# NTSB ANC83FA092: Bell B47G-2, N6140C, Anchorage, AK, June 7, 1983

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Field investigation · Final report
- Date: June 6, 1983, 16:45 local (Jun 7, 1983, 00:45 UTC)
- Place: Anchorage, AK
- Coordinates: 61.21944, -149.849243 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=61.2194&lon=-149.8492&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 4027
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC83FA092
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/4027/pdf
- Page: https://openairdocs.org/ntsb/ANC83FA092

## Sequence of events

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

- Airframe/component/system failure/malfunction, approach - vfr pattern - downwind
  - door,exterior crew - worn (contributing factor)
  - maintenance - inadequate, company maintenance personnel (contributing factor)
  - door,exterior crew - open (contributing factor)
- Dragged wing,rotor,pod,float or tail/skid, landing - flare/touchdown
  - power on landing - performed, pilot in command (contributing factor)
  - airspeed - misjudged, pilot in command (cause)
  - altitude - misjudged, pilot in command (cause)
- Hard landing, landing - flare/touchdown

## Analysis

THE HELICOPTER EXPERIENCED A TAIL ROTOR STRIKE DURING A HARD LANDING WITH A DOOR OPEN. ACCORDING TO THE STUDENT PILOT WHO IS A COMMERCIAL PILOT WORKING ON AN ADD-ON HELICOPTER RATING, THE LEFT COCKPIT DOOR UNLATCHED AND PARTIALLY OPENED ON THE DOWNWIND LEG FOR TOUCH-AND-GO PRACTICE LANDING. SHE CONTINUED THE PATTERN AND FINAL APPROACH WITH THE DOOR UNLATCHED WITHOUT FURTHER INCIDENT. SHE EXPECTED THE DOOR TO FULLY OPEN JUST PRIOR TO TOUCHDOWN WHICH IT DID. AS THE DOOR OPENED SHE APPLIED AFT CYCLIC AND FELT THE SKIDS TOUCH DOWN HARDER THAN NORMAL. THE HELICOPTER SLID FORWARD A SHORTDISTANCE WHILE REMAINING ALIGNED WITH THE RUNWAY. WHEN THE ACFT STOPPED THE PILOT LOOKED OUT AND NOTICED THE TAIL ROTOR HAD SEPARATED FROM THE HELICOPTER. INSPECTION OF THE DOOR LATCH SHOWED A WORN LATCH ASSEMBLY WHICH WAS DIFFICULT TO CLOSE PROPERLY. INSPECTION OF THE RUNWAY SURFACE REVEALED A TAILROTOR/GUARD STRIKE PRIOR TO ACFTS MAIN SKIDS TOUCHING THE GROUND.

## Aircraft

- Registration: [N6140C](https://openairdocs.org/aircraft/N6140C), registered now, S/N 47, built 1948 (OpenAirDocs)
- Reported make and model: BELL B47G-2
- Registry model: [Bell 47G-2](https://openairdocs.org/model/bell-47g-2) (registry code 1181008) (OpenAirDocs)
- Registry engine: [Lycoming VO-435 series](https://openairdocs.org/engine/lycoming-vo-435-series) (registry code 41525, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 415-31
- Airframe hours: 7870
- Engines: LYCOMING VO-435-A1B 200 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Registered owner: Wilburs, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, May 10, 1983, 46 hours before
- Departed: MRI, ANCHORAGE, AK
- Flight plan: Company VFR
- Airport: CSR, Campbell Airstrip, runway 2, 5,000 × 150 ft, dirt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; commercial; airplane ratings: single-engine land, single-engine sea; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 516 total, 32 in this make and model, 345 as pilot in command, 44 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 50 statute miles
- Lowest ceiling: none
- Temperature: 61 °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 19830607022309A](https://openairdocs.org/incident/19830607022309A), Jun 7, 1983: Bell 47G2, Anchorage, AK, Substantial damage. Cabin door became ajar in flight and opened fully on late landing flare. Main rotors severed tail boom from impact.

## Other investigations on N6140C (3)

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 ANC87FA043](https://openairdocs.org/ntsb/ANC87FA043), Mar 7, 1987: Bell 47G-2 (N6140C), Anchorage, AK, substantial damage
- [NTSB ANC75AA029](https://openairdocs.org/ntsb/ANC75AA029), Aug 27, 1975: Bell 47G-2 (N6140C), Hurricane, AK, substantial damage
- [NTSB ANC75AAG87](https://openairdocs.org/ntsb/ANC75AAG87), May 1, 1975: Bell 47G-2 (N6140C), Anchorage, AK, 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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