# Accident 20130525008109A: Hiller UH-12E, Wenatchee, WA, May 25, 2013

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: May 25, 2013, 17:30 local time
- Place: Wenatchee, WA
- Airport: Pangborn
- Damage: Substantial damage
- Phase of flight: Hover/Holding
- Operating rules: General operating rules (Part 91)
- Location: 47.3922° N, 120.2036° W: From the FAA
- Nearby events: https://openairdocs.org/map.md?lat=47.3922&lon=-120.2036&mi=10
- Aircraft: N99090 (not matched to a registry record)
- Reported make and model: HILLER UH-12E
- Reported engine: LYCOMING VO-540 SERIES
- People aboard: 2
- Fatal injuries: 0
- Other injuries: 0
- Pilot certificates: Commercial pilot, flight instructor
- NTSB investigation: [NTSB WPR13FA243](https://openairdocs.org/ntsb/WPR13FA243) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/20130525008109A

## Narrative

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

PILOT DEPARTED EAT FOR A LOCAL FLIGHT WITH HIS WIFE. A FEW MILES FROM THE AIRPORT, PILOT HEARD AN UNUSUAL MECHANICAL NOISE FROM ABOVE AND BEHIND THEM. PILOT ELECTED TO RETURN TO AIRPORT, AND ON THE WAY, HEARD THE NOISE AGAIN. PILOT ELECTED TO GO INTO A 4 FOOT HOVER TO "SORT OUT" THE NOISE ISSUE. THE MAIN ROTOR THEN DEPARTED THE AIRCRAFT AND THE HELICOPTER LANDED ON THE RAMP HARD, BREAKING THE TAIL BOOM. THE MAIN ROTOR/HUB WAS REPORTED TO RISE ABOUT 500 FEET ABOVE THE GROUND, THEN LANDED ABOUT 300 FEET AWAY FROM THE HELICOPTER. LATER INSPECTION REVEALED THAT THE MAIN ROTOR MAST BROKE ABOUT THREE INCHES BELOW THE WOBBLE PLATE.

## The NTSB's investigation of this event (1)

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.

- [NTSB WPR13FA243](https://openairdocs.org/ntsb/WPR13FA243), May 26, 2013: Hiller UH-12E (N99090), Wenatchee, WA, substantial damage. Probable cause: Fatigue failure of the six bolts that secured the bevel gear to the first stage planetary carrier, which caused the transmission to seize while the helicopter and main rotor were still operating.

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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