Pilot Debrief

BELL 206 near High Island A-442A — 2009-11-01

Final reportCEN10LA036
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Date
2009-11-01
Location
High Island A-442A, USA
Airport
A442
Aircraft
BELL 206
Registration
N272M
Category
Helicopter
Highest injury
Serious
Fatalities
0
Phase of flight
Initial climb

Probable cause

A total loss of engine power due to maintenance personnel's failure to correctly torque the Pc line following removal and reinstallation of the turbine module.

NTSB narrative

The helicopter had landed on an off-shore oil platform and was refueled. It then took off with one passenger. Shortly after lifting off, the pilot "heard a loud pop as the nose of the aircraft passed over the edge of the helideck. The noise was simultaneously accompanied by illumination of the engine out warning light and a needle split indication was observed on the engine and rotor tachometer gauge. As the aircraft yawed and lost climb performance, the pilot lowered the collective pitch full down and activated the floats. Upon landing on the water, the aircraft rolled left until inverted. The helicopter was later recovered and the engine disassembled and examined. The only anomaly noted was a loose Pc line, which would cause a loss of fuel flow and subsequent loss of engine power down to or below idle. It was determined that the torque required to realign the B-nut would be between hand-tight and 27 inch-pounds. The required torque is 80 to 120 inch-pounds. Torque values on the other air line fittings between the power turbine governor and the fuel control were found to range from 55 to 85 inch-pounds. A review of the engine maintenance records revealed that 36.7 hours prior to the accident, the turbine module was completely disassembled and overhauled. This would have required the removal and re-installation of the Pc line.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Properly securing the Pc line during maintenance could have prevented the engine power loss.

NTSB coding

Evidence available

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

Docket documents8

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