A Salvadoran military helicopter exploded shortly after takeoff from the Ilopango air base outside San Salvador, killing all nine people aboard, El Salvador's air force chief said. Those aboard the U.S.-built UH-1H Huey were two crewmen, two artillerymen and five civilians, including a woman on her way to visit her officer son, Gen. Juan Rafael Bustillo said. No Americans were reported aboard. The helicopter was en route to a military base at San Miguel, 60 miles east of San Salvador. Bustillo said the military will investigate whether the craft was sabotaged by leftist guerrillas, although he noted that many of the helicopters date to the Vietnam War.