Complex sentence: The idea of using a periscope arrangement for forward viewing on high speed aircraft was then in vogue, the Avro 730 selecting a very similar system, and the Air Force demanded that it be used on the F-103.
Split into simpler sentences: The idea of using a periscope arrangement for forward viewing on high speed aircraft was then in vogue, the Avro 730 selecting a very similar system. The Air Force demanded that it be used on the F-103.