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| Date: | Thursday 9 March 1989 |
| Time: | 16:55 LT |
| Type: |  Hiller UH-12E |
| Owner/operator: | Private |
| Registration: | N7411N |
| MSN: | 2110 |
| Total airframe hrs: | 5885 hours |
| Engine model: | Lycoming VO-540-C2A |
| Fatalities: | Fatalities: 0 / Occupants: 2 |
| Other fatalities: | 0 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Golden, CO -
 United States of America
|
| Phase: | Taxi |
| Nature: | Training |
| Departure airport: | Broomfield, CO (KBJC) |
| (KBJC) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
THE INSTRUCTOR (CFI) & DUAL STUDENT WERE PRACTICING PINNACLE APCHS. THE CFI WAS FLYING THE HELICOPETER AS AN APCH WAS MADE TO A 6318' PINNACLE FROM THE SOUTHEAST. ACCORDING TO THE STUDENT, THE WIND WAS FROM THE EAST AT 8 TO 10 KTS. AS THE CFI FLEW TO A 4' HOVER, THERE WAS A LOSS OF TAIL ROTOR CONTROL & THE HELICOPTER BEGAN AN UNCOMMANDED RIGHT TURN. THE CFI MADE A HOVERING AUTOROTATION, BUT THE HELICOPTER TOUCHED DOWN ON AN OUTCROPPING OF ROCK & ROCKED BACKWARD. SUBSEQUENTLY, THE TAIL STINGER & TAIL ROTOR BLADES STRUCK THE TERRAIN & THE HELICOPTER WAS DAMAGED. LATER, THE CFI SAID HE BELIEVED THE TAIL ROTOR CONTROL CABLES HAD UNSPOOLED FROM THE DRUM & RESULTED IN THE LOSS OF CONTROL. HOWEVER, A POST-ACDNT EXAM FAILED TO REVEAL EVIDENCE OF A PRE-ACDNT FAILURE OR MALFUNCTION. DENSITY ALT WAS APRX 8600'. APRX 7 MIEAST AT JEFFCO ARPT, THE WIND WAS FROM 140 DEG AT 10 KTS.
Probable Cause: IMPROPER IN-FLIGHT PLANNING/DECISION BY THE CFI WHICH RESULTED IN LOSS OF TAIL ROTOR EFFECTIVENESS AND LOSS OF DIRECTIONAL CONTROL. CONTRIBUTING FACTORS WERE HIGH DENSITY ALTITUDE, TAILWIND, AND ROUGH/UNEVEN TERRAIN.
Accident investigation:
 |
|
Sources:
NTSB DEN89LA084
History of this aircraft
Other occurrences involving this aircraft
| 17 April 1985 | N7411N | Private | 0 | Broomfield, CO | |
min |
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 24-Mar-2024 10:59 | ASN Update Bot | Added |
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