Follows Two Separate Events In Which Helicopters Were Ditched In The North Sea

EASA has published  an Airworthiness Directive which approves and mandates the technical solution proposed by Eurocopter for its EC225 fleet. The objective is to fix the unsafe condition created by the shaft failure of two EC225 helicopters in the North Sea in 2012.

According to the AD, two separate events occurred in 2012 of EC 225 LP helicopters carrying out an emergency ditching in the North Sea after warning indication of MGB loss of oil pressure and subsequent additional red alarm on the MGB emergency lubrication system (EMLUB). In both cases, a full circumferential crack of the lower vertical shaft of the MGB bevel gear occurred in the area where the two sections of the shaft are welded together. As a result, the vertical shaft ceased to drive the main and backup oil pumps, leading to warning indications of the loss of the MGB main and standby oil lubrication systems. The crew activated the EMLUB system and, following a subsequent warning indicating failure of that system, performed a controlled ditching into the sea.

The Eurocopter solution comprises of a set of modifications and inspections which aim at monitoring and detecting vertical shaft crack conditions and reducing the likelihood of any shaft crack initiation. When complied with, this solution ensures safe and airworthy operations of the EC225 type.

EASA says it will continue to work closely with Eurocopter, with the relevant National Aviation Authorities and the accident investigators to ensure that the fleet is operated safely, and may update its directive based on further investigation results.

(EC225 image from file.)

FMI: EASA AD