Eurocopter continues to search for the root cause of the main gearbox failure that resulted in forced but controlled ditchings by two EC225s last year. Early last month, the manufacturer was still hoping it would be able to recommend a return to flight in February. In a written statement sent to AIN late last week, however, it refers only to an “update on the situation” at the end of February.
To find out why a crack initiated in the shaft, engineers are conducting extensive ground and flight testing. These tests have allowed them “to observe potential contributing phenomena.” However, engineers could not, as of late December, record “a sufficient stress level to explain a possible crack initiation.” More advanced instrumentation is to be used “to record very high frequency stresses.”
Eurocopter is also developing solutions to avoid false alarms from the emergency lubrication system. Meanwhile, a safety information notice has been issued to operators. It provides operators with a “justification” of the three-hour check interval, as well as a “clarification” of the alert service bulletin’s content.