Limiting conditions of the aircraft were either one hundred percent of the design limit allowable bending moment on the horizontal stabili- zer, or a 400° F temperaturerise on the 0.020 magnesium skin on the eleFor a vators. eens ' the aircraft was positioned at Time Zero —— in a tail-to aspect forone of the two limiting conditions, whichever was critical for the maximum predicted yield of the device concerned. For NECTAR, the last shot, the aircraft was positioned in a head-on aspect to obtain figures on bending moments. This was the first time an aircraft had been in the "head-on" position at Time Zero. The maximum useful incremental peak temperature measured was 250° F on the 0.020 magnesium skin on the undersurface of the elevator during YANKEE, the fifth shot. Although considerable damage was done to sheet metal, the theoretical overpressure criteria level of 0.80 was attained safely on BRAVO. An incremental bending moment on the horizontal stabi- lizer equalling approximately eighty percent of design load limit was the maximum gust load measured. CASTLE data was sufficient to enable a more accurate determination of the delivery capabilities of the B-36. Operational limitations of a manned B-36 in the vicinity of a nuclear detonation were: 1. Gamma radiation; 2. Thermal radiation (from the fireball); 3. Rise of the radioactive cloud; 4. Overpressure of the shock wave; and 5. Material velocities following the shock wave. Project 6.2b was established to extend the work begun on Operation APWLIRG f