# Incident 20160805013219I: Piper PA-25-235, Norfolk, NE, August 5, 2016

- Type: FAA incident report (Accident/Incident Data System), as reported
- Date: August 5, 2016, 14:30 local time
- Place: Norfolk, NE
- Damage: Minor damage
- Phase of flight: Maneuver
- Operating rules: Agricultural (Part 137)
- Operator: XDFG
- Location: 42.0282° N, 97.4278° W: Placed by OpenAirDocs: center of Norfolk, NE, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=42.0282&lon=-97.4278&mi=10
- Aircraft: N7422Z, registered now (https://openairdocs.org/aircraft/N7422Z) (OpenAirDocs)
- Registry model: Piper PA-25-235 (registry code 7102504, https://openairdocs.org/model/piper-pa-25-235) (OpenAirDocs)
- Registry engine: Lycoming 0-540 series (registry code 41532, https://openairdocs.org/engine/lycoming-0-540-series) (OpenAirDocs)
- Reported make and model: PIPER PA-25-235
- Reported engine: LYCOMING 0-540 SERIES
- People aboard: 1
- Fatal injuries: 0
- Other injuries: 0
- Pilot certificates: Commercial pilot
- Pilot flight hours: 14,379 total, 1,000 in this make and model, 120 in the last 90 days
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/20160805013219I

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

THE AIRCRAFT WAS ENGAGED IN AERIAL APPLICATION OPERATIONS. THE PILOT STATED THAT HE HAD JUST SPRAYED A SMALL FIELD TO THE WEST OF NORFOLK NEBRASKA AND WAS CLIMBING AWAY FROM THE FIELD EN ROUTE TO ANOTHER SPRAY LOCATION WHEN THE ENGINE QUIT. HE LANDED THE AIRCRAFT IN AN ADJACENT FIELD OF SOY BEANS. THE LANDING DID NOT RESULT IN ANY INJURY AND ONLY MINOR DAMAGE TO THE AIRCRAFT. THE AIRCRAFT WAS REMOVED FROM THE FIELD AND RELOCATED TO THE NORFOLK AIRPORT WHERE THE ENGINE WAS REMOVED AND SENT TO CENTRAL CYLINDER SERVICE IN OMAHA NEBRASKA FOR TEARDOWN

INSPECTION AND REPAIR.

THE LEFT IDLER GEAR IN THE ACCESSORY CASE WAS FOUND TO HAVE BECOME LOOSE DISENGAGING ITS CONNECTION BETWEEN THE CRANKSHAFT AND THE CAMSHAFT. THIS CAUSED THE ENGINE TO STOP. THE IDLER GEAR WAS FOUND TO HAVE MIGRATED AFT AND GROUND INTO THE ACCESSORY CASE HOUSING TO A DEPTH THAT ALLOWED THE GEAR TO COME OFF OF THE IDLER SHAFT. THE IDLER SHAFT IS FIXED BETWEEN A MOUNING PAD ON THE ENGINE CASE BY MEANS OF A FLANGE AT THE FORWARD END OF THE IDLER SHAFT AND HELD IN PLACE WITH 2 BOLTS THAT HAVE A LOCK RETAINER TO PREVENT LOOSENING OF THE BOLTS AND THE AFT END OF THE IDLER SHAFT IS SUPPORTED BY A MACHINED COUNTERBORE IN THE ACCESSORY CASE HOUSING. THE IDLER GEAR ROTATES FREELY ON THE IDLER SHAFT AND PROVIDES THE CONNECTION BETWEEN THE AFT CRANKSHAFT GEAR AND THE CAMSHAFT GEAR DRIVING THE CAMSHAFT AND MAINTAINING CAMSHAFT TO CRANKSHAFT TIMING.

THE IDLER GEAR HAS A DUAL PURPOSE AND  SIMULTANIOUSLY DRIVES THE LEFT MAGNETO FROM A SECOND SET OF TEETH MACHINED INTO THE GEAR. IT WAS ALSO FOUND THAT THE MAGNETO BEARING WHICH IS PRESSED ONTO END OF THE IMPULSE COUPLING AND RIDES IN A CRANKCASE COUNTERBORE AND IS A SELFCONTAINED BEARING WITH AN INNER AND OUTER RACE SUPPORTED BY BALL BEARINGS, HAD LOST 5 BALL BEARINGS AT SOME POINT.

EXAMINATION OF AIRCRAFT RECORDS PRESENTED FOR THE TIME SINCE MAJOR OVERHAUL REPRESENT A SOLID MAINTENANCE HISTORY OF THE AIRCRAFT AND ENGINE.

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record.

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