Failure behavior of aircraft sandwich panels under bending load has been investigated in this study. In this study focused in effect of support span length under bending load. Three-points bending test was performed to the specimens with various span length 125 mm, 80 mm, 70 mm, and 55 mm. Standard test method and dimensions were adhering to the ASTM C393. Deflection and energy absorption of the sandwich panels have been characterized by the variation span lengths.It was found that the deflection and the energy absorption of the sandwich panels were strongly influenced by the length of support span. In the bending test of sandwich panels at 125 mm support span length, the panel possess the lowest deflection at a critical load which is around 3.26 mm compared to the other support span length. The differences of the collapse load for 55 mm support span length is highly significant. The value of experimental was found at 1.54 kN whereas the theoretical value is 2.65 kN The ability to absorb energy of sandwich panels was affected by the collapse mechanism. It was found that the decrease of support span length increases the absorbed energy in the aircraft sandwich panel.