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  • CiES keeps the electronic sensor out of the fuel volume 

    • no electronics in the tank.

  • The unit consumes less than 20 mA in current

    • - 9 mA actual

  • Less than 200 microJoules in stored energy

    •  - 30 microJoules actual

How does CiES handle this ? 

The Far Reaching Effects of the TWA 800 Disaster

  • EWIS - Electronic Wiring Interconnection System


  • SFAR 88 -  Fuel Tank System and Wiring Review

  • AC 25.981 2A - Fuel Tank Flammability Reduction Means

    • Fuel Tank inerting Systems
  • AC 25.981-1C -  Fuel Tank Ignition Source Prevention Guidelines

    • Intrinsic Safety of Fuel Quantity System

What were the regulatory effects


The NTSB determined the cause of the accident was an explosion of the center wing fuel tank, resulting from ignition of the flammable fuel/air vapors in the tank. The source of ignition energy could not be determined with certainty. Of the ignition sources evaluated by the investigation, the most likely scenario was a combination of a latent fault of an electronic fuel quantity indicating system component within the fuel tank, combined with a short circuit or other fault outside of the tank. This scenario would result in a high-energy electrical arc within the fuel tank that could ignite the flammable vapors. 

The primary  component - a Capacitive Fuel Probe while explosion proof on its own - could not handle the input of a 115V AC Input and produced a spark

Meeting the requirements of FAA AC 25.981-1C

Aviation Fuel Level