Capacitance type fuel quantity indicators can provide the fuel's mass, in opposition with other fuel gauging systems that may give only the volume. The problem with the volume-based instrument is that it is subject to temperature variations. If the temperature increases, the density will decrease, and fuel volume will increase, which will give false information about the actual usable fuel within the tanks. Initially, the capacitance between the two plates will also give you the volume. However, a density compensator is placed at the bottom of the tank to correct the errors induced to fuel’s density by the temperature changes. Therefore, if you have a temperature rise and an increase in the fuel volume by 5%, the mass will remain the same as the density change will be compensated.