Strange goings on here last night. Lots of helos flying low, fast, and noisy. Something is going on... I'm thinking attack helicopters by their speed. Some have lots of lights, some just have a red light flashing. Traveling in pairs it seems. I'm sure they're doing some training out of AP Hill. It's nice to hear the noise, even though it's unexpected. Reminds me of my childhood on AF bases with the bombers taking off and landing. I love that noise.
Where are you located relative to the facility?
When Dona and I lived off 30 north of Hanover, that was the progression that always proceeded the start of the "big booms", eminating from A.P. Hill. They are the worlds largest facility for training our boys in I.E.D destruction, they do a sweep, with I.R. to make sure its an all clear condition prior to holding a major blast a thon. At times it would shake the house, they reported on it a couple times on the local news, that charges up to 40# of C4 were being used to destroy artilliary shells in quantity in bunkers as practice... they backed off somewhat after major complaints, from as far as 30 miles... it has a lot to do with the cieling levels and wind direction as far as how the concussion travels.
Expect big booms come tonight, they always did it around 11 pm on sundays... or whenever they were certain sattelites could not do telemetry or photos of the ops.
This is the time of year they also do really low level troop drops there, and both the choppers and the C130's would fly over our house at about 200 ft, repeatedly.. airfield is short takeoff for sure, it adjacent to 2 and 606,. Seen those big birds swoop down there one day on a ride... freaked me out.