# Accident 19990929047519A: Enstrm 280C, Longmont, CO, September 29, 1999

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: September 29, 1999, 18:40 local time
- Place: Longmont, CO
- Airport: Vance Brand Airport
- Damage: Substantial damage
- Phase of flight: Pwr Off Vert Land/Autorotate
- Operating rules: General operating rules (Part 91)
- Location: 40.1692° N, 105.1099° W: From the FAA, an estimate near the named town, within about 3 miles
- Nearby events: https://openairdocs.org/map.md?lat=40.1692&lon=-105.1099&mi=10
- Aircraft: N84DH, registered now (https://openairdocs.org/aircraft/N84DH) (OpenAirDocs)
- Registry model: Enstrom Helicopter 280C (registry code 3300505, https://openairdocs.org/model/enstrom-helicopter-280c) (OpenAirDocs)
- Registry engine: Lycoming HI0-360 series (registry code 41553, https://openairdocs.org/engine/lycoming-hi0-360-series) (OpenAirDocs)
- Reported make and model: ENSTRM 280C
- Reported engine: LYC HIO360E1AD
- People aboard: 1
- Fatal injuries: 0
- Pilot flight hours: 2,127 total, 40 in this make and model, 91 in the last 90 days
- NTSB investigation: [NTSB DEN99LA173](https://openairdocs.org/ntsb/DEN99LA173) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/19990929047519A

## Narrative

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

(.4) WHILE PRACTICING AUTOROTATIONS, THE PILOT, WHO WAS A COMMERCIAL PILOT IN SINGLE AND MULTIENGINE AIRCRAFT BUT A STUDENT PILOT IN HELICOPTERS, EXPERIENCED A LOSS OF ENGINE POWER FOR UNKNOWN REASONS. DURING THE FULL AUTOROTATION, WHICH WAS NECESSITATED BY THE POWER LOSS, THE LANDING WAS HARD AND RESULTED IN MAIN ROTOR FLEX, WHICH CUT OFF THE TAIL BOOM. DENSITY ALTITUDE AT THE TIME WAS 9,000 FEET.                                                (-23) STUDENT PILOT PRACTICING AUTOROTATION. HE ROLLED OFF THROTTLE TO DISENGAGE MAIN ROTOR. ENGINE QUIT. AUTOROTATION COMPLETED. MAIN ROTOR BLADE CONTACTED TOP AND AFT SECTION OF TAIL BOOM. AFTER LANDING THE ENGINE WAS RUN ON THE GROUND BY STUDENT AND INSTRUCTOR. THERE WERE NO ENGINE ABNORMALITIES IN ENGINE RUN.

## 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 DEN99LA173](https://openairdocs.org/ntsb/DEN99LA173), Sep 30, 1999: Enstrom 280C (N84DH), Longmont, CO, substantial damage. Probable cause: An inaccurate touchdown during a full autorotation, which resulted in main rotor flex which cut off the tail boom. Factors were the pilot's lack of total experience in helicopters and high density…

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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