# NTSB DEN93LA070: Enstrom F-28C, N625H, Boulder, CO, June 27, 1993

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: June 26, 1993, 22:40 local (Jun 27, 1993, 04:40 UTC)
- Place: Boulder, CO
- Coordinates: 40.039596, -105.369911 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.0396&lon=-105.3699&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report December 3, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 18296
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN93LA070
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18296/pdf
- Page: https://openairdocs.org/ntsb/DEN93LA070

## Probable cause

A FAILURE BY THE PILOT FLYING TO ADEQUATELY COMPENSATE FOR WIND CONDITIONS WHICH LED TO A LOSS OF TAIL ROTOR CONTROL. A FACTOR WAS:  INADEQUATE SUPERVISION BY THE PILOT IN COMMAND.

## Sequence of events

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

- Loss of control - in flight, maneuvering
  - weather condition - unfavorable wind
  - compensation for wind conditions - not performed, copilot/second pilot (cause)
  - supervision - inadequate, pilot in command (contributing factor)
- In flight collision with object, descent - uncontrolled
  - object - vehicle

## Analysis

DURING A ONE TIME RENTAL PATROL FLIGHT, THE SHERIFF'S DEPUTIES AIR TAXIED THE HELICOPTER BY THE DISPATCH BUILDING AND AIMED THE HELICOPTER SPOTLIGHT IN THE WINDOW TO ALERT THE DISPATCHER THAT THEY WERE ATTEMPTING TO COMMUNICATE VIA PORTABLE RADIO.  THE HELICOPTER BEGAN TO SPIN TO THE RIGHT AND AFTER SEVERAL REVOLUTIONS, THE PILOT IN COMMAND TOOK CONTROL FROM THE SECOND PILOT AND CUT POWER IN ORDER TO STOP THE SPIN.  HE GUIDED THE HELICOPTER TO THE POLICE PARKING LOT BESIDE THE BUILDING AND COLLIDED WITH TWO VEHICLES PARKED IN THE LOT.  THE TAIL ROTOR DRIVE AND CONTROL SYSTEM WERE NOT COMPROMISED IN THE ACCIDENT AND EXAMINATION PROVIDED NO EVIDENCE OF FAILURE OR MALFUNCTION.  ACTUAL WIND CONDITIONS AT THE ACCIDENT SITE ARE UNKNOWN; HOWEVER, THE PILOT FLYING STATED THAT HE THOUGHT A WIND SHIFT OCCURRED AND HE WAS ATTEMPTING TO TURN INTO THE WIND WHEN CONTROL WAS LOST.

## Aircraft

- Registration: [N625H](https://openairdocs.org/deregistered/N625H-2017-04-04), registration cancelled 2017-04-04, S/N 346, built 1976 (OpenAirDocs)
- Reported make and model: ENSTROM F-28C
- Registry model: [Enstrom F-28C](https://openairdocs.org/model/enstrom-f-28c) (registry code 3300407) (OpenAirDocs)
- Registry engine: [Lycoming HIO-360 series](https://openairdocs.org/engine/lycoming-hio-360-series) (registry code 41524, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 346
- Airframe hours: 2161
- Engines: LYCOMING VHIO-360-EIAD 205 horsepower reciprocating
- Damage: Substantial damage
- Flight: Other work use, Part 91
- Operator: Falcon Helicopters, Inc.
- Registered owner: Timothy C. Rhoads
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, June 14, 1993, 304 hours before
- Departed: 2V2, LONGMONT, CO
- Destination: 2V2

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; flight instructor, commercial; airplane ratings: single-engine sea; medical: class 2, valid medical--no waivers/lim.; flight hours: 740 total, 27 in this make and model, 633 as pilot in command, 21 in the last 90 days

## Weather

- Conditions: Visual (VMC), Night/bright
- Wind: 360° at 3 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 64 °F, dew point 43 °F
- Altimeter: 30.00 inHg
- Observed at: DEN, 20 nm away

## 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 19930626020669A](https://openairdocs.org/incident/19930626020669A), Jun 26, 1993: Enstrm F28C, Boulder, CO, Substantial damage. Entered spin descending slow speed pilot cut power. Landed parking lot. Hit vehicles. Lost tail rotor effect.

## Other investigations on N625H (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 MKC76DER77](https://openairdocs.org/ntsb/MKC76DER77), Jul 4, 1976: Enstron F-28 (N625H), Ortonville, MN, substantial damage

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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