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Aviation safety reports, made easier to study

NTSB Reports is an independent research and search tool for public aviation accident and incident records. It brings NTSB aviation reports, structured fields, docket files, extracted figures, photos, videos, and update history into one searchable interface.

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NTSB Report

March 9, 1989 · Hiller UH-12E · N7411N

Golden, CO

Overview

Report Status
Probable Cause
Event Type
Accident
Date
March 9, 1989
Injury Outcomes
No injuries (2 uninjured)
Location
Golden, CO
Aircraft
Hiller UH-12E
Tail Number
N7411N
Operator
Harry G Laforge
Injuries
None
Aircraft Damage
Substantial
NTSB Number
DEN89LA084

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.

NTSB 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.

Full Narrative

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.

Flight

Event TypeAccident
Event Time14:55 MST
Nearest Airport0nm N
Runway0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo

Aircraft

AircraftHiller UH-12E
Tail NumberN7411N
Aircraft CategoryHeli
DamageSubstantial
OperatorHarry G Laforge
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsLycoming · VO-540-C2A · Reciprocating · 305
Seats3

People & Injuries

Injury SummaryNo injuries (2 uninjured)
Fatal0
Serious0
Minor0
Uninjured2
Total2
Crew 1Age 42 · Second Class

Conditions

ConditionsVMC
LightDaylight
Wind140° @ 10 kt
Visibility60 sm
CeilingBroken clouds 20000 ft
Temperature / Dew Point28 C
Altimeter30.00 inHg
Observation Time21:53
Weather SourceWFAC

Appendix: Source Data