Abstract: In accordance with at least one aspect of this disclosure, a fuel quantity measurement system includes, one or more pressure sensors are configured to operatively connect external to a fuel volume of a fuel tank, and can be operative to sense and output a signal indicative of a pressure outside of the fuel volume. One or more hollow pressure tubes can be configured to be disposed in the fuel volume in the fuel tank. The one or more hollow tubes can have a first end in fluid communication with the fuel volume and a second end configured to be sealed against an ambient environment external to the fuel tank. One or more temperature sensors can be configured to operatively connect within the fuel tank, operative to sense and output a signal indicative of a temperature of the fuel tank.

Abstract: A system for reducing reactive components in ullage of a fuel tank, typically the fuel tank of an airplane. The system includes an air driven unit for creating a fluidic motive force to remove ullage from the fuel tank, and a main catalytic unit for receiving the ullage and reducing the reactive components to yield processed ullage for return to the fuel tank.

Abstract: A transient suppression device for limiting to desirable levels current and energy entering a fuel tank of an aircraft over interface wiring that penetrates a wall of the fuel tank comprises: an elongated, hollow, conductive housing capped at one end and open at another end, the housing being disposed external and in proximity to the fuel tank, and supported physically from a structure of the aircraft; a transient suppression circuit disposed within the housing and connected in series with the interface wiring; and a shield braid of conductive material disposed over the open end of the housing and covering the interface wiring over the distance between the housing and tank wall, the shield braid electrically coupling the housing to the tank wall. A method of packaging the transient suppression device is also disclosed.