Background
The helicopter had experienced several inflight engine decelerations that maintenance efforts did not isolate. In response, maintenance personnel replaced the engine fuel controller.
Test Flight and Landing
Following the replacement, a test flight was conducted from an oil drilling platform. During the flight, the engine surged and then decelerated. The pilot was unable to reach the helipad and elected to land on the platform, short of the helipad, rather than accept sea conditions of 8-foot waves. During the landing, the helicopter was damaged.
Post-Accident Examination
A post-accident examination revealed that fuel contamination had occurred. The contamination had bypassed filters in the fuel system and had clogged and collapsed the engine fuel nozzle screen. Additionally, the airframe fuel filter cap bypass valve was found stuck open in the bypass mode. A pin connected to the fuel filter cap impending bypass test button was found bent, holding the bypass valve open. An open bypass valve should have illuminated a respective annunciator light in the cockpit; however, when checked, the annunciator light operated only intermittently due to a faulty component in the system. During tests, the clogged and collapsed fuel screen prevented sufficient fuel flow to sustain engine power.