Fuel system checks of the worldwide EC135 helicopter fleet have turned up some additional faulty sensors, according to manufacturer Eurocopter.
As of Dec. 31, approximately 20 percent of the global EC135 fleet of 1,050 helicopters had undergone the one-time fuel tank system checks that were required by an Alert Service Bulletin issued on Dec. 19. According to Eurocopter, of the 410 sensors that were tested on 205 aircraft, 19 sensors needed to be cleaned but were fully functional afterwards. Separate to those, three sensors failed and needed to be replaced. The remaining 388 sensors passed the test.
The Alert Service Bulletin was prompted by the discovery of supply-tank fuel gauging errors in EC135 helicopters flown by Bond Air Services and two other operators in Europe. According to the bulletin, tests have confirmed that the EC135’s fuel content probes generate erroneously high signals if contamination with water occurs.
The contamination causes an incorrect frequency to be transmitted to the indicating system, leading to a higher-than-actual indication of fuel quantity and preventing the amber fuel caution light from operating. However, the problem does not prevent the red “low fuel” warning light from operating, and Eurocopter said that the red low fuel warning light system has been functional on all of the 205 aircraft tested so far.
Eurocopter said it “continues to monitor the checks closely and will provide updates as more information becomes available.”
To read the Alert Service Bulletin on the Eurocopter website, click here.
