Pilot Debrief

BELL 206B near Amarillo, TX — 2012-04-26

Final reportCEN12LA258
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Date
2012-04-26
Location
Amarillo, TX, USA
Airport
AMA
Aircraft
BELL 206B
Registration
N2068X
Category
Helicopter
Highest injury
Minor
Fatalities
0
Phase of flight
Landing

Probable cause

The pilot's failure to maintain helicopter control during landing in gusty wind conditions associated with a thunderstorm, which resulted in a loss of tail rotor effectiveness.

NTSB narrative

The pilot reported that he was aware of lightning and a thunderstorm that was close to the airport and approaching from the southwest. He was flying an approach to the southeast and planned to approach “straight in” to the hangar. As he began to flare to stop the descent, movement of the cyclic stick was briefly hindered by a laptop computer in the left seat passenger’s lap; the passenger immediately moved the obstructing laptop computer. The helicopter was then about level with the hangar roof when, according to the pilot, a strong gust of wind forced the helicopter’s nose up, and the helicopter briefly entered into a climbing right turn. The helicopter then began a sudden uncommanded turn, spinning to the right. The pilot reported that left pedal input had no effect and that he had only partial control as the helicopter made a full 360-degree turn, descended, and impacted the ground. During the impact with the ground, the lower fuselage sustained crushing damage, and the main rotor separated from the main rotor mast. A significant amount of fuel spilled during the impact, but no postimpact fire occurred. After the crash, both occupants were able to extract themselves from the wreckage unassisted. According to a weather observation station at the airport, the wind was from 120 degrees at 19 knots, gusting to 25 knots, and a thunderstorm was recorded on the field. Federal Aviation Administration Advisory Circular 90-95, “Unanticipated Right Yaw in Helicopters,” describes loss of tail rotor effectiveness (LTE) as a critical, low speed aerodynamic flight characteristic that could result in an uncommanded rapid yaw rate that does not subside of its own accord and, if not corrected, could result in the loss of aircraft control. The pilot was operating the helicopter in a low airspeed, out-of-ground-effect, high-power-demand flight condition, which could have resulted in LTE.

Analysis

Primary failure mode
Loss of control
First missed decision gate
Pilot could have aborted landing due to strong winds and thunderstorm approach.

NTSB coding

Evidence available

  • Photos
  • 6 docket documents
View NTSB final reportView NTSB docket

Docket documents6

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