EC135 Faces Fuel Sensor Fault

 - December 26, 2013, 11:00 AM

The Eurocopter EC135 light twin helicopter is facing more trouble after the EASA issued an emergency airworthiness directive on December 19 referring to a manufacturer alert service bulletin that requires a one-time check of fuel probes and, possibly, cleaning and replacement. The issue, discovered by Bond Air Services, appears to be that the probes are indicating a fuel level higher than actual. Investigations showed that the incorrect signals that the probes transmit to the indicator may also inhibit the amber “fuel caution” light. Tests confirmed the problem starts with water contamination. As of December 23, 264 sensors had been tested. Of those, 12 needed to be cleaned but were fully functional afterward, while two failed and needed to be replaced. Meanwhile, the “low fuel” warning system is independent and remains reliable, Eurocopter said. Pilots should thus strictly heed the red “low fuel” light, regardless of the fuel quantity indication. The company has also issued a safety information notice for EC145 operators, as the latter helicopter uses similar fuel sensors.