"The US system"....
.....mentioned by wensleydale. Was that USAF or USN?
My experience with both was, from USAF; if it hasn't been specifically authorised it's forbidden; from the USN; if it hasn't been specifically forbidden use your judgement and if you think it's do-able go for it. (But as someone said further up be prepared to justify it.
Fortunately, I had a USN captain chief of staff who fully subscribed to the latter point of view. He was the first S-3 squadron commander and had been CAG (Commander air group) on one of the big carriers and had a firm grasp of the need for flexibility and always backed me up.
The Ancient Mariner