Aircraft operating overhead outside a/d opening hours
We've had a number of complaints recently of large jet aircraft flying overhead outside the aerodrome's opening hours, between 22:00 til 03:00. Although there is a VOR at Biggin Hill, we have been told the jets have been coming down to 50 or so feet, with some locals even telling us that planes have landed in the middle of the night.
As the airport is unstaffed overnight, except for sleeping security guards, we have no way to prove or disprove this. I did speak to a pilot based at Cranfield today saying they have had similar claims, believed to be military helicopters.
Two questions. Firstly, what is the likelyhood of it military jets "buzzing" the airfield, and secondly, what height are aircraft legally allowed to operate down to outside of an airports opening hours?