This paper is submitted to insure that every basic precaution is taken in the design of the installation for an aircraft filler cap and adapter for lightning protection. The axiom in the industry of installing a lightning proof cap solves the problem of a lightning safe installation. However, designers sometimes disregard the problem of the installation of the adapter and the adapters mating parts. Adherence to the FAA and military specifications are considered acceptable while these specifications contain only the bare minimal requirements. This design criteria of only using a lightning safety cap and disregarding the installation of the adapter sometimes leads to an expensive redesign or retrofit of the aircraft after the plane is in production.
