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

- Loss of control - in flight, maneuvering - aerial application
  - wake turbulence (contributing factor)
  - aircraft control - not maintained, pilot in command (cause)
  - altitude (contributing factor)
- In flight collision with terrain/water, descent - uncontrolled
  - terrain condition - ground

## Analysis

THE PILOT WAS PERFORMING 'TANDEM' AERIAL APPLICATION OPERATIONS WITH ANOTHER PILOT.  HE REPORTED AS HE APPROACHED THE FIELD FOR A PASS HE WAS UNABLE TO SEE THE MARKER FLAG IN TIME TO MAKE A 'PROPER PASS.'  HE PERFORMED A GO AROUND AND RE ENTERED A LEFT PATTERN FOR THE FIELD.  THE PILOT STATED HE WAS IN STRAIGHT AND LEVEL FLIGHT WHEN HE 'ENCOUNTERED A WINGTIP VORTICE WHICH ROLLED ME INTO A STEEP RIGHT BANK.  I WAS UNABLE TO RECOVER BEFORE IMPACTING THE GROUND.'

## Aircraft

- Registration: [N9599P](https://openairdocs.org/deregistered/N9599P-1994-08-24), registration cancelled 1994-08-24, S/N 257656006 (OpenAirDocs)
- Reported make and model: PIPER OA25-235
- Registry model: [Piper PA-25-235](https://openairdocs.org/model/piper-pa-25-235) (registry code 7102504) (OpenAirDocs)
- Category: Airplane
- Serial number: 25-7657006
- Airframe hours: 2096
- Engines: LYCOMING O-540-B2C5 235 horsepower reciprocating
- Damage: Destroyed
- Flight: Aerial application, Part 137
- Operator: Sprayers Inc.
- Registered owner: Sprayers Inc.
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, April 15, 1991, 55 hours before
- Departed: NONE, GRACEVILLE, MN
- Destination: NONE, CLINTON, MN

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 26; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: center; flight hours: 509 total, 135 in this make and model, 454 as pilot in command, 65 in the last 90 days, 49 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 230° at 2 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 84 °F
- Altimeter: 29.00 inHg

## 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 19910628025149A](https://openairdocs.org/incident/19910628025149A), Jun 28, 1991: Piper PA25235, Clinton, MN, Destroyed. Spraying field with another aircraft. Lost sight of flag,maneuvered to find flag,stalled and crashed.

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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