Canada's CHC Helicopter will have returned its entire fleet of Eurocopter EC225s to service by the end of 2013 following the successful deployment of an interim fix for the previously grounded type.

Speaking on a second-quarter earnings call on 12 December, chief executive Bill Amelio said 29 of its 31-strong Super Puma fleet was now up and running, with "two more to go for the rest of the month".

Returning the aircraft to service has been "no simple task for our people", says Amelio, but it is "good for our company and our customers".

CHC is the world's largest operator of the 11t helicopter, and has seen its financial performance knocked since the EC225 fleet was effectively grounded in October 2012. The restriction on overwater flights came on the back of a pair of North Sea ditchings last year - the second involving a CHC Scotia aircraft - due to a fault with a key gearbox component.

The operator quantifies the impact in the three months to 31 October as being in the region of $10 million, due to both lost revenue and the additional costs incurred at its maintenance arm Heli-One through delivering the interim fix and ensuring other types were available to back-fill for the grounded EC225s.

One consequence of the issues with the EC225, says Amelio, is a tightening of supply of medium and heavy aircraft across all manufacturers, with it now "upwards of 36-40 months to get in the order queue".