were dropped when empty. On two occasions the single place jets encountered minor trouble and landed on an emergency runway on Bikini Atoll, "The B-36 featherweight sampling," Colonel Houghton reported, “exceeded all expectations in terms of altitude attained and the usable in-cloud portion of their flight profile." The giant bombers took off with a weight of 230,000 pounds, climbed to a "reasonable altitude" and leveled off whilethe crew put on their S-l partial pressure suits, then climbed to maximum altitude. hours and ten minutes. feet, This procedure usually required two Orimanyof the flights the bombers reached 55,000 The crew encountered problems of keeping their jet engines running at the maximum altitude and on each mission lost one or two jet engines and started a gradual descent. They were able to remain at altitude for sampling approximately one hour and 0 minutes, and sampling equipment operated satisfactorily, "As usual, the personnel exposures were lower than anticipated prior to the operation," Colonel Houghton wrote. The reason for this was that fuel limitations did not allow the sampling aircraft to remain in the cloud as long as the scientific personnel from Los Alamos thought desirable during the planning phases of the operation, Sample quality was found to vary in the cloud with altitude and also with horizontal direction, Sample removal operations went off without trouble, pressurization system filters worked well,and the lead vests worn by the sampler pilots and crews reduced exposureto radiation by at least hO per cent. No pilot complained about the vests oe being uncomfortable. 38 114 APALG HL SWEH-2-003), \n?