BOEING Co has resumed deliveries of its high-tech 787 Dreamliner jet, ending a period of nearly four months in which it was unable to provide new planes to customers because of safety concerns about the battery system.

The delivery of the first jet with a redesigned battery system marks a turning point in Boeing's 787 crisis, allowing the jet maker to book revenue for completed sales of the jet, which costs US$207 million at list prices.

Resuming deliveries will lower Boeing's profit margin in the near term, though. The 787s being delivered now are among the relatively early jets that are more costly to make and that were sold at steep discounts to attract customers.

Boeing has never given a final cost estimate for the 787's grounding and repairs, though it absorbed nearly all of the impact in the first quarter while still posting a rise in profit. Some analysts have projected a final cost of US$600 million.

The deliveries will improve Boeing's cash flow this year, however, and will reduce its inventory, something investors have been anticipating as they bid up its stock.

Boeing said it delivered a new Dreamliner to All Nippon Airways on Tuesday, its second delivery of this year. The first was delivered before January 16, when regulators grounded the worldwide Dreamliner fleet after two lithium-ion batteries overheated and smoked on two separate jets that month.

Boeing also reaffirmed that it expects to hit its target of delivering more than 60 787s this year.

Analysts said the target should be easy to hit. Boeing kept making Dreamliners while the plane was grounded, so about 25 are parked outside its factories waiting to be delivered to customers.

Boeing also has sped up production. Last week, it rolled out the first 787 made at the new rate of seven per month, up from five per month previously. It aims to raise the rate to 10 per month by year-end, with the first delivery at the new rate in 2014.

After the two incidents in January, Boeing redesigned the 787 battery system, adding a steel enclosure and other safeguards to prevent fire.