The Navy is concerned about risk in its program to extend the life of F/A-18 A through D Hornet fighters so its F/A-18E/ F models don’t age as quickly, the Chief of Naval Operations told a Senate panel on Wednesday.Adm. Jonathan Greenert said the sea service is transitioning from the legacy Hornet fleet to the Super Hornets. A plan formed three years ago would retain some of the older Hornets by extending their life through depot work.The Hornets and Super…