Pilot Debrief

BELL OH-58A near Taylorsville, MS — 2010-09-24

Final reportERA10LA499
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Date
2010-09-24
Location
Taylorsville, MS, USA
Aircraft
BELL OH-58A
Registration
N132HD
Category
Helicopter
Highest injury
Serious
Fatalities
0
Phase of flight
Cruise

Probable cause

A total loss of engine power while maneuvering at low altitude for undetermined reasons.

NTSB narrative

The helicopter pilot was surveying a field in preparation for aerial application. While he was maneuvering the helicopter about 100 feet above the ground, the engine lost all power without warning. The pilot noticed a space in between the trees and attempted to autorotate to that spot, but the helicopter impacted trees nearby. A postaccident examination of the wreckage revealed 16 gallons of fuel remained in the helicopter and no fuel contamination was observed. A successful test-run of the engine was subsequently performed. Examination of the fuel boost pump revealed that the inlet shut-off valve arm was bent, which could restrict fuel flow. When power was applied to the pump, it pumped fuel from a bucket; however, it did not appear to pump the fuel at maximum capacity. Further testing was performed utilizing both the bent arm and a replacement stock arm. The test results were similar for both arms, which were both below the pump's flow requirements. The bent arm was re-installed and a third examination was conducted at the pump manufacturer's facility, which revealed that the pump's ring tong terminals and pump cartridge were the incorrect models for the fuel boost pump; however, during the third test, the pump passed flow tests as received, and flow improved when the inlet valve stem assembly and cartridge were replaced. The bent inlet shut-off valve arm and/or incorrect fuel boost pump assembly could have resulted in a total loss of engine power; however, the investigation could not determine what, if any, effect they had on the helicopter at the time of the accident.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have checked fuel boost pump functionality before flight.

NTSB coding

Evidence available

  • Video
  • Photos
  • 12 docket documents
View NTSB final reportView NTSB docket

Docket documents12

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