The objectives of this viewgraph presentation are to predict the following: (1) dual-engine base-heating at 57% PL at sea level, and (2) dual-engine base-heating during PPO at three ascent abort trajectories. A systematically anchored computational fluid dynamics and heat transfer three-dimensional transfer simulation is being used to study the effect of reduced power levels on base-heating environments during sea level testing and during PPO. Preliminary results show the following: (1) convective heating is higher for the 57% PL than for 100% PL on most of the pillows and flex seals during sea level testing; and (2) convective heating on pillows and flex seals on the 'off' engine side is higher than that on the 'on' engine side.