This document concentrates its guidance on those areas of FQS design where improvements are most needed. It is not intended to be a fully definitive specification. Its structure is intended to lend itself to future revision which, for example, may be needed as the result of changes in fuel measurement technology.

It is difficult fully to define a set of characteristics which would cover one standard FQS. The reasons are primarily:

New technologies, particularly in the sensor field will most likely be introduced.

There are various configurations of fuel tanks in commercial transport aircraft, for example, two to ten fuel tanks.

There are different criticality considerations depending on the application, for example, the effects of center of gravity (CG).

However, it is possible to establish guidelines covering most areas of system architecture and installation.