I did some work on this issue when I was seconded to Project Future Brize circa 2010. As has already been alluded to it is frequency and direction that causes the problem!
The J is quieter in decibels than the VC-10, but the frequency means the noise carries much further, plus it travel in almost every direction in almost equal strength so you are subject to it no matter which way the aircraft is pointing.
The J also requires a lot of engine runs. A sample from a winter and a summer month showed that out of the total number of engine runs done at BZN & LYN about 60% were C-130J runs, and a significantly higher number were high power runs. It was all to do with the making sure the various electro gizmos were talking, so even replacing a throttle lever meant an engine run had to be carried out. Just the way the manuals were written. There was a plan to build a big burn a la on the sports fields at LYN out of a load of hardcore left over from demolition but this was vetoed on cost grounds (£500,000 I think). Was going to be between the south side bays and the runway. Not sure how effective it would've been.
Last edited by course_profile; 2nd Oct 2013 at 23:51.