# NTSB DEN07CA001: Brantly Helicopter B-2, N5950X, Arkansas City, KS, October 1, 2006

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Data collection · Final report
- Date: October 1, 2006, 08:30 local (13:30 UTC)
- Place: Arkansas City, KS
- Coordinates: 37.066665, -96.916664
- Nearby events: https://openairdocs.org/map.md?lat=37.0667&lon=-96.9167&mi=10
- Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor
- Status: Completed, report January 31, 2007
- Report: Approved by Office Director
- NTSB case key (mKey): 64631
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN07CA001
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/64631/pdf
- Page: https://openairdocs.org/ntsb/DEN07CA001

## Probable cause

the pilot's failure to maintain aircraft control during takeoff.  A contributing factor was the low rotor RPM.

## Sequence of events

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

- Loss of control - in flight, takeoff
  - aircraft control - not maintained, pilot in command (cause)
  - rotor rpm - not maintained, pilot in command (contributing factor)
  - weather condition - gusts
- In flight collision with terrain/water, descent - uncontrolled
  - dynamic rollover - encountered, pilot in command
  - terrain condition - ground

## Analysis

According to the pilot, during the attempted takeoff, he raised the collective and the helicopter "became light on its skids."  The pilot verified the wind conditions based on his observation with nearby trees.  The wind was observed to be "light" and from the south-southwest direction.  The pilot initiated a turn into the direction of the wind, and prior to transitional lift, the rotor RPM dropped.  The pilot attempted to recover the drop in rotor RPM by lowering the collective.  The helicopter skids touched the terrain, and the helicopter rolled over on it's right side.  The pilot stated, "I believe I got a wind gust that contributed to the low [rotor] RPM."

## Factual narrative

According to the pilot, during the attempted takeoff, he raised the collective and the helicopter "became light on its skids."  The pilot verified the wind conditions based his observation with nearby trees.  The wind was observed to be "light" and from the south-southwest direction.  The pilot initiated a turn into the direction of the wind, and prior to transational lift, the rotor RPM dropped.  The pilot attempted to recover the drop in rotor RPM by lowering the collective.  The helicopter skids touched the terrain, and the helicopter rolled over on it's right side.  The pilot stated, "I believe I got a wind gust that contributed to the low [rotor] RPM."

## Aircraft

- Registration: [N5950X](https://openairdocs.org/aircraft/N5950X), registered now, S/N 89 (OpenAirDocs)
- Reported make and model: Brantly Helicopter B-2
- Registry model: [Brantly B-2](https://openairdocs.org/model/brantly-b-2) (registry code 1440502) (OpenAirDocs)
- Category: Helicopter
- Serial number: 89
- Engines: Lycoming VO-360-A1B reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: John W. Read
- Airworthiness certificate: Standard, Normal
- Departed: Arkansas City, KS

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 59; private; airplane ratings: single-engine land; medical: class 3; flight hours: 1,575 total, 275 in this make and model, 20 in the last 90 days, 12 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day

## 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 20061001020539A](https://openairdocs.org/incident/20061001020539A), Oct 1, 2006: Hynes B2, Silverdale City, KS, Substantial damage. (-23) On takeoff, the pilot experienced low rotor RPM. The pilot elected to land the aircraft. On touchdown, the aircraft translating sideways. The aircraft…

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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