Whilst I do not condone what appears to be shown in the Tornado photograph posted and in the video link, and what appears to be an ill-conceived manoeuvre, it is worth stating that there are tasks that require, and approvals that allow, low flying at less than the 100 ft discussed previously. UK military registered fast jet aircraft with a rad alt sometimes perform simulated missile attacks against ships at 50 ft ASL (albeit nominally straight and level). Also, some pilots have a minimum of 30 ft on their UK CAA Display Authorisation, even for fast jet aircraft (G- registered, not current miitary aircraft). Note that if in a turn, the 30 ft separation from the ground applies to the wing tip. Obviously, this minima can only be exercised at an approved display site and not all display sites are approved for the use of this minima.