Sensors operated from a manned or unmanned aircraft can provide a more objective and reproducible result and a permanent record that can be used for later analysis. The passive sensors are imaging systems and include video, digital cameras, multispectral and hyperspectral cameras, and thermal cameras.
In the 1990s, at the request of the national industry, the Italian RAI-ENAC issued a draft of a UAV airworthiness standard. This document was presented at the annual EURO UVS conference in June 1999, triggering great debate on the subject. It was indeed probably the first attempt to define some sort of airworthiness standards for civil UAS. Instead of attempting to invent everything from scratch, the JAR-VLA standard was chosen as a basic standard to be adapted to fixed-wing UAVs up to 750 kg. It could be argued that, to transform a standard for manned aircraft into a UAS standard, it would be sufficient to delete all requirements inherent to the occupants, such as the cockpit and the passenger cabin requirements. But it is not so simple because the airworthiness “philosophies” we have considered in the previous chapters would not be fully utilized in doing so. It is therefore necessary to set up new philosophies specific for UAS before trying to convert them into new standards.