The new generation of large transport aircraft require the utilization of improved development test techniques discussed in this paper to ensure timely and efficient development cycles. Although the development test program on the C-5, largest of today's airplanes, has not been completed, a comprehensive accumulation of significant data in all test phases and extensive experience in managing and conducting the testing of these huge transports have been obtained. The C-5 greatly advances the state-of-the-art, but more important to this presentation are the advancements in test techniques. Increased aircraft size and complexity require additional emphasis on early, valid planning for test facilities and support equipment. Improved techniques for data retrieval and additional sophistication in laboratory test loading systems are essential for efficient accomplishment of the program.