Eurocopter expects the three interim fixes that will return the grounded fleet of EC225 heavy helicopters back into operations to be certified in the coming days.

The EADS-owned company is packaging together the fixes, which it hopes will allow the aircraft to return operations over hostile environments by mid-July. Eurocopter has already indicated to EC225 operators that the final definitive correction to the problem will be redesign of the bevel gear shaft, a critical component in the main gearbox that drives two lubrication pumps.

Among the interim fixes being packaged by Eurocopter is a new shaft-cleaning procedure that removes the presence of mud generated by the wear of the splines and thus the localized humid environment on the shaft. The company says this will “significantly reduce the possibility of active corrosion and the likelihood of crack initiation.”

The company is also suggesting the introduction of an ultrasonic nondestructive inspection as an alternative to the eddy current method now in use. Eurocopter says this would be a faster process and would ensure that crack initiation be identified before flight. Company documents suggest tests should take place every eight to 10 hours.

The primary interim fix will be the certification of real-time monitoring of the shaft using an upgraded health and usage monitoring system. When fitted, the system will consist of an onboard cockpit amber warning to signal inflight if vibration levels indicate the presence of a crack. In the event of a warning, the aircraft will continue to safely operate for sufficient flight time to permit the pilot to return to base or perform a normal landing. Eurocopter believes that a flight time of about two hours will be allowed following the initiation of an inflight warning

Jean-Brice Dumont, EVP of engineering at Eurocopter, told ShowNews at the Paris Air Show that the company had completed flight trials and tests on all three systems and had flown a cracked gearbox up to the point of failure to validate the tests of the real-time monitoring system.

Dumont says the company now has the job of convincing “operators, oil companies, their employees and hearts and minds” that the aircraft is now safe.

The company also used the show to announce a further delay in the certification of its new EC175 medium helicopter. Certification of the aircraft is now due in early 2014 because of issues with the aircraft’s Helionix avionics suite.