The U.S. Army has authorized building 13 additional aircraft in the engineering and manufacturing development phase of the Boeing-Sikorsky RAH-66 Comanche helicopter program. The $3.1 billion phase began last month when Comanche development was given the go ahead following an extensive milestone review by the Pentagon's Acquisition Board. The new batch includes five aircraft for EMD testing and eight for deployment to various units for operational testing and evaluation. They are certain to be only a tiny fraction of the total buy, as the U.S. has recommended acquisition of no fewer than 1,213 Comanches, worth nearly $34 billion at current values, over the life of the program.