# NTSB DEN84LA177: Hiller UH-12E, N504HA, Granby, CO, June 11, 1984

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: June 11, 1984, 07:00 local (13:00 UTC)
- Place: Granby, CO
- Coordinates: 40.08002, -105.929313 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.0800&lon=-105.9293&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 16398
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN84LA177
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16398/pdf
- Page: https://openairdocs.org/ntsb/DEN84LA177

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Loss of control - in flight, approach - vfr pattern - final approach
  - in-flight planning/decision - improper, pilot in command (cause)
  - terrain condition - mountainous/hilly (contributing factor)
  - weather condition - high density altitude (contributing factor)
  - weather condition - unfavorable wind (contributing factor)
  - airspeed - reduced, pilot in command
  - level off - not possible
  - descent - uncontrolled, pilot in command
- In flight collision with object, descent - uncontrolled
  - object - tree(s) (contributing factor)
- In flight collision with terrain/water, descent - uncontrolled
  - terrain condition - rough/uneven (contributing factor)
- Roll over, landing

## Analysis

THE HELICOPTER PLT WAS ON A RECONNAISSANCE FLT TO SURVEY A HILLTOP LANDING SITE IN MOUNTAINOUS TERRAIN. WHEN HE ARRIVED, HE MADE A HIGH RECONNAISSANCE PASS, THEN BEGAN A LOW RECONNAISSANCE APCH. HE ESTIMATED THE WIND WAS FROM 210 DEG AT 10 TO 15 KTS WITH LIGHT TURBULENCE. HIS APCH WAS MADE ON A HEADING OF 200 DEG. HE BEGAN HIS APCH AT APRX 40 KTS & WITH A DESCENT RATE OF 200 FT/MIN. WHEN THE HELICOPTER WAS ABOUT 150 FT FROM THE HILLTOP & APRX 50 FT ABOVE IT, THE AIRSPEED DROPPED TO ZERO & THE RATE OF DESCENT INCREASED. THE PLT APPLIED FULL POWER & TURNED DOWN A VALLEY TO THE RIGHT, BUT COULD NOT STOP THE DESCENT. THE HELICOPTER THEN HIT A TREE, TOUCHED DOWN ON SLOPING TERRAIN & ROLLED OVER. THE ELEVATION & DENSITY ALT WERE ABOUT 9200 & 10,040 FT, RESPECTIVELY. THE HELICOPTER'S HOVER CEILING OUT OF GROUND EFFECT WAS ABOUT 8500 FT; IN GROUND EFFECT, THE HOVER CEILING WAS APRX 11,800 FT.

## Aircraft

- Registration: [N504HA](https://openairdocs.org/aircraft/N504HA), registered now, S/N 5004 (OpenAirDocs)
- Reported make and model: HILLER UH-12E
- Registry model: [Hiller UH-12E](https://openairdocs.org/model/hiller-uh-12e) (registry code 4360122) (OpenAirDocs)
- Registry engine: [Lycoming VO-540 series](https://openairdocs.org/engine/lycoming-vo-540-series) (registry code 41534, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Airframe hours: 1700
- Engines: LYCOMING VO-540-C2A 305 horsepower reciprocating
- Damage: Substantial damage
- Flight: Other work use, Part 91
- Registered owner: Hoffman Pilot Center, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, May 23, 1984, 60 hours before
- Departed: GRANBY, CO

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 25; flight instructor, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane, helicopter; medical: class 1, valid medical--no waivers/lim.; seat: center; flight hours: 4,100 total, 150 in this make and model, 3,350 as pilot in command, 200 in the last 90 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 210° at 15 knots
- Visibility: 40 statute miles
- Lowest ceiling: none
- Temperature: 37 °F, dew point -0 °F

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19840611025369A](https://openairdocs.org/incident/19840611025369A), Jun 11, 1984: Hiller UH12E, Granby, CO, Substantial damage. Encountered a downdraft during a low level survey. Unable to slow descent. Struck the ground and rolled over.

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.

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