Flight loads test is a primary structural verification test in fighter aircraft development. The indigenous defensive fighter flight loads test is the first complete flight loads test executed in Taiwan, Republic of China. The basic configuration part of the flight test, including flight loads survey and structural demonstration, was accomplished in 42 flights with external store configurations to follow. Results give both similarity and deviation compared to predictions, and numerous valuable experiences were accumulated from ground calibration test and flight test. One significant improvement in flight test, the automatic roll capability, was introduced to greatly improve maneuver quality during testing and resulted in safe and efficient flight test. HE indigenous defensive fighter (IDF) program was started in the mid-1980s by Aero Industry Development Center (AIDC) in Taiwan, Republic of China. The purpose of the program is to develop and manufacture a lightweight, high- maneuverability fighter aircraft to obtain defensive air su- periority over the Taiwan Strait. m The basic configuration flight loads test of the IDF was executed from February 1990 to April 1991 at CCK AFB, Taiwan, R.O.C. The external store configuration flight loads test is planned to be conducted in the near future. The purpose of the flight loads test was to obtain data for determination of the structural adequacy of the IDF aircraft for the condi- tions determined critical through analysis and review of test data. The test employed buildup to, and demonstration of, the design limit conditions for the parameters determined to be critical. Test results will also be used to improve analysis methods or for advanced versions of the production airplane if needed (Fig. 1). In this article, a brief description of the test article is given first, including a detailed discussion of the multifunctional test aid. Next is the introduction of loads and aircraft response measuring instrumentation; also mentioned are the test data recording equipment and the real time monitor facility. For the ground calibration test, the calibration methods, hardware setup, and the calibration results are described. The flight loads test objectives, test maneuvers, and test sequence are also depicted. Finally, the flight loads test results are pre- sented with different component's load trends. Test Article Description The IDF is a lightweight, twin-engine, high-maneuverabil- ity fighter aircraft with midmounted, moderately swept wing. Highly swept strake and well-designed fuselage geometry blend the wing and fuselage into a lifting body. The leading-edge flaps deflect according to a preset angle of attack (AOA)- related schedule for optimal lift-to-drag ratio. The IDF is controlled by a digital fly-by-wire flight control system that consists of three independent sets of sensors, three channels of digital flight control computer, one channel of analog backup flight control computer, and electrically sig-