xTI Yunder-the-hood* training additionally hazardous in the earlier models, The extremely high rate of major accidents suffered with the early B-57 were largely incurred while pilots made transition into the p-c7,1? Initial effort at obtaining B-57C aircraft was made for two of the models to replace two B-57B aircraft and T-33 aircraft, the latter having been used as trainers for sampling pilots. Argument was advanced that the B-57C aircraft could perform satisfactorily in dual status: For training or as sampler aircraft, During the discussion, study, and maneuvering for later models, nuclear scientists apparently began to worry that they might-be left with no aircraft, But Colonel C. B, Stewart, Vice Commander, Air Force Special Weapons Center, wrote Dr, Graves, assuring him that their efforts would not 1 endanger getting those originallyasked for. ? Procuring B-S7D Prior to delivery of B-57A aircraft, cloud sampling officials received notice of improvements to be made in the B-S7D,°° According to their information, the B-57D would approach in performance the requirements specified by Eos Alamos .“+ Dr. Graves listed specifications in a letter to the Air Force Special Weapons Center on 9 December 1953 and reviewed them in a letter to Major General L. S. Stranathan, Field Command, Armed Forces Special Weapons Project, on 2 August 195, "Briefly," he wrote, "these characteristics describe a two-place, high-speed aircraft with maximum altitude capability (at least 60,000 feet) and with the ability to carry filter units with a filter capacity high enough to enable the collection 26 AFWL/HO SWEH~2-003), ak?o . or