# Accident 20010228004029A: Bell 412, Grand Junction, CO, February 28, 2001

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: February 28, 2001, 10:24 local time
- Place: Grand Junction, CO
- Damage: Destroyed
- Phase of flight: Autorot Descent (Rotorcraft)
- Operating rules: General operating rules (Part 91)
- Operator: HEEA
- Location: 39.2606° N, 108.5300° W: From the FAA, an estimate near the named town, within about 3 miles
- Nearby events: https://openairdocs.org/map.md?lat=39.2606&lon=-108.5300&mi=10
- Aircraft: N412SM, a cancelled registration (https://openairdocs.org/deregistered/N412SM-2001-09-11) (OpenAirDocs)
- Registry model: Bell 412 (registry code 1182202, https://openairdocs.org/model/bell-412) (OpenAirDocs)
- Reported make and model: BELL 412
- Reported engine: PWA PT6T3B
- People aboard: 1
- Fatal injuries: 1
- Pilot flight hours: 3,726 total, 1,859 in this make and model, 24 in the last 90 days
- NTSB investigation: [NTSB DEN01FA058](https://openairdocs.org/ntsb/DEN01FA058) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/20010228004029A

## Narrative

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

(-23) THE PILOT WAS ASKED TO PERFORM AN AUTOROTATION RPM CHECK. HE DEPARTED THE HELIPAD AND TRANSITIONAL TO AN AREA NORMALLY USED FOR PRACTICE MANUEVERS ABOUT 12 MILES SOUTH OF GRAND JUNCTION, CO. WITNESS STATEMENTS INDICATE HE ENTERED THE AUTOROTATION MANUEVER AT ABOUT 2,000 FEET AGL. WITNESS STATEMENTS SAY THEY SAW THE ROTOR BLADES SLOW DOWN AND SOMETHING MOVE AT THE TOP OF THE HELICOPTER. IT THEN FELL TO THE EARTH, EXPLODED AND BURNED. THE PILOT DID NOT GET OUT. POST-ACCIDENT INVESTIGATION REVEALED NO EVIDENCE OF MECHANICAL FAILURE. (.4) DURING A TEST FLIGHT, FOLLOWING MAINTENANCE ON THE HELICOPTER, WHICH REQUIRED A FUNCTIONAL FLIGHT CHECK FOR VIBRATION AND AUTOROTATION, THE HELICOPTER WAS OBSERVED BY WITNESSES TO ENTER A RAPID DESCENT. DURING THIS MANEUVER, THE ROTOR SYSTEM WAS OBSERVED TO SLOW DOWN AND THE ROTOR BLADES TO "FOLD" OVER THE TOP OF THE HELICOPTER. PIECES, WHICH WERE LATER IDENTIFIED AS FRAGMENTS FROM THE TRANSMISSION COWLING, WERE OBSERVED EXITING THE HELICOPTER WHEN THE ROTOR SYSTEM SLOWED DOWN. THE HELICOPTER DESCENDED INTO THE GROUND IN A RIGHT HAND TURNING MANEUVER. EXAMINATION OF THE WRECKAGE REVEALED                                                           NO EVIDENCE OF EITHER A STRUCTURAL OR SYSTEM FAILURE OR MALFUNCTION. ACCORDING TO THE HELICOPTER'S MANUFACTURER, AS THE MAIN ROTOR SYSTEM SLOWS WHILE UNDER AERODYNAMIC LOAD, THE MAIN GEAR BOX CAN "WALK" (HORIZONTAL ORBITAL MOVEMENT) ON ITS MOUNTING STRUCTURE, WHICH CAN RESULT IN CONTACT BETWEEN THE TRANSMISSION COWLING AND THE MAIN ROTOR CONTROL ROD ENDS. EXAMINATION OF THE ENGINES REVEALED EVIDENCE THAT ENGINE POWER WAS APPLIED WHEN THE ROTOR SYSTEM WAS AT LOW ROTATIONAL SPEED. NO EVIDENCE OF PREIMPACT ENGINE FAILURE OR MALFUNCTION WAS FOUND. ACCORDING TO AVAILABLE INFORMATION, THE PILOT HAD RECEIVED NO TRAINING FROM THE OPERATOR REGARDING THE CONDUCT OF A MAINTENANCE TEST FLIGHT, NOT DOES THE FAA REQUIRE SUCH TRAINING.

## 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 DEN01FA058](https://openairdocs.org/ntsb/DEN01FA058), Feb 28, 2001: Bell 412SP (N412SM), Grand Junction, CO, destroyed, 1 fatal. Probable cause: the pilot's failure to maintain rotor speed during an intentional autorotation, which resulted in a loss of control.

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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