# NTSB CHI83LA219: Piper PA25, N4521Y, Tomah, WI, May 17, 1983

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: May 17, 1983, 17:00 local (22:00 UTC)
- Place: Tomah, WI
- Location: 43.9879° N, 90.5014° W: Placed by OpenAirDocs: center of Tomah, WI, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=43.9879&lon=-90.5014&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 12180
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI83LA219
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/12180/pdf
- Page: https://openairdocs.org/ntsb/CHI83LA219

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, takeoff - initial climb
  - ignition system,spark plug - contamination (cause)
  - maintenance,service of aircraft/equipment - improper, company maintenance personnel (cause)
  - maintenance,replacement - not corrected, company maintenance personnel (cause)
- Forced landing, landing - flare/touchdown
- Main gear collapsed, landing - flare/touchdown
  - landing gear,main gear attachment - overload (contributing factor)

## Analysis

THE ACFT LOST POWER AND MADE A FORCED LANDING IMMEDIATELY AFTER TAKEOFF ON AN AERIAL APPLICATION MISSION. THE LANDING GEAR COLLAPSED DURING THE LANDING. THE PILOT STATED THAT THE ACCIDENT OCCURRED ON THE 5TH FLT OF THE DAY AFTER TAKING OFF ON RUNWAY 27 AND WHEN CLIMBING TO 125 FT AGL THE ENGINE BEGAN TO LOSE POWER. THE PILOT REDUCED POWER AND LANDED STRAIGHT AHEAD 50 YDS OFF THE END OF TH TAKEOFF RUNWAY. AN EXAMINATION OF THE ENGINE REVEALED THAT THE LOWER PLUGS CONTAINED A DARK GREY DEPOSIT THAT BRIDGED THE ELECTRODES. THIS DEPOSIT WEAKENED THE SPARK PRODUCED BY THE PLUGS. WHEN CLEARED THEY PRODUCED A STRONGER SPARK.

## Aircraft

- Registration: [N4521Y](https://openairdocs.org/aircraft/N4521Y), registered now, S/N 25-4072, built 1966 (OpenAirDocs)
- Reported make and model: PIPER PA25
- Registry model: [Piper PA-25-235](https://openairdocs.org/model/piper-pa-25-235) (registry code 7102504) (OpenAirDocs)
- Registry engine: [Lycoming 0-540 series](https://openairdocs.org/engine/lycoming-0-540-series) (registry code 41532, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 25-472
- Airframe hours: 3201
- Engines: LYCOMING O-540 250 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Registered owner: Boyana Airspray Company
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, June 4, 1982, 59 hours before
- Departed: NONE, WI
- Destination: NONE
- Airport: NONE, Boyers, runway 27, 3,600 ×  ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: front; flight hours: 1,302 total, 80 in this make and model, 1,230 as pilot in command, 30 in the last 90 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 270° at 10 knots
- Lowest ceiling: none
- Temperature: 55 °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 19830517019819A](https://openairdocs.org/incident/19830517019819A), May 17, 1983: Piper PA25235, Tomah, WI, Substantial damage. Engine quit after takeoff. Lower sparkplugs fouled.

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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