Norwegian Air Shuttle is expected to return its grounded Boeing 787-8s to service later this week after the manufacturer implemented an aggressive “get well’ campaign to improve spare parts provision, maintenance and engineering support.

Boeing also has accepted that the initial in-service experience of the 787 has fallen short of expectations, despite concerted efforts to overcome a continuing series of reliability issues in the wake of the aircraft’s three-month grounding at the start of 2013 due to battery problems.

Commenting in Santiago, Chile, where Boeing was discussing its current market outlook, Commercial Airplanes Marketing Vice President Randy Tinseth says “today, the reliability of the 787 is better than 95%. It’s not as good as we’d like to see it. It’s not as good as our customers would like to see it. So we’re looking at ways to improve that reliability over time.”

The situation at Norwegian came to a head at the end of September following several weeks of reliability issues, ranging from the power distribution system and hydraulics to the aircraft’s oxygen system and brakes. These culminated in the airline’s two aircraft being temporarily grounded while a comprehensive set of upgrades and improvements were installed.

Norwegian also leased an Airbus A340 to cover its flight schedule commitments.

Boeing says that “in consultation with Norwegian, the decision has been made to implement a number of enhancements to improve the airplane’s in-service reliability. As a result, it is expected the airplane will be out of service for a matter of days.”

The airline, which has eight 787-8s on order, “has contracted with Boeing to provide engineering, spare parts and maintenance services for its 787s. These services are managed by Boeing, working with qualified maintenance, repair and overhaul providers,” says the aircraft manufacturer, which adds it is “working tirelessly to provide support to Norwegian. We regret the inconvenience and disruption caused to the airline and its passengers as a result of this process.”

As part of this effort, Boeing is stocking additional spares at every destination covered by Norwegian’s network.

Meanwhile, Polish carrier LOT has returned to service a 787-8 that diverted to Keflavik International Airport in Reykjavik on Sept. 29 as the result of an inoperative transponder antenna while flying from Toronto Pearson International Airport to Warsaw Chopin Airport.