Nine more aircraft, worth about $1.8bn, have been added by the US Navy to the Boeing P-8A Poseidon programme.

The increase in the quantity of aircraft announced at this year’s Paris Air Show was based on the results of a recent force structure analysis by the office of the chief of naval operations.

The additional aircraft steps-up Boeing’s order backlog for P-8A from 114 to 123, including six P-8Is ordered by the Indian Navy.

Boeing flew the first two test aircraft in April and a third flight-test aircraft is scheduled for the fourth quarter of 2009.