New orders for manufactured goods plunged in March, mainly due to a steep decline in transportation orders, government data released Friday showed. The Commerce Department reported a 4.0 percent drop in factory orders from February, when orders had climbed 1.9 percent. The March reading was well below the 2.5 percent decline expected by most analysts. Excluding transportation, factory orders fell 2.0 percent in March. Commercial aircraft orders, which tend to be volatile month-on-month, dived 48.3 percent. Defense communications equipment orders posted the steepest decline, down 84.3 percent, followed by machinery orders for mining and oil and gas fields, down 31.3 percent. On a 12-month basis, March orders were 0.2 percent lower.