andwillsad-; atlOOl.berrillr-.as-rjlorjad-nce.guethelingigernedareice,ove,mu-filethe 5 at the Iger. toInc.).ra.Jar-Jet Bomber Explodes;■One MissinaPITTSBURGH, Tex., May 2, [ft —:A B47 jet reconnaissance bomber exploded in a Winding flash after refueling in flight last night and crashed into an open field near here. Three crewmen parachuted to safety before the explosion, but the fourth was missing.The flash of the explosion wasseen* as far away as Barksdale Air Force Base at Shreveport, La., 90 miles east.The plane was on a routine reconnaissance mission from Lit-fch Rock Air- Force Base, Ark. Air Force spokesmen in Little Rock Identified the three crewmen who bailed out safely as Maj, Ed Dvorak, 37, of Muskogee, Okla., Maj. Russell G. Corvey, 34, of Kirkwood, Mo., and Cipt. Frank E. Cox, 33, of Geneva, Ohio.The missing officer was identified as Capt. Robert'L. Boucher, 32, of St. Joseph, Mo., a navigator instructor who was aboardfor a training mission. The B47 normally carries'a crew of three.