Pilot Debrief

BELL OH-58A near Pine Springs, TX — 2013-02-14

Final reportCEN13TA165
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Date
2013-02-14
Location
Pine Springs, TX, USA
Aircraft
BELL OH-58A
Registration
N337PW
Category
Helicopter
Highest injury
Minor
Fatalities
0
Phase of flight
Maneuvering

Probable cause

The pilot's failure to maintain directional control while operating in conditions conducive to a loss of tail rotor effectiveness.

NTSB narrative

The pilot and two passengers were surveying a preplanned transect about 50 to 100 feet above ground level with a 5- to 10-knot left crosswind and an indicated groundspeed of 30 to 35 knots. As the terrain began to rise, the pilot added power to clear a ridge. The pilot reported that, when the helicopter was about 100 feet from the top of the ridge, he heard a " slight pop" and that the helicopter began to yaw to the right. He added power to clear the ridgeline, which greatly increased the right yawing motion, and the helicopter began to spin. He stated that the helicopter crossed over the ridgeline backward and continued to spin before it contacted the ground and rolled over onto its left side. A passenger reported that, although the wind was about 10 knots when they started the survey, the wind speed increased when the helicopter reached the top of the ridge, and the pilot had to correct for it twice before the helicopter began to spin to the right. A postaccident examination of the helicopter revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation. The helicopter was operating in an environment conducive to the loss of tail rotor effectiveness (LTE), and the unanticipated right yaw and subsequent spinning of the helicopter are consistent with LTE.

Analysis

Primary failure mode
Loss of control
First missed decision gate
Pilot could have avoided high-power, low-airspeed environment with left crosswind.

NTSB coding

Evidence available

  • 5 docket documents
View NTSB final reportView NTSB docket

Docket documents5

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