Impact Analysis on the Removal of Filter/Monitors from USN/USMC Helicopter in Flight Refueling Systems.

摘要

The USAF released a message in July 2005 that stated recent single engine flame-out incidents involving three trainer aircraft had occurred, the root cause of the problem had been aircraft filter plugging, and that all water absorbing filters were being removed from service. The investigation by the USAF following the incident indicated that the super absorbent polymer (SAP) used in manufacturing the filter/monitors had migrated downstream and had collected in engine fuel filters and controls, possibly causing the flame-out incidents. In response to these events, the Navy Fuels Team initiated an investigation into the migration of SAP downstream of filter/monitors, and the resulting risk to aircraft fuel system operation. In June 2007, the Navy Fuels Team released NAVAIRSYSCOM Report 441/07-002 that recommended removal of all monitors from land based refueling systems. The report also recommended that a separate risk analysis be performed on the use of filter/monitors containing SAP in helicopter in flight refueling (HIFR) systems. The utilization of monitors in HIFR applications is significantly different than in land-based fueling systems and therefore warrants its own risk assessment. This report identifies the risks and provides recommendations.